Enhance config

mmengine/config/config.py

@@ -1,6 +1,7 @@
 # Copyright (c) OpenMMLab. All rights reserved.
 import ast
 import copy
+import logging
 import os
 import os.path as osp
 import platform
@@ -723,7 +724,16 @@ class Config:
             if isinstance(v, str):
                 v_str = repr(v)
             else:
-                v_str = str(v)
+                try:
+                    ast.parse(str(v))
+                except SyntaxError:
+                    v_str = repr(str(v))
+                    print_log(
+                        f'Cannot parse the value: {v} of key "{k}"',
+                        logger='current',
+                        level=logging.WARNING)
+                else:
+                    v_str = str(v)
 
             if use_mapping:
                 k_str = f"'{k}'" if isinstance(k, str) else str(k)

tests/test_config/test_config.py

@@ -274,6 +274,14 @@ class TestConfig:
         text_cfg = Config.fromfile(text_cfg_filename)
         assert text_cfg._cfg_dict == cfg._cfg_dict
 
+        cfg_file = osp.join(self.data_path,
+                            'config/py_config/test_custom_class.py')
+        cfg = Config.fromfile(cfg_file)
+        with open(text_cfg_filename, 'w') as f:
+            f.write(cfg.pretty_text)
+        text_cfg = Config.fromfile(text_cfg_filename)
+        assert text_cfg.item_a.a == ("<class 'A'>")
+
     def test_repr(self, tmp_path):
         cfg_file = osp.join(self.data_path,
                             'config/py_config/simple_config.py')