UniqueConstraint with InlinePanel

[minusf]

Issue Summary

Converting a unique_together to UniqueConstraint results in an uncaught IntegrityError when trying to add a duplicate in a related model with InlinePanel.

    class Meta:
        # uncaught IntegrityError
        constraints = (
            models.UniqueConstraint(fields=["short_name", "meeting_site"], name="unique_room"),
        )
        # this works
        unique_together = ("short_name", "meeting_site")

I found this older issue relating to unique_together: wagtail/wagtail#2136

I also found this issue, but it seems it's only for images? wagtail/wagtail#8715

Technical details

• Python version: Python 3.12.7
• Django version: 5.1.2
• Wagtail version: 6.2.2
• Browser version: FF 131.0.2

[laymonage]

This likely is an issue in django-modelcluster. The fix might be to pass include_meta_constrains=True to _get_unique_checks() in

django-modelcluster/modelcluster/forms.py

Line 137 in 7e53fce

unique_checks, date_checks = form.instance._get_unique_checks()

.

(Django ref: https://github.com/django/django/blob/97c05a64ca87253e9789ebaab4b6d20a1b2370cf/django/db/models/base.py#L1404)

If you can hack your installed django-modelcluster, could you try making the following changes in modelcluster/forms.py at line 137?

-            unique_checks, date_checks = form.instance._get_unique_checks()
+            unique_checks, date_checks = form.instance._get_unique_checks(include_meta_constraints=True)

[minusf]

This seems to fix it, thanks for the very quick response.

[minusf]

Do you need me to do anything else? Will this be part of the package?