Upgrade to ruff>=0.16.0 (#2857)

* ruff>=0.16.0

See https://astral.sh/blog/ruff-v0.16.0

* uv run ruff check . --fix --unsafe-fixes

* Ruff fixes by Claude Code Opus 5

datasette/_pytest_plugin.py

@@ -89,7 +89,8 @@ def pytest_runtest_protocol(item, nextitem):
                 continue
             try:
                 ds.close()
-            except Exception as e:
+            except Exception as e:  # noqa: BLE001
+                # Surfaced as a pytest warning; teardown must not fail the run
                 item.warn(
                     pytest.PytestUnraisableExceptionWarning(
                         f"Error closing Datasette instance: {e!r}"

datasette/actor_auth_cookie.py

@@ -1,8 +1,10 @@
-from datasette import hookimpl
-from itsdangerous import BadSignature
-from datasette.utils import baseconv
 import time
 
+from itsdangerous import BadSignature
+
+from datasette import hookimpl
+from datasette.utils import baseconv
+
 
 @hookimpl
 def actor_from_request(datasette, request):

datasette/app.py

@@ -2,7 +2,8 @@ from __future__ import annotations
 
 import asyncio
 import contextvars
-from typing import TYPE_CHECKING, Any, Dict, Iterable, List, Sequence
+from collections.abc import Iterable, Sequence
+from typing import TYPE_CHECKING, Any
 
 if TYPE_CHECKING:
     from datasette.permissions import Resource
@@ -12,11 +13,10 @@ import dataclasses
 import datetime
 import functools
 import glob
-import httpx
 import importlib.metadata
 import inspect
-from itsdangerous import BadSignature
 import json
+import logging
 import os
 import re
 import secrets
@@ -28,90 +28,41 @@ import urllib.parse
 from concurrent import futures
 from pathlib import Path
 
-from markupsafe import Markup, escape
+import httpx
-from itsdangerous import URLSafeSerializer
+from itsdangerous import BadSignature, URLSafeSerializer
 from jinja2 import (
     ChoiceLoader,
     Environment,
     FileSystemLoader,
-    pass_context,
     PrefixLoader,
+    pass_context,
 )
 from jinja2.environment import Template
 from jinja2.exceptions import TemplateNotFound
+from markupsafe import Markup, escape
 
-from .events import Event
-from .column_types import SQLiteType
 from . import stored_queries, write_sql
-from .views import Context
+from .column_types import SQLiteType
-from .views.database import (
+from .csrf import CrossOriginProtectionMiddleware
-    database_download,
-    DatabaseView,
-    QueryView,
-)
-from .views.table_create_alter import (
-    DatabaseForeignKeyTargetsView,
-    TableAlterView,
-    TableCreateView,
-    TableForeignKeySuggestionsView,
-)
-from .views.execute_write import ExecuteWriteAnalyzeView, ExecuteWriteView
-from .views.stored_queries import (
-    QueryCreateAnalyzeView,
-    QueryDeleteView,
-    QueryDefinitionView,
-    QueryEditView,
-    GlobalQueryListView,
-    QueryListView,
-    QueryParametersView,
-    QueryStoreView,
-    QueryUpdateView,
-)
-from .views.index import IndexView
-from .views.special import (
-    JsonDataView,
-    PatternPortfolioView,
-    AutocompleteDebugView,
-    AuthTokenView,
-    ApiExplorerView,
-    CreateTokenView,
-    LogoutView,
-    AllowDebugView,
-    PermissionsDebugView,
-    MessagesDebugView,
-    AllowedResourcesView,
-    PermissionRulesView,
-    PermissionCheckView,
-    JumpView,
-    InstanceSchemaView,
-    DatabaseSchemaView,
-    TableSchemaView,
-)
-from .views.table import (
-    TableAutocompleteView,
-    TableInsertView,
-    TableUpsertView,
-    TableSetColumnTypeView,
-    TableDropView,
-    TableFragmentView,
-    table_view,
-)
-from .views.row import RowView, RowDeleteView, RowUpdateView
-from .renderer import json_renderer
-from .url_builder import Urls
 from .database import Database, QueryInterrupted
-
+from .events import Event
+from .plugins import DEFAULT_PLUGINS, get_plugins, pm
+from .renderer import json_renderer
+from .resources import DatabaseResource, TableResource
+from .tokens import TokenInvalid
+from .tracer import AsgiTracer
+from .url_builder import Urls
 from .utils import (
+    SPATIALITE_FUNCTIONS,
     PaginatedResources,
     PrefixedUrlString,
-    SPATIALITE_FUNCTIONS,
     StartupError,
+    add_cors_headers,
     async_call_with_supported_arguments,
     await_me_maybe,
     baseconv,
     call_with_supported_arguments,
     detect_json1,
-    add_cors_headers,
     display_actor,
     escape_css_string,
     escape_sqlite,
@@ -121,47 +72,97 @@ from .utils import (
     move_plugins_and_allow,
     move_table_config,
     parse_metadata,
+    redact_keys,
     resolve_env_secrets,
     resolve_routes,
+    row_sql_params_pks,
     sha256_file,
     tilde_decode,
     tilde_encode,
     to_css_class,
     urlsafe_components,
-    redact_keys,
-    row_sql_params_pks,
 )
-from .tokens import TokenInvalid
 from .utils.asgi import (
     AsgiLifespan,
+    AsgiRunOnFirstRequest,
     BadRequest,
+    DatabaseNotFound,
     Forbidden,
     NotFound,
-    DatabaseNotFound,
-    TableNotFound,
-    RowNotFound,
     Request,
     Response,
-    AsgiRunOnFirstRequest,
+    RowNotFound,
-    asgi_static,
+    TableNotFound,
     asgi_send,
     asgi_send_file,
     asgi_send_redirect,
+    asgi_static,
 )
-from .csrf import CrossOriginProtectionMiddleware
 from .utils.internal_db import init_internal_db, populate_schema_tables
 from .utils.sqlite import (
     sqlite3,
     using_pysqlite3,
 )
-from .tracer import AsgiTracer
-from .plugins import pm, DEFAULT_PLUGINS, get_plugins
 from .version import __version__
-
+from .views import Context
-from .resources import DatabaseResource, TableResource
+from .views.database import (
+    DatabaseView,
+    QueryView,
+    database_download,
+)
+from .views.execute_write import ExecuteWriteAnalyzeView, ExecuteWriteView
+from .views.index import IndexView
+from .views.row import RowDeleteView, RowUpdateView, RowView
+from .views.special import (
+    AllowDebugView,
+    AllowedResourcesView,
+    ApiExplorerView,
+    AuthTokenView,
+    AutocompleteDebugView,
+    CreateTokenView,
+    DatabaseSchemaView,
+    InstanceSchemaView,
+    JsonDataView,
+    JumpView,
+    LogoutView,
+    MessagesDebugView,
+    PatternPortfolioView,
+    PermissionCheckView,
+    PermissionRulesView,
+    PermissionsDebugView,
+    TableSchemaView,
+)
+from .views.stored_queries import (
+    GlobalQueryListView,
+    QueryCreateAnalyzeView,
+    QueryDefinitionView,
+    QueryDeleteView,
+    QueryEditView,
+    QueryListView,
+    QueryParametersView,
+    QueryStoreView,
+    QueryUpdateView,
+)
+from .views.table import (
+    TableAutocompleteView,
+    TableDropView,
+    TableFragmentView,
+    TableInsertView,
+    TableSetColumnTypeView,
+    TableUpsertView,
+    table_view,
+)
+from .views.table_create_alter import (
+    DatabaseForeignKeyTargetsView,
+    TableAlterView,
+    TableCreateView,
+    TableForeignKeySuggestionsView,
+)
 
 app_root = Path(__file__).parent.parent
 
+logger = logging.getLogger(__name__)
+
 
 # Context variable to track when code is executing within a datasette.client request
 _in_datasette_client = contextvars.ContextVar("in_datasette_client", default=False)
@@ -184,7 +185,7 @@ class PermissionCheck:
     """Represents a logged permission check for debugging purposes."""
 
     when: str
-    actor: Dict[str, Any] | None
+    actor: dict[str, Any] | None
     action: str
     parent: str | None
     child: str | None
@@ -434,7 +435,7 @@ class Datasette:
         if config_dir:
             db_files = []
             for ext in ("db", "sqlite", "sqlite3"):
-                db_files.extend(config_dir.glob("*.{}".format(ext)))
+                db_files.extend(config_dir.glob(f"*.{ext}"))
             self.files += tuple(str(f) for f in db_files)
         if (
             config_dir
@@ -675,10 +676,10 @@ class Datasette:
     def get_jinja_environment(self, request: Request = None) -> Environment:
         environment = self._jinja_env
         if request:
-            for environment in pm.hook.jinja2_environment_from_request(
+            for hook_environment in pm.hook.jinja2_environment_from_request(
                 datasette=self, request=request, env=environment
             ):
-                pass
+                environment = hook_environment
         return environment
 
     def get_action(self, name_or_abbr: str):
@@ -732,7 +733,7 @@ class Datasette:
             catalog_database_names.update(
                 row["database_name"]
                 for row in await internal_db.execute(
-                    "select distinct database_name from {}".format(table)
+                    f"select distinct database_name from {table}"
                 )
                 if row["database_name"] is not None
             )
@@ -743,7 +744,7 @@ class Datasette:
                 for stale_db_name in stale_databases:
                     for table in catalog_table_names:
                         conn.execute(
-                            "DELETE FROM {} WHERE database_name = ?".format(table),
+                            f"DELETE FROM {table} WHERE database_name = ?",
                             [stale_db_name],
                         )
 
@@ -753,19 +754,7 @@ class Datasette:
             # Compare schema versions to see if we should skip it
             if schema_version == current_schema_versions.get(database_name):
                 continue
-            placeholders = "(?, ?, ?, ?)"
+            await populate_schema_tables(internal_db, db, schema_version)
-            values = [database_name, str(db.path), db.is_memory, schema_version]
-            if db.path is None:
-                placeholders = "(?, null, ?, ?)"
-                values = [database_name, db.is_memory, schema_version]
-            await internal_db.execute_write(
-                """
-                INSERT OR REPLACE INTO catalog_databases (database_name, path, is_memory, schema_version)
-                VALUES {}
-            """.format(placeholders),
-                values,
-            )
-            await populate_schema_tables(internal_db, db)
 
     @property
     def urls(self):
@@ -804,17 +793,13 @@ class Datasette:
                         action.name in action_names
                         and action != action_names[action.name]
                     ):
-                        raise StartupError(
+                        raise StartupError(f"Duplicate action name: {action.name}")
-                            "Duplicate action name: {}".format(action.name)
-                        )
                     if (
                         action.abbr
                         and action.abbr in action_abbrs
                         and action != action_abbrs[action.abbr]
                     ):
-                        raise StartupError(
+                        raise StartupError(f"Duplicate action abbr: {action.abbr}")
-                            "Duplicate action abbr: {}".format(action.abbr)
-                        )
                     action_names[action.name] = action
                     if action.abbr:
                         action_abbrs[action.abbr] = action
@@ -873,7 +858,7 @@ class Datasette:
         actor_id: str,
         *,
         expires_after: int | None = None,
-        restrictions: "TokenRestrictions | None" = None,
+        restrictions: TokenRestrictions | None = None,
         handler: str | None = None,
     ) -> str:
         """
@@ -930,7 +915,7 @@ class Datasette:
                 raise KeyError
             return matches[0]
         if name is None:
-            name = [key for key in self.databases.keys()][0]
+            name = next(iter(self.databases.keys()))
         return self.databases[name]
 
     def add_database(self, db, name=None, route=None):
@@ -943,7 +928,7 @@ class Datasette:
             suggestion = name
         i = 2
         while name in self.databases:
-            name = "{}_{}".format(suggestion, i)
+            name = f"{suggestion}_{i}"
             i += 1
         db.name = name
         db.route = route or name
@@ -978,13 +963,14 @@ class Datasette:
         for db in dbs:
             try:
                 db.close()
-            except Exception as e:
+            except Exception as e:  # noqa: BLE001
+                # Collect the first failure and re-raise after every close() has run
                 if first_exception is None:
                     first_exception = e
         if self.executor is not None:
             try:
                 self.executor.shutdown(wait=True, cancel_futures=True)
-            except Exception as e:
+            except Exception as e:  # noqa: BLE001
                 if first_exception is None:
                     first_exception = e
         if first_exception is not None:
@@ -1333,24 +1319,15 @@ class Datasette:
         actual = (
             actual_sqlite_type.value
             if actual_sqlite_type is not None
-            else "unrecognized {!r}".format(column_detail.type)
+            else f"unrecognized {column_detail.type!r}"
         )
         raise ValueError(
-            "Column type {!r} is only applicable to SQLite types {} but {}.{}.{} "
+            f"Column type {ct_cls.name!r} is only applicable to SQLite types {allowed} but {database}.{resource}.{column} "
-            "has SQLite type {}".format(
+            f"has SQLite type {actual}"
-                ct_cls.name,
-                allowed,
-                database,
-                resource,
-                column,
-                actual,
-            )
         )
 
     async def _apply_column_types_config(self):
         """Load column_types from datasette.json config into the internal DB."""
-        import logging
-
         for db_name, db_conf in (self.config or {}).get("databases", {}).items():
             for table_name, table_conf in db_conf.get("tables", {}).items():
                 for col_name, ct in table_conf.get("column_types", {}).items():
@@ -1360,7 +1337,7 @@ class Datasette:
                         col_type = ct["type"]
                         config = ct.get("config")
                     if col_type not in self._column_types:
-                        logging.warning(
+                        logger.warning(
                             "column_types config references unknown type %r "
                             "for %s.%s.%s",
                             col_type,
@@ -1373,7 +1350,7 @@ class Datasette:
                             db_name, table_name, col_name, col_type, config
                         )
                     except ValueError as ex:
-                        logging.warning(str(ex))
+                        logger.warning(str(ex))
 
     async def get_column_type(self, database: str, resource: str, column: str):
         """
@@ -1426,7 +1403,7 @@ class Datasette:
         resource: str,
         column: str,
         column_type: str,
-        config: dict = None,
+        config: dict | None = None,
     ) -> None:
         """Assign a column type. Overwrites any existing assignment."""
         ct_cls = self._column_types.get(column_type)
@@ -1510,9 +1487,7 @@ class Datasette:
             possible_names = {plugin["name"], plugin["name"].replace("-", "_")}
             if plugin_name in possible_names:
                 return _resolve_static_asset_path(plugin["static_path"], path)
-        raise FileNotFoundError(
+        raise FileNotFoundError(f"No static assets found for plugin {plugin_name}")
-            "No static assets found for plugin {}".format(plugin_name)
-        )
 
     def _static_mounted_asset(self, mount_name, path):
         mount_name = mount_name.strip("/")
@@ -1522,7 +1497,7 @@ class Datasette:
                     _resolve_static_asset_path(dirname, path),
                     self.urls.path("/{}/{}".format(mount_name, path.lstrip("/"))),
                 )
-        raise FileNotFoundError("No static mount found for {}".format(mount_name))
+        raise FileNotFoundError(f"No static mount found for {mount_name}")
 
     def _static_asset_hash(self, filepath):
         filepath = Path(filepath)
@@ -1613,18 +1588,17 @@ class Datasette:
         if await self.allowed(action="view-instance", actor=actor):
             crumbs.append({"href": self.urls.instance(), "label": "home"})
         # Database link
-        if database:
+        if database and await self.allowed(
-            if await self.allowed(
+            action="view-database",
-                action="view-database",
+            resource=DatabaseResource(database=database),
-                resource=DatabaseResource(database=database),
+            actor=actor,
-                actor=actor,
+        ):
-            ):
+            crumbs.append(
-                crumbs.append(
+                {
-                    {
+                    "href": self.urls.database(database),
-                        "href": self.urls.database(database),
+                    "label": database,
-                        "label": database,
+                }
-                    }
+            )
-                )
         # Table link
         if table:
             assert database, "table= requires database="
@@ -1643,7 +1617,7 @@ class Datasette:
 
     async def actors_from_ids(
         self, actor_ids: Iterable[str | int]
-    ) -> Dict[int | str, Dict]:
+    ) -> dict[int | str, dict]:
         result = pm.hook.actors_from_ids(datasette=self, actor_ids=actor_ids)
         if result is None:
             # Do the default thing
@@ -1652,9 +1626,9 @@ class Datasette:
         return result
 
     async def track_event(self, event: Event):
-        assert isinstance(event, self.event_classes), "Invalid event type: {}".format(
+        assert isinstance(
-            type(event)
+            event, self.event_classes
-        )
+        ), f"Invalid event type: {type(event)}"
         for hook in pm.hook.track_event(datasette=self, event=event):
             await await_me_maybe(hook)
 
@@ -1691,7 +1665,7 @@ class Datasette:
         self,
         actor: dict,
         action: str,
-        resource: "Resource" | None = None,
+        resource: Resource | None = None,
     ):
         """
         Check if actor can see a resource and if it's private.
@@ -1890,10 +1864,7 @@ class Datasette:
         if truncated and resources:
             last_resource = resources[-1]
             # Use tilde-encoding like table pagination
-            next_token = "{},{}".format(
+            next_token = f"{tilde_encode(str(last_resource.parent))},{tilde_encode(str(last_resource.child))}"
-                tilde_encode(str(last_resource.parent)),
-                tilde_encode(str(last_resource.child)),
-            )
 
         return PaginatedResources(
             resources=resources,
@@ -1911,7 +1882,7 @@ class Datasette:
         self,
         *,
         action: str,
-        resource: "Resource" = None,
+        resource: Resource = None,
         actor: dict | None = None,
     ) -> bool:
         """
@@ -1942,7 +1913,7 @@ class Datasette:
         self,
         *,
         actions: Sequence[str],
-        resource: "Resource" = None,
+        resource: Resource = None,
         actor: dict | None = None,
     ) -> dict[str, bool]:
         """
@@ -1963,11 +1934,11 @@ class Datasette:
             )
             # {"edit-schema": True, "drop-table": True, "insert-row": False}
         """
-        from datasette.utils.actions_sql import check_permissions_for_actions
         from datasette.permissions import (
             _permission_check_cache,
             _skip_permission_checks,
         )
+        from datasette.utils.actions_sql import check_permissions_for_actions
 
         # For global actions, resource is None
         parent = resource.parent if resource else None
@@ -2056,7 +2027,7 @@ class Datasette:
         self,
         *,
         action: str,
-        resource: "Resource" = None,
+        resource: Resource = None,
         actor: dict | None = None,
     ):
         """
@@ -2110,13 +2081,15 @@ class Datasette:
         db = self.databases[database]
         foreign_keys = await db.foreign_keys_for_table(table)
         # Find the foreign_key for this column
-        try:
+        fk = next(
-            fk = [
+            (
                 foreign_key
                 for foreign_key in foreign_keys
                 if foreign_key["column"] == column
-            ][0]
+            ),
-        except IndexError:
+            None,
+        )
+        if fk is None:
             return {}
         # Ensure user has permission to view the referenced table
         from datasette.resources import TableResource
@@ -2204,16 +2177,17 @@ class Datasette:
                     sqlite_extensions[extension] = result.fetchone()[0]
                 else:
                     sqlite_extensions[extension] = None
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
+                # Probing for optional SQLite extensions - absence is the normal case
                 pass
         # More details on SpatiaLite
         if "spatialite" in sqlite_extensions:
             spatialite_details = {}
             for fn in SPATIALITE_FUNCTIONS:
                 try:
-                    result = conn.execute("select {}()".format(fn))
+                    result = conn.execute(f"select {fn}()")
                     spatialite_details[fn] = result.fetchone()[0]
-                except Exception as e:
+                except sqlite3.Error as e:
                     spatialite_details[fn] = {"error": str(e)}
             sqlite_extensions["spatialite"] = spatialite_details
 
@@ -2221,9 +2195,7 @@ class Datasette:
         fts_versions = []
         for fts in ("FTS5", "FTS4", "FTS3"):
             try:
-                conn.execute(
+                conn.execute(f"CREATE VIRTUAL TABLE v{fts} USING {fts} (data)")
-                    "CREATE VIRTUAL TABLE v{fts} USING {fts} (data)".format(fts=fts)
-                )
                 fts_versions.append(fts)
             except sqlite3.OperationalError:
                 continue
@@ -2282,7 +2254,7 @@ class Datasette:
                 "static": p["static_path"] is not None,
                 "templates": p["templates_path"] is not None,
                 "version": p.get("version"),
-                "hooks": list(sorted(set(p["hooks"]))),
+                "hooks": sorted(set(p["hooks"])),
             }
             for p in ps
         ]
@@ -2358,13 +2330,15 @@ class Datasette:
 
     async def render_template(
         self,
-        templates: List[str] | str | Template,
+        templates: list[str] | str | Template,
-        context: Dict[str, Any] | Context | None = None,
+        context: dict[str, Any] | Context | None = None,
         request: Request | None = None,
         view_name: str | None = None,
     ):
         if not self._startup_invoked:
-            raise Exception("render_template() called before await ds.invoke_startup()")
+            raise RuntimeError(
+                "render_template() called before await ds.invoke_startup()"
+            )
         context = context or {}
         if isinstance(templates, Template):
             template = templates
@@ -2410,9 +2384,9 @@ class Datasette:
             datasette=self,
         ):
             extra_vars = await await_me_maybe(extra_vars)
-            assert isinstance(extra_vars, dict), "extra_vars is of type {}".format(
+            assert isinstance(
-                type(extra_vars)
+                extra_vars, dict
-            )
+            ), f"extra_vars is of type {type(extra_vars)}"
             extra_template_vars.update(extra_vars)
 
         async def menu_links():
@@ -2431,29 +2405,27 @@ class Datasette:
         # the contract tests fail otherwise
         template_context = {
             **context,
-            **{
+            "request": request,
-                "request": request,
+            "crumb_items": self._crumb_items,
-                "crumb_items": self._crumb_items,
+            "urls": self.urls,
-                "urls": self.urls,
+            "actor": request.actor if request else None,
-                "actor": request.actor if request else None,
+            "menu_links": menu_links,
-                "menu_links": menu_links,
+            "display_actor": display_actor,
-                "display_actor": display_actor,
+            "show_logout": request is not None
-                "show_logout": request is not None
+            and "ds_actor" in request.cookies
-                and "ds_actor" in request.cookies
+            and request.actor,
-                and request.actor,
+            "zip": zip,
-                "zip": zip,
+            "body_scripts": body_scripts,
-                "body_scripts": body_scripts,
+            "format_bytes": format_bytes,
-                "format_bytes": format_bytes,
+            "show_messages": lambda: self._show_messages(request),
-                "show_messages": lambda: self._show_messages(request),
+            "extra_css_urls": await self._asset_urls(
-                "extra_css_urls": await self._asset_urls(
+                "extra_css_urls", template, context, request, view_name
-                    "extra_css_urls", template, context, request, view_name
+            ),
-                ),
+            "extra_js_urls": await self._asset_urls(
-                "extra_js_urls": await self._asset_urls(
+                "extra_js_urls", template, context, request, view_name
-                    "extra_js_urls", template, context, request, view_name
+            ),
-                ),
+            "base_url": self.setting("base_url"),
-                "base_url": self.setting("base_url"),
+            "datasette_version": __version__,
-                "datasette_version": __version__,
-            },
             **extra_template_vars,
         }
         if request and request.args.get("_context") and self.setting("template_debug"):
@@ -2575,7 +2547,7 @@ class Datasette:
             JsonDataView.as_view(
                 self,
                 "plugins.json",
-                lambda request: {"plugins": self._plugins(request)},
+                self._plugins,
                 needs_request=True,
             ),
             r"/-/plugins(\.(?P<format>json))?$",
@@ -2953,7 +2925,8 @@ class DatasetteRouter:
                     custom_response
                 ), "Default forbidden() hook should have been called"
                 return await custom_response.asgi_send(send)
-        except Exception as exception:
+        except Exception as exception:  # noqa: BLE001
+            # This IS the top-level error handler - it must catch everything
             return await self.handle_exception(request, send, exception)
 
     async def handle_401(self, request, send, exception):
@@ -2975,7 +2948,7 @@ class DatasetteRouter:
                 request.path.replace("~", "~7E").replace("%", "~").replace(".", "~2E")
             )
             if request.query_string:
-                new_path += "?{}".format(request.query_string)
+                new_path += f"?{request.query_string}"
             await asgi_send_redirect(send, new_path)
             return
         # If URL has a trailing slash, redirect to URL without it
@@ -3185,8 +3158,7 @@ _curly_re = re.compile(r"({.*?})")
 
 def route_pattern_from_filepath(filepath):
     # Drop the ".html" suffix
-    if filepath.endswith(".html"):
+    filepath = filepath.removesuffix(".html")
-        filepath = filepath[: -len(".html")]
     re_bits = ["/"]
     for bit in _curly_re.split(filepath):
         if _curly_re.match(bit):

datasette/blob_renderer.py

@@ -1,8 +1,9 @@
-from datasette import hookimpl
-from datasette.utils.asgi import Response, BadRequest
-from datasette.utils import to_css_class
 import hashlib
 
+from datasette import hookimpl
+from datasette.utils import to_css_class
+from datasette.utils.asgi import BadRequest, Response
+
 _BLOB_COLUMN = "_blob_column"
 _BLOB_HASH = "_blob_hash"
 

datasette/cli.py

@@ -1,43 +1,45 @@
 import asyncio
-import uvicorn
-import click
-from click import formatting
-from click.types import CompositeParamType
-from click_default_group import DefaultGroup
 import functools
 import json
 import os
 import pathlib
-from runpy import run_module
 import shutil
-from subprocess import call
 import sys
 import textwrap
 import webbrowser
+from runpy import run_module
+from subprocess import call
+
+import click
+import uvicorn
+from click import formatting
+from click.types import CompositeParamType
+from click_default_group import DefaultGroup
+
 from .app import (
-    Datasette,
     DEFAULT_SETTINGS,
     SETTINGS,
     SQLITE_LIMIT_ATTACHED,
+    Datasette,
     pm,
 )
 from .inspect import inspect_tables
 from .utils import (
+    ConnectionProblem,
     LoadExtension,
+    SpatialiteConnectionProblem,
+    SpatialiteNotFound,
     StartupError,
+    StaticMount,
+    ValueAsBooleanError,
     check_connection,
     deep_dict_update,
     find_spatialite,
-    parse_metadata,
-    ConnectionProblem,
-    SpatialiteConnectionProblem,
     initial_path_for_datasette,
     pairs_to_nested_config,
+    parse_metadata,
     temporary_docker_directory,
     value_as_boolean,
-    SpatialiteNotFound,
-    StaticMount,
-    ValueAsBooleanError,
 )
 from .utils.sqlite import sqlite3
 from .utils.testing import TestClient
@@ -75,7 +77,7 @@ class Setting(CompositeParamType):
             # Datasette 1.0, we turn bare setting names into setting.name
             # Type checking for those older settings
             default = DEFAULT_SETTINGS[name]
-            name = "settings.{}".format(name)
+            name = f"settings.{name}"
             if isinstance(default, bool):
                 try:
                     return name, "true" if value_as_boolean(value) else "false"
@@ -171,7 +173,6 @@ async def inspect_(files, sqlite_extensions):
 @cli.group()
 def publish():
     """Publish specified SQLite database files to the internet along with a Datasette-powered interface and API"""
-    pass
 
 
 # Register publish plugins
@@ -578,27 +579,27 @@ def serve(
         # https://github.com/simonw/datasette/issues/2389
         deep_dict_update(config_data, settings_updates)
 
-    kwargs = dict(
+    kwargs = {
-        immutables=immutable,
+        "immutables": immutable,
-        cache_headers=not reload,
+        "cache_headers": not reload,
-        cors=cors,
+        "cors": cors,
-        inspect_data=inspect_data,
+        "inspect_data": inspect_data,
-        config=config_data,
+        "config": config_data,
-        metadata=metadata_data,
+        "metadata": metadata_data,
-        sqlite_extensions=sqlite_extensions,
+        "sqlite_extensions": sqlite_extensions,
-        template_dir=template_dir,
+        "template_dir": template_dir,
-        plugins_dir=plugins_dir,
+        "plugins_dir": plugins_dir,
-        static_mounts=static,
+        "static_mounts": static,
-        settings=None,  # These are passed in config= now
+        "settings": None,  # These are passed in config= now
-        memory=memory,
+        "memory": memory,
-        secret=secret,
+        "secret": secret,
-        version_note=version_note,
+        "version_note": version_note,
-        pdb=pdb,
+        "pdb": pdb,
-        crossdb=crossdb,
+        "crossdb": crossdb,
-        nolock=nolock,
+        "nolock": nolock,
-        internal=internal,
+        "internal": internal,
-        default_deny=default_deny,
+        "default_deny": default_deny,
-    )
+    }
 
     # Separate directories from files
     directories = [f for f in files if os.path.isdir(f)]
@@ -621,9 +622,7 @@ def serve(
                 conn.close()
             else:
                 raise click.ClickException(
-                    "Invalid value for '[FILES]...': Path '{}' does not exist.".format(
+                    f"Invalid value for '[FILES]...': Path '{file}' does not exist."
-                        file
-                    )
                 )
 
     # Check for duplicate files by resolving all paths to their absolute forms
@@ -684,7 +683,7 @@ def serve(
         client = TestClient(ds)
         request_headers = {}
         if token:
-            request_headers["Authorization"] = "Bearer {}".format(token)
+            request_headers["Authorization"] = f"Bearer {token}"
         cookies = {}
         if actor:
             cookies["ds_actor"] = client.actor_cookie(json.loads(actor))
@@ -719,9 +718,13 @@ def serve(
             path = run_sync(lambda: initial_path_for_datasette(ds))
             url = f"http://{host}:{port}{path}"
         webbrowser.open(url)
-    uvicorn_kwargs = dict(
+    uvicorn_kwargs = {
-        host=host, port=port, log_level="info", lifespan="on", workers=1
+        "host": host,
-    )
+        "port": port,
+        "log_level": "info",
+        "lifespan": "on",
+        "workers": 1,
+    }
     if uds:
         uvicorn_kwargs["uds"] = uds
     if ssl_keyfile:
@@ -885,7 +888,7 @@ async def check_databases(ds):
             )
         except ConnectionProblem as e:
             raise click.UsageError(
-                f"Connection to {database.path} failed check: {str(e.args[0])}"
+                f"Connection to {database.path} failed check: {e.args[0]!s}"
             )
     # If --crossdb and more than SQLITE_LIMIT_ATTACHED show warning
     if (
@@ -893,9 +896,5 @@ async def check_databases(ds):
         and len([db for db in ds.databases.values() if not db.is_memory])
         > SQLITE_LIMIT_ATTACHED
     ):
-        msg = (
+        msg = f"Warning: --crossdb only works with the first {SQLITE_LIMIT_ATTACHED} attached databases"
-            "Warning: --crossdb only works with the first {} attached databases".format(
-                SQLITE_LIMIT_ATTACHED
-            )
-        )
         click.echo(click.style(msg, bold=True, fg="yellow"), err=True)

datasette/column_types.py

@@ -64,14 +64,14 @@ class ColumnType:
         Return an HTML string to render this cell value, or None to
         fall through to the default render_cell plugin hook chain.
         """
-        return None
+        return
 
     async def validate(self, value, datasette):
         """
         Validate a value before it is written. Return None if valid,
         or a string error message if invalid.
         """
-        return None
+        return
 
     async def transform_value(self, value, datasette):
         """

datasette/csrf.py

@@ -40,12 +40,12 @@ def _origin_tuple(value):
     scheme = (parsed.scheme or "").lower()
     host = (parsed.hostname or "").lower()
     if not scheme or not host:
-        raise ValueError("missing scheme or host in {!r}".format(value))
+        raise ValueError(f"missing scheme or host in {value!r}")
     port = parsed.port  # may raise ValueError on bad ports
     if port is None:
         port = DEFAULT_PORTS.get(scheme)
     if port is None:
-        raise ValueError("unknown default port for scheme {!r}".format(scheme))
+        raise ValueError(f"unknown default port for scheme {scheme!r}")
     return scheme, host, port
 
 
@@ -125,9 +125,7 @@ class CrossOriginProtectionMiddleware:
                 return
             await self._forbid(
                 send,
-                "Sec-Fetch-Site was {!r}, expected 'same-origin' or 'none'".format(
+                f"Sec-Fetch-Site was {sec_fetch_site!r}, expected 'same-origin' or 'none'",
-                    sec_fetch_site
-                ),
             )
             return
 
@@ -141,11 +139,11 @@ class CrossOriginProtectionMiddleware:
         request_scheme = self._request_scheme(scope)
         try:
             origin_tuple = _origin_tuple(origin)
-            expected_tuple = _origin_tuple("{}://{}".format(request_scheme, host))
+            expected_tuple = _origin_tuple(f"{request_scheme}://{host}")
         except ValueError:
             await self._forbid(
                 send,
-                "Malformed Origin {!r} or Host {!r}".format(origin, host),
+                f"Malformed Origin {origin!r} or Host {host!r}",
             )
             return
 
@@ -155,7 +153,7 @@ class CrossOriginProtectionMiddleware:
 
         await self._forbid(
             send,
-            "Origin {!r} does not match Host {!r}".format(origin, host),
+            f"Origin {origin!r} does not match Host {host!r}",
         )
 
     def _request_scheme(self, scope):
@@ -163,7 +161,8 @@ class CrossOriginProtectionMiddleware:
             try:
                 if self.datasette.setting("force_https_urls"):
                     return "https"
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
+                # Settings may not be readable this early; fall back to the ASGI scheme
                 pass
         return scope.get("scheme") or "http"
 

datasette/database.py

@@ -1,33 +1,35 @@
 import asyncio
 import atexit
-from collections import namedtuple
 import inspect
 import os
-from pathlib import Path
 import queue
-import sqlite_utils
 import sys
 import tempfile
 import threading
 import uuid
+from collections import namedtuple
+from pathlib import Path
 
+import sqlite_utils
+
+from .inspect import inspect_hash
 from .tracer import trace
 from .utils import (
     call_with_supported_arguments,
     detect_fts,
     detect_primary_keys,
     detect_spatialite,
+    escape_sqlite,
     get_all_foreign_keys,
     get_outbound_foreign_keys,
     md5_not_usedforsecurity,
-    sqlite_timelimit,
     sqlite3,
-    table_columns,
+    sqlite_timelimit,
     table_column_details,
+    table_columns,
 )
 from .utils.sql_analysis import SQLAnalysis, analyze_sql_tables
 from .utils.sqlite import sqlite_hidden_table_names
-from .inspect import inspect_hash
 
 connections = threading.local()
 
