Add busy_timeout_ms and journal_mode to expected /-/settings.json

Refs #2831

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N76afGMhBRQk528VF1LTpR

datasette/app.py

@@ -220,6 +220,16 @@ SETTINGS = (
         "Number of threads in the thread pool for executing SQLite queries",
     ),
     Setting("sql_time_limit_ms", 1000, "Time limit for a SQL query in milliseconds"),
+    Setting(
+        "busy_timeout_ms",
+        5000,
+        "How long SQLite waits for a locked database file before giving up",
+    ),
+    Setting(
+        "journal_mode",
+        "",
+        "Journal mode to set on mutable database files, e.g. wal - leave blank to use each file's existing mode",
+    ),
     Setting(
         "default_facet_size", 30, "Number of values to return for requested facets"
     ),
@@ -478,7 +488,11 @@ class Datasette:
         if internal is None:
             self._internal_database = Database(self, is_temp_disk=True)
         else:
-            self._internal_database = Database(self, path=internal, mode="rwc")
+            # WAL for the same reason as the temporary internal database:
+            # the catalog can be read while it is being rewritten
+            self._internal_database = Database(
+                self, path=internal, mode="rwc", enable_wal=True
+            )
         self._internal_database.name = INTERNAL_DB_NAME
 
         self.cache_headers = cache_headers
@@ -753,7 +767,19 @@ class Datasette:
             # Compare schema versions to see if we should skip it
             if schema_version == current_schema_versions.get(database_name):
                 continue
-            await populate_schema_tables(internal_db, db, schema_version)
+            placeholders = "(?, ?, ?, ?)"
+            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):
@@ -1553,6 +1579,10 @@ class Datasette:
                     conn.execute("SELECT load_extension(?)", [extension])
         if self.setting("cache_size_kb"):
             conn.execute(f"PRAGMA cache_size=-{self.setting('cache_size_kb')}")
+        # Consistent trigger semantics on every connection - sqlite-utils
+        # would otherwise enable this on just the write connection, as a
+        # side effect of the first sqlite-utils based write
+        conn.execute("PRAGMA recursive_triggers=on")
         # pylint: disable=no-member
         if database != INTERNAL_DB_NAME:
             pm.hook.prepare_connection(conn=conn, database=database, datasette=self)
@@ -2563,7 +2593,7 @@ class Datasette:
             JsonDataView.as_view(
                 self,
                 "plugins.json",
-                self._plugins,
+                lambda request: {"plugins": self._plugins(request)},
                 needs_request=True,
             ),
             r"/-/plugins(\.(?P<format>json))?$",

datasette/database.py

@@ -5,6 +5,7 @@ import inspect
 import os
 from pathlib import Path
 import queue
+import re
 import sqlite_utils
 import sys
 import tempfile
@@ -17,7 +18,6 @@ from .utils import (
     detect_fts,
     detect_primary_keys,
     detect_spatialite,
-    escape_sqlite,
     get_all_foreign_keys,
     get_outbound_foreign_keys,
     md5_not_usedforsecurity,
@@ -36,6 +36,8 @@ EXECUTE_WRITE_RETURNING_LIMIT = 10
 
 AttachedDatabase = namedtuple("AttachedDatabase", ("seq", "name", "file"))
 
+ALLOWED_JOURNAL_MODES = {"delete", "truncate", "persist", "wal"}
+
 
 class DatasetteClosedError(RuntimeError):
     """Raised when using a Datasette or Database instance after close()."""
@@ -43,6 +45,77 @@ class DatasetteClosedError(RuntimeError):
 
 _SHUTDOWN = object()
 
+# Statements that SQLite refuses to execute inside a transaction. These run
+# without the task transaction - a single statement needs no extra atomicity.
+_STATEMENTS_DISALLOWED_IN_TRANSACTION = {"vacuum", "attach", "detach", "pragma"}
+
+_FIRST_KEYWORD_RE = re.compile(
+    r"^(?:\s+|--[^\n]*(?:\n|$)|/\*.*?\*/)*([a-zA-Z]+)", re.DOTALL
+)
+
+
+def _can_execute_in_transaction(sql):
+    match = _FIRST_KEYWORD_RE.match(sql)
+    if match is None:
+        return True
+    return match.group(1).lower() not in _STATEMENTS_DISALLOWED_IN_TRANSACTION
+
+
+# Scripts that manage their own transactions also cannot run inside the
+# task transaction
+_SCRIPT_STATEMENTS_DISALLOWED_IN_TRANSACTION = _STATEMENTS_DISALLOWED_IN_TRANSACTION | {
+    "begin",
+    "commit",
+    "end",
+    "rollback",
+    "savepoint",
+    "release",
+}
+
+
+def _script_can_execute_in_transaction(statements):
+    for statement in statements:
+        match = _FIRST_KEYWORD_RE.match(statement)
+        if (
+            match is not None
+            and match.group(1).lower() in _SCRIPT_STATEMENTS_DISALLOWED_IN_TRANSACTION
+        ):
+            return False
+    return True
+
+
+def _iter_sql_statements(sql):
+    # Split a multi-statement SQL string into complete statements using
+    # sqlite3.complete_statement()
+    statement = []
+    for char in sql:
+        statement.append(char)
+        statement_sql = "".join(statement).strip()
+        if statement_sql and sqlite3.complete_statement(statement_sql):
+            yield statement_sql
+            statement = []
+    remainder = "".join(statement).strip()
+    if remainder:
+        yield remainder
+
+
+def _run_write_in_transaction(conn, fn):
+    # Open the transaction explicitly instead of relying on the sqlite3
+    # driver's implicit BEGIN, which only fires on the first data-modifying
+    # statement. With a transaction genuinely open, sqlite-utils write
+    # methods nest inside it as savepoints instead of committing their own
+    # transactions mid-task: https://github.com/simonw/datasette/issues/2831
+    conn.execute("BEGIN IMMEDIATE")
+    try:
+        result = fn(conn)
+    except Exception:
+        if conn.in_transaction:
+            conn.rollback()
+        raise
+    if conn.in_transaction:
+        conn.commit()
+    return result
+
 
 class Database:
     # For table counts stop at this many rows:
@@ -58,6 +131,7 @@ class Database:
         memory_name=None,
         mode=None,
         is_temp_disk=False,
+        enable_wal=False,
     ):
         self.name = None
         self._thread_local_id = f"x{self._thread_local_id_counter}"
@@ -69,6 +143,8 @@ class Database:
         self.is_memory = is_memory
         self.memory_name = memory_name
         self.is_temp_disk = is_temp_disk
+        self.enable_wal = enable_wal or is_temp_disk
+        self._wal_enabled = False
         if memory_name is not None:
             self.is_memory = True
         if is_temp_disk:
@@ -77,10 +153,7 @@ class Database:
             self.path = temp_path
             self.is_mutable = True
             self.mode = "rwc"
-            self._wal_enabled = False
             atexit.register(self._cleanup_temp_file)
-        else:
-            self._wal_enabled = False
         self.cached_hash = None
         self.cached_size = None
         self._cached_table_counts = None
@@ -139,6 +212,10 @@ class Database:
         extra_kwargs = {}
         if write:
             extra_kwargs["isolation_level"] = "IMMEDIATE"
+        # An explicit busy timeout policy rather than the driver's silent
+        # 5 second default - matters when external processes write to the
+        # same database files
+        extra_kwargs["timeout"] = self.ds.setting("busy_timeout_ms") / 1000
         if self.memory_name:
             uri = "file:{}?mode=memory&cache=shared".format(self.memory_name)
             conn = sqlite3.connect(
@@ -166,9 +243,23 @@ class Database:
             f"file:{self.path}{qs}", uri=True, check_same_thread=False, **extra_kwargs
         )
         self._all_file_connections.append(conn)
-        if self.is_temp_disk and not self._wal_enabled:
+        if self.enable_wal and not self._wal_enabled:
             conn.execute("PRAGMA journal_mode=WAL")
             self._wal_enabled = True
+        if write and self.is_mutable and not self.enable_wal:
+            journal_mode = self.ds.setting("journal_mode")
+            if journal_mode:
+                if journal_mode not in ALLOWED_JOURNAL_MODES:
+                    raise ValueError(
+                        "journal_mode setting must be one of: {}".format(
+                            ", ".join(sorted(ALLOWED_JOURNAL_MODES))
+                        )
+                    )
+                conn.execute("PRAGMA journal_mode={}".format(journal_mode))
+                if journal_mode == "wal":
+                    # The standard WAL pairing - fewer fsyncs, application
+                    # level consistency guarantees are unchanged
+                    conn.execute("PRAGMA synchronous=NORMAL")
         return conn
 
     def close(self):
@@ -247,7 +338,6 @@ class Database:
         request=None,
         return_all=False,
         returning_limit=EXECUTE_WRITE_RETURNING_LIMIT,
-        transaction=True,
     ):
         self._check_not_closed()
         if returning_limit < 0:
@@ -261,19 +351,30 @@ class Database:
 
         with trace("sql", database=self.name, sql=sql.strip(), params=params):
             results = await self.execute_write_fn(
-                _inner, block=block, request=request, transaction=transaction
+                _inner,
+                block=block,
+                transaction=_can_execute_in_transaction(sql),
+                request=request,
             )
         return results
 
     async def execute_write_script(self, sql, block=True, request=None):
         self._check_not_closed()
+        statements = list(_iter_sql_statements(sql))
+        transaction = _script_can_execute_in_transaction(statements)
 
         def _inner(conn):
-            return conn.executescript(sql)
+            if transaction:
+                # Execute statements one at a time so they run inside the
+                # task transaction - conn.executescript() would commit it
+                for statement in statements:
+                    conn.execute(statement)
+            else:
+                return conn.executescript(sql)
 
         with trace("sql", database=self.name, sql=sql.strip(), executescript=True):
             results = await self.execute_write_fn(
-                _inner, block=block, transaction=False, request=request
+                _inner, block=block, transaction=transaction, request=request
             )
         return results
 
