fix(images): filename search survives a failed prompt-link read

On main a workspace q matched only file paths, so search worked with a
broken database. Since search also matches linked prompts, any q turned
a failed link read into a 500. A q without category, tags or the rating
sort now falls back to filename matches with a null positive_count and
logs the failure with its traceback; those linked filters still fail.

TESTING.md

@@ -490,8 +490,10 @@ set, not the page:
 - Absent on a plain listing's cursor pages, which read no links. The frontend
   keeps the first page's value.
 - Null when a plain first page's link read failed. The listing still returns 200,
-  and consumers then hide "· K positive prompts". A failure under a filter or
-  the rating sort stays a safe 500.
+  and consumers then hide "· K positive prompts". A `q` search alone also
+  survives the failure: it matches filenames only, as before linked search, and
+  every page's count is null (logged with the traceback). A failure under
+  `category`, `tags` or the rating sort stays a safe 500.
 
 Library parents (list, detail and command receipts) gain `run_count` (an int; the
 D23 migration estimate for rows from before 3.2.4) and `last_used_at`, a UTC ISO

py/api/images.py

@@ -1141,7 +1141,8 @@ class ImageRoutesMixin:
         count is _COUNT_OMITTED, so the response leaves ``positive_count`` out
         and the frontend keeps the first page's value. On that plain first
         page a failed read leaves the listing usable and the count unknown
-        (None).
+        (None); so does a failed read under ``q`` alone, whose search then
+        matches filenames only (as before the linked search existed).
         """
         order, category, tags = filters["order"], filters["category"], filters["tags"]
         needed = (
@@ -1161,10 +1162,19 @@ class ImageRoutesMixin:
                     wanted=self._workspace_wanted(listings),
                 )
             except Exception:
-                if needed:
+                # Category, tags and the rating sort cannot be served without
+                # the links. A plain listing and a filename search can: the
+                # search then matches filenames only, and the count is None.
+                if category is not None or tags or order == "rating":
                     raise
                 self.logger.warning(
-                    "Workspace positive count could not be read", exc_info=True
+                    "Workspace prompt links could not be read; %s",
+                    (
+                        "searching filenames only"
+                        if filters["query"]
+                        else "positive count unknown"
+                    ),
+                    exc_info=True,
                 )
         if order == "rating":
 

tests/test_api_workspace_images.py

@@ -988,8 +988,14 @@ class TestWorkspaceImages(ImageAPITestCase):
         self.assertEqual(data["total"], 10)
         self.assertIsNone(data["positive_count"])
         self.assertNotIn("database gone", json.dumps(data))
-        # A filter or the rating sort needs the read, so its failure is an error.
-        for params in ({"q": "zebra"}, {"category": "Night"}, {"sort": "rating"}):
+        # A linked filter or the rating sort needs the read, so its failure is
+        # an error (filename-only search survives it, see below).
+        for params in (
+            {"category": "Night"},
+            {"tags": "a"},
+            {"q": "zebra", "category": "Night"},
+            {"sort": "rating"},
+        ):
             with (
                 self.subTest(failing=params),
                 patch.object(
@@ -1000,6 +1006,35 @@ class TestWorkspaceImages(ImageAPITestCase):
                 self.assertEqual(response.status, 500, data)
                 self.assertNotIn("images", data)
 
+    async def test_filename_search_survives_a_database_failure(self):
+        for name, mtime in (("zebra-1.png", 300), ("zebra-2.png", 200)):
+            self.media(name, mtime)
+        self.media("other.png", 100)
+        with (
+            patch.object(
+                self.api.db,
+                "get_image_link_matches",
+                side_effect=RuntimeError("database gone"),
+            ),
+            self.assertLogs(self.api.logger, "WARNING") as logged,
+        ):
+            response, first = await self.get(q="ZEBRA", limit=1)
+            self.assertEqual(response.status, 200, first)
+            response, second = await self.get(
+                q="ZEBRA", limit=1, cursor=first["next_cursor"]
+            )
+        self.assertEqual(response.status, 200, second)
+        # Filename matches only; the count of linked positives is unknown.
+        self.assertEqual(self._names(first), ["zebra-1.png"])
+        self.assertEqual(self._names(second), ["zebra-2.png"])
+        for page in (first, second):
+            self.assertEqual(page["total"], 2)
+            self.assertIsNone(page["positive_count"])
+            self.assertNotIn("database gone", json.dumps(page))
+        self.assertTrue(
+            all(record.exc_info for record in logged.records), logged.output
+        )
+
     async def test_search_matches_filename_prompt_text_and_tags(self):
         from database.models import normalize_image_path