mirror of
https://github.com/django/django.git
synced 2025-02-11 18:05:20 +00:00
6f7279c4b1
_populate() sets the populating attribute to prevent infinite recursion in case a urlconf includes itself. The flag is a threadlocal to avoid a race condition [1] where one thread sets the flag and another checks it, then proceeds to access data that's supposed to be populated (e.g. _reverse_dict) but isn't yet. The potential still exists for a thread to set the threadlocal, then be interrupted by a signal such as SIGALRM and raise before resetting the threadlocal flag. In this scenario, subsequent calls to _populate() in the same thread will short-circuit erroneously. The bulk of the method was already wrapped in a try/finally in df41b5a, but since a signal interrupt can occur at any line executed by the interpreter, this moves up the try to ensure threadlocal gets reset. [1]: https://groups.google.com/d/msg/django-developers/D_bIeinKHjE/4NmVQUJqAgAJ