@@ -351,9 +452,7 @@ class Database:
                 self._write_connection = self.connect(write=True)
                 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)
+                result = _run_write_in_transaction(self._write_connection, fn)
             else:
                 result = fn(self._write_connection)
         else:
@@ -481,9 +580,7 @@ class Database:
             else:
                 try:
                     if task.transaction:
-                        with conn:
-                            conn.execute("BEGIN IMMEDIATE")
-                            result = task.fn(conn)
+                        result = _run_write_in_transaction(conn, task.fn)
                     else:
                         result = task.fn(conn)
                 except Exception as e:
@@ -609,7 +706,7 @@ class Database:
             try:
                 table_count = (
                     await self.execute(
-                        f"select count(*) from (select * from {escape_sqlite(table)} limit {self.count_limit + 1})",
+                        f"select count(*) from (select * from [{table}] limit {self.count_limit + 1})",
                         custom_time_limit=limit,
                     )
                 ).rows[0][0]
@@ -680,7 +777,7 @@ class Database:
 
         def column_details(conn):
             # Returns {column_name: (type, is_unique)}
-            db = sqlite_utils.Database(conn)
+            db = sqlite_utils.Database(conn, execute_plugins=False)
             columns = db[table].columns_dict
             indexes = db[table].indexes
             details = {}

datasette/default_permissions/config.py

@@ -96,10 +96,6 @@ class ConfigPermissionProcessor:
         """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(

datasette/facets.py

@@ -85,7 +85,7 @@ 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 {escape_sqlite(table)}"
+        self.sql = sql or f"select * from [{table}]"
         self.params = params or []
         self.table_config = table_config
         # row_count can be None, in which case we calculate it ourselves:

datasette/templates/_permission_ui_styles.html

@@ -6,20 +6,8 @@
     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: 1.25em;
+    margin-bottom: 1em;
 }
 .form-section label {
     display: block;
@@ -27,51 +15,22 @@
     font-weight: bold;
 }
 .form-section input[type="text"],
-.form-section input[type="number"],
-.form-section select,
-.permission-textarea {
-    background-color: #fff;
-    border: 1px solid #aaa;
-    border-radius: 4px;
-    box-sizing: border-box;
-    box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.08);
-    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;
+    width: 100%;
+    max-width: 500px;
+    padding: 0.5em;
+    box-sizing: border-box;
+    border: 1px solid #ccc;
+    border-radius: 3px;
 }
 .form-section input[type="text"]:focus,
-.form-section input[type="number"]:focus,
-.form-section select:focus,
-.permission-textarea:focus {
+.form-section select:focus {
+    outline: 2px solid #0066cc;
     border-color: #0066cc;
-    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.18);
-    outline: none;
 }
 .form-section small {
     display: block;
-    margin-top: 0.45em;
+    margin-top: 0.3em;
     color: #666;
 }
 .form-actions {
@@ -183,9 +142,4 @@
     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('-/check') }}{{ query_string }}" {% if current_tab == "check" %}class="active"{% endif %}>Explain</a>
-    <a href="{{ urls.path('-/allowed') }}{{ query_string }}" {% if current_tab == "allowed" %}class="active"{% endif %}>Access map</a>
-    <a href="{{ urls.path('-/rules') }}{{ query_string }}" {% if current_tab == "rules" %}class="active"{% endif %}>Rule explorer</a>
-    <a href="{{ urls.path('-/permissions') }}" {% if current_tab == "permissions" %}class="active"{% endif %}>Activity</a>
+    <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 %}>Check</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 %}>Rules</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

@@ -3,11 +3,29 @@
 {% 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 %}
 
@@ -20,28 +38,24 @@ 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>
 
-<div class="permission-form">
-    <form class="core" action="{{ urls.path('-/allow-debug') }}" method="get">
-        <div class="permission-form-grid">
-            <div class="form-section">
-                <label for="allow-block">Allow block</label>
-                <textarea class="permission-textarea" id="allow-block" name="allow">{{ allow_input }}</textarea>
-            </div>
-            <div class="form-section">
-                <label for="allow-actor">Actor</label>
-                <textarea class="permission-textarea" id="allow-actor" name="actor">{{ actor_input }}</textarea>
-            </div>
-        </div>
-        <div class="form-actions">
-            <button type="submit" class="submit-btn">Apply allow block to actor</button>
-        </div>
-    </form>
+<form class="core" action="{{ urls.path('-/allow-debug') }}" method="get" style="margin-bottom: 1em">
+    <div class="two-col">
+        <p><label>Allow block</label></p>
+        <textarea name="allow">{{ allow_input }}</textarea>
+    </div>
+    <div class="two-col">
+        <p><label>Actor</label></p>
+        <textarea name="actor">{{ actor_input }}</textarea>
+    </div>
+    <div style="margin-top: 1em;">
+        <input type="submit" value="Apply allow block to actor">
+    </div>
+</form>
 
-    {% if error %}<p class="message-warning permission-form-result">{{ error }}</p>{% endif %}
+{% if error %}<p class="message-warning">{{ error }}</p>{% endif %}
 
-    {% if result == "True" %}<p class="message-info permission-form-result">Result: allow</p>{% endif %}
+{% if result == "True" %}<p class="message-info">Result: allow</p>{% endif %}
 
-    {% if result == "False" %}<p class="message-error permission-form-result">Result: deny</p>{% endif %}
-</div>
+{% if result == "False" %}<p class="message-error">Result: deny</p>{% endif %}
 
 {% 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">
+            <input type="number" id="page_size" name="_size" value="50" min="1" max="200" style="max-width: 100px;">
             <small>Number of results per page (max 200)</small>
         </div>
 

datasette/templates/debug_check.html

@@ -1,6 +1,6 @@
 {% extends "base.html" %}
 
-{% block title %}Explain a permission decision{% endblock %}
+{% block title %}Permission Check{% endblock %}
 
 {% block extra_head %}
 <script src="{{ static('json-format-highlight-1.0.1.js') }}"></script>
@@ -13,35 +13,29 @@
     border-radius: 5px;
 }
 #output.allowed {
-    background-color: #f3fbf4;
+    background-color: #e8f5e9;
     border: 2px solid #4caf50;
 }
 #output.denied {
-    background-color: #fff7f7;
+    background-color: #ffebee;
     border: 2px solid #f44336;
 }
 #output h2 {
     margin-top: 0;
 }
-#output h3 {
-    margin-bottom: 0.5em;
-}
-#output .result-badge,
-.effect-badge,
-.rule-status {
+#output .result-badge {
     display: inline-block;
-    padding: 0.2em 0.5em;
+    padding: 0.3em 0.8em;
     border-radius: 3px;
     font-weight: bold;
+    font-size: 1.1em;
 }
-#output .allowed-badge,
-.effect-allow {
-    background-color: #2e7d32;
+#output .allowed-badge {
+    background-color: #4caf50;
     color: white;
 }
-#output .denied-badge,
-.effect-deny {
-    background-color: #c62828;
+#output .denied-badge {
+    background-color: #f44336;
     color: white;
 }
 .details-section {
@@ -54,130 +48,70 @@
 .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>Explain a permission decision</h1>
+<h1>Permission check</h1>
 
 {% set current_tab = "check" %}
 {% include "_permissions_debug_tabs.html" %}
 
-<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>
+<p>Use this tool to test permission checks for the current actor. It queries the <code>/-/check.json</code> API endpoint.</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="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>
+            <label for="action">Action (permission name):</label>
             <select id="action" name="action" required>
                 <option value="">Select an action...</option>
-                {% for action in actions %}
-                <option value="{{ action.name }}">{{ action.name }}{% if action.description %} — {{ action.description }}{% endif %}</option>
+                {% for action_name in sorted_actions %}
+                <option value="{{ action_name }}">{{ action_name }}</option>
                 {% endfor %}
             </select>
-            <small id="action-help">The operation to evaluate</small>
+            <small>The permission action to check</small>
         </div>
 
-        <div class="form-section" id="parent-section">
-            <label for="parent">Parent resource:</label>
+        <div class="form-section">
+            <label for="parent">Parent resource (optional):</label>
             <input type="text" id="parent" name="parent" placeholder="e.g., database name">
-            <small>The database or other parent resource</small>
+            <small>For database-level permissions, specify the database name</small>
         </div>
 
-        <div class="form-section" id="child-section">
-            <label for="child">Child resource:</label>
-            <input type="text" id="child" name="child" placeholder="e.g., table or query name">
-            <small>The table, query or other child resource</small>
+        <div class="form-section">
+            <label for="child">Child resource (optional):</label>
+            <input type="text" id="child" name="child" placeholder="e.g., table name">
+            <small>For table-level permissions, specify the table name (requires parent)</small>
         </div>
 
         <div class="form-actions">
-            <button type="submit" class="submit-btn" id="submit-btn">Explain decision</button>
+            <button type="submit" class="submit-btn" id="submit-btn">Check Permission</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><code id="result-action"></code></dd>
-        <dt>Resource:</dt>
-        <dd><code id="result-resource"></code></dd>
+        <dd id="result-action"></dd>
+
+        <dt>Resource Path:</dt>
+        <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>
@@ -185,134 +119,152 @@
 </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 = 'Explaining...';
-    const params = new URLSearchParams(new FormData(form));
+    submitBtn.textContent = 'Checking...';
+
+    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(), {
-            headers: {'Accept': 'application/json'}
+            method: 'GET',
+            headers: {
+                'Accept': 'application/json',
+            }
         });
+
         const data = await response.json();
+
         if (response.ok) {
             displayResult(data);
         } else {
             displayError(data);
         }
     } catch (error) {
-        displayError({error: error.message});
+        alert('Error: ' + error.message);
     } finally {
         submitBtn.disabled = false;
-        submitBtn.textContent = 'Explain decision';
+        submitBtn.textContent = 'Check Permission';
     }
 }
 
+// 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');
-    output.className = data.allowed ? 'allowed' : 'denied';
-    resultBadge.className = `result-badge ${data.allowed ? 'allowed-badge' : 'denied-badge'}`;
-    resultBadge.textContent = data.allowed ? 'ALLOWED ✓' : 'DENIED ✗';
-    document.getElementById('result-summary').textContent = data.explanation.summary;
-    document.getElementById('result-actor').textContent = data.actor === null ? 'anonymous' : JSON.stringify(data.actor);
-    document.getElementById('result-action').textContent = data.action;
-    document.getElementById('result-resource').textContent = data.resource.path;
-    displayRules(data.explanation);
-    displayRestrictions(data.explanation.restrictions);
-    displayRequirements(data.explanation.required_actions);
+    if (data.allowed) {
+        output.className = 'allowed';
+        resultBadge.className = 'result-badge allowed-badge';
+        resultBadge.textContent = 'ALLOWED ✓';
+    } else {
+        output.className = 'denied';
+        resultBadge.className = 'result-badge denied-badge';
+        resultBadge.textContent = 'DENIED ✗';
+    }
+
+    // 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);
-}
 
-function displayRules(explanation) {
-    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('');
+    // Scroll to output
+    output.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
 }
 
 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-actor').textContent = '—';
-    document.getElementById('result-action').textContent = '—';
-    document.getElementById('result-resource').textContent = '—';
-    document.getElementById('matching-rules').innerHTML = '';
-    document.getElementById('restrictions-section').style.display = 'none';
-    document.getElementById('requirements-section').style.display = 'none';
+
+    document.getElementById('result-action').textContent = 'N/A';
+    document.getElementById('result-resource').textContent = 'N/A';
+    document.getElementById('result-actor').textContent = 'N/A';
+
+    const additionalDetails = document.getElementById('additional-details');
+    additionalDetails.innerHTML = '<dt>Error:</dt><dd>' + (data.error || 'Unknown error') + '</dd>';
+
     document.getElementById('raw-json').innerHTML = jsonFormatHighlight(data);
+
+    output.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
 }
 
