fix: prevent warning logs when cancelling MCP session runner task

PiperOrigin-RevId: 943500722

Author: google-genai-bot

src/google/adk/tools/mcp_tool/session_context.py

@@ -347,8 +347,8 @@ async def _run(self):
 
         # Wait for close signal - the session remains valid while we wait
         await self._close_event.wait()
-    except BaseException as e:
-      logger.warning(f'Error on session runner task: {e}')
+    except Exception as e:
+      logger.warning('Error on session runner task: %s', e)
       raise
     finally:
       self._ready_event.set()

tests/unittests/tools/mcp_tool/test_session_context.py

@@ -609,9 +609,14 @@ async def test_close_handles_cancelled_error(self):
 
     mock_session = MockClientSession()
 
-    with patch(
-        'google.adk.tools.mcp_tool.session_context.ClientSession'
-    ) as mock_session_class:
+    with (
+        patch(
+            'google.adk.tools.mcp_tool.session_context.ClientSession'
+        ) as mock_session_class,
+        patch(
+            'google.adk.tools.mcp_tool.session_context.logger'
+        ) as mock_logger,
+    ):
       mock_session_class.return_value = mock_session
 
       await session_context.start()
@@ -626,6 +631,9 @@ async def test_close_handles_cancelled_error(self):
       # Should not raise exception
       assert session_context._close_event.is_set()
 
+      # Verify no warning logs were generated
+      mock_logger.warning.assert_not_called()
+
   @pytest.mark.asyncio
   async def test_close_handles_exception_during_cleanup(self):
     """Test that close() handles exceptions during cleanup gracefully."""