Fix issues when using keyword argument named self with weak function …

…proxy.

docs/changes.rst

@@ -56,6 +56,10 @@ Version 1.15.0
   Python version of wrapt and did not occur when using the C extension based
   implementation.
 
+* When using ``WeakFunctionProxy`` as a wrapper for a function, when calling the
+  function via the proxy object, it was not possible to pass a keyword argument
+  named ``self``.
+
 Version 1.14.1
 --------------
 

src/wrapt/wrappers.py

@@ -992,7 +992,12 @@ def __init__(self, wrapped, callback=None):
             super(WeakFunctionProxy, self).__init__(
                     weakref.proxy(wrapped, _callback))
 
-    def __call__(self, *args, **kwargs):
+    def __call__(*args, **kwargs):
+        def _unpack_self(self, *args):
+            return self, args
+
+        self, args = _unpack_self(*args)
+
         # We perform a boolean check here on the instance and wrapped
         # function as that will trigger the reference error prior to
         # calling if the reference had expired.

tests/test_weak_function_proxy.py

@@ -190,5 +190,15 @@ def squeal(self):
 
         self.assertEqual(method(), 'bark')
 
+class TestArgumentUnpackingWeakFunctionProxy(unittest.TestCase):
+
+    def test_self_keyword_argument(self):
+        def function(self, *args, **kwargs):
+            return self, args, kwargs
+
+        proxy = wrapt.wrappers.WeakFunctionProxy(function)
+
+        self.assertEqual(proxy(self='self', arg1='arg1'), ('self', (), dict(arg1='arg1')))
+
 if __name__ == '__main__':
     unittest.main()