-form.addEventListener('submit', event => {
-    event.preventDefault();
-    performCheck();
-});
-actionSelect.addEventListener('change', updateResourceFields);
+// Disable child input if parent is empty
+const parentInput = document.getElementById('parent');
+const childInput = document.getElementById('child');
 
-(function initializeFromUrl() {
-    const params = populateFormFromURL();
-    updateResourceFields();
-    if (params.get('action')) {
-        performCheck();
+childInput.addEventListener('focus', () => {
+    if (!parentInput.value) {
+        alert('Please specify a parent resource first before adding a child resource.');
+        parentInput.focus();
     }
-})();
+});
 </script>
+
 {% endblock %}

datasette/templates/debug_permissions_playground.html

@@ -1,6 +1,6 @@
 {% extends "base.html" %}
 
-{% block title %}Permission activity{% endblock %}
+{% block title %}Debug permissions{% endblock %}
 
 {% block extra_head %}
 {% include "_permission_ui_styles.html" %}
@@ -20,45 +20,60 @@
 .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 activity</h1>
+<h1>Permission playground</h1>
 
 {% set current_tab = "permissions" %}
 {% include "_permissions_debug_tabs.html" %}
 
-<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>
+<p>This tool lets you simulate an actor and a permission check for that actor.</p>
 
 <div class="permission-form">
     <form action="{{ urls.path('-/permissions') }}" id="debug-post" method="post">
-        <div class="permission-form-grid">
-            <div>
-                <div class="form-section">
-                    <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 class="two-col">
+            <div class="form-section">
+                <label>Actor</label>
+                <textarea name="actor">{% if actor_input %}{{ actor_input }}{% else %}{"id": "root"}{% endif %}</textarea>
             </div>
-            <div>
-                <div class="form-section">
-                    <label for="permission">Action</label>
-                    <select name="permission" id="permission">
-                        {% for permission in permissions %}
-                            <option value="{{ permission.name }}">{{ permission.name }}</option>
-                        {% endfor %}
-                    </select>
-                </div>
-                <div class="form-section">
-                    <label for="resource_1">Parent</label>
-                    <input type="text" id="resource_1" name="resource_1" placeholder="e.g., database name">
-                </div>
-                <div class="form-section">
-                    <label for="resource_2">Child</label>
-                    <input type="text" id="resource_2" name="resource_2" placeholder="e.g., table name">
-                </div>
+        </div>
+        <div class="two-col" style="vertical-align: top">
+            <div class="form-section">
+                <label for="permission">Action</label>
+                <select name="permission" id="permission">
+                    {% for permission in permissions %}
+                        <option value="{{ permission.name }}">{{ permission.name }}</option>
+                    {% endfor %}
+                </select>
+            </div>
+            <div class="form-section">
+                <label for="resource_1">Parent</label>
+                <input type="text" id="resource_1" name="resource_1" placeholder="e.g., database name">
+            </div>
+            <div class="form-section">
+                <label for="resource_2">Child</label>
+                <input type="text" id="resource_2" name="resource_2" placeholder="e.g., table name">
             </div>
         </div>
         <div class="form-actions">
@@ -110,7 +125,7 @@ debugPost.addEventListener('submit', function(ev) {
 });
 </script>
 
-<h2>Recent permission checks</h2>
+<h1>Recent permissions checks</h1>
 
 <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">
+            <input type="number" id="page_size" name="_size" value="50" min="1" max="200" style="max-width: 100px;">
             <small>Number of results per page (max 200)</small>
         </div>
 

datasette/utils/__init__.py

@@ -636,7 +636,7 @@ def detect_primary_keys(conn, table):
 
 
 def get_outbound_foreign_keys(conn, table):
-    infos = conn.execute(f"PRAGMA foreign_key_list({escape_sqlite(table)})").fetchall()
+    infos = conn.execute(f"PRAGMA foreign_key_list([{table}])").fetchall()
     fks = []
     for info in infos:
         if info is not None:

datasette/utils/actions_sql.py

@@ -252,62 +252,88 @@ async def _build_single_action_sql(
                 ]
             )
 
-    # Continue with the cascading logic.
-    # Aggregate the RULES by cascade level (small), rather than grouping
-    # base x rules (which scales with the number of resources).
-    def _agg(select_key, where, group_by):
-        parts = [
-            f"  SELECT {select_key}",
-            "         MAX(CASE WHEN allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-            "         MAX(CASE WHEN allow = 1 THEN 1 ELSE 0 END) AS any_allow,",
-            "         json_group_array(CASE WHEN allow = 0 THEN source_plugin || ': ' || reason END) AS deny_reasons,",
-            "         json_group_array(CASE WHEN allow = 1 THEN source_plugin || ': ' || reason END) AS allow_reasons",
-            f"  FROM all_rules WHERE {where}",
-        ]
-        if group_by:
-            parts.append(f"  GROUP BY {group_by}")
-        return parts
-
+    # Continue with the cascading logic
     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)
-        + ["),"]
+        [
+            "child_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 = b.child",
+            "  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",
+            "),",
+        ]
     )
 
     # Add anonymous decision logic if needed
     if include_is_private:
-
-        def _anon_agg(select_key, where, group_by):
-            parts = [
-                f"  SELECT {select_key}",
-                "         MAX(CASE WHEN allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-                "         MAX(CASE WHEN allow = 1 THEN 1 ELSE 0 END) AS any_allow",
-                f"  FROM anon_rules WHERE {where}",
-            ]
-            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)
-            + ["),"]
+            [
+                "anon_child_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 = 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))",
+                "),",
+            ]
         )
 
     # Final decisions
@@ -316,28 +342,31 @@ 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  2. Child-level allow",
-            "    --   3. Parent-level deny 4. Parent-level allow",
-            "    --   5. Global-level deny 6. Global-level allow",
+            "    --   1. Child-level deny (most specific, blocks access)",
+            "    --   2. Child-level allow (most specific, grants access)",
+            "    --   3. Parent-level deny (intermediate, blocks access)",
+            "    --   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 ca.any_deny = 1 THEN 0",
-            "      WHEN ca.any_allow = 1 THEN 1",
-            "      WHEN pa.any_deny = 1 THEN 0",
-            "      WHEN pa.any_allow = 1 THEN 1",
-            "      WHEN ga.any_deny = 1 THEN 0",
-            "      WHEN ga.any_allow = 1 THEN 1",
+            "      WHEN cl.any_deny = 1 THEN 0",
+            "      WHEN cl.any_allow = 1 THEN 1",
+            "      WHEN pl.any_deny = 1 THEN 0",
+            "      WHEN pl.any_allow = 1 THEN 1",
+            "      WHEN gl.any_deny = 1 THEN 0",
+            "      WHEN gl.any_allow = 1 THEN 1",
             "      ELSE 0",
             "    END AS is_allowed,",
             "    CASE",
-            "      WHEN ca.any_deny = 1 THEN ca.deny_reasons",
-            "      WHEN ca.any_allow = 1 THEN ca.allow_reasons",
-            "      WHEN pa.any_deny = 1 THEN pa.deny_reasons",
-            "      WHEN pa.any_allow = 1 THEN pa.allow_reasons",
-            "      WHEN ga.any_deny = 1 THEN ga.deny_reasons",
-            "      WHEN ga.any_allow = 1 THEN ga.allow_reasons",
+            "      WHEN cl.any_deny = 1 THEN cl.deny_reasons",
+            "      WHEN cl.any_allow = 1 THEN cl.allow_reasons",
+            "      WHEN pl.any_deny = 1 THEN pl.deny_reasons",
+            "      WHEN pl.any_allow = 1 THEN pl.allow_reasons",
+            "      WHEN gl.any_deny = 1 THEN gl.deny_reasons",
+            "      WHEN gl.any_allow = 1 THEN gl.allow_reasons",
             "      ELSE '[]'",
             "    END AS reason",
         ]
@@ -345,34 +374,21 @@ async def _build_single_action_sql(
 
     if include_is_private:
         query_parts.append(
-            "    , 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"
+            "    , CASE WHEN ad.anon_is_allowed = 0 THEN 1 ELSE 0 END AS is_private"
         )
 
     query_parts.extend(
         [
             "  FROM base b",
-            "  LEFT JOIN child_agg ca ON ca.parent = b.parent AND ca.child = b.child",
-            "  LEFT JOIN parent_agg pa ON pa.parent = b.parent",
-            "  CROSS JOIN global_agg ga",
+            "  JOIN child_lvl cl ON b.parent = cl.parent AND (b.child = cl.child OR (b.child IS NULL AND cl.child IS NULL))",
+            "  JOIN parent_lvl pl ON b.parent = pl.parent AND (b.child = pl.child OR (b.child IS NULL AND pl.child IS NULL))",
+            "  JOIN global_lvl gl ON b.parent = gl.parent AND (b.child = gl.child OR (b.child IS NULL AND gl.child IS NULL))",
         ]
     )
 
     if include_is_private:
-        query_parts.extend(
-            [
-                "  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(
+            "  JOIN anon_decisions ad ON b.parent = ad.parent AND (b.child = ad.child OR (b.child IS NULL AND ad.child IS NULL))"
         )
 
     query_parts.append(")")
@@ -384,28 +400,8 @@ 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_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",
-                ")",
-            ]
+            [",", "restriction_list AS (", f"  {restriction_intersect}", ")"]
         )
 
     # Final SELECT
@@ -420,11 +416,10 @@ async def _build_single_action_sql(
     # Add restriction filter if there are restrictions
     if restriction_sqls:
         query_parts.append("""
-  AND (
-    EXISTS (SELECT 1 FROM restriction_all)
-    OR EXISTS (SELECT 1 FROM restriction_parent_any r WHERE r.parent = decisions.parent)
-    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)
+  AND EXISTS (
+    SELECT 1 FROM restriction_list r
+    WHERE (r.parent = decisions.parent OR r.parent IS NULL)
+      AND (r.child = decisions.child OR r.child IS NULL)
   )""")
 
     # Add parent filter if specified
@@ -678,239 +673,3 @@ 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/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 escape_sqlite, table_column_details
+from datasette.utils import table_column_details
 
 INTERNAL_DB_SCHEMA_TABLES = {
     "catalog_databases",
@@ -180,7 +180,7 @@ async def init_internal_db(db):
     await db.execute_write_fn(apply_migrations, transaction=False)
 
