fix(logging): add async_release_disconnect_state_hook as a default no-op on CustomLogger

Every other optional hook on CustomLogger ships as an empty method a subclass
can override; this one didn't, so _release_disconnect_state_on_all_callbacks
calling it on any callback that doesn't implement it (nearly all of them)
raised AttributeError, caught and debug-logged on every single disconnect.
bugbot caught this on review.

litellm/integrations/custom_logger.py

@@ -187,6 +187,16 @@ class CustomLogger:  # https://docs.litellm.ai/docs/observability/custom_callbac
     async def async_log_failure_event(self, kwargs, response_obj, start_time, end_time):
         pass
 
+    async def async_release_disconnect_state_hook(self, request_data: Mapping[str, object]) -> None:
+        """
+        Called when a client disconnects mid-request, for a callback that reserved
+        per-request state outside async_log_success_event/async_log_failure_event
+        (e.g. a concurrency slot admitted before the first response chunk) -- those
+        two callbacks never run for a client disconnect, so a callback relying on
+        them alone to release such state would otherwise leak it until its own
+        safety-net TTL.
+        """
+
     async def async_log_audit_log_event(self, audit_log: "StandardAuditLogPayload"):
         """Called when an audit log is created. Override in subclasses to handle."""
 

tests/test_litellm/proxy/test_common_request_processing.py

@@ -33,6 +33,7 @@ from litellm.proxy.common_request_processing import (
     ttft_keepalive_interval,
     _override_openai_response_model,
     _parse_event_data_for_error,
+    _release_disconnect_state_on_all_callbacks,
     _resolve_per_request_model_group_alias,
     _should_return_raw_model_name,
     _UpstreamClosingStreamingResponse,
@@ -4091,6 +4092,25 @@ class TestCancelOnDisconnect:
         assert exc_info.value.status_code == 499
         assert recorder.disconnect_hook_calls == 1
 
+    async def test_release_disconnect_state_calls_every_callback_including_ones_without_an_override(
+        self, monkeypatch
+    ):
+        """
+        Bugbot finding: CustomLogger never defined async_release_disconnect_state_hook
+        as an empty default, unlike every other optional hook on that base class, so
+        calling it on a callback that never overrides it (most registered callbacks)
+        raised AttributeError -- caught here, but still a real gap in the base class's
+        own contract that a genuine implementation bug would be indistinguishable from.
+        """
+        overriding = _RecordingDisconnectHookLogger()
+        bare = CustomLogger()
+        monkeypatch.setattr(litellm, "callbacks", [overriding, bare])
+
+        await _release_disconnect_state_on_all_callbacks({"litellm_call_id": "call-1"})
+
+        assert overriding.disconnect_hook_calls == 1
+        assert await bare.async_release_disconnect_state_hook({"litellm_call_id": "call-1"}) is None
+
     async def _drive_base_process_llm_request(
         self, monkeypatch, general_settings: dict, llm_call, request: Request
     ):