Raise a clear exception on functools.partial

test/modules/partial_function.py

@@ -1,9 +1,9 @@
 import functools
+import pytest
 import xmod
 
 
 def base(a, b, c, d):
     return a, b, c, d
 
-
 xmod(functools.partial(base, 0, d=3))

test/test_xmod.py

@@ -105,9 +105,13 @@ def test_decorator_with_parameter(self):
         assert decorator_with_parameter.BAR == 99
 
     def test_partial_function(self):
-        from .modules import partial_function
+        try:
+            from .modules import partial_function
+        except ValueError as e:
+            assert e.args == ('`name` parameter must be set',)
+        else:
+            assert False
 
-        assert partial_function(1, 2) == (0, 1, 2, 3)
 
 COMMON = [
     '__builtins__',

xmod.py

@@ -141,11 +141,9 @@ def prop(k):
             mutator(lambda v: setattr(extension, k, v)),
             mutator(lambda: delattr(extension, k)),
         )
-    if name is None:
-        if isinstance(extension, functools.partial):
-            name = extension.func.__module__
-        else:
-            name = extension.__module__
+    name = name or getattr(extension, '__module__', None)
+    if not name:
+        raise ValueError('`name` parameter must be set')
 
     module = sys.modules[name]