[fix] metaclass conflict for class_deprecated

Actually the old compatibility code actually prevented this bug so back it up.

2 files changed, 33 insertions, 1 deletions

diff --git a/logilab/common/deprecation.py b/logilab/common/deprecation.py
index b5f40dd..a6f448f 100644
--- a/logilab/common/deprecation.py
+++ b/logilab/common/deprecation.py
@@ -177,7 +177,28 @@ def callable_deprecated(reason=None, version=None, stacklevel=2):
 deprecated = callable_renamed(old_name="deprecated", new_function=callable_deprecated)
 
 
-class class_deprecated(type):
+def class_deprecated(old_name, parents, class_dict):
+    try:
+        return _class_deprecated(old_name, parents, clsdict)
+    except (NameError, TypeError):
+        # in case of conflicting metaclass situation
+        class DeprecatedClass(*parents):
+            def __init__(self, *args, **kwargs):
+                msg = class_dict.get("__deprecation_warning__", f"{old_name} is deprecated")
+                send_warning(
+                    msg,
+                    stacklevel=class_dict.get("__deprecation_warning_stacklevel__", 3),
+                    version=class_dict.get("__deprecation_warning_version__", None),
+                    module_name=class_dict.get(
+                        "__deprecation_warning_module_name__", _get_module_name(1)
+                    ),
+                )
+                super(DeprecatedClass, self).__init__(*args, **kwargs)
+
+        return DeprecatedClass
+
+
+class _class_deprecated(type):
     """metaclass to print a warning on instantiation of a deprecated class"""
 
     def __call__(cls, *args, **kwargs):
diff --git a/test/test_deprecation.py b/test/test_deprecation.py
index 78b2256..65ef8fd 100644
--- a/test/test_deprecation.py
+++ b/test/test_deprecation.py
@@ -63,6 +63,17 @@ class RawInputTC(TestCase):
             self.messages, ["[test_deprecation] OldClass is deprecated, use AnyClass instead"]
         )
 
+    def test_class_renamed_conflict_metaclass(self):
+        class SomeMetaClass(type):
+            pass
+
+        class AnyClass(metaclass=SomeMetaClass):
+            pass
+
+        # make sure the "metaclass conflict: the metaclass of a derived class # must be a
+        # (non-strict) subclass of the metaclasses of all its bases" exception won't be raised
+        deprecation.class_renamed("OldClass", AnyClass)
+
     def test_class_moved(self):
         class AnyClass(object):
             pass