bulk_create() with ignore_conflicts=True and ForeignKey fails

[Markus Friedrich]

Creating both objects of a many-to-one relation using bulk_create together with ignore_conflicts=True fails since Django >=3.2!

To enable many-to-one relations in bulk_create the "to_field" of the ForeignKey is defined via a UUIDField with a uuid.UUID4 default value.

Without the ignore_conflicts=True option of bulk_create it works well in all Django versions.
But if ignore_conflicts=True is needed since some of the objects using in the bulk_create may already be saved to the DB then it works only for Django < 3.2.
With Django >= 3.2 (including 4.0.4) it fails with:
ValueError: bulk_create() prohibited to prevent data loss due to unsaved related object 'reporter'.

Find attached a test app which reproduces this issue with a minimal example, see
mysite/polls/models.py and mysite/polls/tests.py

[Mariusz Felisiak]

Thanks for this report. This behavior was intentionally changed in 10f8b82d195caa3745ba37d9424893763f89653e to prevent possible data loss. Using ignore_conflicts=True tells the database to ignore failure to insert any rows that fail constraints such as duplicate unique values, but also disables setting the primary key on each model instance (as ​documented). Therefore a reporter instance doesn't have a primary key set. You need to attached already saved reporter to the article before bulk_create().