[Enhancement] MessageHub.get_info() supports returning a default value

mmengine/logging/message_hub.py

@@ -309,12 +309,7 @@ def get_info(self, key: str, default: Optional[Any] = None) -> Any:
             Any: A copy of corresponding runtime information if the key exists.
         """
         if key not in self.runtime_info:
-            if default is not None:
-                return default
-            else:
-                raise KeyError(
-                    f'{key} is not found in Messagehub.log_buffers: '
-                    f'instance name is: {MessageHub.instance_name}')
+            return default
         else:
             # TODO： There are restrictions on objects that can be saved
             # return copy.deepcopy(self._runtime_info[key])

tests/test_hooks/test_runtime_info_hook.py

@@ -46,9 +46,6 @@ def test_before_train(self):
         self.assertEqual(runner.message_hub.get_info('max_epochs'), 2)
         self.assertEqual(runner.message_hub.get_info('max_iters'), 8)
 
-        with self.assertRaisesRegex(KeyError, 'dataset_meta is not found'):
-            runner.message_hub.get_info('dataset_meta')
-
         cfg.train_dataloader.dataset.type = 'DatasetWithMetainfo'
         runner = self.build_runner(cfg)
         hook.before_train(runner)

tests/test_logging/test_message_hub.py

@@ -82,8 +82,6 @@ def test_get_scalar(self):
 
     def test_get_runtime(self):
         message_hub = MessageHub.get_instance('mmengine')
-        with pytest.raises(KeyError):
-            message_hub.get_info('unknown')
         recorded_dict = dict(a=1, b=2)
         message_hub.update_info('test_value', recorded_dict)
         assert message_hub.get_info('test_value') == recorded_dict
@@ -186,11 +184,6 @@ def test_getstate(self):
         obj = pickle.dumps(message_hub)
         instance = pickle.loads(obj)
 
-        with pytest.raises(KeyError):
-            instance.get_info('feat')
-        with pytest.raises(KeyError):
-            instance.get_info('lr')
-
         instance.get_info('iter')
         instance.get_scalar('loss')