fix: catch CircuitOpenError in stats fallback (#10)

backend/api/v1/routes/navidrome_library.py

@@ -15,6 +15,7 @@ from api.v1.schemas.navidrome import (
 from core.dependencies import get_navidrome_library_service, get_navidrome_repository
 from core.exceptions import ExternalServiceError
 from infrastructure.msgspec_fastapi import MsgSpecRoute
+from infrastructure.resilience.retry import CircuitOpenError
 from repositories.navidrome_repository import NavidromeRepository
 from services.navidrome_library_service import NavidromeLibraryService
 
@@ -50,7 +51,7 @@ async def get_navidrome_albums(
     try:
         stats = await service.get_stats()
         total = stats.total_albums if len(items) >= limit else offset + len(items)
-    except ExternalServiceError:
+    except (ExternalServiceError, CircuitOpenError):
         logger.warning("Navidrome stats unavailable, using heuristic pagination total")
         total = offset + len(items) + (1 if len(items) >= limit else 0)
 

backend/tests/routes/test_navidrome_routes.py

@@ -19,6 +19,7 @@ from api.v1.schemas.navidrome import (
 )
 from core.dependencies import get_navidrome_library_service, get_navidrome_playback_service
 from core.exceptions import ExternalServiceError
+from infrastructure.resilience.retry import CircuitOpenError
 
 
 def _album_summary(id: str = "a1", name: str = "Album") -> NavidromeAlbumSummary:
@@ -110,6 +111,18 @@ class TestLibraryAlbums:
         data = resp.json()
         assert data["total"] == 5
 
+    def test_get_albums_stats_fallback_circuit_open(self, library_client, mock_library_service):
+        """When CB is open, stats raises CircuitOpenError — albums still work."""
+        mock_library_service.get_albums = AsyncMock(return_value=[_album_summary(id=f"a{i}") for i in range(48)])
+        mock_library_service.get_stats = AsyncMock(
+            side_effect=CircuitOpenError("Circuit breaker 'navidrome' is OPEN", breaker_name="navidrome"),
+        )
+        resp = library_client.get("/navidrome/albums?limit=48")
+        assert resp.status_code == 200
+        data = resp.json()
+        assert len(data["items"]) == 48
+        assert data["total"] == 49
+
     def test_get_album_detail(self, library_client):
         resp = library_client.get("/navidrome/albums/a1")
         assert resp.status_code == 200