@@ -98,9 +100,7 @@ class Database:
 
     def _check_not_closed(self):
         if self._closed:
-            raise DatasetteClosedError(
+            raise DatasetteClosedError(f"Database {self.name!r} has been closed")
-                "Database {!r} has been closed".format(self.name)
-            )
 
     def _remove_pending_execute_future(self, future):
         with self._pending_execute_futures_lock:
@@ -139,7 +139,7 @@ class Database:
         if write:
             extra_kwargs["isolation_level"] = "IMMEDIATE"
         if self.memory_name:
-            uri = "file:{}?mode=memory&cache=shared".format(self.memory_name)
+            uri = f"file:{self.memory_name}?mode=memory&cache=shared"
             conn = sqlite3.connect(
                 uri, uri=True, check_same_thread=False, **extra_kwargs
             )
@@ -192,21 +192,20 @@ class Database:
             write_thread.join(timeout=10)
             if write_thread.is_alive():
                 sys.stderr.write(
-                    "Datasette: write thread for {!r} did not exit within 10s\n".format(
+                    f"Datasette: write thread for {self.name!r} did not exit within 10s\n"
-                        self.name
-                    )
                 )
                 sys.stderr.flush()
         for future in pending_execute_futures:
             try:
                 future.result()
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
+                # Shutdown teardown - a failed pending write must not block close()
                 pass
         # Close anything still tracked in _all_file_connections
         for connection in self._all_file_connections:
             try:
                 connection.close()
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
                 pass
         self._all_file_connections = []
         # Drop per-thread cached read connections we can reach
@@ -218,13 +217,13 @@ class Database:
         if self._read_connection is not None:
             try:
                 self._read_connection.close()
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
                 pass
             self._read_connection = None
         if self._write_connection is not None:
             try:
                 self._write_connection.close()
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
                 pass
             self._write_connection = None
         if self.is_temp_disk:
@@ -246,6 +245,7 @@ class Database:
         request=None,
         return_all=False,
         returning_limit=EXECUTE_WRITE_RETURNING_LIMIT,
+        transaction=True,
     ):
         self._check_not_closed()
         if returning_limit < 0:
@@ -258,7 +258,9 @@ class Database:
             )
 
         with trace("sql", database=self.name, sql=sql.strip(), params=params):
-            results = await self.execute_write_fn(_inner, block=block, request=request)
+            results = await self.execute_write_fn(
+                _inner, block=block, request=request, transaction=transaction
+            )
         return results
 
     async def execute_write_script(self, sql, block=True, request=None):
@@ -348,6 +350,7 @@ class Database:
                 self.ds._prepare_connection(self._write_connection, self.name)
             if transaction:
                 with self._write_connection:
+                    self._write_connection.execute("BEGIN IMMEDIATE")
                     result = fn(self._write_connection)
             else:
                 result = fn(self._write_connection)
@@ -366,7 +369,8 @@ class Database:
             async def _dispatch_events_after_write():
                 try:
                     await reply_future
-                except Exception:
+                except Exception:  # noqa: BLE001
+                    # The write failed; skip success events regardless of why
                     # if the write failed, don't emit success events
                     return
                 for event in pending_events:
@@ -419,9 +423,7 @@ class Database:
             self._write_thread = threading.Thread(
                 target=self._execute_writes, daemon=True
             )
-            self._write_thread.name = "_execute_writes for database {}".format(
+            self._write_thread.name = f"_execute_writes for database {self.name}"
-                self.name
-            )
             self._write_thread.start()
         task_id = uuid.uuid5(uuid.NAMESPACE_DNS, "datasette.io")
         loop = asyncio.get_running_loop()
@@ -442,7 +444,8 @@ class Database:
         try:
             conn = self.connect(write=True)
             self.ds._prepare_connection(conn, self.name)
-        except Exception as e:
+        except Exception as e:  # noqa: BLE001
+            # Stored and re-raised to whoever queues the next write
             conn_exception = e
         while True:
             task = self._write_queue.get()
@@ -450,7 +453,8 @@ class Database:
                 if conn is not None:
                     try:
                         conn.close()
-                    except Exception:
+                    except Exception:  # noqa: BLE001, S110
+                        # Best-effort close as the write thread exits
                         pass
                 return
             exception = None
@@ -469,19 +473,21 @@ class Database:
                         except ValueError:
                             # Was probably a memory connection
                             pass
-                except Exception as e:
+                except Exception as e:  # noqa: BLE001
-                    sys.stderr.write("{}\n".format(e))
+                    # Write thread must survive any task failure or the database wedges
+                    sys.stderr.write(f"{e}\n")
                     sys.stderr.flush()
                     exception = e
             else:
                 try:
                     if task.transaction:
                         with conn:
+                            conn.execute("BEGIN IMMEDIATE")
                             result = task.fn(conn)
                     else:
                         result = task.fn(conn)
-                except Exception as e:
+                except Exception as e:  # noqa: BLE001
-                    sys.stderr.write("{}\n".format(e))
+                    sys.stderr.write(f"{e}\n")
                     sys.stderr.flush()
                     exception = e
             _deliver_write_result(task, result, exception)
@@ -548,9 +554,7 @@ class Database:
                         raise QueryInterrupted(e, sql, params)
                     if log_sql_errors:
                         sys.stderr.write(
-                            "ERROR: conn={}, sql = {}, params = {}: {}\n".format(
+                            f"ERROR: conn={conn}, sql = {sql!r}, params = {params}: {e}\n"
-                                conn, repr(sql), params, e
-                            )
                         )
                         sys.stderr.flush()
                     raise
@@ -603,7 +607,7 @@ class Database:
             try:
                 table_count = (
                     await self.execute(
-                        f"select count(*) from (select * from [{table}] limit {self.count_limit + 1})",
+                        f"select count(*) from (select * from {escape_sqlite(table)} limit {self.count_limit + 1})",
                         custom_time_limit=limit,
                     )
                 ).rows[0][0]
@@ -707,9 +711,9 @@ class Database:
             column_names
             and len(column_names) == 2
             and ("id" in column_names or "pk" in column_names)
-            and not set(column_names) == {"id", "pk"}
+            and set(column_names) != {"id", "pk"}
         ):
-            return [c for c in column_names if c not in ("id", "pk")][0]
+            return next(c for c in column_names if c not in ("id", "pk"))
         # Couldn't find a label:
         return None
 
@@ -851,10 +855,10 @@ def _apply_write_wrapper(fn, wrapper_factory, track_event):
 class WriteTask:
     __slots__ = (
         "fn",
-        "task_id",
+        "isolated_connection",
         "loop",
         "reply_future",
-        "isolated_connection",
+        "task_id",
         "transaction",
     )
 
@@ -895,7 +899,7 @@ class QueryInterrupted(Exception):
         self.params = params
 
     def __str__(self):
-        return "QueryInterrupted: {}".format(self.e)
+        return f"QueryInterrupted: {self.e}"
 
 
 class MultipleValues(Exception):

datasette/default_actions.py

@@ -2,8 +2,8 @@ from datasette import hookimpl
 from datasette.permissions import Action
 from datasette.resources import (
     DatabaseResource,
-    TableResource,
     QueryResource,
+    TableResource,
 )
 
 

datasette/default_magic_parameters.py

@@ -1,8 +1,9 @@
-from datasette import hookimpl
 import datetime
 import os
 import time
 
+from datasette import hookimpl
+
 
 def header(key, request):
     key = key.replace("_", "-").encode("utf-8")

datasette/default_permissions/__init__.py

@@ -17,18 +17,29 @@ UNION/INTERSECT operations. The order of evaluation is:
 
 from __future__ import annotations
 
-# Re-export all hooks and public utilities
-from .restrictions import (
-    actor_restrictions_sql as actor_restrictions_sql,
-    restrictions_allow_action as restrictions_allow_action,
-    ActorRestrictions as ActorRestrictions,
-)
-from .root import root_user_permissions_sql as root_user_permissions_sql
 from .config import config_permissions_sql as config_permissions_sql
+from .defaults import (
+    DEFAULT_ALLOW_ACTIONS as DEFAULT_ALLOW_ACTIONS,
+)
+from .defaults import (
+    default_action_permissions_sql as default_action_permissions_sql,
+)
 from .defaults import (
     # Avoid "datasette.default_permissions" does not explicitly export attribute
     default_allow_sql_check as default_allow_sql_check,
-    default_action_permissions_sql as default_action_permissions_sql,
-    default_query_permissions_sql as default_query_permissions_sql,
-    DEFAULT_ALLOW_ACTIONS as DEFAULT_ALLOW_ACTIONS,
 )
+from .defaults import (
+    default_query_permissions_sql as default_query_permissions_sql,
+)
+from .restrictions import (
+    ActorRestrictions as ActorRestrictions,
+)
+
+# Re-export all hooks and public utilities
+from .restrictions import (
+    actor_restrictions_sql as actor_restrictions_sql,
+)
+from .restrictions import (
+    restrictions_allow_action as restrictions_allow_action,
+)
+from .root import root_user_permissions_sql as root_user_permissions_sql

datasette/default_permissions/config.py

@@ -6,7 +6,7 @@ Applies permission rules from datasette.yaml configuration.
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Any, List, Optional, Set, Tuple
+from typing import TYPE_CHECKING, Any
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -55,8 +55,8 @@ class ConfigPermissionProcessor:
 
     def __init__(
         self,
-        datasette: "Datasette",
+        datasette: Datasette,
-        actor: Optional[dict],
+        actor: dict | None,
         action: str,
     ):
         self.datasette = datasette
@@ -74,8 +74,8 @@ class ConfigPermissionProcessor:
         self.restrictions = actor.get("_r", {}) if actor else {}
 
         # Pre-compute restriction info for efficiency
-        self.restricted_databases: Set[str] = set()
+        self.restricted_databases: set[str] = set()
-        self.restricted_tables: Set[Tuple[str, str]] = set()
+        self.restricted_tables: set[tuple[str, str]] = set()
 
         if self.has_restrictions:
             self.restricted_databases = {
@@ -92,16 +92,20 @@ class ConfigPermissionProcessor:
             # Tables implicitly reference their parent databases
             self.restricted_databases.update(db for db, _ in self.restricted_tables)
 
-    def evaluate_allow_block(self, allow_block: Any) -> Optional[bool]:
+    def evaluate_allow_block(self, allow_block: Any) -> bool | None:
         """Evaluate an allow block against the current actor."""
         if allow_block is None:
             return None
+        # Values passed using ``-s permissions.* 1`` or ``0`` are parsed as
+        # integers, but should retain the CLI's boolean 1/0 behavior.
+        if isinstance(allow_block, int) and allow_block in (0, 1):
+            return bool(allow_block)
         return actor_matches_allow(self.actor, allow_block)
 
     def is_in_restriction_allowlist(
         self,
-        parent: Optional[str],
+        parent: str | None,
-        child: Optional[str],
+        child: str | None,
     ) -> bool:
         """Check if resource is allowed by actor restrictions."""
         if not self.has_restrictions:
@@ -143,9 +147,9 @@ class ConfigPermissionProcessor:
 
     def add_permissions_rule(
         self,
-        parent: Optional[str],
+        parent: str | None,
-        child: Optional[str],
+        child: str | None,
-        permissions_block: Optional[dict],
+        permissions_block: dict | None,
         scope_desc: str,
     ) -> None:
         """Add a rule from a permissions:{action} block."""
@@ -165,8 +169,8 @@ class ConfigPermissionProcessor:
 
     def add_allow_block_rule(
         self,
-        parent: Optional[str],
+        parent: str | None,
-        child: Optional[str],
+        child: str | None,
         allow_block: Any,
         scope_desc: str,
     ) -> None:
@@ -198,8 +202,8 @@ class ConfigPermissionProcessor:
 
     def _add_restriction_gate_denies(
         self,
-        parent: Optional[str],
+        parent: str | None,
-        child: Optional[str],
+        child: str | None,
         is_allowed: bool,
         scope_desc: str,
     ) -> None:
@@ -231,7 +235,7 @@ class ConfigPermissionProcessor:
                     if db_name == parent:
                         self.collector.add(db_name, table_name, False, reason)
 
-    def process(self) -> Optional[PermissionSQL]:
+    def process(self) -> PermissionSQL | None:
         """Process all config rules and return combined PermissionSQL."""
         self._process_root_permissions()
         self._process_databases()
@@ -421,10 +425,10 @@ class ConfigPermissionProcessor:
 
 @hookimpl(specname="permission_resources_sql")
 async def config_permissions_sql(
-    datasette: "Datasette",
+    datasette: Datasette,
-    actor: Optional[dict],
+    actor: dict | None,
     action: str,
-) -> Optional[List[PermissionSQL]]:
+) -> list[PermissionSQL] | None:
     """
     Apply permission rules from datasette.yaml configuration.
 

datasette/default_permissions/defaults.py

@@ -6,7 +6,7 @@ Provides default allow rules for standard view/execute actions.
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -29,29 +29,28 @@ DEFAULT_ALLOW_ACTIONS = frozenset(
 
 @hookimpl(specname="permission_resources_sql")
 async def default_allow_sql_check(
-    datasette: "Datasette",
+    datasette: Datasette,
-    actor: Optional[dict],
+    actor: dict | None,
     action: str,
-) -> Optional[PermissionSQL]:
+) -> PermissionSQL | None:
     """
     Enforce the default_allow_sql setting.
 
     When default_allow_sql is false (the default), execute-sql is denied
     unless explicitly allowed by config or other rules.
     """
-    if action == "execute-sql":
+    if action == "execute-sql" and not datasette.setting("default_allow_sql"):
-        if not datasette.setting("default_allow_sql"):
+        return PermissionSQL.deny(reason="default_allow_sql is false")
-            return PermissionSQL.deny(reason="default_allow_sql is false")
 
     return None
 
 
 @hookimpl(specname="permission_resources_sql")
 async def default_action_permissions_sql(
-    datasette: "Datasette",
+    datasette: Datasette,
-    actor: Optional[dict],
+    actor: dict | None,
     action: str,
-) -> Optional[PermissionSQL]:
+) -> PermissionSQL | None:
     """
     Provide default allow rules for standard view/execute actions.
 
@@ -71,10 +70,10 @@ async def default_action_permissions_sql(
 
 @hookimpl(specname="permission_resources_sql")
 async def default_query_permissions_sql(
-    datasette: "Datasette",
+    datasette: Datasette,
-    actor: Optional[dict],
+    actor: dict | None,
     action: str,
-) -> Optional[PermissionSQL]:
+) -> PermissionSQL | None:
     actor_id = actor.get("id") if isinstance(actor, dict) else None
 
     if action not in {"view-query", "update-query", "delete-query"}:

datasette/default_permissions/helpers.py

@@ -5,7 +5,7 @@ Shared helper utilities for default permission implementations.
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, List, Optional, Set
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -13,7 +13,7 @@ if TYPE_CHECKING:
 from datasette.permissions import PermissionSQL
 
 
-def get_action_name_variants(datasette: "Datasette", action: str) -> Set[str]:
+def get_action_name_variants(datasette: Datasette, action: str) -> set[str]:
     """
     Get all name variants for an action (full name and abbreviation).
 
@@ -27,7 +27,7 @@ def get_action_name_variants(datasette: "Datasette", action: str) -> Set[str]:
     return variants
 
 
-def action_in_list(datasette: "Datasette", action: str, action_list: list) -> bool:
+def action_in_list(datasette: Datasette, action: str, action_list: list) -> bool:
     """Check if an action (or its abbreviation) is in a list."""
     return bool(get_action_name_variants(datasette, action).intersection(action_list))
 
@@ -36,8 +36,8 @@ def action_in_list(datasette: "Datasette", action: str, action_list: list) -> bo
 class PermissionRow:
     """A single permission rule row."""
 
-    parent: Optional[str]
+    parent: str | None
-    child: Optional[str]
+    child: str | None
     allow: bool
     reason: str
 
@@ -46,14 +46,14 @@ class PermissionRowCollector:
     """Collects permission rows and converts them to PermissionSQL."""
 
     def __init__(self, prefix: str = "row"):
-        self.rows: List[PermissionRow] = []
+        self.rows: list[PermissionRow] = []
         self.prefix = prefix
 
     def add(
         self,
-        parent: Optional[str],
+        parent: str | None,
-        child: Optional[str],
+        child: str | None,
-        allow: Optional[bool],
+        allow: bool | None,
         reason: str,
         if_not_none: bool = False,
     ) -> None:
@@ -62,7 +62,7 @@ class PermissionRowCollector:
             return
         self.rows.append(PermissionRow(parent, child, allow, reason))
 
-    def to_permission_sql(self) -> Optional[PermissionSQL]:
+    def to_permission_sql(self) -> PermissionSQL | None:
         """Convert collected rows to a PermissionSQL object."""
         if not self.rows:
             return None

datasette/default_permissions/restrictions.py

@@ -8,7 +8,7 @@ contains allowlists of resources the actor can access.
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, List, Optional, Set, Tuple
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -23,12 +23,12 @@ from .helpers import action_in_list, get_action_name_variants
 class ActorRestrictions:
     """Parsed actor restrictions from the _r key."""
 
-    global_actions: List[str]  # _r.a - globally allowed actions
+    global_actions: list[str]  # _r.a - globally allowed actions
     database_actions: dict  # _r.d - {db_name: [actions]}
     table_actions: dict  # _r.r - {db_name: {table: [actions]}}
 
     @classmethod
-    def from_actor(cls, actor: Optional[dict]) -> Optional["ActorRestrictions"]:
+    def from_actor(cls, actor: dict | None) -> ActorRestrictions | None:
         """Parse restrictions from actor dict. Returns None if no restrictions."""
         if not actor:
             return None
@@ -44,11 +44,11 @@ class ActorRestrictions:
             table_actions=restrictions.get("r", {}),
         )
 
-    def is_action_globally_allowed(self, datasette: "Datasette", action: str) -> bool:
+    def is_action_globally_allowed(self, datasette: Datasette, action: str) -> bool:
         """Check if action is in the global allowlist."""
         return action_in_list(datasette, action, self.global_actions)
 
-    def get_allowed_databases(self, datasette: "Datasette", action: str) -> Set[str]:
+    def get_allowed_databases(self, datasette: Datasette, action: str) -> set[str]:
         """Get database names where this action is allowed."""
         allowed = set()
         for db_name, db_actions in self.database_actions.items():
@@ -57,8 +57,8 @@ class ActorRestrictions:
         return allowed
 
     def get_allowed_tables(
-        self, datasette: "Datasette", action: str
+        self, datasette: Datasette, action: str
-    ) -> Set[Tuple[str, str]]:
+    ) -> set[tuple[str, str]]:
         """Get (database, table) pairs where this action is allowed."""
         allowed = set()
         for db_name, tables in self.table_actions.items():
@@ -70,10 +70,10 @@ class ActorRestrictions:
 
 @hookimpl(specname="permission_resources_sql")
 async def actor_restrictions_sql(
-    datasette: "Datasette",
+    datasette: Datasette,
-    actor: Optional[dict],
+    actor: dict | None,
     action: str,
-) -> Optional[List[PermissionSQL]]:
+) -> list[PermissionSQL] | None:
     """
     Handle actor restriction-based permission rules.
 
@@ -140,10 +140,10 @@ async def actor_restrictions_sql(
 
 
 def restrictions_allow_action(
-    datasette: "Datasette",
+    datasette: Datasette,
     restrictions: dict,
     action: str,
-    resource: Optional[str | Tuple[str, str]],
+    resource: str | tuple[str, str] | None,
 ) -> bool:
     """
     Check if restrictions allow the requested action on the requested resource.

datasette/default_permissions/root.py

@@ -6,7 +6,7 @@ Grants full permissions to the root user when --root flag is used.
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -17,9 +17,9 @@ from datasette.permissions import PermissionSQL
 
 @hookimpl(specname="permission_resources_sql")
 async def root_user_permissions_sql(
-    datasette: "Datasette",
+    datasette: Datasette,
-    actor: Optional[dict],
+    actor: dict | None,
-) -> Optional[PermissionSQL]:
+) -> PermissionSQL | None:
     """
     Grant root user full permissions when --root flag is used.
     """

datasette/default_permissions/tokens.py

@@ -7,7 +7,7 @@ to datasette.verify_token() so all registered handlers are tried.
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -17,15 +17,13 @@ from datasette.tokens import SignedTokenHandler
 
 
 @hookimpl
-def register_token_handler(datasette: "Datasette"):
+def register_token_handler(datasette: Datasette):
     """Register the default signed token handler."""
     return SignedTokenHandler()
 
 
 @hookimpl(specname="actor_from_request")
-async def actor_from_signed_api_token(
+async def actor_from_signed_api_token(datasette: Datasette, request) -> dict | None:
-    datasette: "Datasette", request
-) -> Optional[dict]:
     """
     Authenticate requests using API tokens by delegating to all registered
     token handlers via datasette.verify_token().

datasette/default_table_actions.py

@@ -20,7 +20,7 @@ def table_actions(datasette, actor, database, table, request):
                 "label": "Alter table",
                 "description": "Change columns and primary key for this table.",
                 "attrs": {
-                    "aria-label": "Alter table {}".format(table),
+                    "aria-label": f"Alter table {table}",
                     "data-table-action": "alter-table",
                 },
             }

datasette/events.py

@@ -1,8 +1,9 @@
 from abc import ABC, abstractproperty
 from dataclasses import asdict, dataclass, field
-from datasette.hookspecs import hookimpl
 from datetime import datetime, timezone
 
+from datasette.hookspecs import hookimpl
+
 
 @dataclass
 class Event(ABC):

datasette/facets.py

@@ -1,12 +1,13 @@
 import json
 import urllib
+
 from datasette import hookimpl
 from datasette.database import QueryInterrupted
 from datasette.utils import (
+    detect_json1,
     escape_sqlite,
     path_with_added_args,
     path_with_removed_args,
-    detect_json1,
     sqlite3,
 )
 
@@ -30,7 +31,7 @@ def load_facet_configs(request, table_config):
             assert (
                 len(facet_config.values()) == 1
             ), "Metadata config dicts should be {type: config}"
-            type, facet_config = list(facet_config.items())[0]
+            type, facet_config = next(iter(facet_config.items()))
             if isinstance(facet_config, str):
                 facet_config = {"simple": facet_config}
         facet_configs.setdefault(type, []).append(
@@ -85,7 +86,7 @@ class Facet:
         self.database = database
         # For foreign key expansion. Can be None for e.g. stored SQL queries:
         self.table = table
-        self.sql = sql or f"select * from [{table}]"
+        self.sql = sql or f"select * from {escape_sqlite(table)}"
         self.params = params or []
         self.table_config = table_config
         # row_count can be None, in which case we calculate it ourselves:
@@ -160,18 +161,13 @@ class ColumnFacet(Facet):
         for column in columns:
             if column in already_enabled:
                 continue
-            suggested_facet_sql = """
+            suggested_facet_sql = f"""
-                with limited as (select * from ({sql}) limit {suggest_consider})
+                with limited as (select * from ({self.sql}) limit {self.suggest_consider})
-                select {column} as value, count(*) as n from limited
+                select {escape_sqlite(column)} as value, count(*) as n from limited
                 where value is not null
                 group by value
-                limit {limit}
+                limit {facet_size + 1}
-            """.format(
+            """
-                column=escape_sqlite(column),
-                sql=self.sql,
-                limit=facet_size + 1,
-                suggest_consider=self.suggest_consider,
-            )
             distinct_values = None
             try:
                 distinct_values = await self.ds.execute(
@@ -267,7 +263,7 @@ class ColumnFacet(Facet):
                 for row in facet_rows:
                     column_qs = column
                     if column.startswith("_"):
-                        column_qs = "{}__exact".format(column)
+                        column_qs = f"{column}__exact"
                     selected = (column_qs, str(row["value"])) in qs_pairs
                     if selected:
                         toggle_path = path_with_removed_args(
@@ -342,12 +338,12 @@ class ArrayFacet(Facet):
                         for v in await self.ds.execute(
                             self.database,
                             (
-                                "select {column} from ({sql}) "
+                                f"select {escape_sqlite(column)} from ({self.sql}) "
-                                "where {column} is not null "
+                                f"where {escape_sqlite(column)} is not null "
-                                "and {column} != '' "
+                                f"and {escape_sqlite(column)} != '' "
-                                "and json_array_length({column}) > 0 "
+                                f"and json_array_length({escape_sqlite(column)}) > 0 "
                                 "limit 100"
-                            ).format(column=escape_sqlite(column), sql=self.sql),
+                            ),
                             self.params,
                             truncate=False,
                             custom_time_limit=self.ds.setting(
@@ -388,14 +384,14 @@ class ArrayFacet(Facet):
             source = source_and_config["source"]
             column = config.get("column") or config["simple"]
             # https://github.com/simonw/datasette/issues/448
-            facet_sql = """
+            facet_sql = f"""
-                with inner as ({sql}),
+                with inner as ({self.sql}),
                 deduped_array_items as (
                     select
                         distinct j.value,
                         inner.*
                     from
-                        json_each([inner].{col}) j
+                        json_each([inner].{escape_sqlite(column)}) j
                         join inner
                 )
                 select
@@ -406,12 +402,8 @@ class ArrayFacet(Facet):
                 group by
                     value
                 order by
-                    count(*) desc, value limit {limit}
+                    count(*) desc, value limit {facet_size + 1}
-            """.format(
+            """
-                col=escape_sqlite(column),
-                sql=self.sql,
-                limit=facet_size + 1,
-            )
             try:
                 facet_rows_results = await self.ds.execute(
                     self.database,

datasette/filters.py

@@ -1,8 +1,11 @@
+import json
+from typing import ClassVar
+
 from datasette import hookimpl
 from datasette.resources import DatabaseResource
-from datasette.views.base import DatasetteError
 from datasette.utils.asgi import BadRequest
-import json
+from datasette.views.base import DatasetteError
+
 from .utils import detect_json1, escape_sqlite, path_with_removed_args
 
 
@@ -99,9 +102,9 @@ def search_filters(request, database, table, datasette):
                             fts_table=escape_sqlite(fts_table),
                             search_col=escape_sqlite(search_col),
                             match_clause=(
-                                ":search_{}".format(i)
+                                f":search_{i}"
                                 if search_mode_raw
-                                else "escape_fts(:search_{})".format(i)
+                                else f"escape_fts(:search_{i})"
                             ),
                         )
                     )
@@ -134,11 +137,11 @@ def through_filters(request, database, table, datasette):
                 value = through_data["value"]
                 db = datasette.get_database(database)
                 outgoing_foreign_keys = await db.foreign_keys_for_table(through_table)
-                try:
+                fk_to_us = next(
-                    fk_to_us = [
+                    (fk for fk in outgoing_foreign_keys if fk["other_table"] == table),
-                        fk for fk in outgoing_foreign_keys if fk["other_table"] == table
+                    None,
-                    ][0]
+                )
-                except IndexError:
+                if fk_to_us is None:
                     raise DatasetteError(
                         "Invalid _through - could not find corresponding foreign key"
                     )
@@ -365,7 +368,7 @@ class Filters:
             ),
         ]
     )
-    _filters_by_key = {f.key: f for f in _filters}
+    _filters_by_key: ClassVar[dict[str, Filter]] = {f.key: f for f in _filters}
 
     def __init__(self, pairs):
         self.pairs = pairs

datasette/fixtures.py

@@ -1,9 +1,10 @@
-from datasette.utils.sqlite import sqlite3
-from datasette.utils import documented
 import itertools
 import random
 import string
 
+from datasette.utils import documented
+from datasette.utils.sqlite import sqlite3
+
 __all__ = [
     "EXTRA_DATABASE_SQL",
     "TABLES",
@@ -346,9 +347,7 @@ CREATE VIEW searchable_view_configured_by_metadata AS
     + '\nINSERT INTO no_primary_key VALUES ("RENDER_CELL_DEMO", "a202", "b202", "c202");\n'
     + "\n".join(
         [
-            'INSERT INTO compound_three_primary_keys VALUES ("{a}", "{b}", "{c}", "{content}");'.format(
+            f'INSERT INTO compound_three_primary_keys VALUES ("{a}", "{b}", "{c}", "{content}");'
-                a=a, b=b, c=c, content=content
-            )
             for a, b, c, content in generate_compound_rows(1001)
         ]
     )

datasette/forbidden.py

@@ -1,4 +1,5 @@
-from datasette import hookimpl, Response
+from datasette import Response, hookimpl
+
 from .utils import add_cors_headers
 
 

datasette/handle_exception.py

@@ -1,16 +1,21 @@
-from datasette import hookimpl, Response
+import traceback
+
+from markupsafe import Markup
+
+from datasette import Response, hookimpl
+
 from .utils import add_cors_headers, error_body
 from .utils.asgi import (
     Base400,
 )
 from .views.base import DatasetteError
-from markupsafe import Markup
-import traceback
 
+# Debugger imports are deliberate - they back the "pdb" setting, which drops
+# into a debugger on unhandled exceptions
 try:
-    import ipdb as pdb
+    import ipdb as pdb  # noqa: T100
 except ImportError:
-    import pdb
+    import pdb  # noqa: T100
 
 try:
     import rich
@@ -69,7 +74,7 @@ def handle_exception(datasette, request, exception):
                 dict(
                     info,
                     urls=datasette.urls,
-                    menu_links=lambda: [],
+                    menu_links=list,
                 )
             ),
             status=status,

datasette/hookspecs.py

@@ -1,5 +1,4 @@
-from pluggy import HookimplMarker
+from pluggy import HookimplMarker, HookspecMarker
-from pluggy import HookspecMarker
 
 hookspec = HookspecMarker("datasette")
 hookimpl = HookimplMarker("datasette")

datasette/inspect.py

@@ -1,13 +1,13 @@
 import hashlib
 
 from .utils import (
-    detect_spatialite,
     detect_fts,
     detect_primary_keys,
+    detect_spatialite,
     escape_sqlite,
     get_all_foreign_keys,
-    table_columns,
     sqlite3,
+    table_columns,
 )
 
 HASH_BLOCK_SIZE = 1024 * 1024
@@ -95,10 +95,10 @@ def inspect_tables(conn, database_metadata):
                 """)
         ]
 
-    for t in tables.keys():
+    for t, table_info in tables.items():
         for hidden_table in hidden_tables:
             if t == hidden_table or t.startswith(hidden_table):
-                tables[t]["hidden"] = True
+                table_info["hidden"] = True
                 continue
 
     return tables

datasette/jump.py

@@ -21,7 +21,7 @@ class JumpSQL:
         search_text: str | None = None,
         display_name: str | None = None,
         item_type: str = "menu",
-    ) -> "JumpSQL":
+    ) -> JumpSQL:
         if search_text is None:
             search_text = " ".join(
                 text for text in (label, display_name, description) if text is not None

datasette/permissions.py

@@ -1,7 +1,7 @@
+import contextvars
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from typing import Any, NamedTuple
-import contextvars
 
 # Context variable to track when permission checks should be skipped
 _skip_permission_checks = contextvars.ContextVar(
@@ -72,8 +72,8 @@ class Resource(ABC):
         )
 
     def __repr__(self) -> str:
-        return "{}(parent={!r}, child={!r})".format(
+        return (
-            self.__class__.__name__, self.parent, self.child
+            f"{self.__class__.__name__}(parent={self.parent!r}, child={self.child!r})"
         )
 
     @property
@@ -129,7 +129,6 @@ class Resource(ABC):
 
         Must return two columns: parent, child
         """
-        pass
 
 
 class AllowedResource(NamedTuple):

datasette/plugins.py

@@ -1,20 +1,14 @@
 import importlib
+import importlib.metadata as importlib_metadata
+import importlib.resources as importlib_resources
 import os
-import pluggy
-from pprint import pprint
 import sys
+from pprint import pprint
+
+import pluggy
+
 from . import hookspecs
 
-if sys.version_info >= (3, 9):
-    import importlib.resources as importlib_resources
-else:
-    import importlib_resources
-if sys.version_info >= (3, 10):
-    import importlib.metadata as importlib_metadata
-else:
-    import importlib_metadata
-
-
 DEFAULT_PLUGINS = (
     "datasette.publish.heroku",
     "datasette.publish.cloudrun",
@@ -85,7 +79,7 @@ if DATASETTE_LOAD_PLUGINS is not None:
                     # Ensure name can be found in plugin_to_distinfo later:
                     pm._plugin_distinfo.append((mod, distribution))
         except importlib_metadata.PackageNotFoundError:
-            sys.stderr.write("Plugin {} could not be found\n".format(package_name))
+            sys.stderr.write(f"Plugin {package_name} could not be found\n")
 
 
 # Load default plugins

datasette/publish/cloudrun.py

@@ -1,15 +1,17 @@
-from datasette import hookimpl
-import click
 import json
 import os
 import re
 from subprocess import CalledProcessError, check_call, check_output
 
+import click
+
+from datasette import hookimpl
+
+from ..utils import temporary_docker_directory
 from .common import (
     add_common_publish_arguments_and_options,
     fail_if_publish_binary_not_installed,
 )
-from ..utils import temporary_docker_directory
 
 
 @hookimpl
@@ -219,7 +221,7 @@ def publish_subcommand(publish):
 
             check_call(
                 "gcloud builds submit --tag {}{}".format(
-                    image_id, " --timeout {}".format(timeout) if timeout else ""
+                    image_id, f" --timeout {timeout}" if timeout else ""
                 ),
                 shell=True,
             )
@@ -231,7 +233,7 @@ def publish_subcommand(publish):
             ("--min-instances", min_instances),
         ):
             if value is not None:
-                extra_deploy_options.append("{} {}".format(option, value))
+                extra_deploy_options.append(f"{option} {value}")
         check_call(
             "gcloud run deploy --allow-unauthenticated --platform=managed --image {} {}{}".format(
                 image_id,
@@ -258,24 +260,16 @@ def _ensure_artifact_registry(artifact_project, artifact_region, artifact_reposi
         ) from exc
 
     describe_cmd = (
-        "gcloud artifacts repositories describe {repo} --project {project} "
+        f"gcloud artifacts repositories describe {artifact_repository} --project {artifact_project} "
-        "--location {location} --quiet"
+        f"--location {artifact_region} --quiet"
-    ).format(
-        repo=artifact_repository,
-        project=artifact_project,
-        location=artifact_region,
     )
     try:
         check_call(describe_cmd, shell=True)
         return
     except CalledProcessError:
         create_cmd = (
-            "gcloud artifacts repositories create {repo} --repository-format=docker "
+            f"gcloud artifacts repositories create {artifact_repository} --repository-format=docker "
-            '--location {location} --project {project} --description "Datasette Cloud Run images" --quiet'
+            f'--location {artifact_region} --project {artifact_project} --description "Datasette Cloud Run images" --quiet'
-        ).format(
-            repo=artifact_repository,
-            location=artifact_region,
-            project=artifact_project,
         )
         try:
             check_call(create_cmd, shell=True)

datasette/publish/common.py

@@ -1,9 +1,11 @@
-from ..utils import StaticMount
-import click
 import os
 import shutil
 import sys
 
+import click
+
+from ..utils import StaticMount
+
 
 def add_common_publish_arguments_and_options(subcommand):
     for decorator in reversed(
@@ -76,9 +78,7 @@ def fail_if_publish_binary_not_installed(binary, publish_target, install_link):
     """Exit (with error message) if ``binary` isn't installed"""
     if not shutil.which(binary):
         click.secho(
-            "Publishing to {publish_target} requires {binary} to be installed and configured".format(
+            f"Publishing to {publish_target} requires {binary} to be installed and configured",
-                publish_target=publish_target, binary=binary
-            ),
             bg="red",
             fg="white",
             bold=True,

datasette/publish/heroku.py

@@ -1,19 +1,21 @@
-from contextlib import contextmanager
-from datasette import hookimpl
-import click
 import json
 import os
 import pathlib
 import shlex
 import shutil
-from subprocess import call, check_output
 import tempfile
+from contextlib import contextmanager
+from subprocess import call, check_output
+
+import click
+
+from datasette import hookimpl
+from datasette.utils import link_or_copy, link_or_copy_directory, parse_metadata
 
 from .common import (
     add_common_publish_arguments_and_options,
     fail_if_publish_binary_not_installed,
 )
-from datasette.utils import link_or_copy, link_or_copy_directory, parse_metadata
 
 
 @hookimpl
@@ -234,7 +236,7 @@ def temporary_heroku_directory(
             extras.extend(["--static", f"{mount_point}:{mount_point}"])
 
         quoted_files = " ".join(
-            ["-i {}".format(shlex.quote(file_name)) for file_name in file_names]
+            [f"-i {shlex.quote(file_name)}" for file_name in file_names]
         )
         procfile_cmd = "web: datasette serve --host 0.0.0.0 {quoted_files} --cors --port $PORT --inspect-file inspect-data.json {extras}".format(
             quoted_files=quoted_files, extras=" ".join(extras)

datasette/renderer.py

@@ -1,12 +1,13 @@
 import json
+
 from datasette.extras import extra_names_from_request
 from datasette.utils import (
-    error_body,
-    value_as_boolean,
-    remove_infinites,
     CustomJSONEncoder,
+    error_body,
     path_from_row_pks,
+    remove_infinites,
     sqlite3,
+    value_as_boolean,
 )
 from datasette.utils.asgi import Response
 

datasette/static/app.css

@@ -497,10 +497,7 @@ table.rows-and-columns td em {
     color: #aaa;
 }
 table.rows-and-columns th {
-    background: #F8FAFB;
     padding-right: 1em;
-    position: relative;
-    z-index: 1;
 }
 table.rows-and-columns a:link {
     text-decoration: none;

datasette/static/table.js

@@ -506,45 +506,6 @@ function renderActionLink(itemConfig) {
   return newLink;
 }
 
-function initializeStickyTableHeader(tableWrapper) {
-  var table = tableWrapper.querySelector("table.rows-and-columns");
-  var tableHead = table && table.querySelector("thead");
-  if (!tableHead || !window.requestAnimationFrame) {
-    return;
-  }
-
-  var animationFrame = null;
-  function updatePosition() {
-    animationFrame = null;
-    if (window.matchMedia("(max-width: 576px)").matches) {
-      tableHead.style.transform = "";
-      return;
-    }
-    // overflow-x: auto makes tableWrapper the sticky scroll container, even
-    // though the page handles vertical scrolling. Counter the page scroll so
-    // the real header stays aligned with both the viewport and the table.
-    var wrapperTop = tableWrapper.getBoundingClientRect().top;
-    var maximumOffset = Math.max(
-      0,
-      table.offsetHeight - tableHead.offsetHeight,
-    );
-    var offset = Math.min(Math.max(-wrapperTop, 0), maximumOffset);
-    tableHead.style.transform = offset
-      ? `translateY(${offset}px)`
-      : "";
-  }
-
-  function queuePositionUpdate() {
-    if (animationFrame === null) {
-      animationFrame = window.requestAnimationFrame(updatePosition);
-    }
-  }
-
-  window.addEventListener("scroll", queuePositionUpdate, { passive: true });
-  window.addEventListener("resize", queuePositionUpdate);
-  queuePositionUpdate();
-}
-
 /** Main initialization function for Datasette Table interactions */
 const initDatasetteTable = function (manager) {
   // Feature detection
@@ -560,7 +521,6 @@ const initDatasetteTable = function (manager) {
   if (tableWrapper) {
     tableWrapper.addEventListener("scroll", closeMenu);
   }
-  window.addEventListener("scroll", closeMenu, { passive: true });
   document.body.addEventListener("click", (ev) => {
     /* was this click outside the menu? */
     var target = ev.target;
@@ -671,9 +631,6 @@ const initDatasetteTable = function (manager) {
     icon.addEventListener("click", onTableHeaderClick);
     th.appendChild(icon);
   });
-  if (tableWrapper) {
-    initializeStickyTableHeader(tableWrapper);
-  }
 };
 
 function filterRowSelector(manager) {

datasette/stored_queries.py

@@ -1,8 +1,9 @@
 from __future__ import annotations
 
-from dataclasses import dataclass
 import json
-from typing import Any, Iterable
+from collections.abc import Iterable
+from dataclasses import dataclass
+from typing import Any
 
 from .utils import tilde_encode, urlsafe_components
 
@@ -386,7 +387,7 @@ async def count_queries(
                 OR q.sql LIKE :query_search
             )
             """)
-        params["query_search"] = "%{}%".format(q)
+        params["query_search"] = f"%{q}%"
     if is_write is not None:
         where_clauses.append("q.is_write = :query_is_write")
         params["query_is_write"] = int(bool(is_write))
@@ -462,7 +463,7 @@ async def list_queries(
         except ValueError:
             components = []
         if database is None and len(components) == 3:
-            where_clauses.append("""
+            where_clauses.append(f"""
                 (
                     q.database_name > :cursor_database
                     OR (
@@ -476,12 +477,12 @@ async def list_queries(
                         )
                     )
                 )
-                """.format(sort_key_sql=sort_key_sql))
+                """)
             params["cursor_database"] = components[0]
             params["cursor_sort_key"] = components[1]
             params["cursor_name"] = components[2]
         elif database is not None and len(components) == 2:
-            where_clauses.append("""
+            where_clauses.append(f"""
                 (
                     {sort_key_sql} > :cursor_sort_key
                     OR (
@@ -489,7 +490,7 @@ async def list_queries(
                         AND q.name > :cursor_name
                     )
                 )
-                """.format(sort_key_sql=sort_key_sql))
+                """)
             params["cursor_sort_key"] = components[0]
             params["cursor_name"] = components[1]
 
