Non-delegate types should not be callable (#1247)

alxnull · web-flow · commit 03cf4acff424 · 2020-10-05T13:41:42.000-07:00
Removed the ClassObject.tp_call method which seemed to be unused. Also added a test case.
diff --git a/AUTHORS.md b/AUTHORS.md
@@ -77,3 +77,4 @@
 -   ([@stonebig](https://github.com/stonebig))
 -   ([@testrunner123](https://github.com/testrunner123))
 -   ([@DanBarzilian](https://github.com/DanBarzilian))
+-   ([@alxnull](https://github.com/alxnull))
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -28,6 +28,7 @@ details about the cause of the failure
 -    Fix `object[]` parameters taking precedence when should not in overload resolution
 -    Fixed a bug where all .NET class instances were considered Iterable
 -    Fix incorrect choice of method to invoke when using keyword arguments.
+-    Fix non-delegate types incorrectly appearing as callable.
 
 ## [2.5.0][] - 2020-06-14
 
diff --git a/src/runtime/classobject.cs b/src/runtime/classobject.cs
@@ -278,36 +278,5 @@ public static int mp_ass_subscript(IntPtr ob, IntPtr idx, IntPtr v)
 
             return 0;
         }
-
-
-        /// <summary>
-        /// This is a hack. Generally, no managed class is considered callable
-        /// from Python - with the exception of System.Delegate. It is useful
-        /// to be able to call a System.Delegate instance directly, especially
-        /// when working with multicast delegates.
-        /// </summary>
-        public static IntPtr tp_call(IntPtr ob, IntPtr args, IntPtr kw)
-        {
-            //ManagedType self = GetManagedObject(ob);
-            IntPtr tp = Runtime.PyObject_TYPE(ob);
-            var cb = (ClassBase)GetManagedObject(tp);
-
-            if (cb.type != typeof(Delegate))
-            {
-                Exceptions.SetError(Exceptions.TypeError, "object is not callable");
-                return IntPtr.Zero;
-            }
-
-            var co = (CLRObject)GetManagedObject(ob);
-            var d = co.inst as Delegate;
-            BindingFlags flags = BindingFlags.Public |
-                                 BindingFlags.NonPublic |
-                                 BindingFlags.Instance |
-                                 BindingFlags.Static;
-
-            MethodInfo method = d.GetType().GetMethod("Invoke", flags);
-            var binder = new MethodBinder(method);
-            return binder.Invoke(ob, args, kw);
-        }
     }
 }
diff --git a/src/tests/test_class.py b/src/tests/test_class.py
@@ -315,3 +315,13 @@ def test_method_inheritance():
 
     assert base.IsBase() == True
     assert derived.IsBase() == False
+
+
+def test_callable():
+    """Test that only delegate subtypes are callable"""
+
+    def foo():
+        pass
+
+    assert callable(System.String("foo")) == False
+    assert callable(System.Action(foo)) == True
