bug fix: raise exceptions for missing config keys

mmcv/utils/config.py

@@ -6,6 +6,26 @@ from importlib import import_module
 
 from addict import Dict
 
+from .path import check_file_exist
+
+
+class ConfigDict(Dict):
+
+    def __missing__(self, name):
+        raise KeyError(name)
+
+    def __getattr__(self, name):
+        try:
+            value = super(ConfigDict, self).__getattr__(name)
+        except KeyError:
+            ex = AttributeError("'{}' object has no attribute '{}'".format(
+                self.__class__.__name__, name))
+        except Exception as e:
+            ex = e
+        else:
+            return value
+        raise ex
+
 
 def add_args(parser, cfg, prefix=''):
     for k, v in cfg.items():
@@ -55,6 +75,7 @@ class Config(object):
     @staticmethod
     def fromfile(filename):
         filename = osp.abspath(osp.expanduser(filename))
+        check_file_exist(filename)
         if filename.endswith('.py'):
             sys.path.append(osp.dirname(filename))
             module_name = osp.basename(filename)[:-3]
@@ -93,7 +114,7 @@ class Config(object):
             raise TypeError('cfg_dict must be a dict, but got {}'.format(
                 type(cfg_dict)))
 
-        super(Config, self).__setattr__('_cfg_dict', Dict(cfg_dict))
+        super(Config, self).__setattr__('_cfg_dict', ConfigDict(cfg_dict))
         super(Config, self).__setattr__('_filename', filename)
         if filename:
             with open(filename, 'r') as f:
@@ -110,7 +131,7 @@ class Config(object):
         return self._text
 
     def __repr__(self):
-        return 'Config [path: {}]: {}'.format(self.filename,
+        return 'Config (path: {}): {}'.format(self.filename,
                                               self._cfg_dict.__repr__())
 
     def __len__(self):
@@ -124,12 +145,12 @@ class Config(object):
 
     def __setattr__(self, name, value):
         if isinstance(value, dict):
-            value = Dict(value)
+            value = ConfigDict(value)
         self._cfg_dict.__setattr__(name, value)
 
     def __setitem__(self, name, value):
         if isinstance(value, dict):
-            value = Dict(value)
+            value = ConfigDict(value)
         self._cfg_dict.__setitem__(name, value)
 
     def __iter__(self):

tests/test_config.py

 import os.path as osp
 
 import pytest
-from mmcv import Config
+from mmcv import Config, FileNotFoundError
 
 
 def test_empty():
@@ -20,8 +20,10 @@ def test_fromfile():
         assert cfg.filename == cfg_file
         assert cfg.text == open(cfg_file, 'r').read()
 
+    with pytest.raises(FileNotFoundError):
+        Config.fromfile('no_such_file.py')
     with pytest.raises(ValueError):
-        Config.fromfile('a/b/c.d.py')
+        Config.fromfile(osp.join(osp.dirname(__file__), 'data/config/a.b.py'))
 
 
 def test_dict():
@@ -49,12 +51,18 @@ def test_dict():
         assert cfg.item2.a == 0
         assert cfg.item3 == cfg_dict['item3']
         assert cfg.item4 == cfg_dict['item4']
+        with pytest.raises(AttributeError):
+            cfg.not_exist
         # field in cfg, cfg[field], cfg.get()
         for name in ['item1', 'item2', 'item3', 'item4']:
             assert name in cfg
             assert cfg[name] == cfg_dict[name]
             assert cfg.get(name) == cfg_dict[name]
+            assert cfg.get('not_exist') is None
             assert cfg.get('not_exist', 0) == 0
+            with pytest.raises(KeyError):
+                cfg['not_exist']
+        assert 'item1' in cfg
         assert 'not_exist' not in cfg
         # cfg.update()
         cfg.update(dict(item1=0))