Removed incorrect fields.W343 check and notes about limit_choices_to restrictions for ManyToManyField.

[jhbuhrman]

The model setup given below:

class Number(models.Model):
    value = models.IntegerField()

    def __str__(self) -> str:
        return f"{self.value}"


class NumbersToDiceThroughModel(models.Model):
    number = models.ForeignKey("Number", on_delete=models.PROTECT)
    die = models.ForeignKey("Die", on_delete=models.CASCADE)


class Die(models.Model):
    numbers = models.ManyToManyField(
        "Number",
        through="NumbersToDiceThroughModel",
        limit_choices_to=models.Q(value__gte=1),
    )

Results in a correct limitation of possible choices. But at the same time the following warning is issued:

... .Die.numbers: (fields.W343) limit_choices_to has no effect on ManyToManyField with a through model.

[Mariusz Felisiak]

Thanks for the report!

I'm puzzled. I checked with a sample project and the following test:

class MyTests(TestCase):
    def test_limit_choices_through(self):
        for i in range(-10, 10):
            Number.objects.create(value=i)

        class CharacterDetailsForm(forms.ModelForm):
            class Meta:
                model = Die
                fields = ['numbers']

        self.assertEqual(Number.objects.count(), 20)

        form = CharacterDetailsForm()
        self.assertEqual(form.fields['numbers'].queryset.count(), 9)
        self.assertEqual(form.fields['numbers'].queryset.filter(value__lt=1).count(), 0)

and limit_choices_to works since at least Django 1.1 (yes 1.1, I really tried to find when it wasn't working).

It seems that this check is incorrect since its introduction in ba53da894fc713629ae4d3fbdd14eff98c808389 (see #26796) and the ​related note in docs is also incorrect since its introduction in c6c25adf6d9f71ea11f61392f6f3d221f01e5216 (see #9733).

[Hasan Ramezani]

​PR

[Simon Charette]

I'm puzzled as well Mariusz, I could swear something was not working properly when I filed this ticket but it was too long ago for me to remember the proper context.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 0a28b42:

Fixed #33084 -- Removed incorrect system check for ManyToManyField with limit_choices_to.