@@ -502,7 +503,7 @@ async def list_queries(
                 OR q.sql LIKE :query_search
             )
             """)
-        params["query_search"] = "%{}%".format(q)
+        params["query_search"] = f"%{q}%"
     if is_write is not None:
         where_clauses.append("q.is_write = :query_is_write")
         params["query_is_write"] = int(bool(is_write))

datasette/templates/_permission_ui_styles.html

@@ -6,8 +6,20 @@
     padding: 1.5em;
     margin-bottom: 2em;
 }
+.permission-form form {
+    max-width: 60rem;
+}
+.permission-form-grid {
+    display: grid;
+    gap: 1.5rem;
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+}
+.permission-form-result {
+    margin-top: 1rem;
+    max-width: 60rem;
+}
 .form-section {
-    margin-bottom: 1em;
+    margin-bottom: 1.25em;
 }
 .form-section label {
     display: block;
@@ -15,22 +27,51 @@
     font-weight: bold;
 }
 .form-section input[type="text"],
-.form-section select {
+.form-section input[type="number"],
-    width: 100%;
+.form-section select,
-    max-width: 500px;
+.permission-textarea {
-    padding: 0.5em;
+    background-color: #fff;
+    border: 1px solid #aaa;
+    border-radius: 4px;
     box-sizing: border-box;
-    border: 1px solid #ccc;
+    box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.08);
-    border-radius: 3px;
+    color: #222;
+    font-family: inherit;
+    font-size: 1rem;
+    line-height: 1.4;
+    max-width: none;
+    width: 100%;
+}
+.form-section input[type="text"] {
+    height: 3rem;
+    padding: 0.6rem 0.75rem;
+}
+.form-section input[type="number"] {
+    height: 3rem;
+    max-width: 7rem;
+    padding: 0.6rem 0.75rem;
+}
+.form-section select {
+    height: 3rem;
+    padding: 0.6rem 0.75rem;
+}
+.permission-textarea {
+    font-family: monospace;
+    min-height: 12rem;
+    padding: 0.75rem;
+    resize: vertical;
 }
 .form-section input[type="text"]:focus,
-.form-section select:focus {
+.form-section input[type="number"]:focus,
-    outline: 2px solid #0066cc;
+.form-section select:focus,
+.permission-textarea:focus {
     border-color: #0066cc;
+    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.18);
+    outline: none;
 }
 .form-section small {
     display: block;
-    margin-top: 0.3em;
+    margin-top: 0.45em;
     color: #666;
 }
 .form-actions {
@@ -142,4 +183,9 @@
     text-align: center;
     color: #666;
 }
+@media only screen and (max-width: 576px) {
+    .permission-form-grid {
+        grid-template-columns: minmax(0, 1fr);
+    }
+}
 </style>

datasette/templates/_permissions_debug_tabs.html

@@ -44,10 +44,10 @@
 </style>
 
 <nav class="permissions-debug-tabs">
-    <a href="{{ urls.path('-/permissions') }}" {% if current_tab == "permissions" %}class="active"{% endif %}>Playground</a>
+    <a href="{{ urls.path('-/check') }}{{ query_string }}" {% if current_tab == "check" %}class="active"{% endif %}>Explain</a>
-    <a href="{{ urls.path('-/check') }}{{ query_string }}" {% if current_tab == "check" %}class="active"{% endif %}>Check</a>
+    <a href="{{ urls.path('-/allowed') }}{{ query_string }}" {% if current_tab == "allowed" %}class="active"{% endif %}>Access map</a>
-    <a href="{{ urls.path('-/allowed') }}{{ query_string }}" {% if current_tab == "allowed" %}class="active"{% endif %}>Allowed</a>
+    <a href="{{ urls.path('-/rules') }}{{ query_string }}" {% if current_tab == "rules" %}class="active"{% endif %}>Rule explorer</a>
-    <a href="{{ urls.path('-/rules') }}{{ query_string }}" {% if current_tab == "rules" %}class="active"{% endif %}>Rules</a>
+    <a href="{{ urls.path('-/permissions') }}" {% if current_tab == "permissions" %}class="active"{% endif %}>Activity</a>
     <a href="{{ urls.path('-/actions') }}" {% if current_tab == "actions" %}class="active"{% endif %}>Actions</a>
     <a href="{{ urls.path('-/allow-debug') }}" {% if current_tab == "allow_debug" %}class="active"{% endif %}>Allow debug</a>
 </nav>

datasette/templates/allow_debug.html

@@ -3,29 +3,11 @@
 {% block title %}Debug allow rules{% endblock %}
 
 {% block extra_head %}
+{% include "_permission_ui_styles.html" %}
 <style>
-textarea {
-    height: 10em;
-    width: 95%;
-    box-sizing: border-box;
-    padding: 0.5em;
-    border: 2px dotted black;
-}
-.two-col {
-    display: inline-block;
-    width: 48%;
-}
-.two-col label {
-    width: 48%;
-}
 p.message-warning {
     white-space: pre-wrap;
 }
-@media only screen and (max-width: 576px) {
-    .two-col {
-        width: 100%;
-    }
-}
 </style>
 {% endblock %}
 
@@ -38,24 +20,28 @@ p.message-warning {
 
 <p>Use this tool to try out different actor and allow combinations. See <a href="https://docs.datasette.io/en/stable/authentication.html#defining-permissions-with-allow-blocks">Defining permissions with "allow" blocks</a> for documentation.</p>
 
-<form class="core" action="{{ urls.path('-/allow-debug') }}" method="get" style="margin-bottom: 1em">
+<div class="permission-form">
-    <div class="two-col">
+    <form class="core" action="{{ urls.path('-/allow-debug') }}" method="get">
-        <p><label>Allow block</label></p>
+        <div class="permission-form-grid">
-        <textarea name="allow">{{ allow_input }}</textarea>
+            <div class="form-section">
-    </div>
+                <label for="allow-block">Allow block</label>
-    <div class="two-col">
+                <textarea class="permission-textarea" id="allow-block" name="allow">{{ allow_input }}</textarea>
-        <p><label>Actor</label></p>
+            </div>
-        <textarea name="actor">{{ actor_input }}</textarea>
+            <div class="form-section">
-    </div>
+                <label for="allow-actor">Actor</label>
-    <div style="margin-top: 1em;">
+                <textarea class="permission-textarea" id="allow-actor" name="actor">{{ actor_input }}</textarea>
-        <input type="submit" value="Apply allow block to actor">
+            </div>
-    </div>
+        </div>
-</form>
+        <div class="form-actions">
+            <button type="submit" class="submit-btn">Apply allow block to actor</button>
+        </div>
+    </form>
 
-{% if error %}<p class="message-warning">{{ error }}</p>{% endif %}
+    {% if error %}<p class="message-warning permission-form-result">{{ error }}</p>{% endif %}
 
-{% if result == "True" %}<p class="message-info">Result: allow</p>{% endif %}
+    {% if result == "True" %}<p class="message-info permission-form-result">Result: allow</p>{% endif %}
 
-{% if result == "False" %}<p class="message-error">Result: deny</p>{% endif %}
+    {% if result == "False" %}<p class="message-error permission-form-result">Result: deny</p>{% endif %}
+</div>
 
 {% endblock %}

datasette/templates/debug_allowed.html

@@ -49,7 +49,7 @@
 
         <div class="form-section">
             <label for="page_size">Page size:</label>
-            <input type="number" id="page_size" name="_size" value="50" min="1" max="200" style="max-width: 100px;">
+            <input type="number" id="page_size" name="_size" value="50" min="1" max="200">
             <small>Number of results per page (max 200)</small>
         </div>
 

datasette/templates/debug_check.html

@@ -1,6 +1,6 @@
 {% extends "base.html" %}
 
-{% block title %}Permission Check{% endblock %}
+{% block title %}Explain a permission decision{% endblock %}
 
 {% block extra_head %}
 <script src="{{ static('json-format-highlight-1.0.1.js') }}"></script>
@@ -13,29 +13,35 @@
     border-radius: 5px;
 }
 #output.allowed {
-    background-color: #e8f5e9;
+    background-color: #f3fbf4;
     border: 2px solid #4caf50;
 }
 #output.denied {
-    background-color: #ffebee;
+    background-color: #fff7f7;
     border: 2px solid #f44336;
 }
 #output h2 {
     margin-top: 0;
 }
-#output .result-badge {
+#output h3 {
+    margin-bottom: 0.5em;
+}
+#output .result-badge,
+.effect-badge,
+.rule-status {
     display: inline-block;
-    padding: 0.3em 0.8em;
+    padding: 0.2em 0.5em;
     border-radius: 3px;
     font-weight: bold;
-    font-size: 1.1em;
 }
-#output .allowed-badge {
+#output .allowed-badge,
-    background-color: #4caf50;
+.effect-allow {
+    background-color: #2e7d32;
     color: white;
 }
-#output .denied-badge {
+#output .denied-badge,
-    background-color: #f44336;
+.effect-deny {
+    background-color: #c62828;
     color: white;
 }
 .details-section {
@@ -48,70 +54,130 @@
 .details-section dd {
     margin-left: 1em;
 }
+.explanation-section {
+    background: rgba(255, 255, 255, 0.75);
+    border: 1px solid #ddd;
+    border-radius: 4px;
+    margin-top: 1em;
+    padding: 0 1em 1em;
+}
+.rules-table {
+    border-collapse: collapse;
+    width: 100%;
+}
+.rules-table th,
+.rules-table td {
+    border-bottom: 1px solid #ddd;
+    padding: 0.5em;
+    text-align: left;
+    vertical-align: top;
+}
+.rule-status {
+    background: #e8f5e9;
+    color: #1b5e20;
+}
+.rule-ignored {
+    background: #eee;
+    color: #555;
+    font-weight: normal;
+}
+.requirement-allowed {
+    color: #1b5e20;
+}
+.requirement-denied {
+    color: #b71c1c;
+}
+@media only screen and (max-width: 576px) {
+    .rules-table,
+    .rules-table tbody,
+    .rules-table tr,
+    .rules-table td {
+        display: block;
+    }
+    .rules-table thead {
+        display: none;
+    }
+    .rules-table td::before {
+        content: attr(data-label) ": ";
+        font-weight: bold;
+    }
+}
 </style>
 {% endblock %}
 
 {% block content %}
-<h1>Permission check</h1>
+<h1>Explain a permission decision</h1>
 
 {% set current_tab = "check" %}
 {% include "_permissions_debug_tabs.html" %}
 
-<p>Use this tool to test permission checks for the current actor. It queries the <code>/-/check.json</code> API endpoint.</p>
+<p>Test an actor, action and resource. The result explains which rules matched, which specificity level won, and whether actor restrictions or required actions changed the verdict.</p>
-
-{% if request.actor %}
-<p>Current actor: <strong>{{ request.actor.get("id", "anonymous") }}</strong></p>
-{% else %}
-<p>Current actor: <strong>anonymous (not logged in)</strong></p>
-{% endif %}
 
 <div class="permission-form">
-    <form id="check-form" method="get" action="{{ urls.path("-/check") }}">
+    <form id="check-form" method="get" action="{{ urls.path('-/check') }}">
         <div class="form-section">
-            <label for="action">Action (permission name):</label>
+            <label for="actor">Actor JSON:</label>
+            <textarea class="permission-textarea" id="actor" name="actor">{{ actor_json }}</textarea>
+            <small>Use <code>null</code> for an anonymous actor. This actor is simulated; it does not change who you are signed in as.</small>
+        </div>
+
+        <div class="form-section">
+            <label for="action">Action:</label>
             <select id="action" name="action" required>
                 <option value="">Select an action...</option>
-                {% for action_name in sorted_actions %}
+                {% for action in actions %}
-                <option value="{{ action_name }}">{{ action_name }}</option>
+                <option value="{{ action.name }}">{{ action.name }}{% if action.description %} — {{ action.description }}{% endif %}</option>
                 {% endfor %}
             </select>
-            <small>The permission action to check</small>
+            <small id="action-help">The operation to evaluate</small>
         </div>
 
-        <div class="form-section">
+        <div class="form-section" id="parent-section">
-            <label for="parent">Parent resource (optional):</label>
+            <label for="parent">Parent resource:</label>
             <input type="text" id="parent" name="parent" placeholder="e.g., database name">
-            <small>For database-level permissions, specify the database name</small>
+            <small>The database or other parent resource</small>
         </div>
 
-        <div class="form-section">
+        <div class="form-section" id="child-section">
-            <label for="child">Child resource (optional):</label>
+            <label for="child">Child resource:</label>
-            <input type="text" id="child" name="child" placeholder="e.g., table name">
+            <input type="text" id="child" name="child" placeholder="e.g., table or query name">
-            <small>For table-level permissions, specify the table name (requires parent)</small>
+            <small>The table, query or other child resource</small>
         </div>
 
         <div class="form-actions">
-            <button type="submit" class="submit-btn" id="submit-btn">Check Permission</button>
+            <button type="submit" class="submit-btn" id="submit-btn">Explain decision</button>
         </div>
     </form>
 </div>
 
 <div id="output" style="display: none;">
     <h2>Result: <span class="result-badge" id="result-badge"></span></h2>
+    <p id="result-summary"></p>
 
     <dl class="details-section">
+        <dt>Actor:</dt>
+        <dd><code id="result-actor"></code></dd>
         <dt>Action:</dt>
-        <dd id="result-action"></dd>
+        <dd><code id="result-action"></code></dd>
-
+        <dt>Resource:</dt>
-        <dt>Resource Path:</dt>
+        <dd><code id="result-resource"></code></dd>
-        <dd id="result-resource"></dd>
-
-        <dt>Actor ID:</dt>
-        <dd id="result-actor"></dd>
-
-        <div id="additional-details"></div>
     </dl>
 
+    <section class="explanation-section">
+        <h3>Matching rules</h3>
+        <div id="matching-rules"></div>
+    </section>
+
+    <section class="explanation-section" id="restrictions-section">
+        <h3>Actor restrictions</h3>
+        <div id="restriction-results"></div>
+    </section>
+
+    <section class="explanation-section" id="requirements-section">
+        <h3>Required actions</h3>
+        <div id="requirement-results"></div>
+    </section>
+
     <details style="margin-top: 1em;">
         <summary style="cursor: pointer; font-weight: bold;">Raw JSON response</summary>
         <pre id="raw-json" style="margin-top: 1em; padding: 1em; background-color: #f5f5f5; border: 1px solid #ddd; border-radius: 3px; overflow-x: auto;"></pre>
@@ -119,152 +185,134 @@
 </div>
 
 <script>
+const actions = Object.fromEntries({{ actions|tojson }}.map(action => [action.name, action]));
 const form = document.getElementById('check-form');
 const output = document.getElementById('output');
 const submitBtn = document.getElementById('submit-btn');
+const actionSelect = document.getElementById('action');
+
+function updateResourceFields() {
+    const action = actions[actionSelect.value];
+    document.getElementById('parent-section').style.display = action && action.takes_parent ? 'block' : 'none';
+    document.getElementById('child-section').style.display = action && action.takes_child ? 'block' : 'none';
+    let help = action && action.description ? action.description : 'The operation to evaluate';
+    if (action && action.also_requires) {
+        help += `; also requires ${action.also_requires}`;
+    }
+    document.getElementById('action-help').textContent = help;
+}
 
 async function performCheck() {
     submitBtn.disabled = true;
-    submitBtn.textContent = 'Checking...';
+    submitBtn.textContent = 'Explaining...';
-
+    const params = new URLSearchParams(new FormData(form));
-    const formData = new FormData(form);
-    const params = new URLSearchParams();
-
-    for (const [key, value] of formData.entries()) {
-        if (value) {
-            params.append(key, value);
-        }
-    }
 
     try {
         const response = await fetch('{{ urls.path("-/check.json") }}?' + params.toString(), {
-            method: 'GET',
+            headers: {'Accept': 'application/json'}
-            headers: {
-                'Accept': 'application/json',
-            }
         });
-
         const data = await response.json();
-
         if (response.ok) {
             displayResult(data);
         } else {
             displayError(data);
         }
     } catch (error) {
-        alert('Error: ' + error.message);
+        displayError({error: error.message});
     } finally {
         submitBtn.disabled = false;
-        submitBtn.textContent = 'Check Permission';
+        submitBtn.textContent = 'Explain decision';
     }
 }
 
-// Populate form on initial load
-(function() {
-    const params = populateFormFromURL();
-    const action = params.get('action');
-    if (action) {
-        performCheck();
-    }
-})();
-
 function displayResult(data) {
     output.style.display = 'block';
-
-    // Set badge and styling
     const resultBadge = document.getElementById('result-badge');
-    if (data.allowed) {
+    output.className = data.allowed ? 'allowed' : 'denied';
-        output.className = 'allowed';
+    resultBadge.className = `result-badge ${data.allowed ? 'allowed-badge' : 'denied-badge'}`;
-        resultBadge.className = 'result-badge allowed-badge';
+    resultBadge.textContent = data.allowed ? 'ALLOWED ✓' : 'DENIED ✗';
-        resultBadge.textContent = 'ALLOWED ✓';
+    document.getElementById('result-summary').textContent = data.explanation.summary;
-    } else {
+    document.getElementById('result-actor').textContent = data.actor === null ? 'anonymous' : JSON.stringify(data.actor);
-        output.className = 'denied';
+    document.getElementById('result-action').textContent = data.action;
-        resultBadge.className = 'result-badge denied-badge';
+    document.getElementById('result-resource').textContent = data.resource.path;
-        resultBadge.textContent = 'DENIED ✗';
+    displayRules(data.explanation);
-    }
+    displayRestrictions(data.explanation.restrictions);
-
+    displayRequirements(data.explanation.required_actions);
-    // Basic details
-    document.getElementById('result-action').textContent = data.action || 'N/A';
-    document.getElementById('result-resource').textContent = data.resource?.path || '/';
-    document.getElementById('result-actor').textContent = data.actor_id || 'anonymous';
-
-    // Additional details
-    const additionalDetails = document.getElementById('additional-details');
-    additionalDetails.innerHTML = '';
-
-    if (data.reason !== undefined) {
-        const dt = document.createElement('dt');
-        dt.textContent = 'Reason:';
-        const dd = document.createElement('dd');
-        dd.textContent = data.reason || 'N/A';
-        additionalDetails.appendChild(dt);
-        additionalDetails.appendChild(dd);
-    }
-
-    if (data.source_plugin !== undefined) {
-        const dt = document.createElement('dt');
-        dt.textContent = 'Source Plugin:';
-        const dd = document.createElement('dd');
-        dd.textContent = data.source_plugin || 'N/A';
-        additionalDetails.appendChild(dt);
-        additionalDetails.appendChild(dd);
-    }
-
-    if (data.used_default !== undefined) {
-        const dt = document.createElement('dt');
-        dt.textContent = 'Used Default:';
-        const dd = document.createElement('dd');
-        dd.textContent = data.used_default ? 'Yes' : 'No';
-        additionalDetails.appendChild(dt);
-        additionalDetails.appendChild(dd);
-    }
-
-    if (data.depth !== undefined) {
-        const dt = document.createElement('dt');
-        dt.textContent = 'Depth:';
-        const dd = document.createElement('dd');
-        dd.textContent = data.depth;
-        additionalDetails.appendChild(dt);
-        additionalDetails.appendChild(dd);
-    }
-
-    // Raw JSON
     document.getElementById('raw-json').innerHTML = jsonFormatHighlight(data);
+}
 
-    // Scroll to output
+function displayRules(explanation) {
-    output.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
+    const container = document.getElementById('matching-rules');
+    if (!explanation.matched_rules.length) {
+        container.innerHTML = '<p>No rules matched. Datasette denies access when there is no matching rule.</p>';
+        return;
+    }
+    let html = '<table class="rules-table"><thead><tr><th>Effect</th><th>Scope</th><th>Source</th><th>Reason</th><th>Role in decision</th></tr></thead><tbody>';
+    for (const rule of explanation.matched_rules) {
+        const status = rule.decisive
+            ? '<span class="rule-status">Decisive</span>'
+            : `<span class="rule-status rule-ignored">${escapeHtml(rule.ignored_because)}</span>`;
+        html += '<tr>';
+        html += `<td data-label="Effect"><span class="effect-badge effect-${rule.effect}">${rule.effect.toUpperCase()}</span></td>`;
+        html += `<td data-label="Scope">${escapeHtml(rule.scope)}</td>`;
+        html += `<td data-label="Source"><code>${escapeHtml(rule.source || 'unknown')}</code></td>`;
+        html += `<td data-label="Reason">${escapeHtml(rule.reason || 'No reason supplied')}</td>`;
+        html += `<td data-label="Role in decision">${status}</td>`;
+        html += '</tr>';
+    }
+    container.innerHTML = html + '</tbody></table>';
+}
+
+function displayRestrictions(restrictions) {
+    const section = document.getElementById('restrictions-section');
+    const container = document.getElementById('restriction-results');
+    section.style.display = restrictions.length ? 'block' : 'none';
+    container.innerHTML = restrictions.map(restriction => {
+        const className = restriction.allowed ? 'requirement-allowed' : 'requirement-denied';
+        const verdict = restriction.allowed ? 'INCLUDED ✓' : 'EXCLUDED ✗';
+        return `<p class="${className}"><strong>${verdict}</strong> by <code>${escapeHtml(restriction.source || 'unknown')}</code>: ${escapeHtml(restriction.reason)}</p>`;
+    }).join('');
+}
+
+function displayRequirements(requirements) {
+    const section = document.getElementById('requirements-section');
+    const container = document.getElementById('requirement-results');
+    section.style.display = requirements.length ? 'block' : 'none';
+    container.innerHTML = requirements.map(requirement => {
+        const className = requirement.allowed ? 'requirement-allowed' : 'requirement-denied';
+        const verdict = requirement.allowed ? 'ALLOWED ✓' : 'DENIED ✗';
+        return `<p class="${className}"><strong>${escapeHtml(requirement.action)}: ${verdict}</strong> — ${escapeHtml(requirement.summary)}</p>`;
+    }).join('');
 }
 
 function displayError(data) {
     output.style.display = 'block';
     output.className = 'denied';
-
     const resultBadge = document.getElementById('result-badge');
     resultBadge.className = 'result-badge denied-badge';
     resultBadge.textContent = 'ERROR';
-
+    document.getElementById('result-summary').textContent = data.error || 'Unknown error';
-    document.getElementById('result-action').textContent = 'N/A';
+    document.getElementById('result-actor').textContent = '—';
-    document.getElementById('result-resource').textContent = 'N/A';
+    document.getElementById('result-action').textContent = '—';
-    document.getElementById('result-actor').textContent = 'N/A';
+    document.getElementById('result-resource').textContent = '—';
-
+    document.getElementById('matching-rules').innerHTML = '';
-    const additionalDetails = document.getElementById('additional-details');
+    document.getElementById('restrictions-section').style.display = 'none';
-    additionalDetails.innerHTML = '<dt>Error:</dt><dd>' + (data.error || 'Unknown error') + '</dd>';
+    document.getElementById('requirements-section').style.display = 'none';
-
     document.getElementById('raw-json').innerHTML = jsonFormatHighlight(data);
-
-    output.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
 }
 
-// Disable child input if parent is empty
+form.addEventListener('submit', event => {
-const parentInput = document.getElementById('parent');
+    event.preventDefault();
-const childInput = document.getElementById('child');
+    performCheck();
-
-childInput.addEventListener('focus', () => {
-    if (!parentInput.value) {
-        alert('Please specify a parent resource first before adding a child resource.');
-        parentInput.focus();
-    }
 });
-</script>
+actionSelect.addEventListener('change', updateResourceFields);
 
+(function initializeFromUrl() {
+    const params = populateFormFromURL();
+    updateResourceFields();
+    if (params.get('action')) {
+        performCheck();
+    }
+})();
+</script>
 {% endblock %}

datasette/templates/debug_permissions_playground.html

@@ -1,6 +1,6 @@
 {% extends "base.html" %}
 
-{% block title %}Debug permissions{% endblock %}
+{% block title %}Permission activity{% endblock %}
 
 {% block extra_head %}
 {% include "_permission_ui_styles.html" %}
@@ -20,60 +20,45 @@
 .check-action, .check-when, .check-result {
     font-size: 1.3em;
 }
-textarea {
-    height: 10em;
-    width: 95%;
-    box-sizing: border-box;
-    padding: 0.5em;
-    border: 2px dotted black;
-}
-.two-col {
-    display: inline-block;
-    width: 48%;
-}
-.two-col label {
-    width: 48%;
-}
-@media only screen and (max-width: 576px) {
-    .two-col {
-        width: 100%;
-    }
-}
 </style>
 {% endblock %}
 
 {% block content %}
-<h1>Permission playground</h1>
+<h1>Permission activity</h1>
 
 {% set current_tab = "permissions" %}
 {% include "_permissions_debug_tabs.html" %}
 
-<p>This tool lets you simulate an actor and a permission check for that actor.</p>
+<h2>Raw simulator</h2>
+
+<p>This form runs a hypothetical permission check and returns its raw explanation JSON. Use the <a href="{{ urls.path('-/check') }}">Explain tool</a> for a visual explanation of the same decision.</p>
 
 <div class="permission-form">
     <form action="{{ urls.path('-/permissions') }}" id="debug-post" method="post">
-        <div class="two-col">
+        <div class="permission-form-grid">
-            <div class="form-section">
+            <div>
-                <label>Actor</label>
+                <div class="form-section">
-                <textarea name="actor">{% if actor_input %}{{ actor_input }}{% else %}{"id": "root"}{% endif %}</textarea>
+                    <label for="activity-actor">Actor</label>
+                    <textarea class="permission-textarea" id="activity-actor" name="actor">{% if actor_input %}{{ actor_input }}{% else %}{"id": "root"}{% endif %}</textarea>
+                </div>
             </div>
-        </div>
+            <div>
-        <div class="two-col" style="vertical-align: top">
+                <div class="form-section">
-            <div class="form-section">
+                    <label for="permission">Action</label>
-                <label for="permission">Action</label>
+                    <select name="permission" id="permission">
-                <select name="permission" id="permission">
+                        {% for permission in permissions %}
-                    {% for permission in permissions %}
+                            <option value="{{ permission.name }}">{{ permission.name }}</option>
-                        <option value="{{ permission.name }}">{{ permission.name }}</option>
+                        {% endfor %}
-                    {% endfor %}
+                    </select>
-                </select>
+                </div>
-            </div>
+                <div class="form-section">
-            <div class="form-section">
+                    <label for="resource_1">Parent</label>
-                <label for="resource_1">Parent</label>
+                    <input type="text" id="resource_1" name="resource_1" placeholder="e.g., database name">
-                <input type="text" id="resource_1" name="resource_1" placeholder="e.g., database name">
+                </div>
-            </div>
+                <div class="form-section">
-            <div class="form-section">
+                    <label for="resource_2">Child</label>
-                <label for="resource_2">Child</label>
+                    <input type="text" id="resource_2" name="resource_2" placeholder="e.g., table name">
-                <input type="text" id="resource_2" name="resource_2" placeholder="e.g., table name">
+                </div>
             </div>
         </div>
         <div class="form-actions">
@@ -125,7 +110,7 @@ debugPost.addEventListener('submit', function(ev) {
 });
 </script>
 
-<h1>Recent permissions checks</h1>
+<h2>Recent permission checks</h2>
 
 <p>
     {% if filter != "all" %}<a href="?filter=all">All</a>{% else %}<strong>All</strong>{% endif %},

datasette/templates/debug_rules.html

@@ -37,7 +37,7 @@
 
         <div class="form-section">
             <label for="page_size">Page size:</label>
-            <input type="number" id="page_size" name="_size" value="50" min="1" max="200" style="max-width: 100px;">
+            <input type="number" id="page_size" name="_size" value="50" min="1" max="200">
             <small>Number of results per page (max 200)</small>
         </div>
 

datasette/tokens.py

@@ -10,7 +10,7 @@ from __future__ import annotations
 
 import dataclasses
 import time
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING
 
 import itsdangerous
 
@@ -50,24 +50,24 @@ class TokenRestrictions:
     database: dict[str, list[str]] = dataclasses.field(default_factory=dict)
     resource: dict[str, dict[str, list[str]]] = dataclasses.field(default_factory=dict)
 
-    def allow_all(self, action: str) -> "TokenRestrictions":
+    def allow_all(self, action: str) -> TokenRestrictions:
         """Allow an action across all databases and resources."""
         self.all.append(action)
         return self
 
-    def allow_database(self, database: str, action: str) -> "TokenRestrictions":
+    def allow_database(self, database: str, action: str) -> TokenRestrictions:
         """Allow an action on a specific database."""
         self.database.setdefault(database, []).append(action)
         return self
 
     def allow_resource(
         self, database: str, resource: str, action: str
-    ) -> "TokenRestrictions":
+    ) -> TokenRestrictions:
         """Allow an action on a specific resource within a database."""
         self.resource.setdefault(database, {}).setdefault(resource, []).append(action)
         return self
 
-    def abbreviated(self, datasette: "Datasette") -> Optional[dict]:
+    def abbreviated(self, datasette: Datasette) -> dict | None:
         """
         Return the abbreviated ``_r`` dictionary shape for this set of
         restrictions, using action abbreviations registered with ``datasette``.
@@ -112,16 +112,16 @@ class TokenHandler:
 
     async def create_token(
         self,
-        datasette: "Datasette",
+        datasette: Datasette,
         actor_id: str,
         *,
-        expires_after: Optional[int] = None,
+        expires_after: int | None = None,
-        restrictions: Optional[TokenRestrictions] = None,
+        restrictions: TokenRestrictions | None = None,
     ) -> str:
         """Create and return a token string for the given actor."""
         raise NotImplementedError
 
-    async def verify_token(self, datasette: "Datasette", token: str) -> Optional[dict]:
+    async def verify_token(self, datasette: Datasette, token: str) -> dict | None:
         """
         Verify a token and return an actor dict.
 
@@ -142,11 +142,11 @@ class SignedTokenHandler(TokenHandler):
 
     async def create_token(
         self,
-        datasette: "Datasette",
+        datasette: Datasette,
         actor_id: str,
         *,
-        expires_after: Optional[int] = None,
+        expires_after: int | None = None,
-        restrictions: Optional[TokenRestrictions] = None,
+        restrictions: TokenRestrictions | None = None,
     ) -> str:
         if not datasette.setting("allow_signed_tokens"):
             raise ValueError(
@@ -163,7 +163,7 @@ class SignedTokenHandler(TokenHandler):
                 token["_r"] = abbreviated
         return "dstok_{}".format(datasette.sign(token, namespace="token"))
 
-    async def verify_token(self, datasette: "Datasette", token: str) -> Optional[dict]:
+    async def verify_token(self, datasette: Datasette, token: str) -> dict | None:
         prefix = "dstok_"
 
         if not token.startswith(prefix):
@@ -200,9 +200,8 @@ class SignedTokenHandler(TokenHandler):
         ):
             duration = max_signed_tokens_ttl
 
-        if duration:
+        if duration and time.time() - created > duration:
-            if time.time() - created > duration:
+            raise TokenInvalid("Token has expired")
-                raise TokenInvalid("Token has expired")
 
         actor = {"id": decoded["a"], "token": "dstok"}
 

datasette/tracer.py

@@ -1,10 +1,11 @@
 import asyncio
+import json
+import time
+import traceback
 from contextlib import contextmanager
 from contextvars import ContextVar
+
 from markupsafe import escape
-import time
-import json
-import traceback
 
 tracers = {}
 
@@ -132,17 +133,17 @@ class AsgiTracer:
                     "num_traces": len(traces),
                     "traces": traces,
                 }
-                try:
+                content_type = next(
-                    content_type = [
+                    (
                         v.decode("utf8")
                         for k, v in response_headers
                         if k.lower() == b"content-type"
-                    ][0]
+                    ),
-                except IndexError:
+                    "",
-                    content_type = ""
+                )
                 if "text/html" in content_type and b"</body>" in accumulated_body:
                     extra = escape(json.dumps(trace_info, indent=2))
-                    extra_html = f"<pre>{extra}</pre></body>".encode("utf8")
+                    extra_html = f"<pre>{extra}</pre></body>".encode()
                     accumulated_body = accumulated_body.replace(b"</body>", extra_html)
                 elif "json" in content_type and accumulated_body.startswith(b"{"):
                     data = json.loads(accumulated_body.decode("utf8"))

datasette/url_builder.py

@@ -1,6 +1,7 @@
-from .utils import tilde_encode, path_with_format, PrefixedUrlString
 import urllib
 
+from .utils import PrefixedUrlString, path_with_format, tilde_encode
+
 
 class Urls:
     def __init__(self, ds):
@@ -8,8 +9,7 @@ class Urls:
 
     def path(self, path, format=None):
         if not isinstance(path, PrefixedUrlString):
-            if path.startswith("/"):
+            path = path.removeprefix("/")
-                path = path[1:]
             path = self.ds.setting("base_url") + path
         if format is not None:
             path = path_with_format(path=path, format=format)
@@ -56,6 +56,7 @@ class Urls:
         return PrefixedUrlString(path)
 
     def row_blob(self, database, table, row_path, column):
-        return self.table(database, table) + "/{}.blob?_blob_column={}".format(
+        return (
-            row_path, urllib.parse.quote_plus(column)
+            self.table(database, table)
+            + f"/{row_path}.blob?_blob_column={urllib.parse.quote_plus(column)}"
         )

datasette/utils/__init__.py

@@ -1,29 +1,31 @@
 import asyncio
+import base64
 import binascii
-from contextlib import contextmanager
-import aiofiles
-import click
-from collections import OrderedDict, namedtuple, Counter
 import copy
 import dataclasses
-import base64
 import hashlib
 import inspect
 import json
-import markupsafe
-import mergedeep
 import os
 import re
+import secrets
 import shlex
+import shutil
 import tempfile
-import typing
 import time
 import types
-import secrets
+import typing
-import shutil
-from typing import Iterable, List, Tuple
 import urllib
+from collections import Counter, OrderedDict, namedtuple
+from collections.abc import Iterable
+from contextlib import contextmanager
+
+import aiofiles
+import click
+import markupsafe
+import mergedeep
 import yaml
+
 from .shutil_backport import copytree
 from .sqlite import sqlite3, supports_table_xinfo
 
@@ -36,7 +38,7 @@ if typing.TYPE_CHECKING:
 class PaginatedResources:
     """Paginated results from allowed_resources query."""
 