 
-async def populate_schema_tables(internal_db, db, schema_version):
+async def populate_schema_tables(internal_db, db):
     database_name = db.name
 
     tables = (await db.execute("select * from sqlite_master WHERE type = 'table'")).rows
@@ -213,7 +213,7 @@ async def populate_schema_tables(internal_db, db, schema_version):
                 for column in columns
             )
             foreign_keys = conn.execute(
-                f"PRAGMA foreign_key_list({escape_sqlite(table_name)})"
+                f"PRAGMA foreign_key_list([{table_name}])"
             ).fetchall()
             foreign_keys_to_insert.extend(
                 {
@@ -222,9 +222,7 @@ async def populate_schema_tables(internal_db, db, schema_version):
                 }
                 for foreign_key in foreign_keys
             )
-            indexes = conn.execute(
-                f"PRAGMA index_list({escape_sqlite(table_name)})"
-            ).fetchall()
+            indexes = conn.execute(f"PRAGMA index_list([{table_name}])").fetchall()
             indexes_to_insert.extend(
                 {
                     **{"database_name": database_name, "table_name": table_name},
@@ -248,45 +246,38 @@ async def populate_schema_tables(internal_db, db, schema_version):
         indexes_to_insert,
     ) = await db.execute_fn(collect_info)
 
-    def replace_catalog(conn):
-        # Delete child rows before their catalog_tables parents so this also
-        # works if a prepare_connection plugin enables foreign key enforcement.
-        for table in (
-            "catalog_columns",
-            "catalog_foreign_keys",
-            "catalog_indexes",
-            "catalog_views",
-            "catalog_tables",
-        ):
-            conn.execute(
-                "DELETE FROM {} WHERE database_name = ?".format(table),
-                [database_name],
-            )
+    def update_catalog(conn):
+        # Delete and reinsert as one write task so internal database readers
+        # never observe a database with missing catalog rows
+        # https://github.com/simonw/datasette/issues/2831
         conn.execute(
-            """
-            INSERT OR REPLACE INTO catalog_databases (
-                database_name, path, is_memory, schema_version
-            ) VALUES (?, ?, ?, ?)
-            """,
-            [
-                database_name,
-                str(db.path) if db.path is not None else None,
-                db.is_memory,
-                schema_version,
-            ],
+            "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]
         )
         conn.executemany(
             """
             INSERT INTO catalog_tables (database_name, table_name, rootpage, sql)
             values (?, ?, ?, ?)
-            """,
+        """,
             tables_to_insert,
         )
         conn.executemany(
             """
             INSERT INTO catalog_views (database_name, view_name, rootpage, sql)
             values (?, ?, ?, ?)
-            """,
+        """,
             views_to_insert,
         )
         conn.executemany(
@@ -296,7 +287,7 @@ async def populate_schema_tables(internal_db, db, schema_version):
             ) VALUES (
                 :database_name, :table_name, :cid, :name, :type, :notnull, :default_value, :is_pk, :hidden
             )
-            """,
+        """,
             columns_to_insert,
         )
         conn.executemany(
@@ -306,7 +297,7 @@ async def populate_schema_tables(internal_db, db, schema_version):
             ) VALUES (
                 :database_name, :table_name, :id, :seq, :table, :from, :to, :on_update, :on_delete, :match
             )
-            """,
+        """,
             foreign_keys_to_insert,
         )
         conn.executemany(
@@ -316,8 +307,8 @@ async def populate_schema_tables(internal_db, db, schema_version):
             ) VALUES (
                 :database_name, :table_name, :seq, :name, :unique, :origin, :partial
             )
-            """,
+        """,
             indexes_to_insert,
         )
 
-    await internal_db.execute_write_fn(replace_catalog)
+    await internal_db.execute_write_fn(update_catalog)

datasette/version.py

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

datasette/views/database.py

@@ -643,15 +643,8 @@ 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, **execute_write_kwargs
+                stored_query.sql, params_for_query, request=request
             )
             # success message can come from on_success_message or on_success_message_sql
             message = None

datasette/views/row.py

@@ -749,7 +749,9 @@ class RowDeleteView(BaseView):
 
         # Delete table
         def delete_row(conn):
-            sqlite_utils.Database(conn)[resolved.table].delete(resolved.pk_values)
+            sqlite_utils.Database(conn, execute_plugins=False)[resolved.table].delete(
+                resolved.pk_values
+            )
 
         try:
             await resolved.db.execute_write_fn(delete_row, request=request)
@@ -830,7 +832,7 @@ class RowUpdateView(BaseView):
             return Response.error(["Permission denied for alter-table"], 403)
 
         def update_row(conn):
-            sqlite_utils.Database(conn)[resolved.table].update(
+            sqlite_utils.Database(conn, execute_plugins=False)[resolved.table].update(
                 resolved.pk_values, update, alter=alter
             )
 

datasette/views/special.py

@@ -600,7 +600,7 @@ class PermissionRulesView(BaseView):
 
 
 async def _check_permission_for_actor(ds, action, parent, child, actor):
-    """Shared logic for checking and explaining a permission decision."""
+    """Shared logic for checking permissions. Returns a dict with check results."""
     if action not in ds.actions:
         return error_body(f"Unknown action: {action}", 404), 404
 
@@ -629,28 +629,15 @@ 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:
@@ -668,25 +655,11 @@ 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,
                 {
-                    "actions": actions,
-                    "actor_json": request.args.get("actor")
-                    or json.dumps(request.actor, indent=2),
+                    "sorted_actions": sorted(self.ds.actions.keys()),
                     "has_debug_permission": True,
                 },
             )
@@ -698,18 +671,9 @@ 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, actor
+            self.ds, action, parent, child, request.actor
         )
         return Response.json(response, status=status)
 

datasette/views/table.py

@@ -1143,7 +1143,7 @@ class TableInsertView(BaseView):
             row_pk_values_for_later = [tuple(row[pk] for pk in pks) for row in rows]
 
         def insert_or_upsert_rows(conn):
-            table = sqlite_utils.Database(conn)[table_name]
+            table = sqlite_utils.Database(conn, execute_plugins=False)[table_name]
             kwargs = {}
             if upsert:
                 kwargs = {
@@ -1407,7 +1407,7 @@ class TableDropView(BaseView):
 
         # Drop table
         def drop_table(conn):
-            sqlite_utils.Database(conn)[table_name].drop()
+            sqlite_utils.Database(conn, execute_plugins=False)[table_name].drop()
 
         await db.execute_write_fn(drop_table, request=request)
         await self.ds.track_event(

datasette/views/table_create_alter.py

@@ -889,11 +889,13 @@ class TableCreateView(BaseView):
         initial_schema = None
         if table_exists:
             initial_schema = await db.execute_fn(
-                lambda conn: sqlite_utils.Database(conn)[table_name].schema
+                lambda conn: sqlite_utils.Database(conn, execute_plugins=False)[
+                    table_name
+                ].schema
             )
 
         def create_table(conn):
-            db_for_write = sqlite_utils.Database(conn)
+            db_for_write = sqlite_utils.Database(conn, execute_plugins=False)
             table = db_for_write[table_name]
             if rows:
                 table.insert_all(
@@ -1187,7 +1189,9 @@ class TableAlterView(BaseView):
             before_schema = _table_schema_from_conn(conn, table_name)
 
             def apply_operations(operation_conn):
-                db_for_write = sqlite_utils.Database(operation_conn)
+                db_for_write = sqlite_utils.Database(
+                    operation_conn, execute_plugins=False
+                )
                 table = db_for_write[table_name]
                 current_table_name = table_name
 
@@ -1261,62 +1265,62 @@ class TableAlterView(BaseView):
                     elif operation.op == "set_foreign_keys":
                         foreign_keys = [fk.tuple for fk in args.foreign_keys]
 
-                with operation_conn:
-                    for column in add_columns:
-                        not_null_default = None
-                        if column.not_null:
-                            if "default_expr" in column.model_fields_set:
-                                not_null_default = _default_expression_sql(
-                                    column.default_expr
-                                )
-                            else:
-                                not_null_default = _literal_default(
-                                    db_for_write, column.default
-                                )
-                        table.add_column(
-                            column.name,
-                            column.type,
-                            not_null_default=not_null_default,
-                        )
+                # The write task transaction makes these operations atomic
+                for column in add_columns:
+                    not_null_default = None
+                    if column.not_null:
+                        if "default_expr" in column.model_fields_set:
+                            not_null_default = _default_expression_sql(
+                                column.default_expr
+                            )
+                        else:
+                            not_null_default = _literal_default(
+                                db_for_write, column.default
+                            )
+                    table.add_column(
+                        column.name,
+                        column.type,
+                        not_null_default=not_null_default,
+                    )
 
-                    should_transform = any(
-                        (
-                            types,
-                            rename,
-                            drop,
-                            not_null,
-                            defaults,
-                            column_order is not None,
-                            pk is not SQLITE_UTILS_DEFAULT,
-                            add_foreign_keys,
-                            drop_foreign_keys,
-                            foreign_keys is not None,
+                should_transform = any(
+                    (
+                        types,
+                        rename,
+                        drop,
+                        not_null,
+                        defaults,
+                        column_order is not None,
+                        pk is not SQLITE_UTILS_DEFAULT,
+                        add_foreign_keys,
+                        drop_foreign_keys,
+                        foreign_keys is not None,
+                    )
+                )
+                if should_transform:
+                    table.transform(
+                        types=types or None,
+                        rename=rename or None,
+                        drop=drop or None,
+                        pk=pk,
+                        not_null=not_null or None,
+                        defaults=defaults or None,
+                        column_order=column_order,
+                        add_foreign_keys=add_foreign_keys or None,
+                        drop_foreign_keys=drop_foreign_keys or None,
+                        foreign_keys=foreign_keys,
+                    )
+                if (
+                    rename_table_to is not None
+                    and rename_table_to != current_table_name
+                ):
+                    operation_conn.execute(
+                        "alter table {} rename to {}".format(
+                            escape_sqlite(current_table_name),
+                            escape_sqlite(rename_table_to),
                         )
                     )
-                    if should_transform:
-                        table.transform(
-                            types=types or None,
-                            rename=rename or None,
-                            drop=drop or None,
-                            pk=pk,
-                            not_null=not_null or None,
-                            defaults=defaults or None,
-                            column_order=column_order,
-                            add_foreign_keys=add_foreign_keys or None,
-                            drop_foreign_keys=drop_foreign_keys or None,
-                            foreign_keys=foreign_keys,
-                        )
-                    if (
-                        rename_table_to is not None
-                        and rename_table_to != current_table_name
-                    ):
-                        operation_conn.execute(
-                            "alter table {} rename to {}".format(
-                                escape_sqlite(current_table_name),
-                                escape_sqlite(rename_table_to),
-                            )
-                        )
-                        current_table_name = rename_table_to
+                    current_table_name = rename_table_to
 
                 return current_table_name, _table_schema_from_conn(
                     operation_conn, current_table_name

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 starts with **all permissions**: Datasette contributes a global allow rule for every action. More specific deny rules can still override that global rule.
+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 ``--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``.
@@ -138,51 +138,7 @@ This configuration will deny access to everyone except the user with ``id`` of `
 How permissions are resolved
 ----------------------------
 
-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``.
+Datasette performs permission checks using the internal :ref:`datasette_allowed`, method 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.
 
