Version of dumpdata that includes soft deleted models

[danizen]

We had a situation arise with an application written in 2017 using a home-grown ModelManager which works similarly to the SafeDeleteManager. Because we are migrating from one database to another, and there is not too much data, we attempted to use the management commands dumpdata and loaddata to copy the data to the new database instance.

This caused referential integrity errors because dumpdata did not include the deleted models. My suggestion is that safedelete includes its own dumpdata command which avoids the problem:

from types import MethodType
from django.apps import apps
from django.db import models
from django.core.management.commands.dumpdata import Command as BaseCommand

# not quite using django-safedelete, but other apps here do
from lrmaint.models import SoftDeleteManager

class Command(BaseCommand):

    def handle(self, *app_labels, **options):
        print('This is a wrapper around Django default dumpdata')

        # patch each softdeletemanager to avoid overload
        for model in apps.get_app_config('lrmaint').get_models():
            if isinstance(model.objects, SoftDeleteManager):
                model.objects.get_queryset = MethodType(models.Manager.get_queryset, model.objects)

        # defer to dumpdata
        super().handle(*app_labels, **options)

[danizen]

Another way to mitigate this would be to mention it in the documentation as a warning.

[danizen]

The actual result was that dump worked, but load failed with a referential integrity error.

[Gagaro]

Thanks for the report :+1: . Feel free to open a PR implementing this.

[yourcelf]

This can be done using the built-in dumpdata by passing the -a/--all flag:

./manage.py dumpdata --all myapp

That causes dumpdata to use the base manager rather than the default manager, and results in safe-deleted objects being included in the dump.