[Fix] Revise override in init_cfg (#930)

* [Fix] Config deep copy in initialize_override

* add asserts&comments

* add test

* test org init_cfg

* test override without name

* typo

mmcv/cnn/utils/weight_init.py

@@ -376,13 +376,26 @@ def _initialize_override(module, override, cfg):
     override = [override] if isinstance(override, dict) else override
 
     for override_ in override:
-        if 'type' not in override_.keys():
-            override_.update(cfg)
-        name = override_.pop('name', None)
+
+        cp_override = copy.deepcopy(override_)
+        name = cp_override.pop('name', None)
+        if name is None:
+            raise ValueError('`override` must contain the key "name",'
+                             f'but got {cp_override}')
+        # if override only has name kay, it means use args in init_cfg
+        if not cp_override:
+            cp_override.update(cfg)
+        # if override has name key and other args except type key, it will
+        # raise error
+        elif 'type' not in cp_override.keys():
+            raise ValueError(
+                f'`override` need "type" key, but got {cp_override}')
+
         if hasattr(module, name):
-            _initialize(getattr(module, name), override_, wholemodule=True)
+            _initialize(getattr(module, name), cp_override, wholemodule=True)
         else:
-            raise RuntimeError(f'module did not have attribute {name}')
+            raise RuntimeError(f'module did not have attribute {name}, '
+                               f'but init_cfg is {cp_override}.')
 
 
 def initialize(module, init_cfg):
@@ -394,10 +407,9 @@ def initialize(module, init_cfg):
             define initializer. OpenMMLab has implemented 6 initializers
             including ``Constant``, ``Xavier``, ``Normal``, ``Uniform``,
             ``Kaiming``, and ``Pretrained``.
-
     Example:
         >>> module = nn.Linear(2, 3, bias=True)
-        >>> init_cfg = dict(type='Constant', val =1 , bias =2)
+        >>> init_cfg = dict(type='Constant', layer='Linear', val =1 , bias =2)
         >>> initialize(module, init_cfg)
 
         >>> module = nn.Sequential(nn.Conv1d(3, 1, 3), nn.Linear(1,2))
@@ -407,11 +419,7 @@ def initialize(module, init_cfg):
                 dict(type='Constant', layer='Linear', val=2)]
         >>> initialize(module, init_cfg)
 
-        >>> # Omitting ``'layer'`` initialize module with same configuration
-        >>> init_cfg = dict(type='Constant', val=1, bias=2)
-        >>> initialize(module, init_cfg)
-
-        >>> # define key``'override'`` to initialize some specific override in
+        >>> # define key``'override'`` to initialize some specific part in
         >>> # module
         >>> class FooNet(nn.Module):
         >>>     def __init__(self):
@@ -420,7 +428,7 @@ def initialize(module, init_cfg):
         >>>         self.reg = nn.Conv2d(16, 10, 3)
         >>>         self.cls = nn.Conv2d(16, 5, 3)
         >>> model = FooNet()
-        >>> init_cfg = dict(type='Constant', val=1, bias=2,
+        >>> init_cfg = dict(type='Constant', val=1, bias=2, layer='Conv2d',
         >>>     override=dict(type='Constant', name='reg', val=3, bias=4))
         >>> initialize(model, init_cfg)
 

tests/test_cnn/test_weight_init.py

@@ -266,13 +266,17 @@ def test_initialize():
     model = nn.Sequential(nn.Conv2d(3, 1, 3), nn.ReLU(), nn.Linear(1, 2))
     foonet = FooModule()
 
+    # test layer key
     init_cfg = dict(type='Constant', layer=['Conv2d', 'Linear'], val=1, bias=2)
     initialize(model, init_cfg)
     assert torch.equal(model[0].weight, torch.full(model[0].weight.shape, 1.))
     assert torch.equal(model[2].weight, torch.full(model[2].weight.shape, 1.))
     assert torch.equal(model[0].bias, torch.full(model[0].bias.shape, 2.))
     assert torch.equal(model[2].bias, torch.full(model[2].bias.shape, 2.))
+    assert init_cfg == dict(
+        type='Constant', layer=['Conv2d', 'Linear'], val=1, bias=2)
 