@@ -193,12 +149,12 @@ 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 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.
+* 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.
 * Any additional SQL provided by plugins implementing :ref:`plugin_hook_permission_resources_sql`.
 
-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`.
-
-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.
+Datasette evaluates the SQL to determine if the requested ``resource`` is
+included. Explicit deny rules returned by configuration or plugins will block
+access even if other rules allowed it.
 
 .. _authentication_permissions_allow:
 
@@ -1189,21 +1145,11 @@ The debug tool at ``/-/permissions`` is available to any actor with the ``permis
 
     datasette -s permissions.permissions-debug true data.db
 
-The permission debug tools answer four different questions:
+The page shows the permission checks that have been carried out by the Datasette instance.
 
-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.
+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.
 
-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.
+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.
 
 These debug endpoints are exempt from the :ref:`JSON API stability promise <json_api_stability>` - their JSON shapes may change in future releases.
 
@@ -1238,20 +1184,11 @@ This endpoint requires the ``permissions-debug`` permission.
 Permission check view
 ---------------------
 
-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.
+The ``/-/check`` endpoint evaluates a single action/resource pair and returns information indicating whether the access was allowed along with diagnostic information.
 
 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. 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.
+Pass ``?action=`` to specify the action to check, and optional ``?parent=`` and ``?child=`` parameters to specify the resource.
 
 .. _authentication_ds_actor:
 

docs/changelog.rst

@@ -4,19 +4,20 @@
 Changelog
 =========
 
-.. _v1_0_a37:
+.. _v_unreleased:
 
-1.0a37 (2026-07-14)
--------------------
+Unreleased
+----------
 
-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`)
+- Write functions run via ``await db.execute_write_fn()`` now execute inside an explicitly opened ``BEGIN IMMEDIATE`` transaction, committed when the function returns or rolled back if it raises. Previously the transaction was only opened implicitly by the first raw data-modifying statement, which meant writes made through sqlite-utils committed independently mid-task - a function that used sqlite-utils and then failed could leave those writes permanently committed. sqlite-utils write methods now nest inside the task transaction as savepoints, so a failing write function rolls back everything it did. Functions run with ``transaction=True`` should no longer manage transactions themselves - use ``transaction=False`` for manual transaction control. (:issue:`2831`)
+- ``await db.execute_write()`` detects statements that SQLite cannot execute inside a transaction - ``VACUUM``, ``ATTACH``, ``DETACH`` and ``PRAGMA`` - and runs them in autocommit mode instead. (:issue:`2831`)
+- ``await db.execute_write_script()`` is now transactional, matching its documentation: if any statement in the script fails, none of its statements are applied. Scripts containing statements that cannot run inside a transaction, or that manage transactions themselves, fall back to the previous ``conn.executescript()`` autocommit behavior. (:issue:`2831`)
+- The JSON write API is now atomic per request: ``/db/-/create`` with initial rows, multi-operation ``/db/table/-/alter`` calls and inserts using ``"return": true`` now either fully apply or roll back entirely if any part fails. Previously a failure part way through could leave earlier writes from the same request permanently committed. (:issue:`2831`)
+- Rebuilding the internal database catalog for a database is now a single atomic write. Previously the rebuild used six separate transactions, so queries against the internal database could observe a database with missing catalog rows while a rebuild was in progress. (:issue:`2831`)
+- sqlite-utils plugins no longer have their ``prepare_connection()`` hooks executed against Datasette's database connections - use Datasette's own :ref:`prepare_connection() <plugin_hook_prepare_connection>` plugin hook to customize connections. ``PRAGMA recursive_triggers=on`` is now applied consistently to every connection Datasette opens - previously it was enabled just on the write connection, as a side effect of the first sqlite-utils based write. (:issue:`2831`)
+- New :ref:`setting_busy_timeout_ms` setting controlling how long SQLite waits for a locked database file before giving up, previously hard-wired to the ``sqlite3`` driver's silent 5 second default. This matters when external processes write to the same database files Datasette is serving. (:issue:`2831`)
+- New :ref:`setting_journal_mode` setting for opting mutable database files into SQLite's `WAL mode <https://www.sqlite.org/wal.html>`__ (or another journal mode), allowing reads and writes to proceed concurrently. Datasette does not change the journal mode of database files by default. (:issue:`2831`)
+- A persistent internal database specified with ``--internal`` now has WAL mode enabled, matching the behavior of the default temporary internal database. (:issue:`2831`)
 
 .. _v1_0_a36:
 

docs/cli-reference.rst

@@ -251,6 +251,11 @@ These can be passed to ``datasette serve`` using ``datasette serve --setting nam
                                    executing SQLite queries (default=3)
       sql_time_limit_ms            Time limit for a SQL query in milliseconds
                                    (default=1000)
+      busy_timeout_ms              How long SQLite waits for a locked database file
+                                   before giving up (default=5000)
+      journal_mode                 Journal mode to set on mutable database files,
+                                   e.g. wal - leave blank to use each file's
+                                   existing mode (default=)
       default_facet_size           Number of values to return for requested facets
                                    (default=30)
       facet_time_limit_ms          Time limit for calculating a requested facet

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, transaction=True)
---------------------------------------------------------------------------------------------------------------------------
+await db.execute_write(sql, params=None, block=True, request=None, return_all=False, returning_limit=10)
+--------------------------------------------------------------------------------------------------------
 
 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.
 
@@ -2059,18 +2059,18 @@ 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. Pass
-``transaction=False`` for statements such as ``VACUUM`` that cannot run inside
-a transaction.
+Each call to ``execute_write()`` will be executed inside a transaction, with the exception of statements that SQLite does not allow to run inside a transaction: ``VACUUM``, ``ATTACH``, ``DETACH`` and ``PRAGMA``. Those statements are executed in autocommit mode instead.
 
 .. _database_execute_write_script:
 
 await db.execute_write_script(sql, block=True)
 ----------------------------------------------
 
-Like ``execute_write()`` but can be used to send multiple SQL statements in a single string separated by semicolons, using the ``sqlite3`` `conn.executescript() <https://docs.python.org/3/library/sqlite3.html#sqlite3.Cursor.executescript>`__ method.
+Like ``execute_write()`` but can be used to send multiple SQL statements in a single string separated by semicolons.
 
-Each call to ``execute_write_script()`` will be executed inside a transaction.
+Each call to ``execute_write_script()`` will be executed inside a transaction - if any statement fails, none of the statements will be applied.
+
+The exception is scripts that include statements which SQLite cannot execute inside a transaction - ``VACUUM``, ``ATTACH``, ``DETACH``, ``PRAGMA`` - or that manage transactions themselves using ``BEGIN``, ``COMMIT``, ``ROLLBACK``, ``SAVEPOINT`` or ``RELEASE``. Those scripts are executed using the ``sqlite3`` `conn.executescript() <https://docs.python.org/3/library/sqlite3.html#sqlite3.Cursor.executescript>`__ method instead, where each statement is committed as it executes.
 
 .. _database_execute_write_many:
 
@@ -2153,7 +2153,11 @@ The value returned from ``await database.execute_write_fn(...)`` will be the ret
 
 If your function raises an exception that exception will be propagated up to the ``await`` line.
 
-By default your function will be executed inside a transaction. You can pass ``transaction=False`` to disable this behavior, though if you do that you should be careful to manually apply transactions - ideally using the ``with conn:`` pattern, or you may see ``OperationalError: database table is locked`` errors.
+By default your function will be executed inside a transaction. Datasette executes ``BEGIN IMMEDIATE`` on the write connection before calling your function, then commits the transaction when your function returns - or rolls it back if your function raises an exception. Nothing your function writes will be visible to other connections until that final commit.
+
+Because the transaction is already open when your function is called, write methods from libraries such as `sqlite-utils <https://sqlite-utils.datasette.io/>`__ will nest their work inside it (sqlite-utils uses savepoints) rather than committing independently, so an exception rolls back everything the function did.
+
+Your function should not manage transactions itself when ``transaction=True`` - do not execute ``BEGIN`` or call ``conn.commit()`` or ``conn.rollback()`` on the connection. If you need to manage transactions manually, pass ``transaction=False`` - ideally using the ``with conn:`` pattern, or you may see ``OperationalError: database table is locked`` errors.
 
 If you specify ``block=False`` the method becomes fire-and-forget, queueing your function to be executed and then allowing your code after the call to ``.execute_write_fn()`` to continue running while the underlying thread waits for an opportunity to run your function. A UUID representing the queued task will be returned. Any exceptions in your code will be silently swallowed.
 
@@ -2176,6 +2180,17 @@ Functions run using ``execute_isolated_fn()`` share the same queue as ``execute_
 
 The return value of the function will be returned by this method. Any exceptions raised by the function will be raised out of the ``await`` line as well.
 
+.. _internals_database_transactions:
+
+How Datasette manages transactions
+----------------------------------
+
+Each mutable database has a single write connection, owned by a dedicated write thread that executes queued write tasks one at a time. Each task submitted with ``transaction=True`` (the default) runs inside its own transaction: Datasette executes ``BEGIN IMMEDIATE`` before invoking the task, commits if it completes and rolls back if it raises. One write task equals one transaction, and writes made by a task only become visible to readers when the task completes.
+
+Read connections never open transactions - each read statement executes in autocommit mode with its own implicit SQLite read snapshot.
+
+Datasette's write connections rely on the legacy transaction handling of Python's ``sqlite3`` module (connections opened with ``isolation_level=`` rather than the ``autocommit=`` parameter introduced in Python 3.12). This is a deliberate constraint shared with `sqlite-utils <https://sqlite-utils.datasette.io/>`__, which refuses connections created with ``autocommit=True`` or ``autocommit=False`` - any future migration to the modern transaction API would need to be coordinated across both projects. Plugins should not change the transaction control mode of connections Datasette passes to them.
+
 .. _database_close:
 
 db.close()

docs/introspection.rst

@@ -80,15 +80,18 @@ Shows a list of currently installed plugins and their versions. `Plugins example
 
 .. code-block:: json
 
-    [
-        {
-            "name": "datasette_cluster_map",
-            "static": true,
-            "templates": false,
-            "version": "0.10",
-            "hooks": ["extra_css_urls", "extra_js_urls", "extra_body_script"]
-        }
-    ]
+    {
+        "ok": true,
+        "plugins": [
+            {
+                "name": "datasette_cluster_map",
+                "static": true,
+                "templates": false,
+                "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/settings.rst

@@ -103,6 +103,39 @@ You can optionally set a lower time limit for an individual query using the ``?_
 
 This would set the time limit to 100ms for that specific query. This feature is useful if you are working with databases of unknown size and complexity - a query that might make perfect sense for a smaller table could take too long to execute on a table with millions of rows. By setting custom time limits you can execute queries "optimistically" - e.g. give me an exact count of rows matching this query but only if it takes less than 100ms to calculate.
 
