From 5de9842b34cbefbfe74e6a99004616352f223133 Mon Sep 17 00:00:00 2001 From: Tim Peters Date: Sat, 27 Apr 2002 18:44:32 +0000 Subject: Repair widespread misuse of _PyString_Resize. Since it's clear people don't understand how this function works, also beefed up the docs. The most common usage error is of this form (often spread out across gotos): if (_PyString_Resize(&s, n) < 0) { Py_DECREF(s); s = NULL; goto outtahere; } The error is that if _PyString_Resize runs out of memory, it automatically decrefs the input string object s (which also deallocates it, since its refcount must be 1 upon entry), and sets s to NULL. So if the "if" branch ever triggers, it's an error to call Py_DECREF(s): s is already NULL! A correct way to write the above is the simpler (and intended) if (_PyString_Resize(&s, n) < 0) goto outtahere; Bugfix candidate. --- Python/bltinmodule.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Python/bltinmodule.c') diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c index 06d86167aa..aa65ebca41 100644 --- a/Python/bltinmodule.c +++ b/Python/bltinmodule.c @@ -1993,8 +1993,8 @@ filterstring(PyObject *func, PyObject *strobj) Py_DECREF(item); } - if (j < len && _PyString_Resize(&result, j) < 0) - return NULL; + if (j < len) + _PyString_Resize(&result, j); return result; -- cgit v1.2.1