-    resources: List["Resource"]
+    resources: list["Resource"]
     next: str | None  # Keyset token for next page (None if no more results)
     _datasette: typing.Any = dataclasses.field(default=None, repr=False)
     _action: str = dataclasses.field(default=None, repr=False)
@@ -83,22 +85,132 @@ class PaginatedResources:
 
 
 # From https://www.sqlite.org/lang_keywords.html
-reserved_words = set(
+reserved_words = {
-    (
+    "abort",
-        "abort action add after all alter analyze and as asc attach autoincrement "
+    "action",
-        "before begin between by cascade case cast check collate column commit "
+    "add",
-        "conflict constraint create cross current_date current_time "
+    "after",
-        "current_timestamp database default deferrable deferred delete desc detach "
+    "all",
-        "distinct drop each else end escape except exclusive exists explain fail "
+    "alter",
-        "for foreign from full glob group having if ignore immediate in index "
+    "analyze",
-        "indexed initially inner insert instead intersect into is isnull join key "
+    "and",
-        "left like limit match natural no not notnull null of offset on or order "
+    "as",
-        "outer plan pragma primary query raise recursive references regexp reindex "
+    "asc",
-        "release rename replace restrict right rollback row savepoint select set "
+    "attach",
-        "table temp temporary then to transaction trigger union unique update using "
+    "autoincrement",
-        "vacuum values view virtual when where with without"
+    "before",
-    ).split()
+    "begin",
-)
+    "between",
+    "by",
+    "cascade",
+    "case",
+    "cast",
+    "check",
+    "collate",
+    "column",
+    "commit",
+    "conflict",
+    "constraint",
+    "create",
+    "cross",
+    "current_date",
+    "current_time",
+    "current_timestamp",
+    "database",
+    "default",
+    "deferrable",
+    "deferred",
+    "delete",
+    "desc",
+    "detach",
+    "distinct",
+    "drop",
+    "each",
+    "else",
+    "end",
+    "escape",
+    "except",
+    "exclusive",
+    "exists",
+    "explain",
+    "fail",
+    "for",
+    "foreign",
+    "from",
+    "full",
+    "glob",
+    "group",
+    "having",
+    "if",
+    "ignore",
+    "immediate",
+    "in",
+    "index",
+    "indexed",
+    "initially",
+    "inner",
+    "insert",
+    "instead",
+    "intersect",
+    "into",
+    "is",
+    "isnull",
+    "join",
+    "key",
+    "left",
+    "like",
+    "limit",
+    "match",
+    "natural",
+    "no",
+    "not",
+    "notnull",
+    "null",
+    "of",
+    "offset",
+    "on",
+    "or",
+    "order",
+    "outer",
+    "plan",
+    "pragma",
+    "primary",
+    "query",
+    "raise",
+    "recursive",
+    "references",
+    "regexp",
+    "reindex",
+    "release",
+    "rename",
+    "replace",
+    "restrict",
+    "right",
+    "rollback",
+    "row",
+    "savepoint",
+    "select",
+    "set",
+    "table",
+    "temp",
+    "temporary",
+    "then",
+    "to",
+    "transaction",
+    "trigger",
+    "union",
+    "unique",
+    "update",
+    "using",
+    "vacuum",
+    "values",
+    "view",
+    "virtual",
+    "when",
+    "where",
+    "with",
+    "without",
+}
 
 APT_GET_DOCKERFILE_EXTRAS = r"""
 RUN apt-get update && \
@@ -158,7 +270,7 @@ functions_marked_as_documented = []
 
 def documented(fn=None, *, label=None):
     def decorate(fn):
-        fn._datasette_docs_label = label or "internals_utils_{}".format(fn.__name__)
+        fn._datasette_docs_label = label or f"internals_utils_{fn.__name__}"
         functions_marked_as_documented.append(fn)
         return fn
 
@@ -360,7 +472,7 @@ disallawed_sql_res = [
     (
         re.compile(f"pragma(?!_({'|'.join(allowed_pragmas)}))"),
         "Statement contained a disallowed PRAGMA. Allowed pragma functions are {}".format(
-            ", ".join("pragma_{}()".format(pragma) for pragma in allowed_pragmas)
+            ", ".join(f"pragma_{pragma}()" for pragma in allowed_pragmas)
         ),
     )
 ]
@@ -534,10 +646,7 @@ CMD {cmd}""".format(
             else ""
         ),
         environment_variables="\n".join(
-            [
+            [f"ENV {key} '{value}'" for key, value in environment_variables.items()]
-                "ENV {} '{}'".format(key, value)
-                for key, value in environment_variables.items()
-            ]
         ),
         install_from=" ".join(install),
         files=" ".join(files),
@@ -636,11 +745,11 @@ def detect_primary_keys(conn, table):
 
 
 def get_outbound_foreign_keys(conn, table):
-    infos = conn.execute(f"PRAGMA foreign_key_list([{table}])").fetchall()
+    infos = conn.execute(f"PRAGMA foreign_key_list({escape_sqlite(table)})").fetchall()
     fks = []
     for info in infos:
         if info is not None:
-            id, seq, table_name, from_, to_, on_update, on_delete, match = info
+            id, seq, table_name, from_, to_, _on_update, _on_delete, _match = info
             fks.append(
                 {
                     "column": from_,
@@ -741,7 +850,7 @@ def detect_json1(conn=None):
     try:
         conn.execute("SELECT json('{}')")
         return True
-    except Exception:
+    except sqlite3.Error:
         return False
     finally:
         if close_conn:
@@ -821,9 +930,7 @@ def is_url(value):
     if not value.startswith("http://") and not value.startswith("https://"):
         return False
     # Any whitespace at all is invalid
-    if whitespace_re.search(value):
+    return not whitespace_re.search(value)
-        return False
-    return True
 
 
 css_class_re = re.compile(r"^[a-zA-Z]+[_a-zA-Z0-9-]*$")
@@ -876,7 +983,9 @@ def module_from_path(path, name):
     mod.__file__ = path
     with open(path, "r") as file:
         code = compile(file.read(), path, "exec", dont_inherit=True)
-    exec(code, mod.__dict__)
+    # Executing the file is the whole point - this is how --plugins-dir loads
+    # plugins and how metadata/config .py files are evaluated
+    exec(code, mod.__dict__)  # noqa: S102
     return mod
 
 
@@ -1033,9 +1142,7 @@ def escape_fts(query):
         query += '"'
     bits = _escape_fts_re.split(query)
     bits = [b for b in bits if b and b != '""']
-    return " ".join(
+    return " ".join(f'"{bit}"' if not bit.startswith('"') else bit for bit in bits)
-        '"{}"'.format(bit) if not bit.startswith('"') else bit for bit in bits
-    )
 
 
 class MultiParams:
@@ -1047,7 +1154,7 @@ class MultiParams:
                     data[key], (list, tuple)
                 ), "dictionary data should be a dictionary of key => [list]"
             self._data = data
-        elif isinstance(data, list) or isinstance(data, tuple):
+        elif isinstance(data, (list, tuple)):
             new_data = {}
             for item in data:
                 assert (
@@ -1137,9 +1244,7 @@ def _gather_arguments(fn, kwargs):
     for parameter in parameters:
         if parameter not in kwargs:
             raise TypeError(
-                "{} requires parameters {}, missing: {}".format(
+                f"{fn} requires parameters {tuple(parameters)}, missing: {set(parameters) - set(kwargs.keys())}"
-                    fn, tuple(parameters), set(parameters) - set(kwargs.keys())
-                )
             )
         call_with.append(kwargs[parameter])
     return call_with
@@ -1208,9 +1313,9 @@ def resolve_env_secrets(config, environ):
     """Create copy that recursively replaces {"$env": "NAME"} with values from environ"""
     if isinstance(config, dict):
         if list(config.keys()) == ["$env"]:
-            return environ.get(list(config.values())[0])
+            return environ.get(next(iter(config.values())))
         elif list(config.keys()) == ["$file"]:
-            with open(list(config.values())[0]) as fp:
+            with open(next(iter(config.values()))) as fp:
                 return fp.read()
         else:
             return {
@@ -1306,7 +1411,7 @@ _named_param_re = re.compile(r":(\w+)")
 
 
 @documented
-def named_parameters(sql: str) -> List[str]:
+def named_parameters(sql: str) -> list[str]:
     """
     Given a SQL statement, return a list of named parameters that are used in the statement
 
@@ -1319,7 +1424,7 @@ def named_parameters(sql: str) -> List[str]:
     return _named_param_re.findall(sql)
 
 
-async def derive_named_parameters(db: "Database", sql: str) -> List[str]:
+async def derive_named_parameters(db: "Database", sql: str) -> list[str]:
     """
     This undocumented but stable method exists for backwards compatibility
     with plugins that were using it before it switched to named_parameters()
@@ -1343,9 +1448,9 @@ def parse_size_limit(value, default, maximum, name="_size"):
         if size < 0:
             raise ValueError
     except ValueError:
-        raise ValueError("{} must be a positive integer".format(name))
+        raise ValueError(f"{name} must be a positive integer")
     if size > maximum:
-        raise ValueError("{} must be <= {}".format(name, maximum))
+        raise ValueError(f"{name} must be <= {maximum}")
     return size
 
 
@@ -1403,7 +1508,7 @@ class TildeEncoder(dict):
         elif b == _space:
             res = "+"
         else:
-            res = "~{:02X}".format(b)
+            res = f"~{b:02X}"
         self[b] = res
         return res
 
@@ -1498,7 +1603,7 @@ def _combine(base: dict, update: dict) -> dict:
     return base
 
 
-def pairs_to_nested_config(pairs: typing.List[typing.Tuple[str, typing.Any]]) -> dict:
+def pairs_to_nested_config(pairs: list[tuple[str, typing.Any]]) -> dict:
     """
     Parse a list of key-value pairs into a nested dictionary.
     """
@@ -1513,7 +1618,7 @@ def make_slot_function(name, datasette, request, **kwargs):
     from datasette.plugins import pm
 
     method = getattr(pm.hook, name, None)
-    assert method is not None, "No hook found for {}".format(name)
+    assert method is not None, f"No hook found for {name}"
 
     async def inner():
         html_bits = []
@@ -1537,7 +1642,7 @@ def prune_empty_dicts(d: dict):
                 d.pop(key, None)
 
 
-def move_plugins_and_allow(source: dict, destination: dict) -> Tuple[dict, dict]:
+def move_plugins_and_allow(source: dict, destination: dict) -> tuple[dict, dict]:
     """
     Move 'plugins' and 'allow' keys from source to destination dictionary. Creates
     hierarchy in destination if needed. After moving, recursively remove any keys

datasette/utils/actions_sql.py

@@ -252,88 +252,62 @@ async def _build_single_action_sql(
                 ]
             )
 
-    # Continue with the cascading logic
+    # Continue with the cascading logic.
-    query_parts.extend(
+    # Aggregate the RULES by cascade level (small), rather than grouping
-        [
+    # base x rules (which scales with the number of resources).
-            "child_lvl AS (",
+    def _agg(select_key, where, group_by):
-            "  SELECT b.parent, b.child,",
+        parts = [
-            "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
+            f"  SELECT {select_key}",
-            "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow,",
+            "         MAX(CASE WHEN allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-            "         json_group_array(CASE WHEN ar.allow = 0 THEN ar.source_plugin || ': ' || ar.reason END) AS deny_reasons,",
+            "         MAX(CASE WHEN allow = 1 THEN 1 ELSE 0 END) AS any_allow,",
-            "         json_group_array(CASE WHEN ar.allow = 1 THEN ar.source_plugin || ': ' || ar.reason END) AS allow_reasons",
+            "         json_group_array(CASE WHEN allow = 0 THEN source_plugin || ': ' || reason END) AS deny_reasons,",
-            "  FROM base b",
+            "         json_group_array(CASE WHEN allow = 1 THEN source_plugin || ': ' || reason END) AS allow_reasons",
-            "  LEFT JOIN all_rules ar ON ar.parent = b.parent AND ar.child = b.child",
+            f"  FROM all_rules WHERE {where}",
-            "  GROUP BY b.parent, b.child",
-            "),",
-            "parent_lvl AS (",
-            "  SELECT b.parent, b.child,",
-            "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-            "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow,",
-            "         json_group_array(CASE WHEN ar.allow = 0 THEN ar.source_plugin || ': ' || ar.reason END) AS deny_reasons,",
-            "         json_group_array(CASE WHEN ar.allow = 1 THEN ar.source_plugin || ': ' || ar.reason END) AS allow_reasons",
-            "  FROM base b",
-            "  LEFT JOIN all_rules ar ON ar.parent = b.parent AND ar.child IS NULL",
-            "  GROUP BY b.parent, b.child",
-            "),",
-            "global_lvl AS (",
-            "  SELECT b.parent, b.child,",
-            "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-            "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow,",
-            "         json_group_array(CASE WHEN ar.allow = 0 THEN ar.source_plugin || ': ' || ar.reason END) AS deny_reasons,",
-            "         json_group_array(CASE WHEN ar.allow = 1 THEN ar.source_plugin || ': ' || ar.reason END) AS allow_reasons",
-            "  FROM base b",
-            "  LEFT JOIN all_rules ar ON ar.parent IS NULL AND ar.child IS NULL",
-            "  GROUP BY b.parent, b.child",
-            "),",
         ]
+        if group_by:
+            parts.append(f"  GROUP BY {group_by}")
+        return parts
+
+    query_parts.extend(
+        ["child_agg AS ("]
+        + _agg(
+            "parent, child,",
+            "parent IS NOT NULL AND child IS NOT NULL",
+            "parent, child",
+        )
+        + ["),", "parent_agg AS ("]
+        + _agg("parent,", "parent IS NOT NULL AND child IS NULL", "parent")
+        + ["),", "global_agg AS ("]
+        + _agg("", "parent IS NULL AND child IS NULL", None)
+        + ["),"]
     )
 
     # Add anonymous decision logic if needed
     if include_is_private:
-        query_parts.extend(
+
-            [
+        def _anon_agg(select_key, where, group_by):
-                "anon_child_lvl AS (",
+            parts = [
-                "  SELECT b.parent, b.child,",
+                f"  SELECT {select_key}",
-                "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
+                "         MAX(CASE WHEN allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-                "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow",
+                "         MAX(CASE WHEN allow = 1 THEN 1 ELSE 0 END) AS any_allow",
-                "  FROM base b",
+                f"  FROM anon_rules WHERE {where}",
-                "  LEFT JOIN anon_rules ar ON ar.parent = b.parent AND ar.child = b.child",
-                "  GROUP BY b.parent, b.child",
-                "),",
-                "anon_parent_lvl AS (",
-                "  SELECT b.parent, b.child,",
-                "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-                "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow",
-                "  FROM base b",
-                "  LEFT JOIN anon_rules ar ON ar.parent = b.parent AND ar.child IS NULL",
-                "  GROUP BY b.parent, b.child",
-                "),",
-                "anon_global_lvl AS (",
-                "  SELECT b.parent, b.child,",
-                "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-                "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow",
-                "  FROM base b",
-                "  LEFT JOIN anon_rules ar ON ar.parent IS NULL AND ar.child IS NULL",
-                "  GROUP BY b.parent, b.child",
-                "),",
-                "anon_decisions AS (",
-                "  SELECT",
-                "    b.parent, b.child,",
-                "    CASE",
-                "      WHEN acl.any_deny = 1 THEN 0",
-                "      WHEN acl.any_allow = 1 THEN 1",
-                "      WHEN apl.any_deny = 1 THEN 0",
-                "      WHEN apl.any_allow = 1 THEN 1",
-                "      WHEN agl.any_deny = 1 THEN 0",
-                "      WHEN agl.any_allow = 1 THEN 1",
-                "      ELSE 0",
-                "    END AS anon_is_allowed",
-                "  FROM base b",
-                "  JOIN anon_child_lvl acl ON b.parent = acl.parent AND (b.child = acl.child OR (b.child IS NULL AND acl.child IS NULL))",
-                "  JOIN anon_parent_lvl apl ON b.parent = apl.parent AND (b.child = apl.child OR (b.child IS NULL AND apl.child IS NULL))",
-                "  JOIN anon_global_lvl agl ON b.parent = agl.parent AND (b.child = agl.child OR (b.child IS NULL AND agl.child IS NULL))",
-                "),",
             ]
+            if group_by:
+                parts.append(f"  GROUP BY {group_by}")
+            return parts
+
+        query_parts.extend(
+            ["anon_child_agg AS ("]
+            + _anon_agg(
+                "parent, child,",
+                "parent IS NOT NULL AND child IS NOT NULL",
+                "parent, child",
+            )
+            + ["),", "anon_parent_agg AS ("]
+            + _anon_agg("parent,", "parent IS NOT NULL AND child IS NULL", "parent")
+            + ["),", "anon_global_agg AS ("]
+            + _anon_agg("", "parent IS NULL AND child IS NULL", None)
+            + ["),"]
         )
 
     # Final decisions
@@ -342,31 +316,28 @@ async def _build_single_action_sql(
             "decisions AS (",
             "  SELECT",
             "    b.parent, b.child,",
-            "    -- Cascading permission logic: child → parent → global, DENY beats ALLOW at each level",
+            "    -- Cascading permission logic: child -> parent -> global, DENY beats ALLOW at each level",
             "    -- Priority order:",
-            "    --   1. Child-level deny (most specific, blocks access)",
+            "    --   1. Child-level deny  2. Child-level allow",
-            "    --   2. Child-level allow (most specific, grants access)",
+            "    --   3. Parent-level deny 4. Parent-level allow",
-            "    --   3. Parent-level deny (intermediate, blocks access)",
+            "    --   5. Global-level deny 6. Global-level allow",
-            "    --   4. Parent-level allow (intermediate, grants access)",
-            "    --   5. Global-level deny (least specific, blocks access)",
-            "    --   6. Global-level allow (least specific, grants access)",
             "    --   7. Default deny (no rules match)",
             "    CASE",
-            "      WHEN cl.any_deny = 1 THEN 0",
+            "      WHEN ca.any_deny = 1 THEN 0",
-            "      WHEN cl.any_allow = 1 THEN 1",
+            "      WHEN ca.any_allow = 1 THEN 1",
-            "      WHEN pl.any_deny = 1 THEN 0",
+            "      WHEN pa.any_deny = 1 THEN 0",
-            "      WHEN pl.any_allow = 1 THEN 1",
+            "      WHEN pa.any_allow = 1 THEN 1",
-            "      WHEN gl.any_deny = 1 THEN 0",
+            "      WHEN ga.any_deny = 1 THEN 0",
-            "      WHEN gl.any_allow = 1 THEN 1",
+            "      WHEN ga.any_allow = 1 THEN 1",
             "      ELSE 0",
             "    END AS is_allowed,",
             "    CASE",
-            "      WHEN cl.any_deny = 1 THEN cl.deny_reasons",
+            "      WHEN ca.any_deny = 1 THEN ca.deny_reasons",
-            "      WHEN cl.any_allow = 1 THEN cl.allow_reasons",
+            "      WHEN ca.any_allow = 1 THEN ca.allow_reasons",
-            "      WHEN pl.any_deny = 1 THEN pl.deny_reasons",
+            "      WHEN pa.any_deny = 1 THEN pa.deny_reasons",
-            "      WHEN pl.any_allow = 1 THEN pl.allow_reasons",
+            "      WHEN pa.any_allow = 1 THEN pa.allow_reasons",
-            "      WHEN gl.any_deny = 1 THEN gl.deny_reasons",
+            "      WHEN ga.any_deny = 1 THEN ga.deny_reasons",
-            "      WHEN gl.any_allow = 1 THEN gl.allow_reasons",
+            "      WHEN ga.any_allow = 1 THEN ga.allow_reasons",
             "      ELSE '[]'",
             "    END AS reason",
         ]
@@ -374,21 +345,34 @@ async def _build_single_action_sql(
 
     if include_is_private:
         query_parts.append(
-            "    , CASE WHEN ad.anon_is_allowed = 0 THEN 1 ELSE 0 END AS is_private"
+            "    , CASE WHEN ("
+            "CASE"
+            " WHEN aca.any_deny = 1 THEN 0"
+            " WHEN aca.any_allow = 1 THEN 1"
+            " WHEN apa.any_deny = 1 THEN 0"
+            " WHEN apa.any_allow = 1 THEN 1"
+            " WHEN aga.any_deny = 1 THEN 0"
+            " WHEN aga.any_allow = 1 THEN 1"
+            " ELSE 0 END"
+            ") = 0 THEN 1 ELSE 0 END AS is_private"
         )
 
     query_parts.extend(
         [
             "  FROM base b",
-            "  JOIN child_lvl cl ON b.parent = cl.parent AND (b.child = cl.child OR (b.child IS NULL AND cl.child IS NULL))",
+            "  LEFT JOIN child_agg ca ON ca.parent = b.parent AND ca.child = b.child",
-            "  JOIN parent_lvl pl ON b.parent = pl.parent AND (b.child = pl.child OR (b.child IS NULL AND pl.child IS NULL))",
+            "  LEFT JOIN parent_agg pa ON pa.parent = b.parent",
-            "  JOIN global_lvl gl ON b.parent = gl.parent AND (b.child = gl.child OR (b.child IS NULL AND gl.child IS NULL))",
+            "  CROSS JOIN global_agg ga",
         ]
     )
 
     if include_is_private:
-        query_parts.append(
+        query_parts.extend(
-            "  JOIN anon_decisions ad ON b.parent = ad.parent AND (b.child = ad.child OR (b.child IS NULL AND ad.child IS NULL))"
+            [
+                "  LEFT JOIN anon_child_agg aca ON aca.parent = b.parent AND aca.child = b.child",
+                "  LEFT JOIN anon_parent_agg apa ON apa.parent = b.parent",
+                "  CROSS JOIN anon_global_agg aga",
+            ]
         )
 
     query_parts.append(")")
@@ -400,8 +384,28 @@ async def _build_single_action_sql(
         restriction_intersect = "\nINTERSECT\n".join(
             f"SELECT * FROM ({sql})" for sql in restriction_sqls
         )
+        # Decompose by NULL-pattern so the final filter can use pure-equality
+        # EXISTS lookups (satisfiable via automatic indexes) instead of a
+        # correlated OR-scan over the whole list.
         query_parts.extend(
-            [",", "restriction_list AS (", f"  {restriction_intersect}", ")"]
+            [
+                ",",
+                "restriction_list AS (",
+                f"  {restriction_intersect}",
+                "),",
+                "restriction_exact AS (",
+                "  SELECT parent, child FROM restriction_list WHERE parent IS NOT NULL AND child IS NOT NULL",
+                "),",
+                "restriction_parent_any AS (",
+                "  SELECT DISTINCT parent FROM restriction_list WHERE parent IS NOT NULL AND child IS NULL",
+                "),",
+                "restriction_child_any AS (",
+                "  SELECT DISTINCT child FROM restriction_list WHERE parent IS NULL AND child IS NOT NULL",
+                "),",
+                "restriction_all AS (",
+                "  SELECT 1 AS matched FROM restriction_list WHERE parent IS NULL AND child IS NULL LIMIT 1",
+                ")",
+            ]
         )
 
     # Final SELECT
@@ -416,10 +420,11 @@ async def _build_single_action_sql(
     # Add restriction filter if there are restrictions
     if restriction_sqls:
         query_parts.append("""
-  AND EXISTS (
+  AND (
-    SELECT 1 FROM restriction_list r
+    EXISTS (SELECT 1 FROM restriction_all)
-    WHERE (r.parent = decisions.parent OR r.parent IS NULL)
+    OR EXISTS (SELECT 1 FROM restriction_parent_any r WHERE r.parent = decisions.parent)
-      AND (r.child = decisions.child OR r.child IS NULL)
+    OR EXISTS (SELECT 1 FROM restriction_child_any r WHERE r.child = decisions.child)
+    OR EXISTS (SELECT 1 FROM restriction_exact r WHERE r.parent = decisions.parent AND r.child = decisions.child)
   )""")
 
     # Add parent filter if specified
@@ -673,3 +678,239 @@ async def check_permission_for_resource(
         child=child,
     )
     return results[action]
+
+
+async def explain_permission_for_resource(
+    *,
+    datasette: "Datasette",
+    actor: dict | None,
+    action: str,
+    parent: str | None,
+    child: str | None,
+) -> dict:
+    """Explain a permission decision for one action and resource.
+
+    This is intended for Datasette's permission debugging tools. It uses the
+    same ``permission_resources_sql`` hook results and the same resolution
+    rules as :func:`check_permissions_for_actions`, but also returns the
+    matching rules, actor restriction results and ``also_requires`` chain.
+
+    The returned dictionary is part of Datasette's unstable debugging API.
+    """
+
+    action_obj = datasette.actions.get(action)
+    if action_obj is None:
+        raise ValueError(f"Unknown action: {action}")
+
+    explanation = await _explain_single_action(
+        datasette=datasette,
+        actor=actor,
+        action=action,
+        parent=parent,
+        child=child,
+    )
+
+    required_actions = []
+    if action_obj.also_requires:
+        required = await explain_permission_for_resource(
+            datasette=datasette,
+            actor=actor,
+            action=action_obj.also_requires,
+            parent=parent,
+            child=child,
+        )
+        required_actions.append(required)
+
+    explanation["required_actions"] = required_actions
+    explanation["allowed"] = bool(
+        explanation["rule_allowed"]
+        and explanation["restriction_allowed"]
+        and all(required["allowed"] for required in required_actions)
+    )
+    explanation["summary"] = _permission_explanation_summary(explanation)
+    return explanation
+
+
+async def _explain_single_action(
+    *,
+    datasette: "Datasette",
+    actor: dict | None,
+    action: str,
+    parent: str | None,
+    child: str | None,
+) -> dict:
+    """Return matching rules and restrictions for a single action."""
+    from datasette.utils.permissions import SKIP_PERMISSION_CHECKS
+
+    permission_sqls = await gather_permission_sql_from_hooks(
+        datasette=datasette,
+        actor=actor,
+        action=action,
+    )
+
+    if permission_sqls is SKIP_PERMISSION_CHECKS:
+        return {
+            "action": action,
+            "rule_allowed": True,
+            "restriction_allowed": True,
+            "winning_scope": "global",
+            "matched_rules": [
+                {
+                    "scope": "global",
+                    "effect": "allow",
+                    "source": "skip_permission_checks",
+                    "reason": "Permission checks were explicitly skipped",
+                    "decisive": True,
+                    "ignored_because": None,
+                }
+            ],
+            "restrictions": [],
+        }
+
+    db = datasette.get_internal_database()
+    matched_rules = []
+    restrictions = []
+
+    for permission_sql in permission_sqls:
+        params = dict(permission_sql.params or {})
+        parent_param = _unused_parameter_name(params, "_explain_parent")
+        params[parent_param] = parent
+        child_param = _unused_parameter_name(params, "_explain_child")
+        params[child_param] = child
+
+        if permission_sql.sql:
+            rows = await db.execute(
+                f"""
+                SELECT parent, child, allow, reason
+                FROM ({permission_sql.sql}) AS permission_rules
+                WHERE (parent IS NULL OR parent = :{parent_param})
+                  AND (child IS NULL OR child = :{child_param})
+                """,
+                params,
+            )
+            for row in rows:
+                specificity = (
+                    2
+                    if row["child"] is not None
+                    else 1 if row["parent"] is not None else 0
+                )
+                matched_rules.append(
+                    {
+                        "scope": ("resource", "parent", "global")[2 - specificity],
+                        "effect": "allow" if row["allow"] else "deny",
+                        "source": permission_sql.source,
+                        "reason": row["reason"],
+                        "_specificity": specificity,
+                    }
+                )
+
+        if permission_sql.restriction_sql:
+            restriction_row = (
+                await db.execute(
+                    f"""
+                    SELECT EXISTS(
+                        SELECT 1 FROM ({permission_sql.restriction_sql}) AS restriction_rules
+                        WHERE (parent IS NULL OR parent = :{parent_param})
+                          AND (child IS NULL OR child = :{child_param})
+                    ) AS resource_is_in_allowlist
+                    """,
+                    params,
+                )
+            ).first()
+            restriction_allowed = bool(restriction_row[0])
+            restrictions.append(
+                {
+                    "source": permission_sql.source,
+                    "allowed": restriction_allowed,
+                    "reason": params.get("deny")
+                    or (
+                        "Resource is included in this restriction allowlist"
+                        if restriction_allowed
+                        else "Resource is not included in this restriction allowlist"
+                    ),
+                }
+            )
+
+    matched_rules.sort(
+        key=lambda rule: (
+            -rule["_specificity"],
+            0 if rule["effect"] == "deny" else 1,
+            rule["source"] or "",
+            rule["reason"] or "",
+        )
+    )
+
+    if matched_rules:
+        winning_specificity = matched_rules[0]["_specificity"]
+        winning_rules = [
+            rule
+            for rule in matched_rules
+            if rule["_specificity"] == winning_specificity
+        ]
+        rule_allowed = not any(rule["effect"] == "deny" for rule in winning_rules)
+        winning_scope = winning_rules[0]["scope"]
+    else:
+        winning_specificity = None
+        rule_allowed = False
+        winning_scope = None
+
+    for rule in matched_rules:
+        specificity = rule.pop("_specificity")
+        if specificity != winning_specificity:
+            rule["decisive"] = False
+            rule["ignored_because"] = "A more specific rule matched"
+        elif not rule_allowed and rule["effect"] == "allow":
+            rule["decisive"] = False
+            rule["ignored_because"] = "A deny rule matched at the same scope"
+        else:
+            rule["decisive"] = True
+            rule["ignored_because"] = None
+
+    return {
+        "action": action,
+        "rule_allowed": rule_allowed,
+        "restriction_allowed": all(
+            restriction["allowed"] for restriction in restrictions
+        ),
+        "winning_scope": winning_scope,
+        "matched_rules": matched_rules,
+        "restrictions": restrictions,
+    }
+
+
+def _unused_parameter_name(params: dict, preferred: str) -> str:
+    """Return a SQL parameter name that is not already in ``params``."""
+    candidate = preferred
+    suffix = 2
+    while candidate in params:
+        candidate = f"{preferred}_{suffix}"
+        suffix += 1
+    return candidate
+
+
+def _permission_explanation_summary(explanation: dict) -> str:
+    denied_requirement = next(
+        (
+            required
+            for required in explanation["required_actions"]
+            if not required["allowed"]
+        ),
+        None,
+    )
+    if denied_requirement:
+        return (
+            f"Denied because {explanation['action']} also requires "
+            f"{denied_requirement['action']}, which was denied."
+        )
+    if not explanation["matched_rules"]:
+        return "Denied because no permission rule matched this actor and resource."
+    if not explanation["rule_allowed"]:
+        return (
+            f"Denied by a {explanation['winning_scope']}-level rule. "
+            "Deny rules take precedence over allow rules at the same scope."
+        )
+    if not explanation["restriction_allowed"]:
+        return (
+            "Denied because the resource is not included in the actor's restrictions."
+        )
+    return f"Allowed by the matching {explanation['winning_scope']}-level rule."

datasette/utils/asgi.py

@@ -1,28 +1,29 @@
 import json
-from typing import Optional
+import re
+from http.cookies import Morsel, SimpleCookie
+from mimetypes import guess_type
+from pathlib import Path
+from urllib.parse import parse_qs, parse_qsl, urlunparse
+
+import aiofiles
+import aiofiles.os
+
 from datasette.utils import MultiParams, calculate_etag, error_body, sha256_file
 from datasette.utils.multipart import (
-    parse_form_data,
-    MultipartParseError,
-    FormData,
-    DEFAULT_MAX_FILE_SIZE,
-    DEFAULT_MAX_REQUEST_SIZE,
-    DEFAULT_MAX_FIELDS,
-    DEFAULT_MAX_FILES,
-    DEFAULT_MAX_PARTS,
     DEFAULT_MAX_FIELD_SIZE,
+    DEFAULT_MAX_FIELDS,
+    DEFAULT_MAX_FILE_SIZE,
+    DEFAULT_MAX_FILES,
     DEFAULT_MAX_MEMORY_FILE_SIZE,
     DEFAULT_MAX_PART_HEADER_BYTES,
     DEFAULT_MAX_PART_HEADER_LINES,
+    DEFAULT_MAX_PARTS,
+    DEFAULT_MAX_REQUEST_SIZE,
     DEFAULT_MIN_FREE_DISK_BYTES,
+    FormData,
+    MultipartParseError,
+    parse_form_data,
 )
-from mimetypes import guess_type
-from urllib.parse import parse_qs, urlunparse, parse_qsl
-from pathlib import Path
-from http.cookies import SimpleCookie, Morsel
-import aiofiles
-import aiofiles.os
-import re
 
 # Workaround for adding samesite support to pre 3.8 python
 Morsel._reserved["samesite"] = "SameSite"
@@ -88,7 +89,7 @@ class Request:
         self.max_post_body_bytes = max_post_body_bytes
 
     def __repr__(self):
-        return '<asgi.Request method="{}" url="{}">'.format(self.method, self.url)
+        return f'<asgi.Request method="{self.method}" url="{self.url}">'
 
     @property
     def method(self):
@@ -167,7 +168,7 @@ class Request:
         if max_bytes is None:
             max_bytes = self.max_post_body_bytes
         too_large = PayloadTooLarge(
-            "Request body exceeded maximum size of {} bytes".format(max_bytes)
+            f"Request body exceeded maximum size of {max_bytes} bytes"
         )
         if max_bytes:
             # Reject early if the client declares an oversized body
@@ -206,7 +207,7 @@ class Request:
         max_request_size: int = DEFAULT_MAX_REQUEST_SIZE,
         max_fields: int = DEFAULT_MAX_FIELDS,
         max_files: int = DEFAULT_MAX_FILES,
-        max_parts: Optional[int] = DEFAULT_MAX_PARTS,
+        max_parts: int | None = DEFAULT_MAX_PARTS,
         max_field_size: int = DEFAULT_MAX_FIELD_SIZE,
         max_memory_file_size: int = DEFAULT_MAX_MEMORY_FILE_SIZE,
         max_part_header_bytes: int = DEFAULT_MAX_PART_HEADER_BYTES,
@@ -529,9 +530,9 @@ class Response:
         httponly=False,
         samesite="lax",
     ):
-        assert samesite in SAMESITE_VALUES, "samesite should be one of {}".format(
+        assert (
-            SAMESITE_VALUES
+            samesite in SAMESITE_VALUES
-        )
+        ), f"samesite should be one of {SAMESITE_VALUES}"
         cookie = SimpleCookie()
         cookie[key] = value
         for prop_name, prop_value in (

datasette/utils/baseconv.py

@@ -13,7 +13,7 @@ Originally shared here: https://www.djangosnippets.org/snippets/1431/
 """
 
 
-class BaseConverter(object):
+class BaseConverter:
     decimal_digits = "0123456789"
 
     def __init__(self, digits):

datasette/utils/check_callable.py

@@ -1,6 +1,6 @@
 import inspect
 import types
-from typing import NamedTuple, Any
+from typing import Any, NamedTuple
 
 
 class CallableStatus(NamedTuple):
@@ -19,7 +19,7 @@ def check_callable(obj: Any) -> CallableStatus:
     if isinstance(obj, types.FunctionType):
         return CallableStatus(True, inspect.iscoroutinefunction(obj))
 
-    if hasattr(obj, "__call__"):
+    if callable(obj):
         return CallableStatus(True, inspect.iscoroutinefunction(obj.__call__))
 
-    assert False, "obj {} is somehow callable with no __call__ method".format(repr(obj))
+    assert False, f"obj {obj!r} is somehow callable with no __call__ method"

datasette/utils/internal_db.py

@@ -3,7 +3,7 @@ import textwrap
 from sqlite_utils import Database as SQLiteUtilsDatabase
 from sqlite_utils import Migrations
 
-from datasette.utils import table_column_details
+from datasette.utils import escape_sqlite, table_column_details
 
 INTERNAL_DB_SCHEMA_TABLES = {
     "catalog_databases",
@@ -180,29 +180,9 @@ async def init_internal_db(db):
     await db.execute_write_fn(apply_migrations, transaction=False)
 
 
-async def populate_schema_tables(internal_db, db):
+async def populate_schema_tables(internal_db, db, schema_version):
     database_name = db.name
 
-    def delete_everything(conn):
-        conn.execute(
-            "DELETE FROM catalog_tables WHERE database_name = ?", [database_name]
-        )
-        conn.execute(
-            "DELETE FROM catalog_views WHERE database_name = ?", [database_name]
-        )
-        conn.execute(
-            "DELETE FROM catalog_columns WHERE database_name = ?", [database_name]
-        )
-        conn.execute(
-            "DELETE FROM catalog_foreign_keys WHERE database_name = ?",
-            [database_name],
-        )
-        conn.execute(
-            "DELETE FROM catalog_indexes WHERE database_name = ?", [database_name]
-        )
-
-    await internal_db.execute_write_fn(delete_everything)
-
     tables = (await db.execute("select * from sqlite_master WHERE type = 'table'")).rows
     views = (await db.execute("select * from sqlite_master WHERE type = 'view'")).rows
 
@@ -227,25 +207,30 @@ async def populate_schema_tables(internal_db, db):
             columns = table_column_details(conn, table_name)
             columns_to_insert.extend(
                 {
-                    **{"database_name": database_name, "table_name": table_name},
+                    "database_name": database_name,
+                    "table_name": table_name,
                     **column._asdict(),
                 }
                 for column in columns
             )
             foreign_keys = conn.execute(
-                f"PRAGMA foreign_key_list([{table_name}])"
+                f"PRAGMA foreign_key_list({escape_sqlite(table_name)})"
             ).fetchall()
             foreign_keys_to_insert.extend(
                 {
-                    **{"database_name": database_name, "table_name": table_name},
+                    "database_name": database_name,
+                    "table_name": table_name,
                     **dict(foreign_key),
                 }
                 for foreign_key in foreign_keys
             )
-            indexes = conn.execute(f"PRAGMA index_list([{table_name}])").fetchall()
+            indexes = conn.execute(
+                f"PRAGMA index_list({escape_sqlite(table_name)})"
+            ).fetchall()
             indexes_to_insert.extend(
                 {
-                    **{"database_name": database_name, "table_name": table_name},
+                    "database_name": database_name,
+                    "table_name": table_name,
                     **dict(index),
                 }
                 for index in indexes
@@ -266,47 +251,76 @@ async def populate_schema_tables(internal_db, db):
         indexes_to_insert,
     ) = await db.execute_fn(collect_info)
 
-    await internal_db.execute_write_many(
+    def replace_catalog(conn):
-        """
+        # Delete child rows before their catalog_tables parents so this also
-        INSERT INTO catalog_tables (database_name, table_name, rootpage, sql)
+        # works if a prepare_connection plugin enables foreign key enforcement.
-        values (?, ?, ?, ?)
+        for table in (
-    """,
+            "catalog_columns",
-        tables_to_insert,
+            "catalog_foreign_keys",
-    )
+            "catalog_indexes",
-    await internal_db.execute_write_many(
+            "catalog_views",
-        """
+            "catalog_tables",
-        INSERT INTO catalog_views (database_name, view_name, rootpage, sql)
+        ):
-        values (?, ?, ?, ?)
+            conn.execute(
-    """,
+                f"DELETE FROM {table} WHERE database_name = ?",
-        views_to_insert,
+                [database_name],
-    )
+            )
-    await internal_db.execute_write_many(
+        conn.execute(
-        """
+            """
-        INSERT INTO catalog_columns (
+            INSERT OR REPLACE INTO catalog_databases (
-            database_name, table_name, cid, name, type, "notnull", default_value, is_pk, hidden
+                database_name, path, is_memory, schema_version
-        ) VALUES (
+            ) VALUES (?, ?, ?, ?)
-            :database_name, :table_name, :cid, :name, :type, :notnull, :default_value, :is_pk, :hidden
+            """,
+            [
+                database_name,
+                str(db.path) if db.path is not None else None,
+                db.is_memory,
+                schema_version,
+            ],
         )
-    """,
+        conn.executemany(
-        columns_to_insert,
+            """
-    )
+            INSERT INTO catalog_tables (database_name, table_name, rootpage, sql)
-    await internal_db.execute_write_many(
+            values (?, ?, ?, ?)
-        """
+            """,
-        INSERT INTO catalog_foreign_keys (
+            tables_to_insert,
-            database_name, table_name, "id", seq, "table", "from", "to", on_update, on_delete, match
-        ) VALUES (
-            :database_name, :table_name, :id, :seq, :table, :from, :to, :on_update, :on_delete, :match
         )
-    """,
+        conn.executemany(
-        foreign_keys_to_insert,
+            """
-    )
+            INSERT INTO catalog_views (database_name, view_name, rootpage, sql)
-    await internal_db.execute_write_many(
+            values (?, ?, ?, ?)
-        """
+            """,
-        INSERT INTO catalog_indexes (
+            views_to_insert,
-            database_name, table_name, seq, name, "unique", origin, partial
-        ) VALUES (
-            :database_name, :table_name, :seq, :name, :unique, :origin, :partial
         )
-    """,
+        conn.executemany(
-        indexes_to_insert,
+            """
-    )
+            INSERT INTO catalog_columns (
+                database_name, table_name, cid, name, type, "notnull", default_value, is_pk, hidden
+            ) VALUES (
+                :database_name, :table_name, :cid, :name, :type, :notnull, :default_value, :is_pk, :hidden
+            )
+            """,
+            columns_to_insert,
+        )
+        conn.executemany(
+            """
+            INSERT INTO catalog_foreign_keys (
+                database_name, table_name, "id", seq, "table", "from", "to", on_update, on_delete, match
+            ) VALUES (
+                :database_name, :table_name, :id, :seq, :table, :from, :to, :on_update, :on_delete, :match
+            )
+            """,
+            foreign_keys_to_insert,
+        )
+        conn.executemany(
+            """
+            INSERT INTO catalog_indexes (
+                database_name, table_name, seq, name, "unique", origin, partial
+            ) VALUES (
+                :database_name, :table_name, :seq, :name, :unique, :origin, :partial
+            )
+            """,
+            indexes_to_insert,
+        )
+
+    await internal_db.execute_write_fn(replace_catalog)

datasette/utils/multipart.py

@@ -11,15 +11,10 @@ Supports:
 import asyncio
 import shutil
 import tempfile
+from collections.abc import Callable
 from dataclasses import dataclass, field
 from typing import (
     Any,
-    Callable,
-    Dict,
-    List,
-    Optional,
-    Tuple,
-    Union,
 )
 from urllib.parse import parse_qsl
 
@@ -29,7 +24,7 @@ DEFAULT_MAX_REQUEST_SIZE = 100 * 1024 * 1024  # 100MB
 DEFAULT_MAX_FIELDS = 1000
 DEFAULT_MAX_FILES = 100
 # If max_parts is not specified, it defaults to max_fields + max_files
-DEFAULT_MAX_PARTS: Optional[int] = None
+DEFAULT_MAX_PARTS: int | None = None
 DEFAULT_MAX_FIELD_SIZE = 100 * 1024  # 100KB
 DEFAULT_MAX_MEMORY_FILE_SIZE = 1024 * 1024  # 1MB
 DEFAULT_MAX_PART_HEADER_BYTES = 16 * 1024  # 16KB
@@ -40,8 +35,6 @@ DEFAULT_MIN_FREE_DISK_BYTES = 50 * 1024 * 1024  # 50MB
 class MultipartParseError(Exception):
     """Raised when multipart parsing fails."""
 
