Merge pull request #59 from mdickinson/fix/annotation-of-anonymous-function

Fix annotation of anonymous functions.

Author: mdickinson

refcycle/annotations.py

@@ -180,14 +180,21 @@ def object_annotation(obj):
                 im_class_name = "<None>"
             else:
                 im_class_name = im_class.__name__
+
+            try:
+                func_name = obj.__func__.__name__
+            except AttributeError:
+                func_name = "<anonymous>"
             return "instancemethod\\n{}.{}".format(
                 im_class_name,
-                obj.__func__.__name__,
+                func_name,
             )
         else:
-            return "instancemethod\\n{}".format(
-                obj.__func__.__qualname__
-            )
+            try:
+                func_name = obj.__func__.__qualname__
+            except AttributeError:
+                func_name = "<anonymous>"
+            return "instancemethod\\n{}".format(func_name)
     elif isinstance(obj, list):
         return "list[{}]".format(len(obj))
     elif isinstance(obj, tuple):

refcycle/test/test_annotations.py

@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import ctypes
 import gc
 import inspect
 import sys
@@ -315,6 +316,26 @@ def my_method(self):
                 "instancemethod\\n<None>.my_method",
             )
 
+    def test_annotate_instancemethod_with_nameless_function(self):
+        # Regression test for mdickinson/refcycle#25.
+
+        # Create a nameless function: comparison_function.__name__
+        # raise AttributeError.
+        comparison_function_type = ctypes.CFUNCTYPE(
+            ctypes.c_int,
+            ctypes.POINTER(ctypes.c_int),
+            ctypes.POINTER(ctypes.c_int),
+        )
+        comparison_function = comparison_function_type(lambda a, b: 0)
+
+        method = types.MethodType(comparison_function, NewStyle())
+        if six.PY2:
+            expected = "instancemethod\\n<None>.<anonymous>"
+        else:
+            expected = "instancemethod\\n<anonymous>"
+
+        self.assertEqual(object_annotation(method), expected)
+
     def test_annotate_weakref(self):
         a = set()
         ref = weakref.ref(a)