django TransactionManagementError when using signals

Question

I have a one to one field with django\'s users and UserInfo. I want to subscribe to the post_save callback function on the user model so that I can then save the UserInfo as wel

Answer 1

The error is caused by the user.user_info.save() line throwing an exception, and the transaction was flagged as broken (PostgreSQL enforces rolling back either the whole transaction, or to any savepoint stored before doing any more queries inside that transaction).

You can rollback the transaction when an error occurs:

from django.db import IntegrityError, transaction

@receiver(post_save, sender=User) 
def saveUserAndInfo(sender, instance, **kwargs):
    user = instance
    try:
        with transaction.atomic():
            user.user_info.save()
    except IntegrityError:
        info = UserInfo()
        info.user = user
        info.save()

This is greatly described in the documentation.

Also, note that catching all exception types is not generally the best idea as you might silence exceptions you weren't expecting.