-    pass
-
 
 @dataclass
 class UploadedFile:
@@ -57,7 +50,7 @@ class UploadedFile:
 
     name: str
     filename: str
-    content_type: Optional[str]
+    content_type: str | None
     size: int
     _file: tempfile.SpooledTemporaryFile = field(repr=False)
 
@@ -86,7 +79,8 @@ class UploadedFile:
     def __del__(self):
         try:
             self._file.close()
-        except Exception:
+        except Exception:  # noqa: BLE001, S110
+            # __del__ must never raise
             pass
 
 
@@ -98,27 +92,27 @@ class FormData:
     """
 
     def __init__(self):
-        self._data: List[Tuple[str, Union[str, UploadedFile]]] = []
+        self._data: list[tuple[str, str | UploadedFile]] = []
 
-    def append(self, key: str, value: Union[str, UploadedFile]) -> None:
+    def append(self, key: str, value: str | UploadedFile) -> None:
         """Add a key-value pair."""
         self._data.append((key, value))
 
-    def __getitem__(self, key: str) -> Union[str, UploadedFile]:
+    def __getitem__(self, key: str) -> str | UploadedFile:
         """Get the first value for a key."""
         for k, v in self._data:
             if k == key:
                 return v
         raise KeyError(key)
 
-    def get(self, key: str, default: Any = None) -> Optional[Union[str, UploadedFile]]:
+    def get(self, key: str, default: Any = None) -> str | UploadedFile | None:
         """Get the first value for a key, or default if not found."""
         try:
             return self[key]
         except KeyError:
             return default
 
-    def getlist(self, key: str) -> List[Union[str, UploadedFile]]:
+    def getlist(self, key: str) -> list[str | UploadedFile]:
         """Get all values for a key."""
         return [v for k, v in self._data if k == key]
 
@@ -142,15 +136,15 @@ class FormData:
         """Return unique keys."""
         return list(self)
 
-    def items(self) -> List[Tuple[str, Union[str, UploadedFile]]]:
+    def items(self) -> list[tuple[str, str | UploadedFile]]:
         """Return all key-value pairs."""
         return list(self._data)
 
-    def values(self) -> List[Union[str, UploadedFile]]:
+    def values(self) -> list[str | UploadedFile]:
         """Return all values."""
         return [v for _, v in self._data]
 
-    def _uploaded_files(self) -> List[UploadedFile]:
+    def _uploaded_files(self) -> list[UploadedFile]:
         """Return UploadedFile instances contained in this form."""
         return [v for _, v in self._data if isinstance(v, UploadedFile)]
 
@@ -163,7 +157,7 @@ class FormData:
         for uploaded in self._uploaded_files():
             try:
                 uploaded.close_sync()
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
                 # Best-effort cleanup; ignore close errors
                 pass
 
@@ -172,7 +166,7 @@ class FormData:
         for uploaded in self._uploaded_files():
             try:
                 await uploaded.close()
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
                 # Best-effort cleanup; ignore close errors
                 pass
 
@@ -189,13 +183,13 @@ class FormData:
         await self.aclose()
 
 
-def parse_content_disposition(header: str) -> Dict[str, Optional[str]]:
+def parse_content_disposition(header: str) -> dict[str, str | None]:
     """
     Parse Content-Disposition header value.
 
     Returns dict with 'name', 'filename' keys (filename may be None).
     """
-    result: Dict[str, Optional[str]] = {"name": None, "filename": None}
+    result: dict[str, str | None] = {"name": None, "filename": None}
 
     # Split on semicolons, handling quoted strings
     parts = []
@@ -238,7 +232,8 @@ def parse_content_disposition(header: str) -> Dict[str, Optional[str]]:
                         from urllib.parse import unquote
 
                         result["filename"] = unquote(encoded, encoding="utf-8")
-                    except Exception:
+                    except Exception:  # noqa: BLE001, S110
+                        # Malformed RFC 5987 filename* - fall back to the plain filename
                         pass
             continue
 
@@ -250,20 +245,19 @@ def parse_content_disposition(header: str) -> Dict[str, Optional[str]]:
 
         if key == "name":
             result["name"] = value
-        elif key == "filename":
+        # Only set filename if filename* hasn't already set it
-            # Only set if filename* hasn't already set it
+        elif key == "filename" and result["filename"] is None:
-            if result["filename"] is None:
+            # Strip path components (security)
-                # Strip path components (security)
+            # Handle both Unix and Windows paths
-                # Handle both Unix and Windows paths
+            value = value.replace("\\", "/")
-                value = value.replace("\\", "/")
+            if "/" in value:
-                if "/" in value:
+                value = value.rsplit("/", 1)[-1]
-                    value = value.rsplit("/", 1)[-1]
+            result["filename"] = value
-                result["filename"] = value
 
     return result
 
 
-def parse_content_type(header: str) -> Tuple[str, Dict[str, str]]:
+def parse_content_type(header: str) -> tuple[str, dict[str, str]]:
     """
     Parse Content-Type header value.
 
@@ -307,7 +301,7 @@ class MultipartParser:
         max_request_size: int = DEFAULT_MAX_REQUEST_SIZE,
         max_fields: int = DEFAULT_MAX_FIELDS,
         max_files: int = DEFAULT_MAX_FILES,
-        max_parts: Optional[int] = DEFAULT_MAX_PARTS,
+        max_parts: int | None = DEFAULT_MAX_PARTS,
         max_field_size: int = DEFAULT_MAX_FIELD_SIZE,
         max_memory_file_size: int = DEFAULT_MAX_MEMORY_FILE_SIZE,
         max_part_header_bytes: int = DEFAULT_MAX_PART_HEADER_BYTES,
@@ -348,12 +342,12 @@ class MultipartParser:
         self._tempdir = tempfile.gettempdir()
 
         # Current part state
-        self.current_headers: Dict[str, str] = {}
+        self.current_headers: dict[str, str] = {}
-        self.current_file: Optional[tempfile.SpooledTemporaryFile] = None
+        self.current_file: tempfile.SpooledTemporaryFile | None = None
         self.current_body = bytearray()
-        self.current_name: Optional[str] = None
+        self.current_name: str | None = None
-        self.current_filename: Optional[str] = None
+        self.current_filename: str | None = None
-        self.current_content_type: Optional[str] = None
+        self.current_content_type: str | None = None
 
     def feed(self, chunk: bytes) -> None:
         """Feed a chunk of data to the parser."""
@@ -454,7 +448,7 @@ class MultipartParser:
             # Parse header
             try:
                 line_str = line.decode("utf-8", errors="replace")
-            except Exception:
+            except UnicodeDecodeError:
                 line_str = line.decode("latin-1")
 
             if ":" in line_str:
@@ -481,7 +475,9 @@ class MultipartParser:
             if self.file_count > self.max_files:
                 raise MultipartParseError("Too many files")
             if self.handle_files:
-                self.current_file = tempfile.SpooledTemporaryFile(
+                # Outlives this method - it is filled in across parser callbacks
+                # and then handed to the UploadedFile the caller consumes
+                self.current_file = tempfile.SpooledTemporaryFile(  # noqa: SIM115
                     max_size=self.max_memory_file_size
                 )
             else:
@@ -644,7 +640,7 @@ async def parse_form_data(
     max_request_size: int = DEFAULT_MAX_REQUEST_SIZE,
     max_fields: int = DEFAULT_MAX_FIELDS,
     max_files: int = DEFAULT_MAX_FILES,
-    max_parts: Optional[int] = DEFAULT_MAX_PARTS,
+    max_parts: int | None = DEFAULT_MAX_PARTS,
     max_field_size: int = DEFAULT_MAX_FIELD_SIZE,
     max_memory_file_size: int = DEFAULT_MAX_MEMORY_FILE_SIZE,
     max_part_header_bytes: int = DEFAULT_MAX_PART_HEADER_BYTES,

datasette/utils/permissions.py

@@ -2,8 +2,9 @@
 from __future__ import annotations
 
 import json
-from typing import Any, Dict, Iterable, List, Sequence, Tuple
 import sqlite3
+from collections.abc import Iterable, Sequence
+from typing import Any
 
 from datasette.permissions import PermissionSQL
 from datasette.plugins import pm
@@ -15,7 +16,7 @@ SKIP_PERMISSION_CHECKS = object()
 
 async def gather_permission_sql_from_hooks(
     *, datasette, actor: dict | None, action: str
-) -> List[PermissionSQL] | object:
+) -> list[PermissionSQL] | object:
     """Collect PermissionSQL objects from the permission_resources_sql hook.
 
     Ensures that each returned PermissionSQL has a populated ``source``.
@@ -34,7 +35,7 @@ async def gather_permission_sql_from_hooks(
     hookimpls = hook_caller.get_hookimpls()
     hook_results = list(hook_caller(datasette=datasette, actor=actor, action=action))
 
-    collected: List[PermissionSQL] = []
+    collected: list[PermissionSQL] = []
     actor_json = json.dumps(actor) if actor is not None else None
     actor_id = actor.get("id") if isinstance(actor, dict) else None
 
@@ -71,7 +72,7 @@ def _iter_permission_sql_from_result(
     if isinstance(result, PermissionSQL):
         return [result]
     if isinstance(result, (list, tuple)):
-        collected: List[PermissionSQL] = []
+        collected: list[PermissionSQL] = []
         for item in result:
             collected.extend(_iter_permission_sql_from_result(item, action=action))
         return collected
@@ -90,7 +91,7 @@ def _iter_permission_sql_from_result(
 
 def build_rules_union(
     actor: dict | None, plugins: Sequence[PermissionSQL]
-) -> Tuple[str, Dict[str, Any]]:
+) -> tuple[str, dict[str, Any]]:
     """
     Compose plugin SQL into a UNION ALL.
 
@@ -102,10 +103,10 @@ def build_rules_union(
     The system reserves these parameter names: :actor, :actor_id, :action, :filter_parent
     Plugin parameters should be prefixed with a unique identifier (e.g., source name).
     """
-    parts: List[str] = []
+    parts: list[str] = []
     actor_json = json.dumps(actor) if actor else None
     actor_id = actor.get("id") if actor else None
-    params: Dict[str, Any] = {"actor": actor_json, "actor_id": actor_id}
+    params: dict[str, Any] = {"actor": actor_json, "actor_id": actor_id}
 
     for p in plugins:
         # No namespacing - just use plugin params as-is
@@ -141,10 +142,10 @@ async def resolve_permissions_from_catalog(
     plugins: Sequence[Any],
     action: str,
     candidate_sql: str,
-    candidate_params: Dict[str, Any] | None = None,
+    candidate_params: dict[str, Any] | None = None,
     *,
     implicit_deny: bool = True,
-) -> List[Dict[str, Any]]:
+) -> list[dict[str, Any]]:
     """
     Resolve permissions by embedding the provided *candidate_sql* in a CTE.
 
@@ -168,8 +169,8 @@ async def resolve_permissions_from_catalog(
       - parent, child, allow, reason, source_plugin, depth
       - resource (rendered "/parent/child" or "/parent" or "/")
     """
-    resolved_plugins: List[PermissionSQL] = []
+    resolved_plugins: list[PermissionSQL] = []
-    restriction_sqls: List[str] = []
+    restriction_sqls: list[str] = []
 
     for plugin in plugins:
         if callable(plugin) and not isinstance(plugin, PermissionSQL):
@@ -398,11 +399,11 @@ async def resolve_permissions_with_candidates(
     db,
     actor: dict | None,
     plugins: Sequence[Any],
-    candidates: List[Tuple[str, str | None]],
+    candidates: list[tuple[str, str | None]],
     action: str,
     *,
     implicit_deny: bool = True,
-) -> List[Dict[str, Any]]:
+) -> list[dict[str, Any]]:
     """
     Resolve permissions without any external candidate table by embedding
     the candidates as a UNION of parameterized SELECTs in a CTE.
@@ -411,8 +412,8 @@ async def resolve_permissions_with_candidates(
     actor: actor dict (or None), made available as :actor (JSON), :actor_id, and :action
     """
     # Build a small CTE for candidates.
-    cand_rows_sql: List[str] = []
+    cand_rows_sql: list[str] = []
-    cand_params: Dict[str, Any] = {}
+    cand_params: dict[str, Any] = {}
     for i, (parent, child) in enumerate(candidates):
         pkey = f"cand_p_{i}"
         ckey = f"cand_c_{i}"

datasette/utils/shutil_backport.py

@@ -6,7 +6,7 @@ https://github.com/python/cpython/blob/v3.8.3/LICENSE
 """
 
 import os
-from shutil import copy, copy2, copystat, Error
+from shutil import Error, copy, copy2, copystat
 
 
 def _copytree(

datasette/utils/sql_analysis.py

@@ -413,12 +413,12 @@ def analyze_sql_tables(
                 database=None,
                 table=None,
                 sqlite_schema=sqlite_schema,
-                target="{} {}".format(arg1, arg2) if arg2 is not None else arg1,
+                target=f"{arg1} {arg2}" if arg2 is not None else arg1,
                 source=source,
             )
             return sqlite3.SQLITE_OK
 
-        action_name = _AUTHORIZER_ACTION_NAMES.get(action, "SQLITE_{}".format(action))
+        action_name = _AUTHORIZER_ACTION_NAMES.get(action, f"SQLITE_{action}")
         record(
             "unknown",
             "unknown",
@@ -521,9 +521,7 @@ def analyze_sql_tables(
             and key.target in _SQLITE_INTERNAL_SCHEMA_FUNCTIONS
         ):
             return True
-        if key_is_drop_table_delete(key):
+        return bool(key_is_drop_table_delete(key))
-            return True
-        return False
 
     def table_kind_for(key: OperationKey) -> SQLiteTableType | None:
         if (

datasette/utils/sqlite.py

@@ -100,7 +100,7 @@ def sqlite_hidden_table_names(conn, *, schema: str | None = "main") -> list[str]
     schema_table = _sqlite_schema_table(schema)
     try:
         rows = conn.execute(
-            "select name, sql from {} where type = 'table'".format(schema_table)
+            f"select name, sql from {schema_table} where type = 'table'"
         ).fetchall()
     except sqlite3.DatabaseError:
         return []
@@ -127,7 +127,7 @@ def _sqlite_table_type_from_schema(
     schema_table = _sqlite_schema_table(schema)
     try:
         row = conn.execute(
-            "select type, sql from {} where name = ?".format(schema_table),
+            f"select type, sql from {schema_table} where name = ?",
             (table,),
         ).fetchone()
     except sqlite3.DatabaseError:
@@ -155,7 +155,7 @@ def _is_known_shadow_table(
     schema_table = _sqlite_schema_table(schema)
     try:
         rows = conn.execute(
-            "select name, sql from {} where type = 'table'".format(schema_table)
+            f"select name, sql from {schema_table} where type = 'table'"
         ).fetchall()
     except sqlite3.DatabaseError:
         return False
@@ -174,7 +174,7 @@ def _sqlite_schema_table(schema: str | None) -> str:
         return "sqlite_master"
     if schema == "temp":
         return "sqlite_temp_master"
-    return "{}.sqlite_master".format(_quote_identifier(schema))
+    return f"{_quote_identifier(schema)}.sqlite_master"
 
 
 def _quote_identifier(value: str) -> str:

datasette/utils/testing.py

@@ -1,6 +1,7 @@
-from asgiref.sync import async_to_sync
-from urllib.parse import urlencode
 import json
+from urllib.parse import urlencode
+
+from asgiref.sync import async_to_sync
 
 # These wrapper classes pre-date the introduction of
 # datasette.client and httpx to Datasette. They could

datasette/version.py

@@ -1,2 +1,2 @@
-__version__ = "1.0a36"
+__version__ = "1.0a37"
 __version_info__ = tuple(__version__.split("."))

datasette/views/__init__.py

@@ -1,7 +1,7 @@
-from dataclasses import dataclass
 import dataclasses
 import types
 import typing
+from dataclasses import dataclass
 
 
 @dataclass(frozen=True)
@@ -74,16 +74,14 @@ class Context:
             extra_class = table_extra_registry.classes_by_name[name]
         except KeyError:
             raise KeyError(
-                "{}.{} is declared with from_extra() but there is no "
+                f"{cls.__name__}.{name} is declared with from_extra() but there is no "
-                "registered extra of that name".format(cls.__name__, name)
+                "registered extra of that name"
             )
         if cls.extras_scope is not None and not extra_class.available_for(
             cls.extras_scope
         ):
             raise ValueError(
-                "{}.{} is declared with from_extra() but the {} extra is "
+                f"{cls.__name__}.{name} is declared with from_extra() but the {name} extra is "
-                "not available for scope {}".format(
+                f"not available for scope {cls.extras_scope}"
-                    cls.__name__, name, name, cls.extras_scope
-                )
             )
         return extra_class.description or ""

datasette/views/base.py

@@ -2,20 +2,20 @@ import csv
 import hashlib
 import sys
 
-from datasette.utils.asgi import Request
 from datasette.utils import (
-    add_cors_headers,
     EscapeHtmlWriter,
     InvalidSql,
     LimitedWriter,
+    add_cors_headers,
     path_from_row_pks,
     path_with_format,
     sqlite3,
 )
 from datasette.utils.asgi import (
     AsgiStream,
-    Response,
     BadRequest,
+    Request,
+    Response,
 )
 
 
@@ -129,12 +129,10 @@ class BaseView:
         template = environment.select_template(templates)
         template_context = {
             **context,
-            **{
+            "select_templates": [
-                "select_templates": [
+                f"{'*' if template_name == template.name else ''}{template_name}"
-                    f"{'*' if template_name == template.name else ''}{template_name}"
+                for template_name in templates
-                    for template_name in templates
+            ],
-                ],
-            },
         }
         headers = {}
         if self.has_json_alternate:
@@ -151,9 +149,7 @@ class BaseView:
             template_context["alternate_url_json"] = alternate_url_json
             headers.update(
                 {
-                    "Link": '<{}>; rel="alternate"; type="application/json+datasette"'.format(
+                    "Link": f'<{alternate_url_json}>; rel="alternate"; type="application/json+datasette"'
-                        alternate_url_json
-                    )
                 }
             )
         return Response.html(
@@ -184,9 +180,7 @@ async def stream_csv(datasette, fetch_data, request, database):
     stream = request.args.get("_stream")
     # Do not calculate facets or counts:
     extra_parameters = [
-        "{}=1".format(key)
+        f"{key}=1" for key in ("_nofacet", "_nocount") if not request.args.get(key)
-        for key in ("_nofacet", "_nocount")
-        if not request.args.get(key)
     ]
     if extra_parameters:
         # Replace request object with a new one with modified scope
@@ -216,9 +210,6 @@ async def stream_csv(datasette, fetch_data, request, database):
     except (sqlite3.OperationalError, InvalidSql) as e:
         raise DatasetteError(str(e), title="Invalid SQL", status=400)
 
-    except sqlite3.OperationalError as e:
-        raise DatasetteError(str(e))
-
     except DatasetteError:
         raise
 
@@ -325,8 +316,9 @@ async def stream_csv(datasette, fetch_data, request, database):
                             else:
                                 new_row.append(cell)
                         await writer.writerow(new_row)
-            except Exception as ex:
+            except Exception as ex:  # noqa: BLE001
-                sys.stderr.write("Caught this error: {}\n".format(ex))
+                # Streaming CSV: report the error into the response body and stop
+                sys.stderr.write(f"Caught this error: {ex}\n")
                 sys.stderr.flush()
                 await r.write(str(ex))
                 return

datasette/views/database.py

@@ -1,49 +1,52 @@
-from dataclasses import asdict, dataclass, field
-from urllib.parse import parse_qsl, urlencode
 import asyncio
 import hashlib
 import itertools
 import json
-import markupsafe
 import os
 import textwrap
+from dataclasses import asdict, dataclass, field
+from urllib.parse import parse_qsl, urlencode
+
+import markupsafe
 
-from datasette.extras import extra_names_from_request, ExtraScope
 from datasette.database import QueryInterrupted
+from datasette.extras import ExtraScope, extra_names_from_request
+from datasette.plugins import pm
 from datasette.resources import DatabaseResource, QueryResource
 from datasette.stored_queries import StoredQuery, stored_query_to_dict
-from datasette.write_sql import QueryWriteRejected
 from datasette.utils import (
+    InvalidSql,
     add_cors_headers,
     await_me_maybe,
-    error_body,
     call_with_supported_arguments,
-    named_parameters as derive_named_parameters,
+    error_body,
     format_bytes,
-    make_slot_function,
-    tilde_decode,
-    to_css_class,
-    validate_sql_select,
     is_url,
+    make_slot_function,
     path_with_added_args,
     path_with_format,
     path_with_removed_args,
     sqlite3,
+    tilde_decode,
+    to_css_class,
     truncate_url,
-    InvalidSql,
+    validate_sql_select,
 )
-from datasette.utils.asgi import AsgiFileDownload, NotFound, Response, Forbidden
+from datasette.utils import (
-from datasette.plugins import pm
+    named_parameters as derive_named_parameters,
+)
+from datasette.utils.asgi import AsgiFileDownload, Forbidden, NotFound, Response
+from datasette.write_sql import QueryWriteRejected
 
+from . import Context
 from .base import DatasetteError, View, stream_csv
 from .query_helpers import _ensure_stored_query_execution_permissions, _table_columns
+from .table_create_alter import _create_table_ui_context
 from .table_extras import (
     QueryExtraContext,
     resolve_query_extras,
     table_extra_registry,
 )
-from .table_create_alter import _create_table_ui_context
-from . import Context
 
 
 @dataclass
@@ -100,7 +103,7 @@ class DatabaseView(View):
             return response
 
         if format_ not in ("html", "json"):
-            raise NotFound("Invalid format: {}".format(format_))
+            raise NotFound(f"Invalid format: {format_}")
 
         metadata = await datasette.get_database_metadata(database)
 
@@ -164,7 +167,7 @@ class DatabaseView(View):
                         "label": "Create table",
                         "description": "Create a new table in this database.",
                         "attrs": {
-                            "aria-label": "Create table in {}".format(database),
+                            "aria-label": f"Create table in {database}",
                             "data-database-action": "create-table",
                         },
                     }
@@ -271,9 +274,7 @@ class DatabaseView(View):
                 view_name="database",
             ),
             headers={
-                "Link": '<{}>; rel="alternate"; type="application/json+datasette"'.format(
+                "Link": f'<{alternate_url_json}>; rel="alternate"; type="application/json+datasette"'
-                    alternate_url_json
-                )
             },
         )
 
@@ -556,7 +557,7 @@ async def database_download(request, datasette):
     if datasette.cors:
         add_cors_headers(headers)
     if db.hash:
-        etag = '"{}"'.format(db.hash)
+        etag = f'"{db.hash}"'
         headers["Etag"] = etag
         # Has user seen this already?
         if_none_match = request.headers.get("if-none-match")
@@ -643,8 +644,15 @@ class QueryView(View):
         ok = None
         redirect_url = None
         try:
+            execute_write_kwargs = {"request": request}
+            if stored_query.is_trusted:
+                analysis = await db.analyze_sql(stored_query.sql, params_for_query)
+                if any(
+                    operation.operation == "vacuum" for operation in analysis.operations
+                ):
+                    execute_write_kwargs["transaction"] = False
             cursor = await db.execute_write(
-                stored_query.sql, params_for_query, request=request
+                stored_query.sql, params_for_query, **execute_write_kwargs
             )
             # success message can come from on_success_message or on_success_message_sql
             message = None
@@ -657,8 +665,9 @@ class QueryView(View):
                     ).first()
                     if message_result:
                         message = message_result[0]
-                except Exception as ex:
+                except Exception as ex:  # noqa: BLE001
-                    message = "Error running on_success_message_sql: {}".format(ex)
+                    # Stored-query on_success_message_sql is user-authored
+                    message = f"Error running on_success_message_sql: {ex}"
                     message_type = datasette.ERROR
             if not message:
                 if stored_query.on_success_message:
@@ -672,7 +681,8 @@ class QueryView(View):
 
             redirect_url = stored_query.on_success_redirect
             ok = True
-        except Exception as ex:
+        except Exception as ex:  # noqa: BLE001
+            # Stored-query execution is user-authored SQL
             message = stored_query.on_error_message or str(ex)
             message_type = datasette.ERROR
             redirect_url = stored_query.on_error_redirect
@@ -806,16 +816,16 @@ class QueryView(View):
                 rows = results.rows
             except QueryInterrupted as ex:
                 raise DatasetteError(
-                    textwrap.dedent("""
+                    textwrap.dedent(f"""
                     <p>SQL query took too long. The time limit is controlled by the
                     <a href="https://docs.datasette.io/en/stable/settings.html#sql-time-limit-ms">sql_time_limit_ms</a>
                     configuration option.</p>
-                    <textarea style="width: 90%">{}</textarea>
+                    <textarea style="width: 90%">{markupsafe.escape(ex.sql)}</textarea>
                     <script>
                     let ta = document.querySelector("textarea");
                     ta.style.height = ta.scrollHeight + "px";
                     </script>
-                """.format(markupsafe.escape(ex.sql))).strip(),
+                """).strip(),
                     title="SQL Interrupted",
                     status=400,
                     message_is_html=True,
@@ -831,8 +841,6 @@ class QueryView(View):
                 columns = []
             except (sqlite3.OperationalError, InvalidSql) as ex:
                 raise DatasetteError(str(ex), title="Invalid SQL", status=400)
-            except sqlite3.OperationalError as ex:
-                raise DatasetteError(str(ex))
             except DatasetteError:
                 raise
 
@@ -854,7 +862,7 @@ class QueryView(View):
                 return data, None, None
 
             return await stream_csv(datasette, fetch_data_for_csv, request, db.name)
-        elif format_ in datasette.renderers.keys():
+        elif format_ in datasette.renderers:
             if not sql:
                 raise DatasetteError("?sql= is required", status=400)
             data = {"ok": True, "rows": rows, "columns": columns}
@@ -946,9 +954,7 @@ class QueryView(View):
             }
             headers.update(
                 {
-                    "Link": '<{}>; rel="alternate"; type="application/json+datasette"'.format(
+                    "Link": f'<{alternate_url_json}>; rel="alternate"; type="application/json+datasette"'
-                        alternate_url_json
-                    )
                 }
             )
             metadata = await query_metadata()
@@ -1029,9 +1035,7 @@ class QueryView(View):
                         + "?"
                         + urlencode(
                             {
-                                **{
+                                "sql": sql,
-                                    "sql": sql,
-                                },
                                 **named_parameter_values,
                             }
                         )
@@ -1133,7 +1137,7 @@ class QueryView(View):
                 headers=headers,
             )
         else:
-            assert False, "Invalid format: {}".format(format_)
+            assert False, f"Invalid format: {format_}"
         if datasette.cors:
             add_cors_headers(r.headers)
         return r
@@ -1234,7 +1238,7 @@ async def display_rows(datasette, database, request, rows, columns):
                         '<a class="blob-download" href="{}"{}>&lt;Binary:&nbsp;{:,}&nbsp;byte{}&gt;</a>'.format(
                             blob_url,
                             (
-                                ' title="{}"'.format(formatted)
+                                f' title="{formatted}"'
                                 if "bytes" not in formatted
                                 else ""
                             ),

datasette/views/execute_write.py

@@ -8,8 +8,8 @@ from datasette.utils.asgi import Response
 from .base import BaseView
 from .database import display_rows as display_query_rows
 from .query_helpers import (
-    QueryValidationError,
     SQL_PARAMETER_FORM_PREFIX,
+    QueryValidationError,
     _analysis_is_write,
     _analysis_rows,
     _analysis_rows_with_permissions,
@@ -31,15 +31,7 @@ WRITE_TEMPLATE_LABELS = {
     "delete": "Delete rows",
 }
 WRITE_TEMPLATE_OPERATIONS = tuple(WRITE_TEMPLATE_LABELS)
-CREATE_TABLE_TEMPLATE_SQL = "\n".join(
+CREATE_TABLE_TEMPLATE_SQL = "create table new_table (\n  id integer primary key,\n  name text\n  -- created text default (datetime('now'))\n)"
-    (
-        "create table new_table (",
-        "  id integer primary key,",
-        "  name text",
-        "  -- created text default (datetime('now'))",
-        ")",
-    )
-)
 
 
 def _parameter_names(columns):
@@ -49,11 +41,11 @@ def _parameter_names(columns):
         base = re.sub(r"[^a-z0-9_]+", "_", column.lower())
         base = base.strip("_") or "value"
         if base[0].isdigit():
-            base = "p_{}".format(base)
+            base = f"p_{base}"
         name = base
         index = 2
         while name in seen:
-            name = "{}_{}".format(base, index)
+            name = f"{base}_{index}"
             index += 1
         seen.add(name)
         names[column] = name
@@ -65,7 +57,7 @@ def _quote_identifier(identifier):
 
 
 def _preferred_where_column(table, columns):
-    lower_table_id = "{}_id".format(table.lower())
+    lower_table_id = f"{table.lower()}_id"
     return (
         next((column for column in columns if column.lower() == "id"), None)
         or next(
@@ -90,17 +82,15 @@ def _insert_template_sql(table, columns):
     auto_pk = _auto_incrementing_primary_key(columns)
     insert_columns = [column for column in column_names if column != auto_pk]
     if not insert_columns:
-        return "insert into {}\ndefault values".format(_quote_identifier(table))
+        return f"insert into {_quote_identifier(table)}\ndefault values"
     names = _parameter_names(insert_columns)
     return "\n".join(
         (
-            "insert into {} (".format(_quote_identifier(table)),
+            f"insert into {_quote_identifier(table)} (",
-            ",\n".join(
+            ",\n".join(f"  {_quote_identifier(column)}" for column in insert_columns),
-                "  {}".format(_quote_identifier(column)) for column in insert_columns
-            ),
             ")",
             "values (",
-            ",\n".join("  :{}".format(names[column]) for column in insert_columns),
+            ",\n".join(f"  :{names[column]}" for column in insert_columns),
             ")",
         )
     )
@@ -114,18 +104,14 @@ def _update_template_sql(table, columns):
     if not set_columns:
         return "\n".join(
             (
-                "update {}".format(_quote_identifier(table)),
+                f"update {_quote_identifier(table)}",
-                "set {} = :new_{}".format(
+                f"set {_quote_identifier(where_column)} = :new_{names[where_column]}",
-                    _quote_identifier(where_column), names[where_column]
+                f"where {_quote_identifier(where_column)} = :{names[where_column]}",
-                ),
-                "where {} = :{}".format(
-                    _quote_identifier(where_column), names[where_column]
-                ),
             )
         )
     return "\n".join(
         (
-            "update {}".format(_quote_identifier(table)),
+            f"update {_quote_identifier(table)}",
             "set "
             + ",\n".join(
                 "{}{} = :{}".format(
@@ -135,9 +121,7 @@ def _update_template_sql(table, columns):
                 )
                 for index, column in enumerate(set_columns)
             ),
-            "where {} = :{}".format(
+            f"where {_quote_identifier(where_column)} = :{names[where_column]}",
-                _quote_identifier(where_column), names[where_column]
-            ),
         )
     )
 
@@ -148,10 +132,8 @@ def _delete_template_sql(table, columns):
     where_column = _preferred_where_column(table, column_names)
     return "\n".join(
         (
-            "delete from {}".format(_quote_identifier(table)),
+            f"delete from {_quote_identifier(table)}",
-            "where {} = :{}".format(
+            f"where {_quote_identifier(where_column)} = :{names[where_column]}",
-                _quote_identifier(where_column), names[where_column]
-            ),
         )
     )
 

datasette/views/index.py

@@ -2,11 +2,11 @@ import json
 
 from datasette.plugins import pm
 from datasette.utils import (
+    UNSTABLE_API_MESSAGE,
+    CustomJSONEncoder,
     add_cors_headers,
     await_me_maybe,
     make_slot_function,
-    CustomJSONEncoder,
-    UNSTABLE_API_MESSAGE,
 )
 from datasette.utils.asgi import Response
 from datasette.version import __version__
@@ -46,15 +46,15 @@ class IndexView(BaseView):
 
         databases = []
         # Iterate over allowed databases instead of all databases
-        for name in allowed_db_dict.keys():
+        for name, allowed_db in allowed_db_dict.items():
             db = self.ds.databases[name]
-            database_private = allowed_db_dict[name].private
+            database_private = allowed_db.private
 
             # Get allowed tables/views for this database
             allowed_for_db = tables_by_db.get(name, {})
 
             # Get table names from allowed set instead of db.table_names()
-            table_names = [child_name for child_name in allowed_for_db.keys()]
+            table_names = [child_name for child_name in allowed_for_db]
 
             hidden_table_names = set(await db.hidden_table_names())
 
@@ -99,7 +99,7 @@ class IndexView(BaseView):
                 # We will be sorting by number of relationships, so populate that field
                 all_foreign_keys = await db.get_all_foreign_keys()
                 for table, foreign_keys in all_foreign_keys.items():
-                    if table in tables.keys():
+                    if table in tables:
                         count = len(foreign_keys["incoming"] + foreign_keys["outgoing"])
                         tables[table]["num_relationships_for_sorting"] = count
 
@@ -121,8 +121,7 @@ class IndexView(BaseView):
             # Only add views if this is less than TRUNCATE_AT
             if len(tables_and_views_truncated) < TRUNCATE_AT:
                 num_views_to_add = TRUNCATE_AT - len(tables_and_views_truncated)
-                for view in views[:num_views_to_add]:
+                tables_and_views_truncated.extend(views[:num_views_to_add])
-                    tables_and_views_truncated.append(view)
 
             databases.append(
                 {

datasette/views/query_helpers.py

@@ -5,6 +5,19 @@ from datasette.resources import DatabaseResource
 from datasette.stored_queries import (
     StoredQuery,
 )
+from datasette.utils import (
+    InvalidSql,
+    escape_sqlite,
+    parse_size_limit,
+    path_from_row_pks,
+    sqlite3,
+    validate_sql_select,
+)
+from datasette.utils import (
+    named_parameters as derive_named_parameters,
+)
+from datasette.utils.asgi import Forbidden
+from datasette.utils.sql_analysis import Operation, SQLAnalysis
 from datasette.write_sql import (
     IgnoreWriteSqlOperation,
     QueryWriteRejected,
@@ -12,17 +25,6 @@ from datasette.write_sql import (
     decision_for_write_sql_operation,
     operation_is_write,
 )
-from datasette.utils import (
-    parse_size_limit,
-    named_parameters as derive_named_parameters,
-    escape_sqlite,
-    path_from_row_pks,
-    sqlite3,
-    validate_sql_select,
-    InvalidSql,
-)
-from datasette.utils.asgi import Forbidden
-from datasette.utils.sql_analysis import Operation, SQLAnalysis
 
