SF #532767: isinstance(x, X) should work when x is a proxy for an X

instance, as long as x.__class__ is X or a subclass thereof.
Did a little cleanup of PyObject_IsInstance() too.

1 files changed, 29 insertions, 1 deletions

diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index f481205..75ad135 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -3735,7 +3735,8 @@ def dict_type_with_metaclass():
 
 def meth_class_get():
     # Full coverage of descrobject.c::classmethod_get()
-    if verbose: print "Testing __get__ method of METH_CLASS C methods..."
+    if verbose:
+        print "Testing __get__ method of METH_CLASS C methods..."
     # Baseline
     arg = [1, 2, 3]
     res = {1: None, 2: None, 3: None}
@@ -3772,6 +3773,32 @@ def meth_class_get():
     else:
         raise TestFailed, "shouldn't have allowed descr.__get__(None, int)"
 
+def isinst_isclass():
+    if verbose:
+        print "Testing proxy isinstance() and isclass()..."
+    class Proxy(object):
+        def __init__(self, obj):
+            self.__obj = obj
+        def __getattribute__(self, name):
+            if name.startswith("_Proxy__"):
+                return object.__getattribute__(self, name)
+            else:
+                return getattr(self.__obj, name)
+    # Test with a classic class
+    class C:
+        pass
+    a = C()
+    pa = Proxy(a)
+    verify(isinstance(a, C))  # Baseline
+    verify(isinstance(pa, C)) # Test
+    # Test with a new-style class
+    class C(object):
+        pass
+    a = C()
+    pa = Proxy(a)
+    verify(isinstance(a, C))  # Baseline
+    verify(isinstance(pa, C)) # Test
+
 
 def test_main():
     do_this_first()
@@ -3859,6 +3886,7 @@ def test_main():
     subclass_right_op()
     dict_type_with_metaclass()
     meth_class_get()
+    isinst_isclass()
 
     if verbose: print "All OK"