Merge pull request PythonCharmers#107 from infoxchange/super-properties

edschofield · edschofield · commit a138a12af2dd · 2014-10-02T14:06:04.000+10:00
Do not attempt to run the properties code in super()
diff --git a/future/builtins/newsuper.py b/future/builtins/newsuper.py
@@ -79,10 +79,16 @@ def newsuper(typ=_SENTINEL, type_or_obj=_SENTINEL, framedepth=1):
                 # This handles e.g. classmethod() and staticmethod().
                 try:
                     while not isinstance(meth,FunctionType):
-                        try:
-                            meth = meth.__func__
-                        except AttributeError:
-                            meth = meth.__get__(type_or_obj)
+                        if isinstance(meth, property):
+                            # Calling __get__ on the property will invoke
+                            # user code which might throw exceptions or have
+                            # side effects
+                            meth = meth.fget
+                        else:
+                            try:
+                                meth = meth.__func__
+                            except AttributeError:
+                                meth = meth.__get__(type_or_obj)
                 except (AttributeError, TypeError):
                     continue
                 if meth.func_code is f.f_code:
diff --git a/future/tests/test_super.py b/future/tests/test_super.py
@@ -150,6 +150,26 @@ def g():
         c = f().__closure__[0]
         self.assertRaises(TypeError, X.meth, c)
 
+    def test_properties(self):
+        class Harmless(object):
+            bomb = ''
+
+            def walk(self):
+                return self.bomb
+
+        class Dangerous(Harmless):
+            @property
+            def bomb(self):
+                raise Exception("Kaboom")
+
+            def walk(self):
+                return super().walk()
+
+        class Elite(Dangerous):
+            bomb = 'Defused'
+
+        self.assertEqual(Elite().walk(), 'Defused')
+
 
 class TestSuperFromTestDescrDotPy(unittest.TestCase):
     """
