sys_pyfile_write() does nothing if file is NULL
mywrite() falls back to the C file object if sys_pyfile_write() returns an
error. This patch fixes a segfault is Py_FatalError() is called in an early
stage of Python initialization.
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index f1da9730c..9ec8ab1 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -1839,6 +1839,9 @@
PyObject *unicode = NULL, *writer = NULL, *args = NULL, *result = NULL;
int err;
+ if (file == NULL)
+ return -1;
+
unicode = PyUnicode_FromString(text);
if (unicode == NULL)
goto error;