Autocomplete broken on ManyToManyField

[Filipe]

I've bumped into ​https://github.com/django/django/blob/3.2.8/django/contrib/admin/views/autocomplete.py#L42 after upgrading from django 3.1.5 to 3.2.8 (introduced in 3.2 looking at the tags, so adds up)

My current setup is a parent class:

# app "vulns"
class Finding(models.Model):
    ...
    related_to = models.ManyToManyField('self', blank=True, help_text='Other findings related to this one')

And then child class (adding for completeness but not sure it matters)

# app "burp"
class Finding(vuln_models.Finding):
 ...

vulns.Finding has an admin model defined with search fields id and title

When editing a burp.Finding (changeform) the autocomplete for related_to sends related_to_rel+ as field_name resulting self.source_field being set to the ManyToManyRel (not the ManyToManyField).

The Rel has limit_choices_to but it does not have a get_limit_choices_to (while the Field does).

I've been trying to find if it's me doing something wrong in the model definition but it's pretty straightforward...

[Mariusz Felisiak]

Thanks for the report, however I cannot reproduce this issue with described models. Can you provide a small sample project?

[Filipe]

So I've pushed a sample app (​https://github.com/fopinappb/django-bug-reports/tree/main/autocompleteM2M_3.2) but was also unable to reproduce. I'll try to find the quirks in the original code and I'll update the ticket (if it's not something in the project code/setup)

[Filipe]

ok, found the culprit line and it was not even in the custom theme, it was directly in the project code...

Should've started a sample app from the start and would've saved some bytes and bandwidth on this ticket :)

cheers

[Mariusz Felisiak]

Thanks for checking.