[Docs] Refine registry docs (#443)

* [Docs] Refine registry docs

* explain how to use _scope_

* refine

mmengine/registry/registry.py

@@ -190,45 +190,45 @@ class Registry:
             scope (str): The target scope.
 
         Examples:
-        >>> from mmengine.registry import Registry, DefaultScope, MODELS
-        >>> import time
-        >>> # External Registry
-        >>> MMDET_MODELS = Registry('mmdet_model', scope='mmdet',
-        >>>     parent=MODELS)
-        >>> MMCLS_MODELS = Registry('mmcls_model', scope='mmcls',
-        >>>     parent=MODELS)
-        >>> # Local Registry
-        >>> CUSTOM_MODELS = Registry('custom_model', scope='custom',
-        >>>     parent=MODELS)
-        >>>
-        >>> # Initiate DefaultScope
-        >>> DefaultScope.get_instance(f'scope_{time.time()}',
-        >>>     scope_name='custom')
-        >>> # Check default scope
-        >>> DefaultScope.get_current_instance().scope_name
-        custom
-        >>> # Switch to mmcls scope and get `MMCLS_MODELS` registry.
-        >>> with CUSTOM_MODELS.switch_scope_and_registry(scope='mmcls') as registry:  # noqa: E501
-        >>>     DefaultScope.get_current_instance().scope_name
-        mmcls
-        >>>     registry.scope
-        mmcls
-        >>> # Nested switch scope
-        >>> with CUSTOM_MODELS.switch_scope_and_registry(scope='mmdet') as mmdet_registry:  # noqa: E501
-        >>>     DefaultScope.get_current_instance().scope_name
-        mmdet
-        >>>     mmdet_registry.scope
-        mmdet
-        >>>     with CUSTOM_MODELS.switch_scope_and_registry(scope='mmcls') as mmcls_registry:  # noqa: E501
-        >>>         DefaultScope.get_current_instance().scope_name
-        mmcls
-        >>>         mmcls_registry.scope
-        mmcls
-        >>>
-        >>> # Check switch back to original scope.
-        >>> DefaultScope.get_current_instance().scope_name
-        custom
-        """
+            >>> from mmengine.registry import Registry, DefaultScope, MODELS
+            >>> import time
+            >>> # External Registry
+            >>> MMDET_MODELS = Registry('mmdet_model', scope='mmdet',
+            >>>     parent=MODELS)
+            >>> MMCLS_MODELS = Registry('mmcls_model', scope='mmcls',
+            >>>     parent=MODELS)
+            >>> # Local Registry
+            >>> CUSTOM_MODELS = Registry('custom_model', scope='custom',
+            >>>     parent=MODELS)
+            >>>
+            >>> # Initiate DefaultScope
+            >>> DefaultScope.get_instance(f'scope_{time.time()}',
+            >>>     scope_name='custom')
+            >>> # Check default scope
+            >>> DefaultScope.get_current_instance().scope_name
+            custom
+            >>> # Switch to mmcls scope and get `MMCLS_MODELS` registry.
+            >>> with CUSTOM_MODELS.switch_scope_and_registry(scope='mmcls') as registry:
+            >>>     DefaultScope.get_current_instance().scope_name
+            mmcls
+            >>>     registry.scope
+            mmcls
+            >>> # Nested switch scope
+            >>> with CUSTOM_MODELS.switch_scope_and_registry(scope='mmdet') as mmdet_registry:
+            >>>     DefaultScope.get_current_instance().scope_name
+            mmdet
+            >>>     mmdet_registry.scope
+            mmdet
+            >>>     with CUSTOM_MODELS.switch_scope_and_registry(scope='mmcls') as mmcls_registry:
+            >>>         DefaultScope.get_current_instance().scope_name
+            mmcls
+            >>>         mmcls_registry.scope
+            mmcls
+            >>>
+            >>> # Check switch back to original scope.
+            >>> DefaultScope.get_current_instance().scope_name
+            custom
+        """  # noqa: E501
         from ..logging import print_log
 
         # Switch to the given scope temporarily. If the corresponding registry

mmengine/registry/utils.py

@@ -54,10 +54,20 @@ def count_registered_modules(save_path: Optional[str] = None,
 
     Args:
         save_path (str, optional): Path to save the json file.
-        verbose (bool): Whether to print log. Default: True
+        verbose (bool): Whether to print log. Defaults to True.
+
     Returns:
         dict: Statistic results of all registered modules.
     """
+    # import modules to trigger registering
+    import mmengine.dataset
+    import mmengine.evaluator
+    import mmengine.hooks
+    import mmengine.model
+    import mmengine.optim
+    import mmengine.runner
+    import mmengine.visualization  # noqa: F401
+
     registries_info = {}
     # traverse all registries in MMEngine
     for item in dir(root):

tests/test_registry/test_registry_utils.py

 # Copyright (c) OpenMMLab. All rights reserved.
 import os.path as osp
 from tempfile import TemporaryDirectory
-from unittest import TestCase
+from unittest import TestCase, skipIf
 
 from mmengine.registry import (Registry, count_registered_modules, root,
                                traverse_registry_tree)
+from mmengine.utils import is_installed
 
 
 class TestUtils(TestCase):
@@ -42,6 +43,7 @@ class TestUtils(TestCase):
         # result from any node should be the same
         self.assertEqual(result, result_leaf)
 
+    @skipIf(not is_installed('torch'), 'tests requires torch')
     def test_count_all_registered_modules(self):
         temp_dir = TemporaryDirectory()
         results = count_registered_modules(temp_dir.name, verbose=True)