[Enhancement] Deprecate _save_to_state_dict implemented in mmengine (#610)

* [Refine] Make get_state_dict directly call nn.Module._save_to_state_dict

* deprecate _save_to_state_dict

* deprecate _save_to_state_dict in 0.5.0

* deprecate in 0.3.0

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>

Author: HAOCHENYE

mmengine/runner/checkpoint.py

@@ -19,7 +19,7 @@
 from mmengine.fileio import load as load_file
 from mmengine.logging import print_log
 from mmengine.model import BaseTTAModel, is_model_wrapper
-from mmengine.utils import mkdir_or_exist
+from mmengine.utils import deprecated_function, mkdir_or_exist
 from mmengine.utils.dl_utils import load_url
 
 # `MMENGINE_HOME` is the highest priority directory to save checkpoints
@@ -574,6 +574,11 @@ def weights_to_cpu(state_dict):
     return state_dict_cpu
 
 
+@deprecated_function(
+    since='0.3.0',
+    removed_in='0.5.0',
+    instructions='`_save_to_state_dict` will be deprecated in the future, '
+    'please use `nn.Module._save_to_state_dict` directly.')
 def _save_to_state_dict(module, destination, prefix, keep_vars):
     """Saves module state to `destination` dictionary.
 
@@ -626,7 +631,7 @@ def get_state_dict(module, destination=None, prefix='', keep_vars=False):
         destination._metadata = OrderedDict()
     destination._metadata[prefix[:-1]] = local_metadata = dict(
         version=module._version)
-    _save_to_state_dict(module, destination, prefix, keep_vars)
+    module._save_to_state_dict(destination, prefix, keep_vars)
     for name, child in module._modules.items():
         if child is not None:
             get_state_dict(

mmengine/utils/__init__.py

@@ -1,7 +1,8 @@
 # Copyright (c) OpenMMLab. All rights reserved.
 from .manager import ManagerMeta, ManagerMixin
 from .misc import (check_prerequisites, concat_list, deprecated_api_warning,
-                   has_method, import_modules_from_strings, is_list_of,
+                   deprecated_function, has_method,
+                   import_modules_from_strings, is_list_of,
                    is_method_overridden, is_seq_of, is_str, is_tuple_of,
                    iter_cast, list_cast, requires_executable, requires_package,
                    slice_list, to_1tuple, to_2tuple, to_3tuple, to_4tuple,
@@ -26,5 +27,5 @@
     'is_abs', 'is_method_overridden', 'has_method', 'digit_version',
     'get_git_hash', 'ManagerMeta', 'ManagerMixin', 'Timer', 'check_time',
     'TimerError', 'ProgressBar', 'track_iter_progress',
-    'track_parallel_progress', 'track_progress'
+    'track_parallel_progress', 'track_progress', 'deprecated_function'
 ]