Allow wrapping of closures

get_wrapped_function() assumes that any function which is a closure is a
decorator, and therefore has a function argument. This assumption fails
when the function is just a regular closure, and we end up falling
through and returning None.

Change-Id: I18da02d83fd9884e2e8c2173acf124140bd43525

nova/safe_utils.py

@@ -36,4 +36,6 @@ def get_wrapped_function(function):
             elif hasattr(closure.cell_contents, '__call__'):
                 return closure.cell_contents
 
+        return function
+
     return _get_wrapped_function(function)

nova/tests/unit/test_safeutils.py

@@ -18,6 +18,15 @@ from nova import safe_utils
 from nova import test
 
 
+def get_closure():
+    x = 1
+
+    def wrapper(self, instance, red=None, blue=None):
+        return x
+
+    return wrapper
+
+
 class WrappedCodeTestCase(test.NoDBTestCase):
     """Test the get_wrapped_function utility method."""
 
@@ -68,3 +77,13 @@ class WrappedCodeTestCase(test.NoDBTestCase):
         self.assertIn('instance', func_code.co_varnames)
         self.assertIn('red', func_code.co_varnames)
         self.assertIn('blue', func_code.co_varnames)
+
+    def test_closure(self):
+        closure = get_closure()
+        func = safe_utils.get_wrapped_function(closure)
+        func_code = func.__code__
+        self.assertEqual(4, len(func_code.co_varnames))
+        self.assertIn('self', func_code.co_varnames)
+        self.assertIn('instance', func_code.co_varnames)
+        self.assertIn('red', func_code.co_varnames)
+        self.assertIn('blue', func_code.co_varnames)