Fix comic issues/details vanishing after tracking

- comicvine.comic() discarded the entire cached volume response if
  either the publisher-recommendations or issues sub-call raised a
  ProviderAPIError, even though the primary volume details had already
  been fetched successfully
- Comics have no persisted fallback fields (unlike movies/TV, which
  reconstruct Details from stored Item/credit rows), so hitting the
  ProviderAPIError fallback in media_details_views wiped Issues and
  Details entirely
- Catch failures in the two secondary sub-calls individually and
  default to an empty list instead, so a transient rate-limit hit on
  one endpoint no longer nukes the whole payload

Fixes #975

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: dannyvfilms

src/app/providers/comicvine.py

@@ -129,7 +129,18 @@ def comic(media_id):
         publisher_id = response.get("publisher", {}).get("id")
         publisher_comics = []
         if publisher_id:
-            publisher_comics = get_publisher_comics(publisher_id, media_id)
+            try:
+                publisher_comics = get_publisher_comics(publisher_id, media_id)
+            except services.ProviderAPIError:
+                logger.warning(
+                    "Failed to fetch publisher comics for volume %s", media_id
+                )
+
+        try:
+            issues = get_volume_issues(media_id)
+        except services.ProviderAPIError:
+            logger.warning("Failed to fetch issues for volume %s", media_id)
+            issues = []
 
         data = {
             "media_id": media_id,
@@ -161,7 +172,7 @@ def comic(media_id):
             },
             # used for events fetching
             "last_issue_id": response["last_issue"]["id"],
-            "issues": get_volume_issues(media_id),
+            "issues": issues,
         }
 
         cache.set(cache_key, data)

src/app/tests/providers/test_metadata.py

@@ -1869,6 +1869,39 @@ def test_comic(self):
         response = comicvine.comic("155969")
         self.assertEqual(response["title"], "Ultimate Spider-Man")
 
+    @patch("app.providers.comicvine.services.api_request")
+    def test_comic_survives_issues_provider_error(self, mock_api_request):
+        """A failing issues/recommendations call shouldn't discard volume details."""
+        media_id = "provider-error-test"
+        cache_key = f"{Sources.COMICVINE.value}_{MediaTypes.COMIC.value}_{media_id}"
+        comicvine.cache.delete(cache_key)
+        self.addCleanup(comicvine.cache.delete, cache_key)
+
+        def side_effect(_source, _method, url, **_kwargs):
+            if url.endswith("/issues/"):
+                raise services.ProviderAPIError(Sources.COMICVINE.value, Exception())
+            return {
+                "results": {
+                    "site_detail_url": "https://example.com/volume",
+                    "name": "Test Volume",
+                    "last_issue": {"issue_number": "5", "id": 5},
+                    "description": "",
+                    "publisher": {"id": None, "name": "Test Publisher"},
+                    "start_year": "2020",
+                    "count_of_issues": 5,
+                    "people": [],
+                    "date_last_updated": "2024-01-01 00:00:00",
+                },
+            }
+
+        mock_api_request.side_effect = side_effect
+
+        response = comicvine.comic(media_id)
+
+        self.assertEqual(response["title"], "Test Volume")
+        self.assertEqual(response["details"]["publisher"], "Test Publisher")
+        self.assertEqual(response["issues"], [])
+
     @patch("app.providers.comicvine.services.api_request")
     def test_comic_volume_issues_sort_numerically(self, mock_api_request):
         """Comic volume issues should use numeric rather than lexical ordering."""