+    # test init_cfg with list type
     init_cfg = [
         dict(type='Constant', layer='Conv2d', val=1, bias=2),
         dict(type='Constant', layer='Linear', val=3, bias=4)
@@ -282,7 +286,12 @@ def test_initialize():
     assert torch.equal(model[2].weight, torch.full(model[2].weight.shape, 3.))
     assert torch.equal(model[0].bias, torch.full(model[0].bias.shape, 2.))
     assert torch.equal(model[2].bias, torch.full(model[2].bias.shape, 4.))
+    assert init_cfg == [
+        dict(type='Constant', layer='Conv2d', val=1, bias=2),
+        dict(type='Constant', layer='Linear', val=3, bias=4)
+    ]
 
+    # test layer key and override key
     init_cfg = dict(
         type='Constant',
         val=1,
@@ -302,6 +311,31 @@ def test_initialize():
                        torch.full(foonet.conv2d_2.weight.shape, 3.))
     assert torch.equal(foonet.conv2d_2.bias,
                        torch.full(foonet.conv2d_2.bias.shape, 4.))
+    assert init_cfg == dict(
+        type='Constant',
+        val=1,
+        bias=2,
+        layer=['Conv2d', 'Linear'],
+        override=dict(type='Constant', name='conv2d_2', val=3, bias=4))
+
+    # test override key
+    init_cfg = dict(
+        type='Constant', val=5, bias=6, override=dict(name='conv2d_2'))
+    initialize(foonet, init_cfg)
+    assert not torch.equal(foonet.linear.weight,
+                           torch.full(foonet.linear.weight.shape, 5.))
+    assert not torch.equal(foonet.linear.bias,
+                           torch.full(foonet.linear.bias.shape, 6.))
+    assert not torch.equal(foonet.conv2d.weight,
+                           torch.full(foonet.conv2d.weight.shape, 5.))
+    assert not torch.equal(foonet.conv2d.bias,
+                           torch.full(foonet.conv2d.bias.shape, 6.))
+    assert torch.equal(foonet.conv2d_2.weight,
+                       torch.full(foonet.conv2d_2.weight.shape, 5.))
+    assert torch.equal(foonet.conv2d_2.bias,
+                       torch.full(foonet.conv2d_2.bias.shape, 6.))
+    assert init_cfg == dict(
+        type='Constant', val=5, bias=6, override=dict(name='conv2d_2'))
 
     init_cfg = dict(
         type='Pretrained',
@@ -325,6 +359,11 @@ def test_initialize():
                            torch.full(foonet.conv2d_2.weight.shape, 3.))
         assert torch.equal(foonet.conv2d_2.bias,
                            torch.full(foonet.conv2d_2.bias.shape, 4.))
+    assert init_cfg == dict(
+        type='Pretrained',
+        checkpoint='modelA.pth',
+        override=dict(type='Constant', name='conv2d_2', val=3, bias=4))
+
     # test init_cfg type
     with pytest.raises(TypeError):
         init_cfg = 'init_cfg'
@@ -362,3 +401,21 @@ def test_initialize():
                 dict(type='Constant', name='conv2d_3', val=5, bias=6)
             ])
         initialize(foonet, init_cfg)
+
+    # test override with args except type key
+    with pytest.raises(ValueError):
+        init_cfg = dict(
+            type='Constant',
+            val=1,
+            bias=2,
+            override=dict(name='conv2d_2', val=3, bias=4))
+        initialize(foonet, init_cfg)
+
+    # test override without name
+    with pytest.raises(ValueError):
+        init_cfg = dict(
+            type='Constant',
+            val=1,
+            bias=2,
+            override=dict(type='Constant', val=3, bias=4))
+        initialize(foonet, init_cfg)