review actions

lib/iris/common/metadata.py

@@ -1344,10 +1344,12 @@ def __init__(self, cls, **kwargs):
         #: The metadata class to be manufactured by this factory.
         self.cls = cls
 
-        # Proxy for self.cls._fields
+        # Proxy for self.cls._fields for later internal use, as this
+        # saves on indirect property lookup via self.cls
         self._fields = cls._fields
 
         # Initialise the metadata class fields in the instance.
+        # Use cls directly here since it's available.
         for field in cls._fields:
             setattr(self, field, None)
 
@@ -1411,12 +1413,7 @@ def values(self):
         fields = {field: getattr(self, field) for field in self._fields}
         return self.cls(**fields)
 
-    # Restrict factory to appropriate metadata classes only.
-    if not issubclass(cls, BaseMetadata):
-        emsg = "Require a subclass of {!r}, got {!r}."
-        raise TypeError(emsg.format(BaseMetadata.__name__, cls))
-
-    # Define the name, (inheritance) bases and namespace of the dynamic class.
+    # Define the name, (inheritance) bases, and namespace of the dynamic class.
     name = "MetadataManager"
     bases = ()
     namespace = {

lib/iris/tests/unit/common/metadata/test_metadata_manager_factory.py

@@ -36,14 +36,6 @@
 
 
 class Test_factory(tests.IrisTest):
-    def test__subclass_invalid(self):
-        class Other:
-            pass
-
-        emsg = "Require a subclass of 'BaseMetadata'"
-        with self.assertRaisesRegex(TypeError, emsg):
-            _ = metadata_manager_factory(Other)
-
     def test__kwargs_invalid(self):
         emsg = "Invalid 'BaseMetadata' field parameters, got 'wibble'."
         with self.assertRaisesRegex(ValueError, emsg):