+.. _setting_busy_timeout_ms:
+
+busy_timeout_ms
+~~~~~~~~~~~~~~~
+
+How long SQLite should wait when a database file is locked by another connection or process before giving up with a ``database is locked`` error, in milliseconds. The default is 5000 (five seconds), matching the default used by Python's ``sqlite3`` module.
+
+This mostly matters when other processes write to the same database files that Datasette is serving - a common pattern is a separate script (using `sqlite-utils <https://sqlite-utils.datasette.io/>`__ or similar) that periodically updates a database while Datasette serves it. A larger value makes Datasette more patient with long write transactions from those processes::
+
+    datasette mydatabase.db --setting busy_timeout_ms 10000
+
+.. _setting_journal_mode:
+
+journal_mode
+~~~~~~~~~~~~
+
+`Journal mode <https://www.sqlite.org/pragma.html#pragma_journal_mode>`__ to set on mutable database files. Leave blank (the default) to use whatever journal mode each database file already uses.
+
+Setting this to ``wal`` enables SQLite's `Write-Ahead Logging <https://www.sqlite.org/wal.html>`__ mode, which allows reads and writes to proceed concurrently - in the default rollback journal mode each commit blocks readers, and long reads block the writer::
+
+    datasette mydatabase.db --setting journal_mode wal
+
+When ``wal`` is selected Datasette also sets ``PRAGMA synchronous=NORMAL`` on the write connection, the standard pairing for WAL which reduces the number of ``fsync`` operations without weakening application-level consistency guarantees.
+
+Other allowed values are ``delete``, ``truncate`` and ``persist``.
+
+Things to be aware of before enabling WAL:
+
+- WAL mode is persistent - it is recorded in the database file and stays in effect when other tools open the same file later.
+- SQLite creates ``-wal`` and ``-shm`` files alongside the database file.
+- WAL does not work reliably on network filesystems such as NFS.
+- The directory containing the database must be writable by Datasette.
+
 .. _setting_max_returned_rows:
 
 max_returned_rows

tests/test_api.py

@@ -1,6 +1,6 @@
 from datasette.app import Datasette
 from datasette.plugins import DEFAULT_PLUGINS
-from datasette.utils import UNSTABLE_API_MESSAGE, escape_sqlite, tilde_encode
+from datasette.utils import UNSTABLE_API_MESSAGE
 from datasette.utils.sqlite import sqlite_version
 from datasette.version import __version__
 from .fixtures import make_app_client, EXPECTED_PLUGINS
@@ -614,13 +614,13 @@ 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() if p["name"] != "TrackEventPlugin"],
+        [p for p in response.json()["plugins"] 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()}
+    names = {p["name"] for p in response.json()["plugins"]}
     assert names.issuperset(p["name"] for p in EXPECTED_PLUGINS)
     assert names.issuperset(DEFAULT_PLUGINS)
 
@@ -694,6 +694,8 @@ async def test_settings_json(ds_client):
         "max_insert_rows": 100,
         "max_post_body_bytes": 2 * 1024 * 1024,
         "sql_time_limit_ms": 200,
+        "busy_timeout_ms": 5000,
+        "journal_mode": "",
         "allow_download": True,
         "allow_signed_tokens": True,
         "max_signed_tokens_ttl": 0,
@@ -930,37 +932,6 @@ 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(
-        "create table {} (id integer primary key, name text)".format(
-            escape_sqlite(table_name)
-        )
-    )
-    await db.execute_write(
-        "insert into {} (id, name) values (1, 'one')".format(escape_sqlite(table_name))
-    )
-    # 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(
-        "/test_reserved_table_names/{}.json?_shape=array".format(
-            tilde_encode(table_name)
-        )
-    )
-    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

@@ -2717,3 +2717,103 @@ async def test_create_using_alter_against_existing_table(
         insert_rows_event = ds_write._tracked_events[1]
         assert insert_rows_event.name == "insert-rows"
         assert insert_rows_event.num_rows == 1
+
+
+@pytest.mark.asyncio
+async def test_create_table_with_failing_rows_is_atomic(ds_write):
+    # https://github.com/simonw/datasette/issues/2831
+    # If inserting the initial rows fails, the create table should
+    # be rolled back as well
+    token = write_token(ds_write)
+    response = await ds_write.client.post(
+        "/data/-/create",
+        json={
+            "table": "atomic_create",
+            "rows": [{"id": 1, "name": "one"}, {"id": 1, "name": "dupe"}],
+            "pk": "id",
+        },
+        headers=_headers(token),
+    )
+    assert response.status_code == 400
+    assert not await ds_write.get_database("data").table_exists("atomic_create")
+
+
+@pytest.mark.asyncio
+async def test_alter_table_with_failing_operation_is_atomic(ds_write):
+    # https://github.com/simonw/datasette/issues/2831
+    # If a later operation fails, earlier operations should be rolled back
+    token = write_token(ds_write)
+    response = await ds_write.client.post(
+        "/data/docs/-/alter",
+        json={
+            "operations": [
+                {"op": "add_column", "args": {"name": "new_col", "type": "text"}},
+                # Fails - column "title" already exists
+                {"op": "add_column", "args": {"name": "title", "type": "text"}},
+            ]
+        },
+        headers=_headers(token),
+    )
+    assert response.status_code == 400
+    columns = await ds_write.get_database("data").table_columns("docs")
+    assert "new_col" not in columns
+
+
+@pytest.mark.asyncio
+async def test_insert_with_return_failing_row_is_atomic(ds_write):
+    # https://github.com/simonw/datasette/issues/2831
+    # Insert with "return": true runs one insert per row - a failure
+    # part way through should roll back the earlier rows
+    token = write_token(ds_write)
+    response = await ds_write.client.post(
+        "/data/docs/-/insert",
+        json={
+            "rows": [
+                {"id": 1, "title": "one"},
+                {"id": 2, "title": "two"},
+                {"id": 2, "title": "dupe"},
+            ],
+            "return": True,
+        },
+        headers=_headers(token),
+    )
+    assert response.status_code == 400
+    count = (
+        await ds_write.get_database("data").execute("select count(*) from docs")
+    ).single_value()
+    assert count == 0
+
+
+@pytest.mark.asyncio
+async def test_write_api_does_not_run_sqlite_utils_plugins(ds_write):
+    # https://github.com/simonw/datasette/issues/2831
+    # sqlite-utils plugins should not have their prepare_connection hooks
+    # executed against Datasette's connections
+    import sqlite_utils.plugins
+    from sqlite_utils import hookimpl
+
+    prepared = []
+
+    class TrackingPlugin:
+        @hookimpl
+        def prepare_connection(self, conn):
+            prepared.append(conn)
+
+    sqlite_utils.plugins.pm.register(TrackingPlugin(), name="datasette-test-tracking")
+    try:
+        token = write_token(ds_write)
+        response = await ds_write.client.post(
+            "/data/docs/-/insert",
+            json={"rows": [{"id": 1, "title": "one"}]},
+            headers=_headers(token),
+        )
+        assert response.status_code == 201
+        response = await ds_write.client.post(
+            "/data/docs/1/-/update",
+            json={"update": {"title": "two"}},
+            headers=_headers(token),
+        )
+        assert response.status_code == 200
+        assert prepared == []
+    finally:
+        sqlite_utils.plugins.pm.unregister(name="datasette-test-tracking")

tests/test_config_dir.py

@@ -109,7 +109,7 @@ 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 = response.json["plugins"]
     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}

tests/test_internal_db.py

@@ -334,3 +334,51 @@ async def test_orphan_stale_catalog_child_entries_removed(tmp_path):
     assert response.status_code == 200
 
     ds2.close()
+
+
+@pytest.mark.asyncio
+async def test_populate_schema_tables_is_a_single_write_task(tmp_path):
+    # https://github.com/simonw/datasette/issues/2831
+    # The catalog rebuild should be one atomic write task, so readers of the
+    # internal database never observe a database with deleted-but-not-yet-
+    # reinserted catalog rows
+    from datasette.app import Datasette
+    from datasette.utils.internal_db import populate_schema_tables
+
+    path = str(tmp_path / "data.db")
+    conn = sqlite3.connect(path)
+    conn.execute("create table t (id integer primary key, name text)")
+    conn.execute("create view v as select * from t")
+    conn.close()
+    ds = Datasette([path])
+    await ds.invoke_startup()
+    await ds.refresh_schemas()
+    internal_db = ds.get_internal_database()
+
+    write_fns = []
+    original_execute_write_fn = internal_db.execute_write_fn
+
+    async def counting_execute_write_fn(fn, *args, **kwargs):
+        write_fns.append(fn)
+        return await original_execute_write_fn(fn, *args, **kwargs)
+
+    internal_db.execute_write_fn = counting_execute_write_fn
+    try:
+        await populate_schema_tables(internal_db, ds.get_database("data"))
+    finally:
+        internal_db.execute_write_fn = original_execute_write_fn
+
+    assert len(write_fns) == 1
+    # And the catalog should be correct
+    tables = await internal_db.execute(
+        "select table_name from catalog_tables where database_name = 'data'"
+    )
+    assert [row["table_name"] for row in tables.rows] == ["t"]
+    views = await internal_db.execute(
+        "select view_name from catalog_views where database_name = 'data'"
+    )
+    assert [row["view_name"] for row in views.rows] == ["v"]
+    columns = await internal_db.execute(
+        "select name from catalog_columns where database_name = 'data' and table_name = 't'"
+    )
+    assert {row["name"] for row in columns.rows} == {"id", "name"}

tests/test_internals_database.py

@@ -112,6 +112,129 @@ async def test_execute_fn_transaction_false():
     await db.execute_write_fn(run, transaction=False)
 
