Apply 'Incorrect pickles for subclasses of generic classes ray-projec…

…t#448' from cloudpickle (ray-project#22553)

Co-authored-by: Chen Shen <scv119@gmail.com>

python/ray/cloudpickle/cloudpickle.py

@@ -969,9 +969,13 @@ def _typevar_reduce(obj):
 
 
 def _get_bases(typ):
-    if hasattr(typ, "__orig_bases__"):
+    if '__orig_bases__' in getattr(typ, '__dict__', {}):
         # For generic types (see PEP 560)
-        bases_attr = "__orig_bases__"
+        # Note that simply checking `hasattr(typ, '__orig_bases__')` is not
+        # correct.  Subclasses of a fully-parameterized generic class does not
+        # have `__orig_bases__` defined, but `hasattr(typ, '__orig_bases__')`
+        # will return True because it's defined in the base class.
+        bases_attr = '__orig_bases__'
     else:
         # For regular class objects
         bases_attr = "__bases__"