TypeError: ‘DoesNotExist’ object is not callable

Question

It's not always this code chunk but this is the most recent. It seems to be random, any thoughts?

try:
    u = User.objects.get(email__iexact=useremail)
except User.DoesNotExist:
    ...

Throws this error, randomly.

File "/srv/myapp/registration/models.py", line 23, in get_or_create_user
  u = User.objects.get(email__iexact=useremail)

File "/usr/local/lib/python2.6/dist-packages/django/db/models/manager.py", line 132, in get
  return self.get_query_set().get(*args, **kwargs)

File "/usr/local/lib/python2.6/dist-packages/django/db/models/query.py", line 349, in get
  % self.model._meta.object_name)

TypeError: ‘DoesNotExist’ object is not callable

Answer 1

As Chris says in the comments above, your snippet is valid. Somewhere else in your code, you may be catching exceptions incorrectly.

You may have something like:

try:
    do_something()
except User.MultipleObjectsReturned, User.DoesNotExist:
    pass

instead of:

try:
    do_something()
except (User.MultipleObjectsReturned, User.DoesNotExist):
    pass

Without the parentheses, the except statement is equivalent to the following in Python 2.6+

except User.MultipleObjectsReturned as User.DoesNotExist:

The instance of the User.MultipleObjectsReturned exception overwrites User.DoesNotExist.

When the same process handles a different request later on, you get the TypeError because your code is trying to call the exception instance which has replaced User.DoesNotExist.