 _query_name_re = re.compile(r"^[^/\.\n]+$")
 
@@ -91,7 +93,7 @@ def _as_optional_bool(value, name):
             return True
         if lowered in {"0", "false", "f", "no", "off"}:
             return False
-    raise QueryValidationError("{} must be 0 or 1".format(name))
+    raise QueryValidationError(f"{name} must be 0 or 1")
 
 
 def _query_list_limit(value, default, maximum):
@@ -171,7 +173,7 @@ async def _json_or_form_payload(request):
         try:
             return json.loads(body or b"{}"), True
         except json.JSONDecodeError as e:
-            raise QueryValidationError("Invalid JSON: {}".format(e))
+            raise QueryValidationError(f"Invalid JSON: {e}")
     return await request.post_vars(), False
 
 
@@ -192,7 +194,7 @@ async def _analyze_user_query(datasette, db, sql, *, actor):
     try:
         analysis = await db.analyze_sql(sql, params)
     except sqlite3.DatabaseError as ex:
-        raise QueryValidationError("Could not analyze query: {}".format(ex)) from ex
+        raise QueryValidationError(f"Could not analyze query: {ex}") from ex
 
     is_write = _analysis_is_write(analysis)
     if is_write:
@@ -293,8 +295,7 @@ def _coerce_execute_write_payload(data, is_json):
         for key, value in data.items():
             if key in {"sql", "csrftoken", "_json"}:
                 continue
-            if key.startswith(SQL_PARAMETER_FORM_PREFIX):
+            key = key.removeprefix(SQL_PARAMETER_FORM_PREFIX)
-                key = key[len(SQL_PARAMETER_FORM_PREFIX) :]
             params[key] = value
     if not isinstance(params, dict):
         raise QueryValidationError("params must be a dictionary")
@@ -314,7 +315,7 @@ async def _prepare_execute_write(datasette, db, sql, params, actor):
     try:
         analysis = await db.analyze_sql(sql, params)
     except sqlite3.DatabaseError as ex:
-        raise QueryValidationError("Could not analyze query: {}".format(ex)) from ex
+        raise QueryValidationError(f"Could not analyze query: {ex}") from ex
     if not _analysis_is_write(analysis):
         raise QueryValidationError(
             "Use /-/query for read-only SQL; this endpoint only executes writes"
@@ -496,7 +497,7 @@ async def _inserted_row_url(datasette, db, analysis, cursor):
     )
     try:
         result = await db.execute(
-            "select {} from {} where rowid = ?".format(select, escape_sqlite(table)),
+            f"select {select} from {escape_sqlite(table)} where rowid = ?",
             [lastrowid],
         )
     except sqlite3.DatabaseError:

datasette/views/row.py

@@ -8,34 +8,35 @@ from dataclasses import dataclass, field
 import markupsafe
 import sqlite_utils
 
-from datasette.utils.asgi import NotFound, Forbidden, PayloadTooLarge, Response
 from datasette.database import QueryInterrupted
-from datasette.events import UpdateRowEvent, DeleteRowEvent
+from datasette.events import DeleteRowEvent, UpdateRowEvent
+from datasette.extras import ExtraScope, extra_names_from_request
+from datasette.plugins import pm
 from datasette.resources import TableResource
-from .base import BaseView, DatasetteError, stream_csv
 from datasette.utils import (
+    CustomJSONEncoder,
+    CustomRow,
+    InvalidSql,
+    WriteJsonValueError,
     add_cors_headers,
     await_me_maybe,
     call_with_supported_arguments,
-    CustomJSONEncoder,
-    CustomRow,
     decode_write_json_row,
-    InvalidSql,
+    escape_sqlite,
     make_slot_function,
     path_from_row_pks,
     path_with_format,
     path_with_removed_args,
-    to_css_class,
-    escape_sqlite,
     sqlite3,
-    WriteJsonValueError,
+    to_css_class,
 )
-from datasette.plugins import pm
+from datasette.utils.asgi import Forbidden, NotFound, PayloadTooLarge, Response
-from datasette.extras import extra_names_from_request, ExtraScope
+
 from . import Context, from_extra
+from .base import BaseView, DatasetteError, stream_csv
 from .table import (
-    display_columns_and_rows,
     _table_page_data,
+    display_columns_and_rows,
     row_label_from_label_column,
 )
 from .table_extras import RowExtraContext, resolve_row_extras, table_extra_registry
@@ -187,16 +188,16 @@ class RowView(BaseView):
                 data, extra_template_data, templates = response_or_template_contexts
         except QueryInterrupted as ex:
             raise DatasetteError(
-                textwrap.dedent("""
+                textwrap.dedent(f"""
                 <p>SQL query took too long. The time limit is controlled by the
                 <a href="https://docs.datasette.io/en/stable/settings.html#sql-time-limit-ms">sql_time_limit_ms</a>
                 configuration option.</p>
-                <textarea style="width: 90%">{}</textarea>
+                <textarea style="width: 90%">{markupsafe.escape(ex.sql)}</textarea>
                 <script>
                 let ta = document.querySelector("textarea");
                 ta.style.height = ta.scrollHeight + "px";
                 </script>
-            """.format(markupsafe.escape(ex.sql))).strip(),
+            """).strip(),
                 title="SQL Interrupted",
                 status=400,
                 message_is_html=True,
@@ -207,15 +208,13 @@ class RowView(BaseView):
             )
         except (sqlite3.OperationalError, InvalidSql) as e:
             raise DatasetteError(str(e), title="Invalid SQL", status=400)
-        except sqlite3.OperationalError as e:
-            raise DatasetteError(str(e))
         except DatasetteError:
             raise
 
         end = time.perf_counter()
         data["query_ms"] = (end - start) * 1000
 
-        if format_ in self.ds.renderers.keys():
+        if format_ in self.ds.renderers:
             # Dispatch request to the correct output format renderer
             # (CSV is not handled here due to streaming)
             result = call_with_supported_arguments(
@@ -258,7 +257,7 @@ class RowView(BaseView):
             if status_code is not None:
                 response.status = status_code
         else:
-            raise NotFound("Invalid format: {}".format(format_))
+            raise NotFound(f"Invalid format: {format_}")
 
         ttl = request.args.get("_ttl", None)
         if ttl is None or not ttl.isdigit():
@@ -373,9 +372,7 @@ class RowView(BaseView):
                 view_name=self.name,
             ),
             headers={
-                "Link": '<{}>; rel="alternate"; type="application/json+datasette"'.format(
+                "Link": f'<{alternate_url_json}>; rel="alternate"; type="application/json+datasette"'
-                    alternate_url_json
-                )
             },
         )
 
@@ -500,7 +497,7 @@ class RowView(BaseView):
 
             row_action_label = pk_path
             if row_label and row_label != pk_path:
-                row_action_label = "{} {}".format(pk_path, row_label)
+                row_action_label = f"{pk_path} {row_label}"
 
             row_action_permissions = {}
             if is_table and db.is_mutable:
@@ -513,7 +510,7 @@ class RowView(BaseView):
             row_actions = []
             if row_action_permissions.get("update-row"):
                 attrs = {
-                    "aria-label": "Edit row {}".format(row_action_label),
+                    "aria-label": f"Edit row {row_action_label}",
                     "data-row": row_path,
                     "data-row-action": "edit",
                 }
@@ -529,7 +526,7 @@ class RowView(BaseView):
                 )
             if row_action_permissions.get("delete-row"):
                 attrs = {
-                    "aria-label": "Delete row {}".format(row_action_label),
+                    "aria-label": f"Delete row {row_action_label}",
                     "data-row": row_path,
                     "data-row-action": "delete",
                 }
@@ -679,7 +676,7 @@ class RowView(BaseView):
                 key,
                 ",".join(pk_values),
             )
-            foreign_key_tables.append({**fk, **{"count": count, "link": link}})
+            foreign_key_tables.append({**fk, "count": count, "link": link})
         return foreign_key_tables
 
 
@@ -705,23 +702,21 @@ async def _row_flash_message(db, action, resolved, row=None):
     if label:
         label = _truncated_row_flash_label(label)
     if label and label != pk_label:
-        return "{} row {} ({})".format(action, pk_label, label)
+        return f"{action} row {pk_label} ({label})"
-    return "{} row {}".format(action, pk_label)
+    return f"{action} row {pk_label}"
 
 
 async def _resolve_row_and_check_permission(datasette, request, permission):
-    from datasette.app import DatabaseNotFound, TableNotFound, RowNotFound
+    from datasette.app import DatabaseNotFound, RowNotFound, TableNotFound
 
     try:
         resolved = await datasette.resolve_row(request)
     except DatabaseNotFound as e:
-        return False, Response.error(
+        return False, Response.error([f"Database not found: {e.database_name}"], 404)
-            ["Database not found: {}".format(e.database_name)], 404
-        )
     except TableNotFound as e:
-        return False, Response.error(["Table not found: {}".format(e.table)], 404)
+        return False, Response.error([f"Table not found: {e.table}"], 404)
     except RowNotFound as e:
-        return False, Response.error(["Record not found: {}".format(e.pk_values)], 404)
+        return False, Response.error([f"Record not found: {e.pk_values}"], 404)
 
     # Ensure user has permission to delete this row
     if not await datasette.allowed(
@@ -753,7 +748,8 @@ class RowDeleteView(BaseView):
 
         try:
             await resolved.db.execute_write_fn(delete_row, request=request)
-        except Exception as e:
+        except Exception as e:  # noqa: BLE001
+            # TODO: narrow to expected write errors so Datasette bugs surface as 500s
             return Response.error([str(e)], 400)
 
         await self.ds.track_event(
@@ -793,7 +789,7 @@ class RowUpdateView(BaseView):
         try:
             data = await request.json()
         except json.JSONDecodeError as e:
-            return Response.error(["Invalid JSON: {}".format(e)])
+            return Response.error([f"Invalid JSON: {e}"])
         except PayloadTooLarge as e:
             return Response.error([str(e)], 413)
 
@@ -836,7 +832,8 @@ class RowUpdateView(BaseView):
 
         try:
             await resolved.db.execute_write_fn(update_row, request=request)
-        except Exception as e:
+        except Exception as e:  # noqa: BLE001
+            # TODO: narrow to expected write errors so Datasette bugs surface as 500s
             return Response.error([str(e)], 400)
 
         result = {"ok": True}

datasette/views/special.py

@@ -1,23 +1,25 @@
 import json
 import logging
+import secrets
+import urllib
+
+from datasette.events import CreateTokenEvent, LoginEvent, LogoutEvent
 from datasette.jump import JumpSQL, namespace_sql_params
 from datasette.plugins import pm
-from datasette.events import LogoutEvent, LoginEvent, CreateTokenEvent
 from datasette.resources import DatabaseResource, TableResource
-from datasette.utils.asgi import Response, Forbidden
 from datasette.utils import (
     UNSTABLE_API_MESSAGE,
     actor_matches_allow,
-    parse_size_limit,
     add_cors_headers,
     await_me_maybe,
     error_body,
-    tilde_encode,
+    parse_size_limit,
     tilde_decode,
+    tilde_encode,
 )
+from datasette.utils.asgi import Forbidden, Response
+
 from .base import BaseView, View
-import secrets
-import urllib
 
 logger = logging.getLogger(__name__)
 
@@ -179,9 +181,7 @@ class AutocompleteDebugView(BaseView):
                     )
                     context.update(
                         {
-                            "autocomplete_url": "{}/-/autocomplete".format(
+                            "autocomplete_url": f"{self.ds.urls.table(database_name, table_name)}/-/autocomplete",
-                                self.ds.urls.table(database_name, table_name)
-                            ),
                             "label_column": await db.label_column_for_table(table_name),
                         }
                     )
@@ -420,8 +420,11 @@ class AllowedResourcesView(BaseView):
                     row["reason"] = resource.reasons
 
                 allowed_rows.append(row)
-        except Exception:
+        except Exception:  # noqa: BLE001
-            # If catalog tables don't exist yet, return empty results
+            # Returns empty results if the catalog tables don't exist yet, but
+            # also swallows the AttributeError raised for instance-level actions
+            # such as view-instance, which have no resource_class.
+            # TODO: handle that case explicitly and narrow this to sqlite3.Error
             return (
                 {
                     "ok": True,
@@ -523,7 +526,7 @@ class PermissionRulesView(BaseView):
 
         from datasette.utils.actions_sql import build_permission_rules_sql
 
-        union_sql, union_params, restriction_sqls = await build_permission_rules_sql(
+        union_sql, union_params, _restriction_sqls = await build_permission_rules_sql(
             self.ds, actor, action
         )
         await self.ds.refresh_schemas()
@@ -600,7 +603,7 @@ class PermissionRulesView(BaseView):
 
 
 async def _check_permission_for_actor(ds, action, parent, child, actor):
-    """Shared logic for checking permissions. Returns a dict with check results."""
+    """Shared logic for checking and explaining a permission decision."""
     if action not in ds.actions:
         return error_body(f"Unknown action: {action}", 404), 404
 
@@ -629,15 +632,28 @@ async def _check_permission_for_actor(ds, action, parent, child, actor):
 
     allowed = await ds.allowed(action=action, resource=resource_obj, actor=actor)
 
+    from datasette.utils.actions_sql import explain_permission_for_resource
+
+    explanation = await explain_permission_for_resource(
+        datasette=ds,
+        actor=actor,
+        action=action,
+        parent=parent,
+        child=child,
+    )
+
     response = {
         "ok": True,
+        "unstable": UNSTABLE_API_MESSAGE,
         "action": action,
         "allowed": bool(allowed),
+        "actor": actor,
         "resource": {
             "parent": parent,
             "child": child,
             "path": _resource_path(parent, child),
         },
+        "explanation": explanation,
     }
 
     if actor and "id" in actor:
@@ -655,11 +671,25 @@ class PermissionCheckView(BaseView):
         as_format = request.url_vars.get("format")
 
         if not as_format:
+            actions = [
+                {
+                    "name": action.name,
+                    "description": action.description,
+                    "takes_parent": action.takes_parent,
+                    "takes_child": action.takes_child,
+                    "also_requires": action.also_requires,
+                }
+                for action in sorted(
+                    self.ds.actions.values(), key=lambda action: action.name
+                )
+            ]
             return await self.render(
                 ["debug_check.html"],
                 request,
                 {
-                    "sorted_actions": sorted(self.ds.actions.keys()),
+                    "actions": actions,
+                    "actor_json": request.args.get("actor")
+                    or json.dumps(request.actor, indent=2),
                     "has_debug_permission": True,
                 },
             )
@@ -671,9 +701,18 @@ class PermissionCheckView(BaseView):
 
         parent = request.args.get("parent")
         child = request.args.get("child")
+        actor = request.actor
+        actor_json = request.args.get("actor")
+        if actor_json is not None:
+            try:
+                actor = json.loads(actor_json)
+            except json.JSONDecodeError as ex:
+                return Response.error(f"Invalid actor JSON: {ex}", 400)
+            if actor is not None and not isinstance(actor, dict):
+                return Response.error("actor must be a JSON object or null", 400)
 
         response, status = await _check_permission_for_actor(
-            self.ds, action, parent, child, request.actor
+            self.ds, action, parent, child, actor
         )
         return Response.json(response, status=status)
 
@@ -900,7 +939,7 @@ class ApiExplorerView(BaseView):
                 tables.append({"name": table, "links": table_links})
                 table_links.append(
                     {
-                        "label": "Get rows for {}".format(table),
+                        "label": f"Get rows for {table}",
                         "method": "GET",
                         "path": self.ds.urls.table(name, table, format="json"),
                     }
@@ -920,7 +959,7 @@ class ApiExplorerView(BaseView):
                             {
                                 "path": self.ds.urls.table(name, table) + "/-/insert",
                                 "method": "POST",
-                                "label": "Insert rows into {}".format(table),
+                                "label": f"Insert rows into {table}",
                                 "json": {
                                     "rows": [
                                         {
@@ -934,7 +973,7 @@ class ApiExplorerView(BaseView):
                             {
                                 "path": self.ds.urls.table(name, table) + "/-/upsert",
                                 "method": "POST",
-                                "label": "Upsert rows into {}".format(table),
+                                "label": f"Upsert rows into {table}",
                                 "json": {
                                     "rows": [
                                         {
@@ -964,7 +1003,7 @@ class ApiExplorerView(BaseView):
                     table_links.append(
                         {
                             "path": self.ds.urls.table(name, table) + "/-/drop",
-                            "label": "Drop table {}".format(table),
+                            "label": f"Drop table {table}",
                             "json": {"confirm": False},
                             "method": "POST",
                         }
@@ -981,7 +1020,7 @@ class ApiExplorerView(BaseView):
                 database_links.append(
                     {
                         "path": self.ds.urls.database(name) + "/-/create",
-                        "label": "Create table in {}".format(name),
+                        "label": f"Create table in {name}",
                         "json": {
                             "table": "new_table",
                             "columns": [

datasette/views/stored_queries.py

@@ -124,7 +124,7 @@ class QueryListView(BaseView):
             pairs.append(("_next", page.next))
             next_url = self.ds.absolute_url(
                 request,
-                "{}?{}".format(request.path, urlencode(pairs)),
+                f"{request.path}?{urlencode(pairs)}",
             )
 
         current_filters = {
@@ -415,7 +415,7 @@ class QueryDefinitionView(BaseView):
         query_name = tilde_decode(request.url_vars["query"])
         query = await self.ds.get_query(db.name, query_name)
         if query is None:
-            return Response.error(["Query not found: {}".format(query_name)], 404)
+            return Response.error([f"Query not found: {query_name}"], 404)
         if not await self.ds.allowed(
             action="view-query",
             resource=QueryResource(db.name, query_name),
@@ -439,7 +439,7 @@ class QueryUpdateView(BaseView):
         query_name = tilde_decode(request.url_vars["query"])
         existing = await self.ds.get_query(db.name, query_name)
         if existing is None:
-            return Response.error(["Query not found: {}".format(query_name)], 404)
+            return Response.error([f"Query not found: {query_name}"], 404)
         if not await self.ds.allowed(
             action="update-query",
             resource=QueryResource(db.name, query_name),
@@ -532,7 +532,7 @@ class QueryEditView(BaseView):
     async def get(self, request):
         db, query_name, existing = await self._load(request)
         if existing is None:
-            return Response.error(["Query not found: {}".format(query_name)], 404)
+            return Response.error([f"Query not found: {query_name}"], 404)
         await self.ds.ensure_permission(
             action="update-query",
             resource=QueryResource(db.name, query_name),
@@ -545,7 +545,7 @@ class QueryEditView(BaseView):
     async def post(self, request):
         db, query_name, existing = await self._load(request)
         if existing is None:
-            return Response.error(["Query not found: {}".format(query_name)], 404)
+            return Response.error([f"Query not found: {query_name}"], 404)
         if not await self.ds.allowed(
             action="update-query",
             resource=QueryResource(db.name, query_name),
@@ -629,7 +629,7 @@ class QueryDeleteView(BaseView):
     async def get(self, request):
         db, query_name, existing = await self._load(request)
         if existing is None:
-            return Response.error(["Query not found: {}".format(query_name)], 404)
+            return Response.error([f"Query not found: {query_name}"], 404)
         await self.ds.ensure_permission(
             action="delete-query",
             resource=QueryResource(db.name, query_name),
@@ -653,7 +653,7 @@ class QueryDeleteView(BaseView):
     async def post(self, request):
         db, query_name, existing = await self._load(request)
         if existing is None:
-            return Response.error(["Query not found: {}".format(query_name)], 404)
+            return Response.error([f"Query not found: {query_name}"], 404)
         if not await self.ds.allowed(
             action="delete-query",
             resource=QueryResource(db.name, query_name),
@@ -665,13 +665,13 @@ class QueryDeleteView(BaseView):
                 ["Trusted queries cannot be deleted using the API"], 403
             )
 
-        data, is_json = await _json_or_form_payload(request)
+        _data, is_json = await _json_or_form_payload(request)
         await self.ds.remove_query(db.name, query_name)
         if is_json:
             return Response.json({"ok": True})
         self.ds.add_message(
             request,
-            "Query “{}” deleted".format(existing.title or query_name),
+            f"Query “{existing.title or query_name}” deleted",
             self.ds.INFO,
         )
         return Response.redirect(self.ds.urls.path(self.ds.urls.database(db.name)))

datasette/views/table.py

@@ -3,48 +3,51 @@ import itertools
 import json
 import urllib
 import urllib.parse
+from dataclasses import dataclass, field
 
 import markupsafe
+import sqlite_utils
 
+from datasette import tracer
 from datasette.column_types import SQLiteType
-from datasette.extras import extra_names_from_request
+from datasette.database import QueryInterrupted
-from datasette.plugins import pm
 from datasette.events import (
     AlterTableEvent,
     DropTableEvent,
     InsertRowsEvent,
     UpsertRowsEvent,
 )
-from datasette.database import QueryInterrupted
+from datasette.extras import ExtraScope, extra_names_from_request
-from datasette import tracer
+from datasette.filters import Filters
+from datasette.plugins import pm
 from datasette.resources import DatabaseResource, TableResource
 from datasette.utils import (
-    add_cors_headers,
-    await_me_maybe,
-    call_with_supported_arguments,
     CustomJSONEncoder,
     CustomRow,
+    InvalidSql,
+    WriteJsonValueError,
+    add_cors_headers,
     append_querystring,
+    await_me_maybe,
+    call_with_supported_arguments,
     compound_keys_after_sql,
     decode_write_json_rows,
-    format_bytes,
-    make_slot_function,
-    tilde_encode,
     escape_sqlite,
     filters_should_redirect,
+    format_bytes,
     is_url,
+    make_slot_function,
     path_from_row_pks,
     path_with_added_args,
     path_with_format,
     path_with_removed_args,
     path_with_replaced_args,
+    sqlite3,
+    tilde_encode,
     to_css_class,
     truncate_url,
     urlsafe_components,
     value_as_boolean,
-    InvalidSql,
-    WriteJsonValueError,
-    sqlite3,
 )
 from datasette.utils.asgi import (
     BadRequest,
@@ -54,11 +57,7 @@ from datasette.utils.asgi import (
     Request,
     Response,
 )
-from datasette.filters import Filters
-import sqlite_utils
-from dataclasses import dataclass, field
 
-from datasette.extras import ExtraScope
 from . import Context, from_extra
 from .base import BaseView, DatasetteError, stream_csv
 from .database import QueryView
@@ -536,7 +535,7 @@ async def _table_insert_ui(
         columns.append(column_data)
 
     data = {
-        "path": "{}/-/insert".format(datasette.urls.table(database_name, table_name)),
+        "path": f"{datasette.urls.table(database_name, table_name)}/-/insert",
         "tableName": table_name,
         "columns": columns,
         "bulkColumns": bulk_columns,
@@ -544,8 +543,8 @@ async def _table_insert_ui(
         "maxInsertRows": datasette.setting("max_insert_rows"),
     }
     if can_update:
-        data["upsertPath"] = "{}/-/upsert".format(
+        data["upsertPath"] = (
-            datasette.urls.table(database_name, table_name)
+            f"{datasette.urls.table(database_name, table_name)}/-/upsert"
         )
     return data
 
@@ -604,7 +603,7 @@ async def _table_alter_ui(
         columns.append(column_data)
 
     data = {
-        "path": "{}/-/alter".format(datasette.urls.table(database_name, table_name)),
+        "path": f"{datasette.urls.table(database_name, table_name)}/-/alter",
         "tableName": table_name,
         "columns": columns,
         "primaryKeys": pks,
@@ -630,9 +629,7 @@ async def _table_alter_ui(
         actor=request.actor,
     )
     if can_drop_table:
-        data["dropPath"] = "{}/-/drop".format(
+        data["dropPath"] = f"{datasette.urls.table(database_name, table_name)}/-/drop"
-            datasette.urls.table(database_name, table_name)
-        )
     return data
 
 
@@ -728,12 +725,10 @@ async def display_columns_and_rows(
             row_label = row_label_from_label_column(row, label_column)
             row_action_label = pk_path
             if row_label and row_label != pk_path:
-                row_action_label = "{} {}".format(pk_path, row_label)
+                row_action_label = f"{pk_path} {row_label}"
             table_path = datasette.urls.table(database_name, table_name)
-            row_link = '<a href="{table_path}/{flat_pks_quoted}">{flat_pks}</a>'.format(
+            row_link = (
-                table_path=table_path,
+                f'<a href="{table_path}/{row_path}">{markupsafe.escape(pk_path)!s}</a>'
-                flat_pks=str(markupsafe.escape(pk_path)),
-                flat_pks_quoted=row_path,
             )
             edit_icon = (
                 '<svg class="row-inline-action-icon" aria-hidden="true" '
@@ -760,22 +755,16 @@ async def display_columns_and_rows(
             if row_action_permissions.get("update-row"):
                 row_actions.append(
                     '<button type="button" class="row-inline-action row-inline-action-edit" '
-                    'aria-label="Edit row {row_label}" title="Edit row" '
+                    f'aria-label="Edit row {markupsafe.escape(row_action_label)}" title="Edit row" '
                     'data-row-action="edit">'
-                    "{edit_icon}</button>".format(
+                    f"{edit_icon}</button>"
-                        edit_icon=edit_icon,
-                        row_label=markupsafe.escape(row_action_label),
-                    )
                 )
             if row_action_permissions.get("delete-row"):
                 row_actions.append(
                     '<button type="button" class="row-inline-action row-inline-action-delete" '
-                    'aria-label="Delete row {row_label}" title="Delete row" '
+                    f'aria-label="Delete row {markupsafe.escape(row_action_label)}" title="Delete row" '
                     'data-row-action="delete">'
-                    "{delete_icon}</button>".format(
+                    f"{delete_icon}</button>"
-                        delete_icon=delete_icon,
-                        row_label=markupsafe.escape(row_action_label),
-                    )
                 )
             if row_actions:
                 row_link = (
@@ -843,11 +832,7 @@ async def display_columns_and_rows(
                             path_from_row_pks(row, pks, not pks),
                             column,
                         ),
-                        (
+                        (f' title="{formatted}"' if "bytes" not in formatted else ""),
-                            ' title="{}"'.format(formatted)
-                            if "bytes" not in formatted
-                            else ""
-                        ),
                         len(value),
                         "" if len(value) == 1 else "s",
                     )
@@ -959,7 +944,7 @@ class TableInsertView(BaseView):
         try:
             data = await request.json()
         except json.JSONDecodeError as e:
-            return _errors(["Invalid JSON: {}".format(e)])
+            return _errors([f"Invalid JSON: {e}"])
         if not isinstance(data, dict):
             return _errors(["JSON must be a dictionary"])
         keys = data.keys()
@@ -987,9 +972,7 @@ class TableInsertView(BaseView):
         # Does this exceed max_insert_rows?
         max_insert_rows = self.ds.setting("max_insert_rows")
         if len(rows) > max_insert_rows:
-            return _errors(
+            return _errors([f"Too many rows, maximum allowed is {max_insert_rows}"])
-                ["Too many rows, maximum allowed is {}".format(max_insert_rows)]
-            )
 
         # Validate other parameters
         extras = {
@@ -1047,7 +1030,7 @@ class TableInsertView(BaseView):
         # Table must exist (may handle table creation in the future)
         db = self.ds.get_database(database_name)
         if not await db.table_exists(table_name):
-            return Response.error(["Table not found: {}".format(table_name)], 404)
+            return Response.error([f"Table not found: {table_name}"], 404)
 
         if upsert:
             # Must have insert-row AND upsert-row permissions
@@ -1170,14 +1153,15 @@ class TableInsertView(BaseView):
 
         try:
             rows = await db.execute_write_fn(insert_or_upsert_rows, request=request)
-        except Exception as e:
+        except Exception as e:  # noqa: BLE001
+            # TODO: narrow to expected write errors so Datasette bugs surface as 500s
             return Response.error([str(e)])
         result = {"ok": True}
         if should_return:
             if upsert:
                 # Fetch based on initial input IDs
                 where_clause = " OR ".join(
-                    ["({})".format(" AND ".join("{} = ?".format(pk) for pk in pks))]
+                    ["({})".format(" AND ".join(f"{pk} = ?" for pk in pks))]
                     * len(row_pk_values_for_later)
                 )
                 args = list(itertools.chain.from_iterable(row_pk_values_for_later))
@@ -1267,7 +1251,7 @@ class TableSetColumnTypeView(BaseView):
         try:
             data = await request.json()
         except json.JSONDecodeError as e:
-            return Response.error(["Invalid JSON: {}".format(e)], 400)
+            return Response.error([f"Invalid JSON: {e}"], 400)
         except PayloadTooLarge as e:
             return Response.error([str(e)], 413)
 
@@ -1294,7 +1278,7 @@ class TableSetColumnTypeView(BaseView):
             database_name, table_name
         )
         if column not in column_details:
-            return Response.error(["Column not found: {}".format(column)], 400)
+            return Response.error([f"Column not found: {column}"], 400)
 
         column_type_data = data["column_type"]
         if column_type_data is None:
@@ -1335,7 +1319,7 @@ class TableSetColumnTypeView(BaseView):
             return Response.error(['"column_type.config" must be a dictionary'], 400)
 
         if column_type not in self.ds._column_types:
-            return Response.error(["Unknown column type: {}".format(column_type)], 400)
+            return Response.error([f"Unknown column type: {column_type}"], 400)
 
         try:
             await self.ds.set_column_type(
@@ -1373,7 +1357,7 @@ class TableDropView(BaseView):
         # Table must exist
         db = self.ds.get_database(database_name)
         if not await db.table_exists(table_name):
-            return Response.error(["Table not found: {}".format(table_name)], 404)
+            return Response.error([f"Table not found: {table_name}"], 404)
         if not await self.ds.allowed(
             action="drop-table",
             resource=TableResource(database=database_name, table=table_name),
@@ -1398,7 +1382,7 @@ class TableDropView(BaseView):
                     "database": database_name,
                     "table": table_name,
                     "row_count": (
-                        await db.execute("select count(*) from [{}]".format(table_name))
+                        await db.execute(f"select count(*) from [{table_name}]")
                     ).single_value(),
                     "message": 'Pass "confirm": true to confirm',
                 },
@@ -1417,7 +1401,7 @@ class TableDropView(BaseView):
         )
         self.ds.add_message(
             request,
-            "Table {} dropped".format(table_name),
+            f"Table {table_name} dropped",
             self.ds.WARNING,
         )
         return Response.json({"ok": True}, status=200)
@@ -1477,32 +1461,28 @@ def _prefix_range_end(value):
 
 
 def _autocomplete_like(column):
-    return "{} like :like escape char(92)".format(escape_sqlite(column))
+    return f"{escape_sqlite(column)} like :like escape char(92)"
 
 
 def _autocomplete_prefix_like(column):
-    return "{} like :prefix escape char(92)".format(escape_sqlite(column))
+    return f"{escape_sqlite(column)} like :prefix escape char(92)"
 
 
 def _autocomplete_order_by(pks, label_column, exact_pk, label_matches_first=True):
     clauses = []
     if exact_pk:
         clauses.append(
-            "case when cast({} as text) = :q then 0 else 1 end".format(
+            f"case when cast({escape_sqlite(pks[0])} as text) = :q then 0 else 1 end"
-                escape_sqlite(pks[0])
-            )
         )
     if label_column:
         label_like = _autocomplete_like(label_column)
         if label_matches_first:
-            clauses.append("case when {} then 0 else 1 end".format(label_like))
+            clauses.append(f"case when {label_like} then 0 else 1 end")
         clauses.append(
-            "case when {} then length(cast({} as text)) end".format(
+            f"case when {label_like} then length(cast({escape_sqlite(label_column)} as text)) end"
-                label_like, escape_sqlite(label_column)
-            )
         )
     else:
-        clauses.append("length(cast({} as text))".format(escape_sqlite(pks[0])))
+        clauses.append(f"length(cast({escape_sqlite(pks[0])} as text))")
     clauses.extend(escape_sqlite(pk) for pk in pks)
     return ", ".join(clauses)
 
@@ -1569,8 +1549,8 @@ class TableAutocompleteView(BaseView):
             return Response.json({"ok": True, "rows": []})
         params = {
             "q": q,
-            "like": "%{}%".format(_escape_like(q)),
+            "like": f"%{_escape_like(q)}%",
-            "prefix": "{}%".format(_escape_like(q)),
+            "prefix": f"{_escape_like(q)}%",
         }
 
         like_columns = pks[:]
@@ -1584,18 +1564,13 @@ class TableAutocompleteView(BaseView):
             where_sql = "1 = 1"
             order_by = _autocomplete_initial_order_by(pks)
 
-        sql = """
+        sql = f"""
             select {select_sql}
-            from {table}
+            from {escape_sqlite(table_name)}
-            where {where}
+            where {where_sql}
             order by {order_by}
             limit 10
-        """.format(
+        """
-            select_sql=select_sql,
-            table=escape_sqlite(table_name),
-            where=where_sql,
-            order_by=order_by,
-        )
 
         try:
             results = await db.execute(
@@ -1607,21 +1582,14 @@ class TableAutocompleteView(BaseView):
             if prefix_end:
                 params["prefix_end"] = prefix_end
                 first_pk = escape_sqlite(pks[0])
-                fallback_where = (
+                fallback_where = f"{first_pk} >= :q and {first_pk} < :prefix_end and {fallback_where}"
-                    "{first_pk} >= :q and {first_pk} < :prefix_end and {like}"
+            fallback_sql = f"""
-                ).format(first_pk=first_pk, like=fallback_where)
-            fallback_sql = """
                 select {select_sql}
-                from {table}
+                from {escape_sqlite(table_name)}
-                where {where}
+                where {fallback_where}
-                order by {order_by}
+                order by {_autocomplete_pk_order_by(pks)}
                 limit 10
-            """.format(
+            """
-                select_sql=select_sql,
-                table=escape_sqlite(table_name),
-                where=fallback_where,
-                order_by=_autocomplete_pk_order_by(pks),
-            )
             try:
                 results = await db.execute(
                     fallback_sql,
@@ -1777,7 +1745,7 @@ async def table_view_traced(datasette, request):
     )
     if isinstance(view_data, Response):
         return view_data
-    data, rows, columns, expanded_columns, sql, next_url = view_data
+    data, rows, columns, _expanded_columns, sql, next_url = view_data
 
     # Handle formats from plugins
     if format_ == "csv":
@@ -1788,8 +1756,8 @@ async def table_view_traced(datasette, request):
                 rows,
                 columns,
                 expanded_columns,
-                sql,
+                _sql,
-                next_url,
+                _next_url,
             ) = await table_view_data(
                 datasette,
                 request,
@@ -1806,7 +1774,7 @@ async def table_view_traced(datasette, request):
             return data, None, None
 
         return await stream_csv(datasette, fetch_data, request, resolved.db.name)
-    elif format_ in datasette.renderers.keys():
+    elif format_ in datasette.renderers:
         # Dispatch request to the correct output format renderer
         # (CSV is not handled here due to streaming)
         result = call_with_supported_arguments(
@@ -1864,9 +1832,7 @@ async def table_view_traced(datasette, request):
         )
         headers.update(
             {
-                "Link": '<{}>; rel="alternate"; type="application/json+datasette"'.format(
+                "Link": f'<{alternate_url_json}>; rel="alternate"; type="application/json+datasette"'
-                    alternate_url_json
-                )
             }
         )
         table_context = TableContext(
@@ -1951,7 +1917,7 @@ async def table_view_traced(datasette, request):
             headers=headers,
         )
     else:
-        assert False, "Invalid format: {}".format(format_)
+        assert False, f"Invalid format: {format_}"
     if next_url:
         r.headers["link"] = f'<{next_url}>; rel="next"'
     return r
@@ -2142,9 +2108,7 @@ async def table_view_data(
                             extra_desc_only=(
                                 ""
                                 if sort
-                                else " or {column2} is null".format(
+                                else f" or {escape_sqlite(sort or sort_desc)} is null"
-                                    column2=escape_sqlite(sort or sort_desc)
-                                )
                             ),
                             next_clauses=" and ".join(next_by_pk_clauses),
                         )
@@ -2186,22 +2150,11 @@ async def table_view_data(
 
     # Facets are calculated against SQL without order by or limit
     sql_no_order_no_limit = (
-        "select {select_all_columns} from {table_name} {where}".format(
+        f"select {select_all_columns} from {escape_sqlite(table_name)} {where_clause}"
-            select_all_columns=select_all_columns,
-            table_name=escape_sqlite(table_name),
-            where=where_clause,
-        )
     )
 
     # This is the SQL that populates the main table on the page
-    sql = "select {select_specified_columns} from {table_name} {where}{order_by} limit {page_size}{offset}".format(
+    sql = f"select {select_specified_columns} from {escape_sqlite(table_name)} {where_clause}{order_by} limit {page_size + 1}{offset}"
-        select_specified_columns=select_specified_columns,
-        table_name=escape_sqlite(table_name),
-        where=where_clause,
-        order_by=order_by,
-        page_size=page_size + 1,
-        offset=offset,
-    )
 
     if request.args.get("_timelimit"):
         extra_args["custom_time_limit"] = int(request.args.get("_timelimit"))
@@ -2212,9 +2165,6 @@ async def table_view_data(
     except (sqlite3.OperationalError, InvalidSql) as e:
         raise DatasetteError(str(e), title="Invalid SQL", status=400)
 