 
+@pytest.mark.asyncio
+async def test_execute_write_fn_wraps_sqlite_utils_writes_in_transaction():
+    # https://github.com/simonw/datasette/issues/2831
+    # sqlite-utils write methods commit their own transactions unless one is
+    # already open - the write thread must open one before running each task
+    # so that a failing task rolls back everything, including those writes.
+    datasette = Datasette(memory=True)
+    db = datasette.add_memory_database("test_txn_sqlite_utils")
+    await db.execute_write("create table t (a integer)")
+
+    def failing_task(conn):
+        sqlite_utils.Database(conn)["t"].insert_all({"a": i} for i in range(5))
+        assert conn.in_transaction
+        raise ValueError("boom")
+
+    with pytest.raises(ValueError):
+        await db.execute_write_fn(failing_task)
+    count = (await db.execute("select count(*) from t")).single_value()
+    assert count == 0
+    # The write connection should be back in autocommit mode
+    assert (
+        await db.execute_write_fn(lambda conn: conn.in_transaction, transaction=False)
+    ) is False
+    # And a transaction=True task should see a transaction already open
+    assert (await db.execute_write_fn(lambda conn: conn.in_transaction)) is True
+
+
+@pytest.mark.asyncio
+async def test_execute_write_statements_disallowed_in_transaction(tmp_path):
+    # VACUUM (and ATTACH/DETACH/PRAGMA) cannot run inside a transaction, so
+    # execute_write() must run them outside one
+    # https://github.com/simonw/datasette/issues/2831
+    path = str(tmp_path / "test.db")
+    setup_conn = sqlite3.connect(path)
+    setup_conn.execute("create table t (a integer)")
+    setup_conn.close()
+    datasette = Datasette([path])
+    db = datasette.get_database("test")
+    await db.execute_write("vacuum")
+    await db.execute_write("  -- a comment\n  VACUUM")
+    # But regular DML statements still run inside a transaction
+    from datasette.database import _can_execute_in_transaction
+
+    assert _can_execute_in_transaction("insert into t values (1)")
+    assert _can_execute_in_transaction("with x as (select 1) insert into t select 1")
+    assert not _can_execute_in_transaction("vacuum")
+    assert not _can_execute_in_transaction("/* hi */ PRAGMA optimize")
+
+
+@pytest.mark.asyncio
+async def test_execute_write_fn_sqlite_utils_integrity_error_rolls_back_task():
+    # https://github.com/simonw/datasette/issues/2831
+    datasette = Datasette(memory=True)
+    db = datasette.add_memory_database("test_txn_integrity")
+    await db.execute_write("create table t (id integer primary key)")
+
+    def two_inserts(conn):
+        table = sqlite_utils.Database(conn)["t"]
+        table.insert({"id": 1})
+        table.insert({"id": 1})  # IntegrityError
+
+    with pytest.raises(sqlite3.IntegrityError):
+        await db.execute_write_fn(two_inserts)
+    count = (await db.execute("select count(*) from t")).single_value()
+    assert count == 0
+
+
+@pytest.mark.asyncio
+async def test_execute_write_script_is_transactional():
+    # https://github.com/simonw/datasette/issues/2831
+    # A script that fails part way through should apply none of its statements
+    datasette = Datasette(memory=True)
+    db = datasette.add_memory_database("test_write_script_txn")
+    with pytest.raises(sqlite3.OperationalError):
+        await db.execute_write_script(
+            "create table one (id integer primary key);\n"
+            "insert into one (id) values (1);\n"
+            "insert into no_such_table (id) values (2);"
+        )
+    assert "one" not in await db.table_names()
+
+
+@pytest.mark.asyncio
+async def test_execute_write_script_with_transaction_unsafe_statements(tmp_path):
+    # Scripts containing statements that cannot run inside a transaction
+    # (VACUUM, BEGIN etc) still execute, using the previous autocommit behavior
+    path = str(tmp_path / "test.db")
+    sqlite3.connect(path).close()
+    datasette = Datasette([path])
+    db = datasette.get_database("test")
+    await db.execute_write_script("create table t (id integer primary key);\nvacuum;")
+    assert "t" in await db.table_names()
+    await db.execute_write_script("begin;\ninsert into t (id) values (1);\ncommit;")
+    count = (await db.execute("select count(*) from t")).single_value()
+    assert count == 1
+
+
+@pytest.mark.asyncio
+async def test_execute_write_fn_writes_invisible_to_readers_until_task_ends(tmp_path):
+    # https://github.com/simonw/datasette/issues/2831
+    path = str(tmp_path / "test.db")
+    setup_conn = sqlite3.connect(path)
+    setup_conn.execute("create table t (a integer)")
+    setup_conn.close()
+    datasette = Datasette([path])
+    db = datasette.get_database("test")
+
+    def insert_and_check(conn):
+        sqlite_utils.Database(conn)["t"].insert_all({"a": i} for i in range(5))
+        # A separate read-only connection must not see the rows mid-task
+        reader = sqlite3.connect("file:{}?mode=ro".format(path), uri=True)
+        try:
+            return reader.execute("select count(*) from t").fetchone()[0]
+        finally:
+            reader.close()
+
+    mid_task_count = await db.execute_write_fn(insert_and_check)
+    assert mid_task_count == 0
+    # After the task commits the rows are visible
+    count = (await db.execute("select count(*) from t")).single_value()
+    assert count == 5
+
+
 @pytest.mark.parametrize(
     "tables,exists",
     (
@@ -719,41 +842,6 @@ async def test_execute_write_fn_exception(db):
         await db.execute_write_fn(write_fn)
 
 
-@pytest.mark.asyncio
-@pytest.mark.parametrize("num_sql_threads", (0, 1))
-async def test_execute_write_fn_sqlite_utils_transaction(tmp_path, num_sql_threads):
-    # A write inside a failing Datasette task must never become visible or
-    # survive the rollback. Exercise both the synchronous and writer-thread
-    # paths against a file-backed database so a second connection can observe
-    # committed state independently.
-    db_path = tmp_path / "test.db"
-    sqlite3.connect(db_path).close()
-    ds = Datasette([str(db_path)], settings={"num_sql_threads": num_sql_threads})
-    db = ds.get_database("test")
-    await db.execute_write("create table items (id integer primary key)")
-    # This reader is used inside the write callback, which may run on another
-    # thread, but it is never accessed concurrently.
-    reader = sqlite3.connect(db_path, check_same_thread=False)
-
-    def insert_then_fail(conn):
-        # Datasette must open the outer transaction before sqlite-utils writes.
-        assert conn.in_transaction
-        sqlite_utils.Database(conn)["items"].insert({"id": 1})
-        # If sqlite-utils committed its own transaction, this would return 1.
-        assert reader.execute("select count(*) from items").fetchone()[0] == 0
-        # Simulate a later step failing after the sqlite-utils write succeeded.
-        raise ValueError("deliberate")
-
-    try:
-        with pytest.raises(ValueError, match="deliberate"):
-            await db.execute_write_fn(insert_then_fail)
-        # The outer transaction must roll back the sqlite-utils write as well.
-        assert reader.execute("select count(*) from items").fetchone()[0] == 0
-    finally:
-        reader.close()
-        db.close()
-
-
 @pytest.mark.asyncio
 @pytest.mark.parametrize("param_name", ["conn", "connection", "db", "c"])
 async def test_execute_write_fn_accepts_any_single_param_name(db, param_name):
@@ -1214,3 +1302,107 @@ async def test_database_close_is_idempotent(tmpdir):
     # Second call should be a no-op, not raise
     db.close()
     ds._internal_database.close()
+
+
+@pytest.mark.asyncio
+async def test_recursive_triggers_enabled_on_all_connections(tmp_path):
+    # https://github.com/simonw/datasette/issues/2831
+    # Previously recursive_triggers was only enabled on the write connection,
+    # and only as a side effect of the first sqlite-utils based write - so
+    # trigger semantics could differ between connections
+    path = str(tmp_path / "test.db")
+    sqlite3.connect(path).close()
+    datasette = Datasette([path])
+    db = datasette.get_database("test")
+    write_value = await db.execute_write_fn(
+        lambda conn: conn.execute("PRAGMA recursive_triggers").fetchone()[0],
+        transaction=False,
+    )
+    read_value = await db.execute_fn(
+        lambda conn: conn.execute("PRAGMA recursive_triggers").fetchone()[0]
+    )
+    assert write_value == 1
+    assert read_value == 1
+
+
+@pytest.mark.asyncio
+async def test_busy_timeout_ms_setting(tmp_path):
+    # https://github.com/simonw/datasette/issues/2831
+    # The SQLite busy timeout should be an explicit, configurable policy
+    # instead of the sqlite3 driver's inherited 5 second default
+    path = str(tmp_path / "test.db")
+    sqlite3.connect(path).close()
+    datasette = Datasette([path], settings={"busy_timeout_ms": 250})
+    db = datasette.get_database("test")
+    read_value = await db.execute_fn(
+        lambda conn: conn.execute("PRAGMA busy_timeout").fetchone()[0]
+    )
+    write_value = await db.execute_write_fn(
+        lambda conn: conn.execute("PRAGMA busy_timeout").fetchone()[0],
+        transaction=False,
+    )
+    assert read_value == 250
+    assert write_value == 250
+
+
+@pytest.mark.asyncio
+async def test_busy_timeout_ms_default(tmp_path):
+    # Default matches the sqlite3 driver's historical 5 second default
+    path = str(tmp_path / "test.db")
+    sqlite3.connect(path).close()
+    datasette = Datasette([path])
+    db = datasette.get_database("test")
+    read_value = await db.execute_fn(
+        lambda conn: conn.execute("PRAGMA busy_timeout").fetchone()[0]
+    )
+    assert read_value == 5000
+
+
+@pytest.mark.asyncio
+async def test_journal_mode_setting_applies_wal(tmp_path):
+    # https://github.com/simonw/datasette/issues/2831
+    # Opt-in WAL support for mutable database files - not the default
+    path = str(tmp_path / "test.db")
+    sqlite3.connect(path).close()
+    datasette = Datasette([path], settings={"journal_mode": "wal"})
+    db = datasette.get_database("test")
+    mode = await db.execute_write_fn(
+        lambda conn: conn.execute("PRAGMA journal_mode").fetchone()[0],
+        transaction=False,
+    )
+    assert mode == "wal"
+    # WAL is paired with synchronous=NORMAL (1) on the write connection
+    synchronous = await db.execute_write_fn(
+        lambda conn: conn.execute("PRAGMA synchronous").fetchone()[0],
+        transaction=False,
+    )
+    assert synchronous == 1
+
+
+@pytest.mark.asyncio
+async def test_journal_mode_defaults_to_leaving_files_alone(tmp_path):
+    path = str(tmp_path / "test.db")
+    sqlite3.connect(path).close()
+    datasette = Datasette([path])
+    db = datasette.get_database("test")
+    mode = await db.execute_write_fn(
+        lambda conn: conn.execute("PRAGMA journal_mode").fetchone()[0],
+        transaction=False,
+    )
+    assert mode == "delete"
+
+
+@pytest.mark.asyncio
+async def test_persistent_internal_database_gets_wal(tmp_path):
+    # https://github.com/simonw/datasette/issues/2831
+    # The temporary internal database enables WAL - a persistent one passed
+    # via --internal should get the same treatment
+    internal_path = str(tmp_path / "internal.db")
+    datasette = Datasette(memory=True, internal=internal_path)
+    await datasette.invoke_startup()
+    internal_db = datasette.get_internal_database()
+    mode = await internal_db.execute_write_fn(
+        lambda conn: conn.execute("PRAGMA journal_mode").fetchone()[0],
+        transaction=False,
+    )
+    assert mode == "wal"

tests/test_permissions.py

@@ -457,20 +457,6 @@ async def test_permissions_debug(ds_client, filter_):
     assert checks == expected_checks
 
