Fixed config import in config file (#261)

* fixed config import in code

* fixed isort

mmcv/utils/config.py

@@ -85,10 +85,14 @@ class Config(object):
         check_file_exist(filename)
         if filename.endswith('.py'):
             with tempfile.TemporaryDirectory() as temp_config_dir:
+                temp_config_file = tempfile.NamedTemporaryFile(
+                    dir=temp_config_dir, suffix='.py')
+                temp_config_name = osp.basename(temp_config_file.name)
                 shutil.copyfile(filename,
-                                osp.join(temp_config_dir, '_tempconfig.py'))
+                                osp.join(temp_config_dir, temp_config_name))
+                temp_module_name = osp.splitext(temp_config_name)[0]
                 sys.path.insert(0, temp_config_dir)
-                mod = import_module('_tempconfig')
+                mod = import_module(temp_module_name)
                 sys.path.pop(0)
                 cfg_dict = {
                     name: value
@@ -96,7 +100,9 @@ class Config(object):
                     if not name.startswith('__')
                 }
                 # delete imported module
-                del sys.modules['_tempconfig']
+                del sys.modules[temp_module_name]
+                # close temp file
+                temp_config_file.close()
         elif filename.endswith(('.yml', '.yaml', '.json')):
             import mmcv
             cfg_dict = mmcv.load(filename)

tests/data/config/code.py

@@ -0,0 +1,3 @@
+from mmcv import Config  # isort:skip
+cfg = Config.fromfile('./tests/data/config/a.py')
+item5 = cfg.item1[0] + cfg.item2.a

tests/test_config.py

@@ -134,6 +134,17 @@ def test_merge_intermediate_variable():
     assert cfg.item6 == dict(cfg=dict(b=2))
 
 
+def test_fromfile_in_config():
+    cfg_file = osp.join(osp.dirname(__file__), 'data/config/code.py')
+    cfg = Config.fromfile(cfg_file)
+    # cfg.field
+    assert cfg.cfg.item1 == [1, 2]
+    assert cfg.cfg.item2 == dict(a=0)
+    assert cfg.cfg.item3 is True
+    assert cfg.cfg.item4 == 'test'
+    assert cfg.item5 == 1
+
+
 def test_dict():
     cfg_dict = dict(item1=[1, 2], item2=dict(a=0), item3=True, item4='test')