-    except sqlite3.OperationalError as e:
-        raise DatasetteError(str(e))
-
     columns = [r[0] for r in results.description]
     rows = list(results.rows)
 
@@ -2261,7 +2211,8 @@ async def table_view_data(
             new_rows = []
             for row in rows:
                 new_row = CustomRow(columns)
-                for column in row.keys():
+                # CustomRow/sqlite3.Row iterate over values, so .keys() is required
+                for column in row.keys():  # noqa: SIM118
                     value = row[column]
                     if (column, value) in expanded_labels and value is not None:
                         new_row[column] = {
@@ -2298,7 +2249,7 @@ async def table_view_data(
         # Data formats reject unknown extras; the HTML path (which passes
         # extra_extras={"_html"}) resolves internal extras of its own
         table_extra_registry.validate_requested(extras, ExtraScope.TABLE)
-    if any(k for k in request.args.keys() if k == "_facet" or k.startswith("_facet_")):
+    if any(k for k in request.args if k == "_facet" or k.startswith("_facet_")):
         extras.add("facet_results")
     if request.args.get("_shape") == "object":
         extras.add("primary_keys")
@@ -2479,20 +2430,13 @@ async def _next_value_and_url(
             except IndexError:
                 # sort/sort_desc column missing from SELECT - look up value by PK instead
                 prefix_where_clause = " and ".join(
-                    "[{}] = :pk{}".format(pk, i) for i, pk in enumerate(pks)
+                    f"[{pk}] = :pk{i}" for i, pk in enumerate(pks)
-                )
-                prefix_lookup_sql = "select [{}] from [{}] where {}".format(
-                    sort or sort_desc, table_name, prefix_where_clause
                 )
+                prefix_lookup_sql = f"select [{sort or sort_desc}] from [{table_name}] where {prefix_where_clause}"
                 prefix = (
                     await db.execute(
                         prefix_lookup_sql,
-                        {
+                        {**{f"pk{i}": rows[-2][pk] for i, pk in enumerate(pks)}},
-                            **{
-                                "pk{}".format(i): rows[-2][pk]
-                                for i, pk in enumerate(pks)
-                            }
-                        },
                     )
                 ).single_value()
             if isinstance(prefix, dict) and "value" in prefix:

datasette/views/table_create_alter.py

@@ -1,9 +1,9 @@
 import json
 import re
 import time
-from typing import Annotated, Any, Literal, Union
+from typing import Annotated, Any, Literal
 
-from datasette.database import QueryInterrupted
+import sqlite_utils
 from pydantic import (
     BaseModel,
     ConfigDict,
@@ -13,18 +13,18 @@ from pydantic import (
     model_validator,
 )
 from pydantic_core import PydanticCustomError
-import sqlite_utils
 from sqlite_utils.db import DEFAULT as SQLITE_UTILS_DEFAULT
 
 from datasette.column_types import SQLiteType
+from datasette.database import QueryInterrupted
 from datasette.events import AlterTableEvent, CreateTableEvent, InsertRowsEvent
 from datasette.resources import DatabaseResource, TableResource
 from datasette.utils import (
+    WriteJsonValueError,
     decode_write_json_rows,
     escape_sqlite,
     get_outbound_foreign_keys,
     table_column_details,
-    WriteJsonValueError,
 )
 from datasette.utils.asgi import NotFound, PayloadTooLarge, Response
 from datasette.utils.sqlite import sqlite_hidden_table_names
@@ -136,14 +136,14 @@ def _foreign_key_name_reasons(source_column, target):
     singular_table = _singular(table)
     column = target["fk_column"].lower()
     possible_names = {
-        "{}_{}".format(table, column),
+        f"{table}_{column}",
-        "{}_{}".format(singular_table, column),
+        f"{singular_table}_{column}",
     }
     if column == "id":
         possible_names.update(
             {
-                "{}_id".format(table),
+                f"{table}_id",
-                "{}_id".format(singular_table),
+                f"{singular_table}_id",
             }
         )
     return ["name_match"] if source in possible_names else []
@@ -262,10 +262,8 @@ async def _create_table_ui_context(
     if not database_action_permissions.get("create-table"):
         return None
     data = {
-        "path": "{}/-/create".format(datasette.urls.database(database_name)),
+        "path": f"{datasette.urls.database(database_name)}/-/create",
-        "foreignKeyTargetsPath": "{}/-/foreign-key-targets".format(
+        "foreignKeyTargetsPath": f"{datasette.urls.database(database_name)}/-/foreign-key-targets",
-            datasette.urls.database(database_name)
-        ),
         "databaseName": database_name,
         "columnTypes": CREATE_TABLE_COLUMN_TYPES,
         "defaultExpressions": default_expression_options(),
@@ -398,15 +396,15 @@ def default_expr_for_sql(expression):
 
 def _quoted_options(options):
     if len(options) == 1:
-        return "'{}'".format(options[0])
+        return f"'{options[0]}'"
     return "{} or '{}'".format(
-        ", ".join("'{}'".format(option) for option in options[:-1]),
+        ", ".join(f"'{option}'" for option in options[:-1]),
         options[-1],
     )
 
 
 def _default_expr_error_message():
-    return "Input should be {}".format(_quoted_options(list(DEFAULT_EXPRESSIONS)))
+    return f"Input should be {_quoted_options(list(DEFAULT_EXPRESSIONS))}"
 
 
 def default_expression_options():
@@ -715,18 +713,16 @@ class SetForeignKeysOperation(_StrictPydanticModel):
 
 
 AlterTableOperation = Annotated[
-    Union[
+    AddColumnOperation
-        AddColumnOperation,
+    | RenameColumnOperation
-        RenameColumnOperation,
+    | RenameTableOperation
-        RenameTableOperation,
+    | AlterColumnOperation
-        AlterColumnOperation,
+    | DropColumnOperation
-        DropColumnOperation,
+    | SetPrimaryKeyOperation
-        SetPrimaryKeyOperation,
+    | ReorderColumnsOperation
-        ReorderColumnsOperation,
+    | AddForeignKeyOperation
-        AddForeignKeyOperation,
+    | DropForeignKeyOperation
-        DropForeignKeyOperation,
+    | SetForeignKeysOperation,
-        SetForeignKeysOperation,
-    ],
     Field(discriminator="op"),
 ]
 
@@ -740,7 +736,7 @@ def _pydantic_errors(validation_error):
     for error in validation_error.errors():
         location = ".".join(str(item) for item in error["loc"])
         message = error["msg"]
-        errors.append("{}: {}".format(location, message) if location else message)
+        errors.append(f"{location}: {message}" if location else message)
     return errors
 
 
@@ -761,7 +757,7 @@ def _create_table_pydantic_errors(validation_error):
             output.append(message)
             continue
         location = ".".join(str(item) for item in error["loc"])
-        output.append("{}: {}".format(location, message) if location else message)
+        output.append(f"{location}: {message}" if location else message)
     return output
 
 
@@ -810,7 +806,7 @@ class TableCreateView(BaseView):
         try:
             data = await request.json()
         except json.JSONDecodeError as e:
-            return Response.error(["Invalid JSON: {}".format(e)])
+            return Response.error([f"Invalid JSON: {e}"])
         except PayloadTooLarge as e:
             return Response.error([str(e)], 413)
 
@@ -825,14 +821,13 @@ class TableCreateView(BaseView):
         ignore = create_request.ignore
         replace = create_request.replace
 
-        if replace:
+        # Replacing rows requires update-row permission
-            # Must have update-row permission
+        if replace and not await self.ds.allowed(
-            if not await self.ds.allowed(
+            action="update-row",
-                action="update-row",
+            resource=DatabaseResource(database=database_name),
-                resource=DatabaseResource(database=database_name),
+            actor=request.actor,
-                actor=request.actor,
+        ):
-            ):
+            return Response.error(["Permission denied: need update-row"], 403)
-                return Response.error(["Permission denied: need update-row"], 403)
 
         table_name = create_request.table
         table_exists = await db.table_exists(table_name)
@@ -878,9 +873,14 @@ class TableCreateView(BaseView):
             actual_pks = await db.primary_keys(table_name)
             # if pk passed and table already exists check it does not change
             bad_pks = False
-            if len(actual_pks) == 1 and pk and pk != actual_pks[0]:
+            if (
-                bad_pks = True
+                len(actual_pks) == 1
-            elif len(actual_pks) > 1 and pks and set(pks) != set(actual_pks):
+                and pk
+                and pk != actual_pks[0]
+                or len(actual_pks) > 1
+                and pks
+                and set(pks) != set(actual_pks)
+            ):
                 bad_pks = True
             if bad_pks:
                 return Response.error(["pk cannot be changed for existing table"])
@@ -925,7 +925,8 @@ class TableCreateView(BaseView):
 
         try:
             schema = await db.execute_write_fn(create_table, request=request)
-        except Exception as e:
+        except Exception as e:  # noqa: BLE001
+            # TODO: narrow to expected write errors so Datasette bugs surface as 500s
             return Response.error([str(e)])
 
         if initial_schema is not None and initial_schema != schema:
@@ -1171,7 +1172,7 @@ class TableAlterView(BaseView):
         try:
             data = await request.json()
         except json.JSONDecodeError as e:
-            return Response.error(["Invalid JSON: {}".format(e)], 400)
+            return Response.error([f"Invalid JSON: {e}"], 400)
         except PayloadTooLarge as e:
             return Response.error([str(e)], 413)
 
@@ -1311,10 +1312,7 @@ class TableAlterView(BaseView):
                         and rename_table_to != current_table_name
                     ):
                         operation_conn.execute(
-                            "alter table {} rename to {}".format(
+                            f"alter table {escape_sqlite(current_table_name)} rename to {escape_sqlite(rename_table_to)}"
-                                escape_sqlite(current_table_name),
-                                escape_sqlite(rename_table_to),
-                            )
                         )
                         current_table_name = rename_table_to
 
@@ -1329,7 +1327,8 @@ class TableAlterView(BaseView):
             before_schema, after_schema, after_table_name = await db.execute_write_fn(
                 alter_table, request=request
             )
-        except Exception as e:
+        except Exception as e:  # noqa: BLE001
+            # TODO: narrow to expected write errors so Datasette bugs surface as 500s
             return Response.error([str(e)], 400)
 
         altered = before_schema != after_schema

datasette/views/table_extras.py

@@ -1,5 +1,6 @@
 import itertools
 from dataclasses import dataclass
+from typing import ClassVar
 
 from datasette.column_types import SQLiteType
 from datasette.database import QueryInterrupted
@@ -101,7 +102,7 @@ class QueryExtraContext:
 class CountSqlExtra(Extra):
     description = "SQL query string used to calculate the total count for the current table view, including active filters."
     example = ExtraExample("/fixtures/facetable.json?_size=0&_extra=count_sql")
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context):
         return context.count_sql
@@ -110,7 +111,7 @@ class CountSqlExtra(Extra):
 class CountExtra(Extra):
     description = "Total count of rows matching these filters"
     example = ExtraExample("/fixtures/facetable.json?_extra=count")
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
     expensive = True
 
     async def resolve(self, context):
@@ -128,9 +129,7 @@ class CountExtra(Extra):
                 pass
 
         if context.count_sql and count is None and not context.nocount:
-            count_sql_limited = "select count(*) from (select * {} limit {})".format(
+            count_sql_limited = f"select count(*) from (select * {context.from_sql} limit {context.db.count_limit + 1})"
-                context.from_sql, context.db.count_limit + 1
-            )
             try:
                 count_rows = list(
                     await context.db.execute(count_sql_limited, context.from_sql_params)
@@ -160,7 +159,7 @@ def count_is_truncated(datasette, db, database_name, table_name, count_sql, coun
 class CountTruncatedExtra(Extra):
     description = "True if the count hit Datasette's counting limit, meaning the real number of matching rows is at least the reported count."
     example = ExtraExample("/fixtures/facetable.json?_extra=count,count_truncated")
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
     expensive = True
 
     async def resolve(self, context, count):
@@ -175,7 +174,7 @@ class CountTruncatedExtra(Extra):
 
 
 class FacetInstancesProvider(Provider):
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context, count):
         facet_instances = []
@@ -216,7 +215,7 @@ class FacetResultsExtra(Extra):
         },
         note="Shape abbreviated from /fixtures/facetable.json?_facet=state&_extra=facet_results.",
     )
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
     expensive = True
     docs_note = "See :ref:`facets` for details of how facets work."
 
@@ -259,7 +258,7 @@ class FacetsTimedOutExtra(Extra):
             "if every facet calculation completed."
         ),
     )
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context, facet_results):
         return facet_results["timed_out"]
@@ -276,7 +275,7 @@ class SuggestedFacetsExtra(Extra):
         ],
         note="Shape abbreviated from /fixtures/facetable.json?_extra=suggested_facets.",
     )
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
     expensive = True
     docs_note = (
         "Suggestions are controlled by the :ref:`setting_suggest_facets` setting."
@@ -304,7 +303,7 @@ class HumanDescriptionEnExtra(Extra):
     example = ExtraExample(
         "/fixtures/facetable.json?state=CA&_sort=pk&_extra=human_description_en"
     )
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context):
         human_description_en = context.filters.human_description_en(
@@ -324,7 +323,7 @@ class HumanDescriptionEnExtra(Extra):
 class ColumnsExtra(Extra):
     description = "List of column names returned by this table, row or query."
     example = ExtraExample("/fixtures/facetable.json?_extra=columns")
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             "/fixtures/simple_primary_key/1.json?_extra=columns"
         ),
@@ -332,7 +331,11 @@ class ColumnsExtra(Extra):
             "/fixtures/-/query.json?sql=select+1+as+one&_extra=columns"
         ),
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW, ExtraScope.QUERY}
+    scopes: ClassVar[set[ExtraScope]] = {
+        ExtraScope.TABLE,
+        ExtraScope.ROW,
+        ExtraScope.QUERY,
+    }
 
     async def resolve(self, context):
         return context.columns
@@ -341,7 +344,7 @@ class ColumnsExtra(Extra):
 class AllColumnsExtra(Extra):
     description = "List of all column names in the table, regardless of ``_col=`` or ``_nocol=`` filtering."
     example = ExtraExample("/fixtures/facetable.json?_col=pk&_extra=all_columns")
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context):
         return list(context.table_columns)
@@ -350,12 +353,12 @@ class AllColumnsExtra(Extra):
 class PrimaryKeysExtra(Extra):
     description = "List of primary key column names for this table, or an empty list if the table has no explicit primary key."
     example = ExtraExample("/fixtures/facetable.json?_extra=primary_keys")
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             "/fixtures/simple_primary_key/1.json?_extra=primary_keys"
         )
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE, ExtraScope.ROW}
 
     async def resolve(self, context):
         return context.pks
@@ -393,12 +396,12 @@ class ColumnDetailsExtra(Extra):
         "virtual generated columns and ``3`` for stored generated columns."
     )
     example = ExtraExample("/fixtures/binary_data.json?_size=0&_extra=column_details")
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             "/fixtures/binary_data/1.json?_extra=column_details"
         )
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE, ExtraScope.ROW}
 
     async def resolve(self, context):
         column_details = await context.datasette._get_resource_column_details(
@@ -412,7 +415,7 @@ class ColumnDetailsExtra(Extra):
 
 class ActionsExtra(Extra):
     description = 'Async callable returning table or view actions made available by core and plugin hooks. Each item is either a link with ``href``, ``label`` and optional ``description`` keys, or a button with ``type: "button"``, ``label``, optional ``description`` and optional ``attrs``. See :ref:`plugin_actions`, :ref:`plugin_hook_table_actions` and :ref:`plugin_hook_view_actions`.'
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
     # Returns an async function for the HTML templates - not JSON serializable
     public = False
 
@@ -484,7 +487,7 @@ async def precompute_database_action_permissions(datasette, actor, database_name
 class IsViewExtra(Extra):
     description = "Whether this resource is a view instead of a table"
     example = ExtraExample("/fixtures/simple_view.json?_extra=is_view")
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context):
         return context.is_view
@@ -497,7 +500,7 @@ class DebugExtra(Extra):
         "API and may change without warning."
     )
     example = ExtraExample("/fixtures/facetable.json?_extra=debug")
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             "/fixtures/simple_primary_key/1.json?_extra=debug"
         ),
@@ -505,7 +508,11 @@ class DebugExtra(Extra):
             "/fixtures/-/query.json?sql=select+1+as+one&_extra=debug"
         ),
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW, ExtraScope.QUERY}
+    scopes: ClassVar[set[ExtraScope]] = {
+        ExtraScope.TABLE,
+        ExtraScope.ROW,
+        ExtraScope.QUERY,
+    }
 
     async def resolve(self, context):
         debug = {
@@ -529,7 +536,7 @@ class DebugExtra(Extra):
 class RequestExtra(Extra):
     description = "Dictionary with request details: ``url``, ``path``, ``full_path``, ``host`` and ``args`` where ``args`` maps query string parameter names to their values."
     example = ExtraExample("/fixtures/facetable.json?_extra=request")
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             "/fixtures/simple_primary_key/1.json?_extra=request"
         ),
@@ -537,7 +544,11 @@ class RequestExtra(Extra):
             "/fixtures/-/query.json?sql=select+1+as+one&_extra=request"
         ),
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW, ExtraScope.QUERY}
+    scopes: ClassVar[set[ExtraScope]] = {
+        ExtraScope.TABLE,
+        ExtraScope.ROW,
+        ExtraScope.QUERY,
+    }
 
     async def resolve(self, context):
         return {
@@ -550,7 +561,7 @@ class RequestExtra(Extra):
 
 
 class DisplayColumnsAndRowsProvider(Provider):
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context):
         display_columns, display_rows = await context.display_columns_and_rows(
@@ -594,7 +605,7 @@ class DisplayColumnsExtra(Extra):
         ],
         note="Shape abbreviated from /fixtures/facetable.json?_size=1&_extra=display_columns.",
     )
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context, display_columns_and_rows):
         return display_columns_and_rows["columns"]
@@ -602,7 +613,7 @@ class DisplayColumnsExtra(Extra):
 
 class DisplayRowsExtra(Extra):
     description = "Rows formatted for the HTML table display. Each row is iterable and contains cell dictionaries with ``column``, ``value``, ``raw`` and ``value_type`` keys; table pages may also provide ``pk_path``, ``row_path`` and ``row_label`` attributes on each row object."
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
     # Contains markupsafe/sqlite3.Row values - not JSON serializable
     public = False
 
@@ -633,7 +644,7 @@ class RenderCellExtra(Extra):
             "whose rendered value differs from the default are included."
         ),
     )
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             value={
                 "rows": [{"id": 4, "content": "RENDER_CELL_DEMO"}],
@@ -658,7 +669,11 @@ class RenderCellExtra(Extra):
             ),
         ),
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW, ExtraScope.QUERY}
+    scopes: ClassVar[set[ExtraScope]] = {
+        ExtraScope.TABLE,
+        ExtraScope.ROW,
+        ExtraScope.QUERY,
+    }
 
     async def resolve(self, context):
         table_name = context.table_name
@@ -712,7 +727,7 @@ class RenderCellExtra(Extra):
 class QueryExtra(Extra):
     description = "Details of the underlying SQL query as a dictionary with ``sql`` and ``params`` keys."
     example = ExtraExample("/fixtures/facetable.json?_size=1&_extra=query")
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             "/fixtures/simple_primary_key/1.json?_extra=query"
         ),
@@ -721,7 +736,11 @@ class QueryExtra(Extra):
             ExtraExample("/fixtures/neighborhood_search.json?text=town&_extra=query"),
         ],
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW, ExtraScope.QUERY}
+    scopes: ClassVar[set[ExtraScope]] = {
+        ExtraScope.TABLE,
+        ExtraScope.ROW,
+        ExtraScope.QUERY,
+    }
 
     async def resolve(self, context):
         return {
@@ -745,7 +764,7 @@ class ColumnTypesExtra(Extra):
             "been assigned the ``json`` column type."
         ),
     )
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             "/fixtures/facetable/1.json?_extra=column_types",
             note=(
@@ -754,7 +773,7 @@ class ColumnTypesExtra(Extra):
             ),
         )
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE, ExtraScope.ROW}
 
     async def resolve(self, context):
         ct_map = await context.datasette.get_column_types(
@@ -804,7 +823,7 @@ class SetColumnTypeUiExtra(Extra):
             "types that could be assigned to it."
         ),
     )
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context):
         if context.is_view:
@@ -846,9 +865,7 @@ class SetColumnTypeUiExtra(Extra):
                 ],
             }
         return {
-            "path": "{}/-/set-column-type".format(
+            "path": f"{context.datasette.urls.table(context.database_name, context.table_name)}/-/set-column-type",
-                context.datasette.urls.table(context.database_name, context.table_name)
-            ),
             "columns": columns,
         }
 
@@ -866,7 +883,7 @@ class MetadataExtra(Extra):
             "descriptions."
         ),
     )
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             "/fixtures/simple_primary_key/1.json?_extra=metadata",
             note=(
@@ -884,7 +901,11 @@ class MetadataExtra(Extra):
             ),
         ),
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW, ExtraScope.QUERY}
+    scopes: ClassVar[set[ExtraScope]] = {
+        ExtraScope.TABLE,
+        ExtraScope.ROW,
+        ExtraScope.QUERY,
+    }
 
     async def resolve(self, context):
         if context.scope == ExtraScope.QUERY:
@@ -913,7 +934,7 @@ class MetadataExtra(Extra):
 class DatabaseExtra(Extra):
     description = "Database name"
     example = ExtraExample("/fixtures/facetable.json?_extra=database")
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             "/fixtures/simple_primary_key/1.json?_extra=database"
         ),
@@ -921,7 +942,11 @@ class DatabaseExtra(Extra):
             "/fixtures/-/query.json?sql=select+1+as+one&_extra=database"
         ),
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW, ExtraScope.QUERY}
+    scopes: ClassVar[set[ExtraScope]] = {
+        ExtraScope.TABLE,
+        ExtraScope.ROW,
+        ExtraScope.QUERY,
+    }
 
     async def resolve(self, context):
         return context.database_name
@@ -930,10 +955,10 @@ class DatabaseExtra(Extra):
 class TableExtra(Extra):
     description = "Table name"
     example = ExtraExample("/fixtures/facetable.json?_extra=table")
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample("/fixtures/simple_primary_key/1.json?_extra=table")
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE, ExtraScope.ROW}
 
     async def resolve(self, context):
         return context.table_name
@@ -946,7 +971,7 @@ class DatabaseColorExtra(Extra):
         "a hash of the database name and used in the Datasette interface."
     )
     example = ExtraExample("/fixtures/facetable.json?_extra=database_color")
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             "/fixtures/simple_primary_key/1.json?_extra=database_color"
         ),
@@ -954,7 +979,11 @@ class DatabaseColorExtra(Extra):
             "/fixtures/-/query.json?sql=select+1+as+one&_extra=database_color"
         ),
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW, ExtraScope.QUERY}
+    scopes: ClassVar[set[ExtraScope]] = {
+        ExtraScope.TABLE,
+        ExtraScope.ROW,
+        ExtraScope.QUERY,
+    }
 
     async def resolve(self, context):
         return context.db.color
@@ -965,7 +994,7 @@ class FormHiddenArgsExtra(Extra):
     example = ExtraExample(
         "/fixtures/facetable.json?_facet=state&_size=1&_extra=form_hidden_args"
     )
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context):
         form_hidden_args = []
@@ -982,7 +1011,7 @@ class FormHiddenArgsExtra(Extra):
 
 class FiltersExtra(Extra):
     description = "``Filters`` object used by the HTML table interface. Useful methods include ``filters.human_description_en()``; this is not JSON serializable."
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
     # Returns a Filters instance for the HTML templates - not JSON serializable
     public = False
 
@@ -998,7 +1027,7 @@ class CustomTableTemplatesExtra(Extra):
         ":ref:`customization_custom_templates`."
     )
     example = ExtraExample("/fixtures/facetable.json?_extra=custom_table_templates")
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context):
         return [
@@ -1019,7 +1048,7 @@ class SortedFacetResultsExtra(Extra):
     example = ExtraExample(
         "/fixtures/facetable.json?_facet=state&_extra=sorted_facet_results"
     )
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context, facet_results):
         facet_configs = context.table_metadata.get("facets", [])
@@ -1029,7 +1058,7 @@ class SortedFacetResultsExtra(Extra):
                 if isinstance(fc, str):
                     metadata_facet_names.append(fc)
                 elif isinstance(fc, dict):
-                    metadata_facet_names.append(list(fc.values())[0])
+                    metadata_facet_names.append(next(iter(fc.values())))
             metadata_order = {name: i for i, name in enumerate(metadata_facet_names)}
             metadata_facets = []
             request_facets = []
@@ -1055,7 +1084,7 @@ class SortedFacetResultsExtra(Extra):
 class TableDefinitionExtra(Extra):
     description = "SQL definition for this table"
     example = ExtraExample("/fixtures/facetable.json?_extra=table_definition")
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context):
         return await context.db.get_table_definition(context.table_name)
@@ -1064,7 +1093,7 @@ class TableDefinitionExtra(Extra):
 class ViewDefinitionExtra(Extra):
     description = "SQL definition for this view"
     example = ExtraExample("/fixtures/simple_view.json?_extra=view_definition")
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context):
         return await context.db.get_view_definition(context.table_name)
@@ -1081,7 +1110,7 @@ class RenderersExtra(Extra):
             "<plugin_register_output_renderer>`."
         ),
     )
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context, expandable_columns, query):
         renderers = {}
@@ -1123,7 +1152,7 @@ class PrivateExtra(Extra):
         "anonymous user could not. See :ref:`authentication_permissions`."
     )
     example = ExtraExample("/fixtures/facetable.json?_extra=private")
-    examples = {
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {
         ExtraScope.ROW: ExtraExample(
             "/fixtures/simple_primary_key/1.json?_extra=private"
         ),
@@ -1131,7 +1160,11 @@ class PrivateExtra(Extra):
             "/fixtures/-/query.json?sql=select+1+as+one&_extra=private"
         ),
     }
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW, ExtraScope.QUERY}
+    scopes: ClassVar[set[ExtraScope]] = {
+        ExtraScope.TABLE,
+        ExtraScope.ROW,
+        ExtraScope.QUERY,
+    }
 
     async def resolve(self, context):
         return context.private
@@ -1148,7 +1181,7 @@ class ExpandableColumnsExtra(Extra):
             "that would be used as the label for each expanded value."
         ),
     )
-    scopes = {ExtraScope.TABLE}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.TABLE}
 
     async def resolve(self, context):
         expandables = []
@@ -1168,7 +1201,7 @@ class ForeignKeyTablesExtra(Extra):
             "reference this row, and ``link`` is a URL to browse those rows."
         ),
     )
-    scopes = {ExtraScope.ROW}
+    scopes: ClassVar[set[ExtraScope]] = {ExtraScope.ROW}
     expensive = True
 
     async def resolve(self, context):
@@ -1202,7 +1235,11 @@ class ExtrasExtra(Extra):
             "the current request."
         ),
     )
-    scopes = {ExtraScope.TABLE, ExtraScope.ROW, ExtraScope.QUERY}
+    scopes: ClassVar[set[ExtraScope]] = {
+        ExtraScope.TABLE,
+        ExtraScope.ROW,
+        ExtraScope.QUERY,
+    }
 
     async def resolve(self, context):
         all_extras = [

docs/authentication.rst

@@ -45,7 +45,7 @@ Using the "root" actor
 
 Datasette currently leaves almost all forms of authentication to plugins - `datasette-auth-github <https://github.com/simonw/datasette-auth-github>`__ for example.
 
-The one exception is the "root" account, which you can sign into while using Datasette on your local machine. The root user has **all permissions** - they can perform any action regardless of other permission rules.
+The one exception is the "root" account, which you can sign into while using Datasette on your local machine. The root user starts with **all permissions**: Datasette contributes a global allow rule for every action. More specific deny rules can still override that global rule.
 
 The ``--root`` flag is designed for local development and testing. When you start Datasette with ``--root``, the root user automatically receives every permission, including:
 
@@ -84,12 +84,12 @@ Click on that link and then visit ``http://127.0.0.1:8001/-/actor`` to confirm t
 Permissions
 ===========
 
-Datasette's permissions system is built around SQL queries. Datasette and its plugins construct SQL queries to resolve the list of resources that an actor cas access.
-
 The key question the permissions system answers is this:
 
     Is this **actor** allowed to perform this **action**, optionally against this particular **resource**?
 
+Every permission decision can be understood in terms of those three values. Datasette implements the decisions using SQL, but you do not need to understand the generated SQL to configure or debug permissions.
+
 **Actors** are :ref:`described above <authentication_actor>`.
 
 An **action** is a string describing the action the actor would like to perform. A full list is :ref:`provided below <actions>` - examples include ``view-table`` and ``execute-sql``.
@@ -138,7 +138,51 @@ This configuration will deny access to everyone except the user with ``id`` of `
 How permissions are resolved
 ----------------------------
 
-Datasette performs permission checks using the internal :ref:`datasette_allowed`, method which accepts keyword arguments for ``action``, ``resource`` and an optional ``actor``.
+Permission rules describe an effect (``allow`` or ``deny``) at one of three levels:
+
+``resource``
+    A specific child resource, such as the ``analytics/sales`` table.
+
+``parent``
+    A parent resource, such as the ``analytics`` database. A parent rule also applies to its child resources.
+
+``global``
+    Every resource for that action.
+
+Datasette resolves matching rules from most specific to least specific:
+
+#. Resource rules take precedence over parent and global rules.
+#. Parent rules take precedence over global rules.
+#. If both allow and deny rules match at the same level, deny takes precedence.
+#. If no rule matches, access is denied.
+
+This means a resource-level allow can provide an exception to a parent-level deny. It also means that two plugins which disagree at the same level resolve to deny.
+
+.. list-table:: Permission rule examples
+   :header-rows: 1
+
+   * - Matching rules
+     - Result
+     - Explanation
+   * - Global allow
+     - Allow
+     - The global rule is the most specific matching rule.
+   * - Global allow, parent deny
+     - Deny
+     - The parent rule is more specific.
+   * - Parent deny, resource allow
+     - Allow
+     - The resource rule is more specific.
+   * - Resource allow and resource deny
+     - Deny
+     - Deny takes precedence at the same level.
+   * - No matching rules
+     - Deny
+     - Permissions default to deny when no rule applies.
+
+The built-in public defaults are global allow rules for actions such as ``view-instance``, ``view-database`` and ``view-table``. They follow the same precedence rules as configuration and plugin rules. The ``--default-deny`` option prevents Datasette from contributing those default allow rules.
+
+Datasette performs checks using :ref:`datasette_allowed`, which accepts keyword arguments for ``action``, ``resource`` and an optional ``actor``.
 
 ``resource`` should be an instance of the appropriate ``Resource`` subclass from :mod:`datasette.resources`—for example ``InstanceResource()``, ``DatabaseResource(database="...``)`` or ``TableResource(database="...", table="...")``. This defaults to ``InstanceResource()`` if not specified.
 
@@ -149,12 +193,12 @@ resources were allowed or denied. The combined sources are:
 
 * ``allow`` blocks configured in :ref:`datasette.yaml <authentication_permissions_config>`.
 * :ref:`Actor restrictions <authentication_cli_create_token_restrict>` encoded into the actor dictionary or API token.
-* The "root" user shortcut when ``--root`` (or :attr:`Datasette.root_enabled <datasette.app.Datasette.root_enabled>`) is active, replying ``True`` to all permission chucks unless configuration rules deny them at a more specific level.
+* The "root" user rule when ``--root`` (or :attr:`Datasette.root_enabled <datasette.app.Datasette.root_enabled>`) is active. This is a global allow rule, so a more specific configuration deny can override it.
 * Any additional SQL provided by plugins implementing :ref:`plugin_hook_permission_resources_sql`.
 
-Datasette evaluates the SQL to determine if the requested ``resource`` is
+Actor restrictions are applied after the allow/deny rules. They act as an additional allowlist: a restriction can remove access but cannot grant access that the actor did not already have. See :ref:`authentication_cli_create_token_restrict`.
-included. Explicit deny rules returned by configuration or plugins will block
+
-access even if other rules allowed it.
+Some actions have dependencies on other actions. These are evaluated as an ``AND`` condition. For example, ``execute-sql`` also requires ``view-database``: both decisions must be allowed for the final result to be allowed.
 
 .. _authentication_permissions_allow:
 
@@ -1145,11 +1189,21 @@ The debug tool at ``/-/permissions`` is available to any actor with the ``permis
 
     datasette -s permissions.permissions-debug true data.db
 
-The page shows the permission checks that have been carried out by the Datasette instance.
+The permission debug tools answer four different questions:
 
-It also provides an interface for running hypothetical permission checks against a hypothetical actor. This is a useful way of confirming that your configured permissions work in the way you expect.
+Why was this decision allowed or denied?
+    Use :ref:`PermissionCheckView`. It shows every matching rule, identifies the winning specificity level, applies actor restrictions and evaluates any required actions.
 
-This is designed to help administrators and plugin authors understand exactly how permission checks are being carried out, in order to effectively configure Datasette's permission system.
+Which resources can the current actor access?
+    Use :ref:`AllowedResourcesView` to view an access map for a selected action.
+
+Which raw rules did Datasette and its plugins contribute?
+    Use :ref:`PermissionRulesView` to inspect the rules before they are resolved into decisions.
+
+Which checks has this Datasette instance performed recently?
+    Use ``/-/permissions`` to view recent permission activity.
+
+These tools are designed to help administrators and plugin authors understand and confirm the effective permissions configuration.
 
 These debug endpoints are exempt from the :ref:`JSON API stability promise <json_api_stability>` - their JSON shapes may change in future releases.
 
@@ -1184,11 +1238,20 @@ This endpoint requires the ``permissions-debug`` permission.
 Permission check view
 ---------------------
 
-The ``/-/check`` endpoint evaluates a single action/resource pair and returns information indicating whether the access was allowed along with diagnostic information.
+The ``/-/check`` endpoint evaluates and explains a single actor, action and resource decision. The explanation includes:
+
+* Every matching allow and deny rule, with its source and reason.
+* The winning resource, parent or global scope.
+* Rules ignored because a more specific rule matched, or because a deny won at the same scope.
+* Actor restriction allowlists that included or excluded the resource.
+* Additional actions required by the requested action.
+* An explicit default-deny explanation when no rule matched.
 
 This endpoint provides an interactive HTML form interface. Add ``.json`` to the URL path (e.g. ``/-/check.json?action=view-instance``) to get the raw JSON response instead.
 
-Pass ``?action=`` to specify the action to check, and optional ``?parent=`` and ``?child=`` parameters to specify the resource.
+Pass ``?action=`` to specify the action to check, and optional ``?parent=`` and ``?child=`` parameters to specify the resource. The interactive form also accepts actor JSON, allowing a hypothetical actor to be tested without signing in as that actor. The JSON endpoint accepts the same value using the ``actor`` query string parameter. Use ``actor=null`` to represent an anonymous actor.
+
+This endpoint requires the ``permissions-debug`` permission. The hypothetical actor is used only for the decision being explained; access to the debug tool is checked against the actor who is actually signed in.
 
 .. _authentication_ds_actor:
 

docs/changelog.rst

@@ -4,6 +4,20 @@
 Changelog
 =========
 
+.. _v1_0_a37:
+
+1.0a37 (2026-07-14)
+-------------------
+
+Performance improvement for SQL-backed permission checks, plus an improved permission debugging interface.
+
+- SQL used to resolve permission checks now aggregates permission rules before joining them to resources, improving performance on instances with large schemas. (:issue:`2832`)
+- The :ref:`PermissionCheckView` permission debugger now explains why a decision was allowed or denied, including the matching rules. The interactive form can also test a hypothetical actor supplied as JSON, and the :ref:`permissions documentation <authentication_permissions_explained>` now describes resolution rules in more detail. (:issue:`2841`)
+- :ref:`db.execute_write(sql, ..., transaction=True) <database_execute_write>` has a new ``transaction=`` parameter, which can be set to ``False`` for statements such as ``VACUUM`` that cannot run inside a transaction. Write tasks now start their transactions using ``BEGIN IMMEDIATE``, which also ensures that writes are rolled back if the task fails. (:issue:`2831`)
+- Refreshing a database's schema in Datasette's internal catalog is now performed as a single atomic operation. (:issue:`2831`)
+- Fixed schema introspection, table pages, facets and table counts for tables with names containing a ``]`` character. Thanks, `TowyTowy <https://github.com/TowyTowy>`__. (:issue:`2431`, :pr:`2846`)
+- ``/-/plugins.json`` once again returns a top-level JSON array of plugin objects, reverting the object envelope introduced in 1.0a36. This should fix a large number of trivial test failures in existing plugins. (:issue:`2842`, :pr:`2843`)
+
 .. _v1_0_a36:
 
 1.0a36 (2026-07-07)

docs/conf.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 #
 # Datasette documentation build configuration file, created by
 # sphinx-quickstart on Thu Nov 16 06:50:13 2017.

docs/internals.rst

@@ -2023,8 +2023,8 @@ Example usage:
 
 .. _database_execute_write:
 
-await db.execute_write(sql, params=None, block=True, request=None, return_all=False, returning_limit=10)
+await db.execute_write(sql, params=None, block=True, request=None, return_all=False, returning_limit=10, transaction=True)
---------------------------------------------------------------------------------------------------------
+--------------------------------------------------------------------------------------------------------------------------
 
 SQLite only allows one database connection to write at a time. Datasette handles this for you by maintaining a queue of writes to be executed against a given database. Plugins can submit write operations to this queue and they will be executed in the order in which they are received.
 