 
-@pytest.mark.asyncio
-@pytest.mark.parametrize(
-    "permissions_debug,expected_status",
-    (
-        (1, 200),
-        (0, 403),
-    ),
-)
-async def test_permissions_debug_numeric_boolean(permissions_debug, expected_status):
-    ds = Datasette(config={"permissions": {"permissions-debug": permissions_debug}})
-    response = await ds.client.get("/-/permissions")
-    assert response.status_code == expected_status
-
-
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
     "actor,allow,expected_fragment",
@@ -762,12 +748,7 @@ async def test_actor_restricted_permissions(
     }
     if actor.get("id"):
         expected["actor_id"] = actor["id"]
-    data = response.json()
-    for key, value in expected.items():
-        assert data[key] == value
-    assert data["actor"] == actor
-    assert data["explanation"]["allowed"] is expected_result
-    assert data["explanation"]["summary"]
+    assert response.json() == expected
 
 
 PermConfigTestCase = collections.namedtuple(
@@ -1753,8 +1734,6 @@ async def test_permission_check_view_requires_debug_permission():
     data = response.json()
     assert data["action"] == "view-instance"
     assert data["allowed"] is True
-    assert data["explanation"]["allowed"] is True
-    assert data["explanation"]["summary"]
 
 
 @pytest.mark.asyncio
@@ -1780,211 +1759,6 @@ async def test_permission_check_view_query_actions(action):
     }
 
 
-@pytest.mark.asyncio
-async def test_permission_check_explains_specificity_for_hypothetical_actor():
-    ds = Datasette(
-        config={
-            "permissions": {"view-table": {"id": "alice"}},
-            "databases": {
-                "analytics": {
-                    "permissions": {"view-table": False},
-                    "tables": {
-                        "public": {"permissions": {"view-table": {"id": "alice"}}}
-                    },
-                }
-            },
-        }
-    )
-    ds.root_enabled = True
-    await ds.invoke_startup()
-
-    def path_for(child):
-        return "/-/check.json?" + urllib.parse.urlencode(
-            {
-                "action": "view-table",
-                "parent": "analytics",
-                "child": child,
-                "actor": json.dumps({"id": "alice"}),
-            }
-        )
-
-    public_response = await ds.client.get(path_for("public"), actor={"id": "root"})
-    assert public_response.status_code == 200
-    public = public_response.json()
-    assert public["actor"] == {"id": "alice"}
-    assert public["allowed"] is True
-    assert public["explanation"]["allowed"] is True
-    assert public["explanation"]["winning_scope"] == "resource"
-    public_rules = public["explanation"]["matched_rules"]
-    assert any(
-        rule["scope"] == "resource" and rule["effect"] == "allow" and rule["decisive"]
-        for rule in public_rules
-    )
-    assert any(
-        rule["scope"] == "parent"
-        and rule["effect"] == "deny"
-        and rule["ignored_because"] == "A more specific rule matched"
-        for rule in public_rules
-    )
-
-    private_response = await ds.client.get(path_for("private"), actor={"id": "root"})
-    assert private_response.status_code == 200
-    private = private_response.json()
-    assert private["allowed"] is False
-    assert private["explanation"]["allowed"] is False
-    assert private["explanation"]["winning_scope"] == "parent"
-    assert private["explanation"]["summary"].startswith("Denied by a parent-level rule")
-
-
-@pytest.mark.asyncio
-async def test_permission_check_explains_deny_wins_at_same_scope():
-    ds = Datasette(config={"permissions": {"view-table": {"id": "someone-else"}}})
-    ds.root_enabled = True
-    await ds.invoke_startup()
-    path = "/-/check.json?" + urllib.parse.urlencode(
-        {
-            "action": "view-table",
-            "parent": "analytics",
-            "child": "users",
-            "actor": json.dumps({"id": "alice"}),
-        }
-    )
-    response = await ds.client.get(path, actor={"id": "root"})
-    assert response.status_code == 200
-    data = response.json()
-    assert data["allowed"] is False
-    assert data["explanation"]["winning_scope"] == "global"
-    rules = data["explanation"]["matched_rules"]
-    assert any(rule["effect"] == "deny" and rule["decisive"] for rule in rules)
-    assert any(
-        rule["effect"] == "allow"
-        and rule["ignored_because"] == "A deny rule matched at the same scope"
-        for rule in rules
-    )
-
-
-@pytest.mark.asyncio
-async def test_permission_check_explains_default_deny():
-    ds = Datasette()
-    ds.root_enabled = True
-    await ds.invoke_startup()
-    path = "/-/check.json?" + urllib.parse.urlencode(
-        {
-            "action": "insert-row",
-            "parent": "analytics",
-            "child": "users",
-            "actor": json.dumps({"id": "alice"}),
-        }
-    )
-    response = await ds.client.get(path, actor={"id": "root"})
-    assert response.status_code == 200
-    data = response.json()
-    assert data["allowed"] is False
-    explanation = data["explanation"]
-    assert explanation["allowed"] is False
-    assert explanation["matched_rules"] == []
-    assert explanation["winning_scope"] is None
-    assert explanation["summary"] == (
-        "Denied because no permission rule matched this actor and resource."
-    )
-
-
-@pytest.mark.asyncio
-async def test_permission_check_explains_actor_restrictions():
-    ds = Datasette()
-    ds.root_enabled = True
-    await ds.invoke_startup()
-    restricted_actor = {
-        "id": "alice",
-        "_r": {"r": {"analytics": {"public": ["vt"]}}},
-    }
-    path = "/-/check.json?" + urllib.parse.urlencode(
-        {
-            "action": "view-table",
-            "parent": "analytics",
-            "child": "private",
-            "actor": json.dumps(restricted_actor),
-        }
-    )
-    response = await ds.client.get(path, actor={"id": "root"})
-    assert response.status_code == 200
-    data = response.json()
-    assert data["allowed"] is False
-    explanation = data["explanation"]
-    assert explanation["rule_allowed"] is True
-    assert explanation["restriction_allowed"] is False
-    assert explanation["allowed"] is False
-    assert explanation["restrictions"]
-    assert any(
-        restriction["allowed"] is False for restriction in explanation["restrictions"]
-    )
-    assert "actor's restrictions" in explanation["summary"]
-
-
-@pytest.mark.asyncio
-async def test_permission_check_explains_required_actions():
-    from datasette import hookimpl
-    from datasette.permissions import PermissionSQL
-
-    class StoreQueryPermissions:
-        @hookimpl
-        def permission_resources_sql(self, actor, action):
-            if not actor or actor.get("id") != "alice":
-                return None
-            if action == "store-query":
-                return PermissionSQL(
-                    sql="SELECT 'analytics' AS parent, NULL AS child, 1 AS allow, 'alice can store queries' AS reason"
-                )
-            if action == "execute-sql":
-                return PermissionSQL(
-                    sql="SELECT 'analytics' AS parent, NULL AS child, 0 AS allow, 'alice cannot execute SQL' AS reason"
-                )
-
-    ds = Datasette()
-    ds.root_enabled = True
-    await ds.invoke_startup()
-    ds.pm.register(StoreQueryPermissions(), name="store-query-test")
-    path = "/-/check.json?" + urllib.parse.urlencode(
-        {
-            "action": "store-query",
-            "parent": "analytics",
-            "actor": json.dumps({"id": "alice"}),
-        }
-    )
-    response = await ds.client.get(path, actor={"id": "root"})
-    assert response.status_code == 200
-    data = response.json()
-    assert data["allowed"] is False
-    explanation = data["explanation"]
-    assert explanation["rule_allowed"] is True
-    assert explanation["required_actions"][0]["action"] == "execute-sql"
-    assert explanation["required_actions"][0]["allowed"] is False
-    assert explanation["summary"] == (
-        "Denied because store-query also requires execute-sql, which was denied."
-    )
-
-
-@pytest.mark.asyncio
-async def test_permission_check_hypothetical_actor_validation():
-    ds = Datasette()
-    ds.root_enabled = True
-    await ds.invoke_startup()
-
-    response = await ds.client.get(
-        "/-/check.json?action=view-instance&actor=not-json",
-        actor={"id": "root"},
-    )
-    assert response.status_code == 400
-    assert response.json()["error"].startswith("Invalid actor JSON:")
-
-    response = await ds.client.get(
-        "/-/check.json?action=view-instance&actor=%5B%5D",
-        actor={"id": "root"},
-    )
-    assert response.status_code == 400
-    assert response.json()["error"] == "actor must be a JSON object or null"
-
-
 @pytest.mark.asyncio
 async def test_root_allow_block_with_table_restricted_actor():
     """

tests/test_plugins.py

@@ -1482,7 +1482,7 @@ async def test_plugin_is_installed():
         datasette.pm.register(DummyPlugin(), name="DummyPlugin")
         response = await datasette.client.get("/-/plugins.json")
         assert response.status_code == 200
-        installed_plugins = {p["name"] for p in response.json()}
+        installed_plugins = {p["name"] for p in response.json()["plugins"]}
         assert "DummyPlugin" in installed_plugins
 
     finally:

tests/test_success_envelope.py

@@ -2,8 +2,8 @@
 Tests for the canonical JSON success envelope.
 
 Every JSON object returned by a Datasette endpoint on success should include
-"ok": true. /-/plugins intentionally returns a top-level array instead, while
-/-/databases and /-/actions use the object envelope.
+"ok": true. (Endpoints that return a top-level array are being converted to
+objects separately - see /-/plugins, /-/databases, /-/actions.)
 """
 
 import pytest
@@ -79,16 +79,17 @@ async def test_permissions_post_success_has_ok_true(ds_envelope):
 
 
 @pytest.mark.asyncio
-async def test_plugins_json_is_array(ds_client):
+async def test_plugins_json_is_object(ds_client):
     response = await ds_client.get("/-/plugins.json")
     assert response.status_code == 200
     data = response.json()
-    assert isinstance(data, list)
-    assert all(isinstance(plugin, dict) for plugin in data)
+    assert set(data.keys()) == {"ok", "plugins"}
+    assert data["ok"] is True
+    assert isinstance(data["plugins"], list)
     # ?all=1 should include Datasette's default plugins in the same shape
     response_all = await ds_client.get("/-/plugins.json?all=1")
-    all_plugins = response_all.json()
-    assert len(all_plugins) > len(data)
+    all_plugins = response_all.json()["plugins"]
+    assert len(all_plugins) > len(data["plugins"])
 
 
 @pytest.mark.asyncio