Failing test for ChoiceField eagerly evaluating choices

[craigds]

refs #1625

[craigds]

@carltongibson that should help^

In case it helps, that test passes when backported on top of 23.2 and fails with 23.3

[carltongibson]

Great. Thanks. Let me have a look. 👀

[carltongibson]

Thanks @craigds.

Since the callable is wrapped by the iterator, it's being cast to a list in super class (forms.ChoiceField):

  File ".../django-filter/django_filters/fields.py", line 284, in choices
    super(ChoiceIteratorMixin, self.__class__).choices.__set__(self, value)
  File ".../django/forms/fields.py", line 880, in _set_choices
    value = list(value)

(Django stable/4.2.x)

In order avoid that I think we need to bypass the superclass setter for Django<5.0.

Something like:

diff --git a/django_filters/fields.py b/django_filters/fields.py
index 3a34365..d6ac79c 100644
--- a/django_filters/fields.py
+++ b/django_filters/fields.py
@@ -275,13 +275,13 @@ class ChoiceIteratorMixin:
     def choices(self, value):
         if DJANGO_50:
             value = self.iterator(self, value)
+            # Simple `super()` syntax for calling a parent property setter is
+            # unsupported. See https://github.com/python/cpython/issues/59170
+            super(ChoiceIteratorMixin, self.__class__).choices.__set__(self, value)
         else:
             super()._set_choices(value)
             value = self.iterator(self, self._choices)
-
-        # Simple `super()` syntax for calling a parent property setter is
-        # unsupported. See https://github.com/python/cpython/issues/59170
-        super(ChoiceIteratorMixin, self.__class__).choices.__set__(self, value)
+            self._choices = self.widget.choices = value

Fancy trying that?

cc @ngnpope

[ngnpope]

Thanks for the ping @carltongibson.

So, yes, it looks as though I was a little too optimistic there - your proposed patch looks like the right approach.

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
django_filters
fields.py
Project Total

This report was generated by python-coverage-comment-action

[craigds]

thanks, sorry I didn't get around to submitting a proper fix

[carltongibson]

No problem @craigds. The reproduce was the key thing. 🎁