Skip retired anthropic-oauth plugin entry point during discovery

Avoid AttributeError warnings when older llm-interactive-proxy-oauth-connectors
metadata still declares the removed backend. Add unit test for silent skip.

Made-with: Cursor

Author: Mateusz

src/core/services/backend_plugin_discovery.py

@@ -32,6 +32,10 @@
 ENTRY_POINT_GROUP = BACKEND_PLUGIN_ENTRY_POINT_GROUP
 _DEFAULT_CORE_VERSION = "0.1.0"
 
+# Entry point names removed from optional oauth-connectors but still present in
+# older installed distributions; skip without loading or logging a failure.
+_RETIRED_BACKEND_PLUGIN_ENTRY_POINTS: frozenset[str] = frozenset({"anthropic-oauth"})
+
 
 def discover_plugin_backends(entry_point_group: str = ENTRY_POINT_GROUP) -> list[str]:
     """Discover and register optional plugin backends.
@@ -58,6 +62,14 @@ def discover_plugin_backends(entry_point_group: str = ENTRY_POINT_GROUP) -> list
     plugin_load_error_first_ep: dict[tuple[str, str], str] = {}
     seen_backend_names: set[str] = set()
     for entry_point in entry_points:
+        if entry_point.name in _RETIRED_BACKEND_PLUGIN_ENTRY_POINTS:
+            if logger.isEnabledFor(logging.DEBUG):
+                logger.debug(
+                    "Skipping retired backend plugin entry point %r.",
+                    entry_point.name,
+                )
+            continue
+
         provider = _load_provider(entry_point, plugin_load_error_first_ep)
         if provider is None:
             continue

tests/unit/core/services/test_backend_plugin_discovery.py

@@ -60,6 +60,28 @@ def test_no_entry_points_is_valid_optional_absence(self) -> None:
 
         assert discovered == []
 
+    def test_retired_entry_point_is_silently_skipped(self, caplog: Any) -> None:
+        """Stale setuptools metadata must not trigger load or WARNING."""
+        retired = _entry_point(
+            name="anthropic-oauth",
+            load_error=RuntimeError("load must not be called for retired entry points"),
+        )
+        with (
+            patch(
+                "src.core.services.backend_plugin_discovery._resolve_core_version",
+                return_value="0.1.0",
+            ),
+            patch(
+                "src.core.services.backend_plugin_discovery._load_entry_points",
+                return_value=[retired],
+            ),
+            caplog.at_level("WARNING"),
+        ):
+            discovered = discover_plugin_backends()
+
+        assert discovered == []
+        assert "Failed to load backend plugin entry point" not in caplog.text
+
     def test_entry_point_load_failure_is_fail_open(self, caplog: Any) -> None:
         broken = _entry_point(
             name="broken-oauth", load_error=ImportError("Cannot import plugin module")