id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
34711	form.has_changed() is always True for IntegerChoices Enum Model Field	GHPS	nobody	"Summary:

While trying to find out why the forms in two different applications are
marked for saving even if no field has been changed, I could pin the problem down
to the integer enum fields used in both models and form.ChoiceField involved.
In short, form.has_changed() is triggered because of a double data conversion
during the round-trip.

The value of the integer enum field is converted to a string and rendered.
The POST request comes back with this string which gets compared to the original 
enum integer which shows that they are different. During the - unnecessary - saving
the string becomes an int again - which is why the original problem is hidden
from the perspective of a user.

This bug seem to be a regression from bug #22097.

Background:

In Django 4.2 on Linux (Kubuntu 22.04) take the following enum and
create a model field in model.py:

{{{
class eAssets(models.IntegerChoices):
    dvd       =1, _('DVD')
    bluray    =3, _('Blu-ray')
    none      =0, _('-')

eAsset=models.PositiveSmallIntegerField(choices=eAssets.choices, default=eAssets.none)
}}}


Create a choice form field in form.py:

{{{
eAsset=forms.ChoiceField(label=mdMovie._meta.get_field('eAsset').verbose_name,
choices=[(dcEntry.value, dcEntry.label) for dcEntry in mdMovie.eAssets],
                          initial=mdMovie.eAssets.none)
}}}

After processing the POST request, form.has_changed() is always true in view.py:

{{{
>fmForm=fmMovie(vRequest.POST, vRequest.FILES or None, instance=rcCurrentMovie)
>fmForm.has_changed()
True
>fmForm.changed_data                                                                         
['eAsset']
}}}

Links:
- I've found an old ticket #22097 and it looks to me like this nine year old bug has shown its ugly face again.
- On Stackoverflow someone reported the same problem.
[https://stackoverflow.com/questions/68763230/django-forms-a-dynamic-integer-model-choice-field-always-fails-form-has-changed|A dynamic integer model choice field always fails form.has_changed()]"	Bug	new	Forms	4.2	Normal				Unreviewed	0	0	0	0	0	0