TypeError: int() argument must be a string or a number, not 'User'

[adam]

Having a hard time with a change I made on a django site, I moved from a single app to multiple apps and now I'm getting a traceback when attempting to migrate an initial installation. Attaching the traceback here to see if anyone can help me out. i tested this again with a single app and large model and it works fine, only difference is in model relationships. (I think...:-)...)

[adam]

traceback file

[Tim Graham]

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[fupduck]

Hello,

this error message comes up when a default user is assigned to a new foreign key field.
Excerpt of the attached project where manage.py migrate is failing:

from django.db import models
from django.contrib.auth.models import User
def get_default_user():
    return User.objects.get(id=1)

class Question(models.Model):
    the_user = models.ForeignKey(User, default=get_default_user)

Then manage.py makemigrations leads to a new migration 0003 with:

migrations.AddField(
            model_name='question',
            name='the_user',
            field=models.ForeignKey(default=polls.models.get_default_user, to=settings.AUTH_USER_MODEL),
        ),

And then manage.py sqlmigrate polls 0003 is enough to get the error message:

  File "/usr/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 985, in get_prep_value
    return int(value)
TypeError: int() argument must be a string or a number, not 'User'

A workaround is directly assining the .id of the wanted user to the default parameter, but I think it would be better if int(user_instance) would either return the id as int or directly user_instance.id is used by get_prep_value.

Regards

Link to example project to reproduce the code (tar.gz):
​https://slack-files.com/T031HCE60-F0FBKUE87-a1a23a53f7

[Tim Graham]

The requirement to use the primary key is documented ​in the documentation and the decision discussed in #25129:

For fields like ForeignKey that map to model instances, defaults should be the value of the field they reference (pk unless to_field is set) instead of model instances.