@@ -2059,7 +2059,9 @@ If you need to retrieve every row returned by a statement, pass ``return_all=Tru
 
 If you pass ``block=False`` this behavior changes to "fire and forget" - queries will be added to the write queue and executed in a separate thread while your code can continue to do other things. The method will return a UUID representing the queued task.
 
-Each call to ``execute_write()`` will be executed inside a transaction.
+Each call to ``execute_write()`` will be executed inside a transaction. Pass
+``transaction=False`` for statements such as ``VACUUM`` that cannot run inside
+a transaction.
 
 .. _database_execute_write_script:
 

docs/introspection.rst

@@ -80,18 +80,15 @@ Shows a list of currently installed plugins and their versions. `Plugins example
 
 .. code-block:: json
 
-    {
+    [
-        "ok": true,
+        {
-        "plugins": [
+            "name": "datasette_cluster_map",
-            {
+            "static": true,
-                "name": "datasette_cluster_map",
+            "templates": false,
-                "static": true,
+            "version": "0.10",
-                "templates": false,
+            "hooks": ["extra_css_urls", "extra_js_urls", "extra_body_script"]
-                "version": "0.10",
+        }
-                "hooks": ["extra_css_urls", "extra_js_urls", "extra_body_script"]
+    ]
-            }
-        ]
-    }
 
 Add ``?all=1`` to include details of the default plugins baked into Datasette.
 

docs/json_api_doc.py

@@ -46,7 +46,7 @@ def table_extras(cog):
     cog.out("\n")
     for scope, heading, intro, classes in classes_by_scope:
         cog.out("{}\n{}\n\n".format(heading, "~" * len(heading)))
-        cog.out("{}\n\n".format(intro))
+        cog.out(f"{intro}\n\n")
         for cls in classes:
             examples = _examples_for_scope(cls, scope)
             description = cls.description or ""
@@ -58,16 +58,16 @@ def table_extras(cog):
             if notes:
                 description = "{} ({})".format(description, " ".join(notes)).strip()
 
-            cog.out("``{}``\n".format(cls.key()))
+            cog.out(f"``{cls.key()}``\n")
-            cog.out("    {}\n\n".format(description))
+            cog.out(f"    {description}\n\n")
             for example in examples:
                 if example.path:
                     value = live_examples[(example.path, example.key or cls.key())]
-                    cog.out("    ``GET {}``\n\n".format(example.path))
+                    cog.out(f"    ``GET {example.path}``\n\n")
                 else:
                     value = example.value
                 if example.note:
-                    cog.out("    {}\n\n".format(example.note))
+                    cog.out(f"    {example.note}\n\n")
                 cog.out("    .. code-block:: json\n\n")
                 cog.out(textwrap.indent(json.dumps(value, indent=2), "        "))
                 cog.out("\n\n")
@@ -139,7 +139,7 @@ async def _fetch_live_examples(scoped_classes):
                     response = await datasette.client.get(example.path)
                     assert response.status_code == 200, example.path
                     data = response.json()
-                    assert key in data, "{} missing from {}".format(key, example.path)
+                    assert key in data, f"{key} missing from {example.path}"
                     examples[(example.path, key)] = data[key]
         finally:
             for db in datasette.databases.values():

docs/metadata_doc.py

@@ -1,7 +1,8 @@
 import json
 import textwrap
-from yaml import safe_dump
+
 from ruamel.yaml import YAML
+from yaml import safe_dump
 
 
 def metadata_example(cog, data=None, yaml=None):
@@ -33,10 +34,10 @@ def config_example(
     else:
         data = input
         output_yaml = safe_dump(input, sort_keys=False)
-    cog.out("\n.. tab:: {}\n\n".format(yaml_title))
+    cog.out(f"\n.. tab:: {yaml_title}\n\n")
     cog.out("    .. code-block:: yaml\n\n")
     cog.out(textwrap.indent(output_yaml, "        "))
-    cog.out("\n\n.. tab:: {}\n\n".format(json_title))
+    cog.out(f"\n\n.. tab:: {json_title}\n\n")
     cog.out("    .. code-block:: json\n\n")
     cog.out(textwrap.indent(json.dumps(data, indent=2), "        "))
     cog.out("\n")
@@ -44,9 +45,11 @@ def config_example(
 
 def internal_schema(cog):
     import asyncio
-    from datasette.app import Datasette
+
     from sqlite_utils import Database
 
+    from datasette.app import Datasette
+
     ds = Datasette()
     db = ds.get_internal_database()
 

docs/template_context_doc.py

@@ -21,14 +21,12 @@ def template_context(cog):
         ),
     )
     for name, doc in TEMPLATE_BASE_CONTEXT.items():
-        cog.out("``{}``\n".format(name))
+        cog.out(f"``{name}``\n")
-        cog.out("    {}\n\n".format(doc))
+        cog.out(f"    {doc}\n\n")
 
     for klass in PAGES.values():
         title = "{} page".format(klass.__name__.removesuffix("Context"))
-        intro = "{} Rendered using the ``{}`` template.".format(
+        intro = f"{klass.__doc__} Rendered using the ``{klass.documented_template}`` template."
-            klass.__doc__, klass.documented_template
-        )
         _section(cog, title, intro)
         if klass.extras_scope is not None:
             cog.out(
@@ -36,10 +34,10 @@ def template_context(cog):
                 "<json_api>` for this page.\n\n"
             )
         for f in sorted(klass.documented_fields(), key=lambda f: f.name):
-            cog.out("``{}`` - ``{}``\n".format(f.name, f.type_name))
+            cog.out(f"``{f.name}`` - ``{f.type_name}``\n")
-            cog.out("    {}\n\n".format(f.help))
+            cog.out(f"    {f.help}\n\n")
 
 
 def _section(cog, title, intro):
     cog.out("{}\n{}\n\n".format(title, "-" * len(title)))
-    cog.out("{}\n\n".format(intro))
+    cog.out(f"{intro}\n\n")

pyproject.toml

@@ -69,7 +69,7 @@ dev = [
     "trustme>=0.7",
     "cogapp>=3.3.0",
     "multipart-form-data-conformance==0.1a0",
-    "ruff>=0.9",
+    "ruff>=0.16.0",
     # docs
     "Sphinx==7.4.7",
     "furo==2025.9.25",
@@ -102,9 +102,5 @@ datasette = ["templates/*.html"]
 [tool.setuptools.dynamic]
 version = {attr = "datasette.version.__version__"}
 
-[tool.ruff]
-line-length = 160
-select = ["E", "F", "W"]
-
 [tool.uv]
 package = true

ruff.toml

@@ -1,2 +1,7 @@
 line-length = 160
-target-version = "py310"
+target-version = "py310"
+
+[lint.flake8-bugbear]
+# from_extra() returns a dataclasses.field(), so it is safe as a dataclass
+# default - ruff cannot see through the wrapper (RUF009)
+extend-immutable-calls = ["datasette.views.from_extra"]

tests/conftest.py

@@ -1,15 +1,17 @@
-import httpx
 import importlib.metadata
 import os
 import pathlib
-import pytest
-import pytest_asyncio
 import re
 import subprocess
 import sys
 import tempfile
 import time
 from dataclasses import dataclass
+
+import httpx
+import pytest
+import pytest_asyncio
+
 from datasette import Event, hookimpl
 
 try:
@@ -38,7 +40,7 @@ def wait_until_responds(url, timeout=5.0, client=httpx, **kwargs):
             return
         except httpx.ConnectError:
             time.sleep(0.1)
-    raise AssertionError("Timed out waiting for {} to respond".format(url))
+    raise AssertionError(f"Timed out waiting for {url} to respond")
 
 
 @pytest.fixture
@@ -54,10 +56,12 @@ def bare_ds():
 
 @pytest_asyncio.fixture(scope="session")
 async def ds_client():
+    import secrets
+
     from datasette.app import Datasette
     from datasette.database import Database
+
     from .fixtures import CONFIG, METADATA, PLUGINS_DIR
-    import secrets
 
     ds = Datasette(
         metadata=METADATA,
@@ -96,8 +100,8 @@ def pytest_report_header(config):
     conn.close()
     sqlite_utils_version = importlib.metadata.version("sqlite-utils")
     headers = [
-        "SQLite: {}".format(version),
+        f"SQLite: {version}",
-        "sqlite-utils: {}".format(sqlite_utils_version),
+        f"sqlite-utils: {sqlite_utils_version}",
     ]
     if config.getoption("--playwright"):
         try:
@@ -175,8 +179,8 @@ def restore_working_directory(tmpdir, request):
 
 @pytest.fixture(scope="session", autouse=True)
 def check_actions_are_documented():
-    from datasette.plugins import pm
     from datasette.default_actions import register_actions as default_register_actions
+    from datasette.plugins import pm
 
     content = (
         pathlib.Path(__file__).parent.parent / "docs" / "authentication.rst"
@@ -202,7 +206,7 @@ def check_actions_are_documented():
             if kwargs["action"] in core_actions:
                 assert (
                     action in documented_actions
-                ), "Undocumented permission action: {}".format(action)
+                ), f"Undocumented permission action: {action}"
 
     pm.add_hookcall_monitoring(
         before=before, after=lambda outcome, hook_name, hook_impls, kwargs: None
@@ -298,7 +302,8 @@ def ds_unix_domain_socket_server(tmp_path_factory):
 
 
 # Import fixtures from fixtures.py to make them available
-from .fixtures import (  # noqa: E402, F401
+from .fixtures import (  # noqa: F401
+    TEMP_PLUGIN_SECRET_FILE,
     app_client,
     app_client_base_url_prefix,
     app_client_conflicting_database_names,
@@ -315,5 +320,4 @@ from .fixtures import (  # noqa: E402, F401
     app_client_with_dot,
     app_client_with_trace,
     make_app_client,
-    TEMP_PLUGIN_SECRET_FILE,
 )

tests/fixtures.py

@@ -1,3 +1,13 @@
+import contextlib
+import json
+import os
+import pathlib
+import tempfile
+import textwrap
+
+import click
+import pytest
+
 from datasette.app import Datasette
 from datasette.fixtures import (
     EXTRA_DATABASE_SQL,
@@ -5,14 +15,6 @@ from datasette.fixtures import (
     write_fixture_database,
 )
 from datasette.utils.testing import TestClient
-import click
-import contextlib
-import json
-import os
-import pathlib
-import pytest
-import tempfile
-import textwrap
 
 # This temp file is used by one of the plugin config tests
 TEMP_PLUGIN_SECRET_FILE = os.path.join(tempfile.gettempdir(), "plugin-secret")

tests/plugins/my_plugin.py

@@ -1,16 +1,16 @@
 import asyncio
-from datasette import hookimpl
-from datasette.facets import Facet
-from datasette.tokens import TokenHandler
-from datasette import tracer
-from datasette.permissions import Action
-from datasette.resources import DatabaseResource
-from datasette.utils import path_with_added_args
-from datasette.utils.asgi import asgi_send_json, Response
 import base64
 import json
 import urllib.parse
 
+from datasette import hookimpl, tracer
+from datasette.facets import Facet
+from datasette.permissions import Action
+from datasette.resources import DatabaseResource
+from datasette.tokens import TokenHandler
+from datasette.utils import path_with_added_args
+from datasette.utils.asgi import Response, asgi_send_json
+
 
 @hookimpl
 def prepare_connection(conn, database, datasette):
@@ -305,11 +305,7 @@ def startup(datasette):
     datasette._startup_hook_fired = True
 
     # And test some import shortcuts too
-    from datasette import Response
+    from datasette import Forbidden, NotFound, Response, actor_matches_allow, hookimpl
-    from datasette import Forbidden
-    from datasette import NotFound
-    from datasette import hookimpl
-    from datasette import actor_matches_allow
 
     _ = (Response, Forbidden, NotFound, hookimpl, actor_matches_allow)
 
@@ -373,7 +369,7 @@ def table_actions(datasette, database, table, actor, request):
                     "label": "Plugin button",
                     "description": "Runs JavaScript from a plugin",
                     "attrs": {
-                        "aria-label": "Plugin button for {}".format(table),
+                        "aria-label": f"Plugin button for {table}",
                         "data-plugin-action": "plugin-button",
                         "data-database": database,
                         "data-table": table,

tests/plugins/my_plugin_2.py

@@ -1,8 +1,10 @@
+import json
+from functools import wraps
+
+import markupsafe
+
 from datasette import hookimpl
 from datasette.utils.asgi import Response
-from functools import wraps
-import markupsafe
-import json
 
 
 @hookimpl
@@ -33,11 +35,7 @@ def render_cell(value, database):
     if set(data.keys()) != {"href", "label"}:
         return None
     href = data["href"]
-    if not (
+    if not (href.startswith(("/", "http://", "https://"))):
-        href.startswith("/")
-        or href.startswith("http://")
-        or href.startswith("https://")
-    ):
         return None
     return markupsafe.Markup(
         '<a data-database="{database}" href="{href}">{label}</a>'.format(
@@ -54,7 +52,7 @@ def extra_template_vars(template, database, table, view_name, request, datasette
     datasette._last_request = request
 
     async def query_database(sql):
-        first_db = list(datasette.databases.keys())[0]
+        first_db = next(iter(datasette.databases.keys()))
         return (await datasette.execute(first_db, sql)).rows[0][0]
 
     async def inner():
@@ -172,10 +170,10 @@ def register_routes(datasette):
     path = config["path"]
 
     def new_table(request):
-        return Response.text("/db/table: {}".format(sorted(request.url_vars.items())))
+        return Response.text(f"/db/table: {sorted(request.url_vars.items())}")
 
     return [
-        (r"/{}/$".format(path), lambda: Response.text(path.upper())),
+        (rf"/{path}/$", lambda: Response.text(path.upper())),
         # Also serves to demonstrate over-ride of default paths:
         (r"/(?P<db_name>[^/]+)/(?P<table_and_format>[^/]+?$)", new_table),
     ]

tests/plugins/register_output_renderer.py

@@ -1,6 +1,7 @@
+import json
+
 from datasette import hookimpl
 from datasette.utils.asgi import Response
-import json
 
 
 async def can_render(
@@ -18,9 +19,7 @@ async def can_render(
         "request": request,
         "view_name": view_name,
     }
-    if request.args.get("_no_can_render"):
+    return not request.args.get("_no_can_render")
-        return False
-    return True
 
 
 async def render_test_all_parameters(

tests/plugins/sleep_sql_function.py

@@ -1,6 +1,7 @@
-from datasette import hookimpl
 import time
 
+from datasette import hookimpl
+
 
 @hookimpl
 def prepare_connection(conn):

tests/test_actions_sql.py

@@ -10,10 +10,11 @@ These tests verify:
 
 import pytest
 import pytest_asyncio
+
+from datasette import hookimpl
 from datasette.app import Datasette
 from datasette.permissions import PermissionSQL
 from datasette.resources import DatabaseResource, QueryResource, TableResource
-from datasette import hookimpl
 
 
 def test_resource_string_representations():
@@ -90,7 +91,7 @@ async def test_allowed_resources_global_allow(test_ds):
         assert all(isinstance(t, TableResource) for t in tables)
 
         # Check specific tables are present
-        table_set = set((t.parent, t.child) for t in tables)
+        table_set = {(t.parent, t.child) for t in tables}
         assert ("analytics", "events") in table_set
         assert ("analytics", "users") in table_set
         assert ("analytics", "sensitive") in table_set

tests/test_actor_restriction_bug.py

@@ -6,6 +6,7 @@ config allow blocks can bypass table-level restrictions.
 """
 
 import pytest
+
 from datasette.app import Datasette
 from datasette.resources import TableResource
 

tests/test_allowed_many.py

@@ -10,6 +10,8 @@ Layer 3: table/database views precompute all registered actions before
 
 import pytest
 import pytest_asyncio
+
+from datasette import hookimpl
 from datasette.app import Datasette
 from datasette.permissions import (
     Action,
@@ -18,7 +20,6 @@ from datasette.permissions import (
     _permission_check_cache,
 )
 from datasette.resources import DatabaseResource, TableResource
-from datasette import hookimpl
 
 
 class CountingRulesPlugin:
@@ -114,7 +115,7 @@ async def test_allowed_not_memoized_without_cache(counting_ds):
 async def test_cache_keyed_on_full_actor_identity(counting_ds):
     """Interleaved checks for different actors never share cache entries."""
     # Uses drop-table because default permissions deny it to non-root actors
-    ds, plugin = counting_ds
+    ds, _plugin = counting_ds
     resource = TableResource("analytics", "users")
     token = _permission_check_cache.set({})
     try:
@@ -180,7 +181,7 @@ async def test_cache_keyed_on_resource(counting_ds):
 
 @pytest.mark.asyncio
 async def test_skip_permission_checks_bypasses_cache(counting_ds):
-    ds, plugin = counting_ds
+    ds, _plugin = counting_ds
     resource = TableResource("analytics", "users")
     token = _permission_check_cache.set({})
     try:

tests/test_allowed_resources.py

@@ -7,9 +7,10 @@ based on permission rules from plugins and configuration.
 
 import pytest
 import pytest_asyncio
+
+from datasette import hookimpl
 from datasette.app import Datasette
 from datasette.permissions import PermissionSQL
-from datasette import hookimpl
 
 
 # Test plugin that provides permission rules

tests/test_api.py

@@ -1,13 +1,15 @@
+import pathlib
+import urllib
+
+import pytest
+
 from datasette.app import Datasette
 from datasette.plugins import DEFAULT_PLUGINS
-from datasette.utils import UNSTABLE_API_MESSAGE
+from datasette.utils import UNSTABLE_API_MESSAGE, escape_sqlite, tilde_encode
 from datasette.utils.sqlite import sqlite_version
 from datasette.version import __version__
-from .fixtures import make_app_client, EXPECTED_PLUGINS
+
-import pathlib
+from .fixtures import EXPECTED_PLUGINS, make_app_client
-import pytest
-import sys
-import urllib
 
 
 @pytest.mark.asyncio
@@ -16,7 +18,7 @@ async def test_homepage(ds_client):
     assert response.status_code == 200
     assert "application/json; charset=utf-8" == response.headers["content-type"]
     data = response.json()
-    assert sorted(list(data.get("metadata").keys())) == [
+    assert sorted(data.get("metadata").keys()) == [
         "about",
         "about_url",
         "description_html",
@@ -384,9 +386,7 @@ async def test_row_pk_arity_mismatch_returns_400(ds_client, row_path, suffix):
     # because the SQL had one bind placeholder per PK column but params were
     # only bound for the supplied components. It should be a 400 instead,
     # mirroring the existing guard in datasette/views/table.py.
-    response = await ds_client.get(
+    response = await ds_client.get(f"/fixtures/compound_primary_key/{row_path}{suffix}")
-        "/fixtures/compound_primary_key/{}{}".format(row_path, suffix)
-    )
     assert response.status_code == 400
     if suffix == ".json":
         assert response.json()["ok"] is False
@@ -600,8 +600,7 @@ async def test_threads_json(ds_client):
     finally:
         ds_client.ds.root_enabled = False
     expected_keys = {"ok", "threads", "num_threads"}
-    if sys.version_info >= (3, 7, 0):
+    expected_keys.update({"tasks", "num_tasks"})
-        expected_keys.update({"tasks", "num_tasks"})
     data = response.json()
     assert set(data.keys()) == expected_keys
     # Should be at least one _execute_writes thread for __INTERNAL__
@@ -614,13 +613,13 @@ async def test_plugins_json(ds_client):
     response = await ds_client.get("/-/plugins.json")
     # Filter out TrackEventPlugin
     actual_plugins = sorted(
-        [p for p in response.json()["plugins"] if p["name"] != "TrackEventPlugin"],
+        [p for p in response.json() if p["name"] != "TrackEventPlugin"],
         key=lambda p: p["name"],
     )
     assert EXPECTED_PLUGINS == actual_plugins
     # Try with ?all=1
     response = await ds_client.get("/-/plugins.json?all=1")
-    names = {p["name"] for p in response.json()["plugins"]}
+    names = {p["name"] for p in response.json()}
     assert names.issuperset(p["name"] for p in EXPECTED_PLUGINS)
     assert names.issuperset(DEFAULT_PLUGINS)
 
@@ -930,6 +929,33 @@ async def test_tilde_encoded_database_names(db_name):
     assert response2.status_code == 200
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize("table_name", ("[foo]", "foo]", "[foo]/bar"))
+async def test_table_with_reserved_characters_in_name(table_name):
+    # Table names containing characters such as "]" that cannot be escaped
+    # using SQLite [bracket] quoting used to break schema introspection and
+    # the table page - https://github.com/simonw/datasette/issues/2431
+    ds = Datasette()
+    db = ds.add_memory_database("test_reserved_table_names")
+    await db.execute_write(
+        f"create table {escape_sqlite(table_name)} (id integer primary key, name text)"
+    )
+    await db.execute_write(
+        f"insert into {escape_sqlite(table_name)} (id, name) values (1, 'one')"
+    )
+    # Schema introspection (populate_schema_tables) must not crash:
+    db_response = await ds.client.get("/test_reserved_table_names.json")
+    assert db_response.status_code == 200
+    tables = {t["name"]: t for t in db_response.json()["tables"]}
+    assert tables[table_name]["count"] == 1
+    # And the table page itself must load and return the row:
+    table_response = await ds.client.get(
+        f"/test_reserved_table_names/{tilde_encode(table_name)}.json?_shape=array"
+    )
+    assert table_response.status_code == 200
+    assert table_response.json() == [{"id": 1, "name": "one"}]
+
+
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
     "config,expected",

tests/test_api_write.py

@@ -1,21 +1,24 @@
+import time
+
+import pytest
+
 from datasette.app import Datasette
 from datasette.events import RenameTableEvent
 from datasette.utils import error_body, escape_sqlite, sqlite3
+
 from .utils import last_event
-import pytest
-import time
 
 
 def assert_schema_contains(fragment, schema):
-    assert fragment in schema, "Expected schema to contain {!r}, got {!r}".format(
+    assert (
-        fragment, schema
+        fragment in schema
-    )
+    ), f"Expected schema to contain {fragment!r}, got {schema!r}"
 
 
 def assert_schema_not_contains(fragment, schema):
     assert (
         fragment not in schema
-    ), "Expected schema not to contain {!r}, got {!r}".format(fragment, schema)
+    ), f"Expected schema not to contain {fragment!r}, got {schema!r}"
 
 
 @pytest.fixture
@@ -47,7 +50,7 @@ def write_token(ds, actor_id="root", permissions=None):
 
 def _headers(token):
     return {
-        "Authorization": "Bearer {}".format(token),
+        "Authorization": f"Bearer {token}",
         "Content-Type": "application/json",
     }
 
@@ -55,9 +58,7 @@ def _headers(token):
 def _insert_and_fetch_created(conn, table, insert_sql):
     cursor = conn.execute(insert_sql)
     return conn.execute(
-        "select created, typeof(created) from {} where rowid = ?".format(
+        f"select created, typeof(created) from {escape_sqlite(table)} where rowid = ?",
-            escape_sqlite(table)
-        ),
         (cursor.lastrowid,),
     ).fetchone()
 
@@ -241,7 +242,7 @@ async def test_insert_row(ds_write, content_type):
         "/data/docs/-/insert",
         json={"row": {"title": "Test", "score": 1.2, "age": 5}},
         headers={
-            "Authorization": "Bearer {}".format(token),
+            "Authorization": f"Bearer {token}",
             "Content-Type": content_type,
         },
     )
@@ -286,11 +287,7 @@ async def test_insert_row_alter(ds_write):
 @pytest.mark.parametrize("return_rows", (True, False))
 async def test_insert_rows(ds_write, return_rows):
     token = write_token(ds_write)
-    data = {
+    data = {"rows": [{"title": f"Test {i}", "score": 1.0, "age": 5} for i in range(20)]}
-        "rows": [
-            {"title": "Test {}".format(i), "score": 1.0, "age": 5} for i in range(20)
-        ]
-    }
     if return_rows:
         data["return"] = True
     response = await ds_write.client.post(
@@ -314,8 +311,7 @@ async def test_insert_rows(ds_write, return_rows):
     ).dicts()
     assert len(actual_rows) == 20
     assert actual_rows == [
-        {"id": i + 1, "title": "Test {}".format(i), "score": 1.0, "age": 5}
+        {"id": i + 1, "title": f"Test {i}", "score": 1.0, "age": 5} for i in range(20)
-        for i in range(20)
     ]
     assert response.json()["ok"] is True
     if return_rows:
@@ -561,13 +557,13 @@ async def test_insert_or_upsert_row_errors(
         )
     if special_case == "bad_token":
         token += "bad"
-    kwargs = dict(
+    kwargs = {
-        json=input,
+        "json": input,
-        headers={
+        "headers": {
-            "Authorization": "Bearer {}".format(token),
+            "Authorization": f"Bearer {token}",
             "Content-Type": "application/json",
         },
-    )
+    }
 
     if special_case != "bad_token":
         actor_response = (
@@ -622,7 +618,7 @@ async def test_upsert_permissions_per_table(ds_write, allowed):
         "/data/docs/-/upsert",
         json={"rows": [{"id": 1, "title": "One"}]},
         headers={
-            "Authorization": "Bearer {}".format(token),
+            "Authorization": f"Bearer {token}",
         },
     )
     if allowed:
@@ -859,9 +855,7 @@ async def test_delete_row(ds_write, table, row_for_create, pks, delete_path):
     # Should be a single row
     assert (
         await ds_write.client.get(
-            "/data/-/query.json?_shape=arrayfirst&sql=select+count(*)+from+{}".format(
+            f"/data/-/query.json?_shape=arrayfirst&sql=select+count(*)+from+{table}"
-                table
-            )
         )
     ).json() == [1]
     # Now delete the row
@@ -869,14 +863,12 @@ async def test_delete_row(ds_write, table, row_for_create, pks, delete_path):
         # Special case for that rowid table
         delete_path = (
             await ds_write.client.get(
-                "/data/-/query.json?_shape=arrayfirst&sql=select+rowid+from+{}".format(
+                f"/data/-/query.json?_shape=arrayfirst&sql=select+rowid+from+{table}"
-                    table
-                )
             )
         ).json()[0]
 
     delete_response = await ds_write.client.post(
-        "/data/{}/{}/-/delete".format(table, delete_path),
+        f"/data/{table}/{delete_path}/-/delete",
         headers=_headers(write_token(ds_write)),
     )
     assert delete_response.status_code == 200
@@ -889,9 +881,7 @@ async def test_delete_row(ds_write, table, row_for_create, pks, delete_path):
     assert event.pks == str(delete_path).split(",")
     assert (
         await ds_write.client.get(
-            "/data/-/query.json?_shape=arrayfirst&sql=select+count(*)+from+{}".format(
+            f"/data/-/query.json?_shape=arrayfirst&sql=select+count(*)+from+{table}"
-                table
-            )
         )
     ).json() == [0]
 
@@ -941,7 +931,7 @@ async def test_update_row_invalid_key(ds_write):
 
     pk = await _insert_row(ds_write)
 
-    path = "/data/docs/{}/-/update".format(pk)
+    path = f"/data/docs/{pk}/-/update"
     response = await ds_write.client.post(
         path,
         json={"update": {"title": "New title"}, "bad_key": 1},
@@ -960,7 +950,7 @@ async def test_update_row_invalid_key(ds_write):
 async def test_update_row_alter(ds_write):
     token = write_token(ds_write, permissions=["ur", "at"])
     pk = await _insert_row(ds_write)
-    path = "/data/docs/{}/-/update".format(pk)
+    path = f"/data/docs/{pk}/-/update"
     response = await ds_write.client.post(
         path,
         json={"update": {"title": "New title", "extra": "extra"}, "alter": True},
@@ -1116,9 +1106,9 @@ async def test_alter_table_integer_default_expr(
     assert expected_schema in data["schema"]
 
     columns = await db.execute("select * from pragma_table_info('docs')")
-    created_column = [
+    created_column = next(
         column for column in columns.dicts() if column["name"] == "created"
-    ][0]
+    )
     assert created_column["type"] == "INTEGER"
     assert expected_schema in created_column["dflt_value"]
 
@@ -1419,7 +1409,8 @@ async def test_foreign_key_targets(ds_write):
     await db.execute_write("create table no_pk (name text)")
     try:
         await db.execute_write("create virtual table search_docs using fts5(body)")
-    except Exception:
+    except Exception:  # noqa: BLE001, S110
+        # FTS5 is not available in every SQLite build
         pass
 
     response = await ds_write.client.get(
@@ -1625,7 +1616,7 @@ async def test_update_row(ds_write, input, expected_errors, use_return):
     token = write_token(ds_write)
     pk = await _insert_row(ds_write)
 
-    path = "/data/docs/{}/-/update".format(pk)
+    path = f"/data/docs/{pk}/-/update"
 
     data = {"update": input}
     if use_return:
@@ -1660,7 +1651,7 @@ async def test_update_row(ds_write, input, expected_errors, use_return):
 
     # And fetch the row to check it's updated
     response = await ds_write.client.get(
-        "/data/docs/{}.json?_shape=array".format(pk),
+        f"/data/docs/{pk}.json?_shape=array",
     )
     assert response.status_code == 200
     row = response.json()[0]
@@ -2306,7 +2297,7 @@ async def test_create_table_integer_default_expr(
     ds_write, default_expr, minimum_value, expected_schema
 ):
     token = write_token(ds_write)
-    table = "default_{}".format(default_expr)
+    table = f"default_{default_expr}"
     response = await ds_write.client.post(
         "/data/-/create",
         json={
@@ -2334,7 +2325,7 @@ async def test_create_table_integer_default_expr(
 
     row = await db.execute_write_fn(
         lambda conn: _insert_and_fetch_created(
-            conn, table, "insert into {} default values".format(escape_sqlite(table))
+            conn, table, f"insert into {escape_sqlite(table)} default values"
         )
     )
     assert row[0] > minimum_value

tests/test_auth.py

@@ -1,14 +1,17 @@
+import time
+
+import pytest
 from bs4 import BeautifulSoup as Soup
-from .utils import cookie_was_deleted, last_event
 from click.testing import CliRunner
-from datasette.utils import baseconv
+
 from datasette.cli import cli
 from datasette.resources import (
     DatabaseResource,
     TableResource,
 )
-import pytest
+from datasette.utils import baseconv
-import time
+
+from .utils import cookie_was_deleted, last_event
 
 
 @pytest.mark.asyncio
@@ -204,7 +207,7 @@ def test_auth_create_token(
     assert response2.status == 200
     if errors:
         for error in errors:
-            assert '<p class="message-error">{}</p>'.format(error) in response2.text
+            assert f'<p class="message-error">{error}</p>' in response2.text
     else:
         # Check create-token event
         event = last_event(app_client.ds)
@@ -228,7 +231,7 @@ def test_auth_create_token(
         # And test that token
         response3 = app_client.get(
             "/-/actor.json",
-            headers={"Authorization": "Bearer {}".format("dstok_{}".format(token))},
+            headers={"Authorization": "Bearer {}".format(f"dstok_{token}")},
         )
         assert response3.status == 200
         assert response3.json["actor"]["id"] == "test"
@@ -241,7 +244,7 @@ async def test_auth_create_token_not_allowed_for_tokens(ds_client):
     )
     response = await ds_client.get(
         "/-/create-token",
-        headers={"Authorization": "Bearer dstok_{}".format(ds_tok)},
+        headers={"Authorization": f"Bearer dstok_{ds_tok}"},
     )
     assert response.status_code == 403
 
@@ -286,12 +289,12 @@ async def test_auth_with_dstok_token(ds_client, scenario, should_work):
     elif scenario == "invalid_token":
         token = "invalid"
     if token:
-        token = "dstok_{}".format(token)
+        token = f"dstok_{token}"
     if scenario == "allow_signed_tokens_off":
         ds_client.ds._settings["allow_signed_tokens"] = False
     headers = {}
     if token:
-        headers["Authorization"] = "Bearer {}".format(token)
+        headers["Authorization"] = f"Bearer {token}"
     response = await ds_client.get("/-/actor.json", headers=headers)
     try:
         if should_work:
@@ -338,7 +341,7 @@ def test_cli_create_token(app_client, expires):
     assert details.keys() == expected_keys
     assert details["a"] == "test"
     response = app_client.get(
-        "/-/actor.json", headers={"Authorization": "Bearer {}".format(token)}
+        "/-/actor.json", headers={"Authorization": f"Bearer {token}"}
     )
     if expires is None or expires > 0:
         expected_actor = {

tests/test_base_view.py

@@ -1,8 +1,10 @@
-from datasette.views.base import View
+import json
+
+import pytest
+
 from datasette import Request, Response
 from datasette.app import Datasette
-import json
+from datasette.views.base import View
-import pytest
 
 
 class GetView(View):

tests/test_cli.py

@@ -1,23 +1,28 @@
-from .fixtures import (
-    make_app_client,
-    TestClient as _TestClient,
-    EXPECTED_PLUGINS,
-)
-from datasette.app import SETTINGS
-from datasette.plugins import DEFAULT_PLUGINS, pm
-from datasette.cli import cli, serve
-from datasette.version import __version__
-from datasette.utils import tilde_encode
-from datasette.utils.sqlite import sqlite3
-from click.testing import CliRunner
 import io
 import json
 import pathlib
-import pytest
 import sys
 import textwrap
 from unittest import mock
 
+import pytest
+from click.testing import CliRunner
+
+from datasette.app import SETTINGS
+from datasette.cli import cli, serve
+from datasette.plugins import DEFAULT_PLUGINS, pm
+from datasette.utils import tilde_encode
+from datasette.utils.sqlite import sqlite3
+from datasette.version import __version__
+
+from .fixtures import (
+    EXPECTED_PLUGINS,
+    make_app_client,
+)
+from .fixtures import (
+    TestClient as _TestClient,
+)
+
 
 def test_inspect_cli(app_client):
     runner = CliRunner()
@@ -460,7 +465,7 @@ def test_serve_create(tmpdir):
 @pytest.mark.parametrize("argument", ("-c", "--config"))
 @pytest.mark.parametrize("format_", ("json", "yaml"))
 def test_serve_config(tmpdir, argument, format_):
-    config_path = tmpdir / "datasette.{}".format(format_)
+    config_path = tmpdir / f"datasette.{format_}"
     config_path.write_text(
         (
             "settings:\n  default_page_size: 5\n"
@@ -513,13 +518,13 @@ def test_weird_database_names(tmpdir, filename):
     result1 = runner.invoke(cli, [db_path, "--get", "/"])
     assert result1.exit_code == 0, result1.output
     filename_no_stem = filename.rsplit(".", 1)[0]
-    expected_link = '<a href="/{}">{}</a>'.format(
+    expected_link = (
-        tilde_encode(filename_no_stem), filename_no_stem
+        f'<a href="/{tilde_encode(filename_no_stem)}">{filename_no_stem}</a>'
     )
     assert expected_link in result1.output
     # Now try hitting that database page
     result2 = runner.invoke(
-        cli, [db_path, "--get", "/{}".format(tilde_encode(filename_no_stem))]
+        cli, [db_path, "--get", f"/{tilde_encode(filename_no_stem)}"]
     )
     assert result2.exit_code == 0, result2.output
 

tests/test_cli_serve_get.py

@@ -1,8 +1,10 @@
+import json
+import textwrap
+
+from click.testing import CliRunner
+
 from datasette.cli import cli
 from datasette.plugins import pm
-from click.testing import CliRunner
-import textwrap
-import json
 
 
 def test_serve_with_get(tmp_path_factory):
@@ -44,9 +46,9 @@ def test_serve_with_get(tmp_path_factory):
 
     # Annoyingly that new test plugin stays resident - we need
     # to manually unregister it to avoid conflict with other tests
-    to_unregister = [
+    to_unregister = next(
         p for p in pm.get_plugins() if p.__name__ == "init_for_serve_with_get.py"
-    ][0]
+    )
     pm.unregister(to_unregister)
 
 

tests/test_cli_serve_server.py

@@ -1,6 +1,7 @@
+import socket
+
 import httpx
 import pytest
-import socket
 
 
 @pytest.mark.serial

tests/test_column_types.py

@@ -1,7 +1,11 @@
 import json
 import logging
+import time
 
+import markupsafe
+import pytest
 from bs4 import BeautifulSoup as Soup
+
 from datasette.app import Datasette
 from datasette.column_types import (
     ColumnType,
@@ -9,11 +13,7 @@ from datasette.column_types import (
 )
 from datasette.hookspecs import hookimpl
 from datasette.plugins import pm
-from datasette.utils import error_body, sqlite3
+from datasette.utils import StartupError, error_body, sqlite3
-from datasette.utils import StartupError
-import markupsafe
-import pytest
-import time
 
 
 @pytest.fixture
@@ -104,7 +104,7 @@ def write_token(ds, actor_id="root", permissions=None):
 
 def _headers(token):
     return {
-        "Authorization": "Bearer {}".format(token),
+        "Authorization": f"Bearer {token}",
         "Content-Type": "application/json",
     }
 

tests/test_config_dir.py

@@ -1,10 +1,12 @@
 import json
 import pathlib
+
 import pytest
 
 from datasette.app import Datasette
-from datasette.utils.sqlite import sqlite3
 from datasette.utils import StartupError
+from datasette.utils.sqlite import sqlite3
+
 from .fixtures import TestClient as _TestClient
 
 PLUGIN = """
@@ -109,7 +111,7 @@ def test_settings(config_dir_client):
 def test_plugins(config_dir_client):
     response = config_dir_client.get("/-/plugins.json")
     assert 200 == response.status
-    plugins = response.json["plugins"]
+    plugins = response.json
     assert "hooray.py" in {p["name"] for p in plugins}
     assert "non_py_file.txt" not in {p["name"] for p in plugins}
     assert "mypy_cache" not in {p["name"] for p in plugins}