Django 1.8.2 release notes

May 20, 2015

Django 1.8.2 fixes a security issue and several bugs in 1.8.1.

Fixed session flushing in the cached_db backend

A change to session.flush() in the cached_db session backend in Django 1.8 mistakenly sets the session key to an empty string rather than None. An empty string is treated as a valid session key and the session cookie is set accordingly. Any users with an empty string in their session cookie will use the same session store. session.flush() is called by django.contrib.auth.logout() and, more seriously, by django.contrib.auth.login() when a user switches accounts. If a user is logged in and logs in again to a different account (without logging out) the session is flushed to avoid reuse. After the session is flushed (and its session key becomes '') the account details are set on the session and the session is saved. Any users with an empty string in their session cookie will now be logged into that account.

Bugfixes

• Fixed check for template engine alias uniqueness (#24685).
• Fixed crash when reusing the same Case instance in a query (#24752).
• Corrected join promotion for Case expressions. For example, annotating a query with a Case expression could unexpectedly filter out results (#24766).
• Fixed negated Q objects in expressions. Cases like Case(When(~Q(friends__age__lte=30))) tried to generate a subquery which resulted in a crash (#24705).
• Fixed incorrect GROUP BY clause generation on MySQL when the query’s model has a self-referential foreign key (#24748).
• Implemented ForeignKey.get_db_prep_value() so that ForeignKeys pointing to UUIDField and inheritance on models with UUIDField primary keys work correctly (#24698, #24712).
• Fixed isnull lookup for HStoreField (#24751).
• Fixed a MySQL crash when a migration removes a combined index (unique_together or index_together) containing a foreign key (#24757).
• Fixed session cookie deletion when using SESSION_COOKIE_DOMAIN (#24799).
• On PostgreSQL, when no access is granted for the postgres database, Django now falls back to the default database when it normally requires a “no database” connection (#24791).
• Fixed display of contrib.admin’s ForeignKey widget when it’s used in a row with other fields (#24784).