From 5bea912c64a5db1cb301ad146d55bf3e5070c39d Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 5 Feb 2019 16:32:47 -0800
Subject: bpo-35766 follow-up: Add an error check to new_type_comment()

If PyUnicode_DecodeUTF8() returns NULL, PyArena_AddPyObject() would crash.
Found by @msullivan for https://github.com/python/typed_ast/pull/93.
---
 Python/ast.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Python/ast.c b/Python/ast.c
index 45578a850f..c47e1accc8 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -702,6 +702,8 @@ static string
 new_type_comment(const char *s, struct compiling *c)
 {
     PyObject *res = PyUnicode_DecodeUTF8(s, strlen(s), NULL);
+    if (res == NULL)
+        return NULL;
     if (PyArena_AddPyObject(c->c_arena, res) < 0) {
         Py_DECREF(res);
         return NULL;
-- 
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