Bug #1651235: When a tuple was passed to a ctypes function call,

Python would crash instead of raising an error.

The crash was caused by a section of code that should have been
removed long ago, at that time ctypes had other ways to pass
parameters to function calls.

Lib/ctypes/test/test_functions.py

@@ -21,7 +21,9 @@ if sys.platform == "win32":
 
 class POINT(Structure):
     _fields_ = [("x", c_int), ("y", c_int)]
-
+class RECT(Structure):
+    _fields_ = [("left", c_int), ("top", c_int),
+                ("right", c_int), ("bottom", c_int)]
 class FunctionTestCase(unittest.TestCase):
 
     def test_mro(self):
@@ -379,5 +381,15 @@ class FunctionTestCase(unittest.TestCase):
             self.failUnlessEqual((s8i.a, s8i.b, s8i.c, s8i.d, s8i.e, s8i.f, s8i.g, s8i.h),
                                  (9*2, 8*3, 7*4, 6*5, 5*6, 4*7, 3*8, 2*9))
 
+    def test_sf1651235(self):
+        # see http://www.python.org/sf/1651235
+
+        proto = CFUNCTYPE(c_int, RECT, POINT)
+        def callback(*args):
+            return 0
+
+        callback = proto(callback)
+        self.failUnlessRaises(ArgumentError, lambda: callback((1, 2, 3, 4), POINT()))
+
 if __name__ == '__main__':
     unittest.main()

Misc/NEWS

@@ -156,6 +156,9 @@ Core and builtins
 Library
 -------
 
+- Bug #1651235: When a tuple was passed to a ctypes function call,
+  Python would crash instead of raising an error.
+
 - Bug #1646630: ctypes.string_at(buf, 0) and ctypes.wstring_at(buf, 0)
   returned string up to the first NUL character.
 

Modules/_ctypes/_ctypes.c

@@ -339,24 +339,6 @@ CDataType_from_param(PyObject *type, PyObject *value)
 			     ((PyTypeObject *)type)->tp_name, ob_name);
 		return NULL;
 	}
-#if 1
-/* XXX Remove this section ??? */
-	/* tuple returned by byref: */
-	/* ('i', addr, obj) */
-	if (PyTuple_Check(value)) {
-		PyObject *ob;
-		StgDictObject *dict;
-
-		dict = PyType_stgdict(type);
-		ob = PyTuple_GetItem(value, 2);
-		if (dict && ob &&
-		    0 == PyObject_IsInstance(value, dict->proto)) {
-			Py_INCREF(value);
-			return value;
-		}
-	}
-/* ... and leave the rest */
-#endif
 
 	as_parameter = PyObject_GetAttrString(value, "_as_parameter_");
 	if (as_parameter) {