Check that the argument is a frame

Author: vstinner

Lib/test/test_frame.py

@@ -507,9 +507,11 @@ def make_frame():
         proxy = FrameLocalsProxy(make_frame())
         self.assertEqual(proxy, {'x': 1, 'y': 2})
 
-        # constructor expects 1 argument (frame)
+        # constructor expects 1 frame argument
         with self.assertRaises(TypeError):
-            FrameLocalsProxy()
+            FrameLocalsProxy()     # no arguments
+        with self.assertRaises(TypeError):
+            FrameLocalsProxy(123)  # wrong type
 
 
 class FrameLocalsProxyMappingTests(mapping_tests.TestHashMappingProtocol):

Objects/frameobject.c

@@ -316,15 +316,19 @@ framelocalsproxy_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
                      PyTuple_GET_SIZE(args));
         return NULL;
     }
+    PyObject *item = PyTuple_GET_ITEM(args, 0);
+
+    if (!PyFrame_Check(item)) {
+        PyErr_Format(PyExc_TypeError, "expect frame, not %T", item);
+        return NULL;
+    }
+    PyFrameObject *frame = (PyFrameObject*)item;
 
     PyFrameLocalsProxyObject *self = (PyFrameLocalsProxyObject *)type->tp_alloc(type, 0);
     if (self == NULL) {
         return NULL;
     }
 
-    PyFrameObject *frame = (PyFrameObject*)PyTuple_GET_ITEM(args, 0);
-    assert(PyFrame_Check(frame));
-
     ((PyFrameLocalsProxyObject*)self)->frame = (PyFrameObject*)Py_NewRef(frame);
 
     return (PyObject *)self;