only warn on direct subclasses of the deprecated class

scrapy/tests/test_utils_deprecate.py

@@ -31,6 +31,9 @@ class WarnWhenSubclassedTest(unittest.TestCase):
             class UserClass(Deprecated):
                 pass
 
+            class NoWarnOnMe(UserClass):
+                pass
+
         self.assertEqual(len(w), 1)
         msg = w[0]
         assert issubclass(msg.category, MyWarning)

scrapy/utils/deprecate.py

@@ -59,7 +59,7 @@ def create_deprecated_class(name, new_class, clsdict=None,
         def __init__(cls, name, bases, clsdict_):
             meta = cls.__class__
             old = meta.deprecated_class
-            if (cls is not old) and not (warn_once and meta.warned_on_subclass):
+            if old in bases and not (warn_once and meta.warned_on_subclass):
                 meta.warned_on_subclass = True
                 msg = subclass_warn_message.format(cls=_clspath(cls),
                                                    old=_clspath(old),