[Enhance] Enhance error message during custom import (open-mmlab#1102)

HAOCHENYE · Apr 26, 2023 · 9868131 · 9868131
1 parent 1c01594
commit 9868131
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Showing 2 changed files with 16 additions and 1 deletion.
diff --git a/mmengine/config/config.py b/mmengine/config/config.py
@@ -5,6 +5,7 @@
 import os.path as osp
 import platform
 import shutil
+import sys
 import tempfile
 import types
 import uuid
@@ -180,7 +181,15 @@ def fromfile(filename: Union[str, Path],
             try:
                 import_modules_from_strings(**cfg_dict['custom_imports'])
             except ImportError as e:
-                raise ImportError('Failed to custom import!') from e
+                err_msg = (
+                    'Failed to import custom modules from '
+                    f"{cfg_dict['custom_imports']}, the current sys.path is: ")
+                for p in sys.path:
+                    err_msg += f'\n    {p}'
+                err_msg += (
+                    '\nYou should set `PYTHONPATH` to make `sys.path` include '
+                    'the directory which contains your custom module')
+                raise ImportError(err_msg) from e
         return Config(
             cfg_dict,
             cfg_text=cfg_text,

diff --git a/tests/test_config/test_config.py b/tests/test_config/test_config.py
@@ -65,8 +65,14 @@ def test_fromfile(self):
         # If import successfully, os.environ[''TEST_VALUE''] will be
         # set to 'test'
         assert os.environ.pop('TEST_VALUE') == 'test'
+        sys.path.pop()
+
         Config.fromfile(cfg_file, import_custom_modules=False)
         assert 'TEST_VALUE' not in os.environ
+        sys.modules.pop('test_custom_import_module')
+        with pytest.raises(
+                ImportError, match='Failed to import custom modules from'):
+            Config.fromfile(cfg_file, import_custom_modules=True)
 
     @pytest.mark.parametrize('file_format', ['py', 'json', 'yaml'])
     def test_fromstring(self, file_format):