From b647b5efc29300f715ba656e41b0591f342938e1 Mon Sep 17 00:00:00 2001
From: Simon Willison <swillison@gmail.com>
Date: Fri, 18 Oct 2019 15:51:07 -0700
Subject: [PATCH] Fix for /foo v.s. /foo-bar issue, closes #597

Pull request #599
---
 datasette/views/base.py | 16 ++++++++--------
 tests/fixtures.py       |  7 +++++++
 tests/test_api.py       | 18 ++++++++++++++++++
 3 files changed, 33 insertions(+), 8 deletions(-)

diff --git a/datasette/views/base.py b/datasette/views/base.py
index db1d69d9..219630af 100644
--- a/datasette/views/base.py
+++ b/datasette/views/base.py
@@ -193,14 +193,14 @@ class DataView(BaseView):
     async def resolve_db_name(self, request, db_name, **kwargs):
         hash = None
         name = None
-        if "-" in db_name:
-            # Might be name-and-hash, or might just be
-            # a name with a hyphen in it
-            name, hash = db_name.rsplit("-", 1)
-            if name not in self.ds.databases:
-                # Try the whole name
-                name = db_name
-                hash = None
+        if db_name not in self.ds.databases and "-" in db_name:
+            # No matching DB found, maybe it's a name-hash?
+            name_bit, hash_bit = db_name.rsplit("-", 1)
+            if name_bit not in self.ds.databases:
+                raise NotFound("Database not found: {}".format(name))
+            else:
+                name = name_bit
+                hash = hash_bit
         else:
             name = db_name
         # Verify the hash
diff --git a/tests/fixtures.py b/tests/fixtures.py
index dac28dc0..a4c32f36 100644
--- a/tests/fixtures.py
+++ b/tests/fixtures.py
@@ -178,6 +178,13 @@ def app_client_two_attached_databases():
     )
 
 
+@pytest.fixture(scope="session")
+def app_client_conflicting_database_names():
+    yield from make_app_client(
+        extra_databases={"foo.db": EXTRA_DATABASE_SQL, "foo-bar.db": EXTRA_DATABASE_SQL}
+    )
+
+
 @pytest.fixture(scope="session")
 def app_client_two_attached_databases_one_immutable():
     yield from make_app_client(
diff --git a/tests/test_api.py b/tests/test_api.py
index cc00b780..826c00f3 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -7,6 +7,7 @@ from .fixtures import (  # noqa
     app_client_larger_cache_size,
     app_client_returned_rows_matches_page_size,
     app_client_two_attached_databases_one_immutable,
+    app_client_conflicting_database_names,
     app_client_with_cors,
     app_client_with_dot,
     generate_compound_rows,
@@ -1652,3 +1653,20 @@ def test_cors(app_client_with_cors, path, status_code):
     response = app_client_with_cors.get(path)
     assert response.status == status_code
     assert "*" == response.headers["Access-Control-Allow-Origin"]
+
+
+def test_common_prefix_database_names(app_client_conflicting_database_names):
+    # https://github.com/simonw/datasette/issues/597
+    assert ["fixtures", "foo", "foo-bar"] == [
+        d["name"]
+        for d in json.loads(
+            app_client_conflicting_database_names.get("/-/databases.json").body.decode(
+                "utf8"
+            )
+        )
+    ]
+    for db_name, path in (("foo", "/foo.json"), ("foo-bar", "/foo-bar.json")):
+        data = json.loads(
+            app_client_conflicting_database_names.get(path).body.decode("utf8")
+        )
+        assert db_name == data["database"]