Ok, it's a bug in the function resize a compact Unicode string,
resize_compact(): wstr field is not updated to the new size.

Attached patch should fix it. The bug was introduced by me in Python 3.3.

I don't think that it's possible to resize wstr buffer instead of
freeing it: it will not be refilled by PyUnicode_AsUnicodeAndSize() if
wstr is not NULL. An alternative is to create a new string (instead of
using realloc) if wstr is not NULL.

2013/2/7 Florent Xicluna <report@bugs.python.org>:
>
> Changes by Florent Xicluna <florent.xicluna@gmail.com>:
>
>
> ----------
> components:  -Windows
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <http://bugs.python.org/issue17137>
> _______________________________________