fix bug of convmodule (#889)

* fix bug of convmodule

* fix bug of convmodule

* fix unitest

* remove assert

mmcv/cnn/bricks/conv_module.py

@@ -146,6 +146,8 @@ class ConvModule(nn.Module):
                 norm_channels = in_channels
             self.norm_name, norm = build_norm_layer(norm_cfg, norm_channels)
             self.add_module(self.norm_name, norm)
+        else:
+            self.norm_name = None
 
         # build activation layer
         if self.with_activation:
@@ -162,7 +164,10 @@ class ConvModule(nn.Module):
 
     @property
     def norm(self):
+        if self.norm_name:
             return getattr(self, self.norm_name)
+        else:
+            return None
 
     def init_weights(self):
         # 1. It is mainly for customized conv layers with their own

tests/test_cnn/test_conv_module.py

@@ -75,7 +75,7 @@ def test_conv_module():
     assert conv.with_activation
     assert hasattr(conv, 'activate')
     assert not conv.with_norm
-    assert not hasattr(conv, 'norm')
+    assert conv.norm is None
     x = torch.rand(1, 3, 256, 256)
     output = conv(x)
     assert output.shape == (1, 8, 255, 255)
@@ -83,7 +83,7 @@ def test_conv_module():
     # conv
     conv = ConvModule(3, 8, 2, act_cfg=None)
     assert not conv.with_norm
-    assert not hasattr(conv, 'norm')
+    assert conv.norm is None
     assert not conv.with_activation
     assert not hasattr(conv, 'activate')
     x = torch.rand(1, 3, 256, 256)