Avoid a crash when unencoding session data for the db backend. This is required

because some configurations of MySQL (with utf8_bin collation) will return
bytestring, rather than unicode data, which was causing problems previously.

Refs #8340.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@8507 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/sessions/backends/db.py

@@ -3,6 +3,7 @@ from django.contrib.sessions.models import Session
 from django.contrib.sessions.backends.base import SessionBase, CreateError
 from django.core.exceptions import SuspiciousOperation
 from django.db import IntegrityError, transaction
+from django.utils.encoding import force_unicode
 
 class SessionStore(SessionBase):
     """
@@ -14,7 +15,7 @@ class SessionStore(SessionBase):
                 session_key = self.session_key,
                 expire_date__gt=datetime.datetime.now()
             )
-            return self.decode(s.session_data)
+            return self.decode(force_unicode(s.session_data))
         except (Session.DoesNotExist, SuspiciousOperation):
             self.create()
             return {}