Switch away from django-multiselectfield.

Review Request #13561 — Created Feb. 20, 2024 and submitted — Latest diff uploaded


Review Board


The django-multiselectfield package hasn't been maintained in a few
years, and it doesn't support Django 4.x+. There's a third-party fork
which has had some updates, but no releases that we can consume.

django-multiselectfield itself isn't very big, and of what it offers, we
don't actually use very much. A new field has been added to Djblets to
handle the list serialization/deserialization for comma-separated
values. This change switches us over to that.

The major difference here is that we have to instantiate the form
field ourselves. While the old MultiSelectField had its own validation
for the database side, we can rely on the form's MultipleChoiceField

This also manually sets a max_length on the field. The MultiSelectField
would compute the max_length based on the provided choices, but that
meant that any change to the choices would need an evolution.

  • Ran unit tests.
  • Ran the new evolution.
  • Tested the WebHookTarget admin form and verified that everything
    worked as expected.