Filter choices in model form

[billybonks]

Bottle feeding, has an option of solid food which makes no sense :).

I would like to filter that option out for bottle feeding for specifically i have tried every option on the internet

class BottleFeedingForm(CoreModelForm, TaggableModelForm):
    fieldsets = [
        {
            "fields": ["child", "type", "start", "amount"],
            "layout": "required",
        },
        {"layout": "advanced", "fields": ["notes", "tags"]},
    ]

    class Meta:
        model = models.Feeding
        fields = ["child", "start", "type", "amount", "notes", "tags"]
        widgets = {
            "child": ChildRadioSelect,
            "start": DateTimeInput(),
            "type": PillRadioSelect(
                choices=[
                    ("breast milk", _("Breast milk")),
                    ("formula", _("Formula")),
                    ("fortified breast milk", _("Fortified breast milk")),
                ],
            ),
            "notes": forms.Textarea(attrs={"rows": 5}),
        }

https://forum.djangoproject.com/t/overriding-models-choices-in-form-init/15048

probably a few more.

before i build FIlterablePillRadioSelect I was wondering if you have a way to do this?

I will be doing using this for a nursing form as well.

[cdubz]

I'm not 100% but this looks like how I would expect it to work: https://forum.djangoproject.com/t/how-to-filter-the-choices-in-forms-select-widget/19974/4

[billybonks]

I tried this and it didn't work, i can create a pr that we can debug together. Maybe i am doing something wrong

[MrApplejuice]

I tried to do the leg-work and it is quite interesting actually. It seems to come down to a conscious choice by django:

class ChoiceField(Field):
    # ...
    @choices.setter
    def choices(self, value):
        # Setting choices on the field also sets the choices on the widget.
        # Note that the property setter for the widget will re-normalize.
        self._choices = self.widget.choices = normalize_choices(value)

Source: https://github.com/django/django/blob/c783e7a3a0e411811aba83158d55e4f2f3091ac7/django/forms/fields.py#L899-L903

The "field" that is meant here, according to my investigation, is the model-field because the stack-trace in question looks as follows (Comment from my side: This feels buggy and not intended, but maybe it is?!):

  File "/home/paul/code/python/babybuddy/core/forms.py", line 207, in <module>                                                                                                                         
    class BottleFeedingForm(CoreModelForm, TaggableModelForm):                                                                                                                                         
  File "/home/paul/.local/share/virtualenvs/babybuddy-bwgPVFMf/lib/python3.10/site-packages/django/forms/models.py", line 309, in __new__                                                              
    fields = fields_for_model(                                                                                                                                                                         
  File "/home/paul/.local/share/virtualenvs/babybuddy-bwgPVFMf/lib/python3.10/site-packages/django/forms/models.py", line 234, in fields_for_model                                                     
    formfield = f.formfield(**kwargs)                                                                                                                                                                  
  File "/home/paul/.local/share/virtualenvs/babybuddy-bwgPVFMf/lib/python3.10/site-packages/django/db/models/fields/__init__.py", line 1298, in formfield                                              
    return super().formfield(**defaults)                                                                                                                                                               
  File "/home/paul/.local/share/virtualenvs/babybuddy-bwgPVFMf/lib/python3.10/site-packages/django/db/models/fields/__init__.py", line 1140, in formfield                                              
    return form_class(**defaults)                                                                                                                                                                      
  File "/home/paul/.local/share/virtualenvs/babybuddy-bwgPVFMf/lib/python3.10/site-packages/django/forms/fields.py", line 932, in __init__                                                             
    super().__init__(**kwargs)                                                                                                                                                                         
  File "/home/paul/.local/share/virtualenvs/babybuddy-bwgPVFMf/lib/python3.10/site-packages/django/forms/fields.py", line 880, in __init__                                                             
    self.choices = choices                                                                                                                                                                             
  File "/home/paul/.local/share/virtualenvs/babybuddy-bwgPVFMf/lib/python3.10/site-packages/django/forms/fields.py", line 895, in choices                                                              
    self._choices = self.widget.choices = normalize_choices(value)                                                                                                                                     
  File "/home/paul/code/python/babybuddy/core/forms.py", line 204, in choices                                                                                                                          
    traceback.print_stack()               

The callstack indicates that forms/models.py calls out -> db/models/... which then causes a -> self.widget.choices = ....

Baby buddy sets choices on the model field:

babybuddy/core/models.py

Lines 237 to 247 in 2d1338a

	color = models.CharField(
	blank=True,
	choices=[
	("black", _("Black")),
	("brown", _("Brown")),
	("green", _("Green")),
	("yellow", _("Yellow")),
	],
	max_length=255,
	verbose_name=_("Color"),
	)

---

How to get it to work

However, independent from my finding above (or coming forth out it), this does the trick: Setting the "choices" not on the widget but on the form-field!

class BottleFeedingForm(CoreModelForm, TaggableModelForm):
    def save(self):
        instance = super(BottleFeedingForm, self).save(commit=False)
        instance.method = "bottle"
        instance.end = instance.start
        instance.save()
        return instance

    type = ChoiceField(
        choices=(
            ("breast milk", _("Breast milk")),
            ("formula", _("Formula")),
            ("fortified breast milk", _("Fortified breast milk")),
        ),
    )

    class Meta:
        model = models.Feeding
        fields = ["child", "start", "type", "amount", "notes", "tags"]
        widgets = {
            "child": ChildRadioSelect,
            "start": DateTimeInput(),
            "notes": forms.Textarea(attrs={"rows": 5}),
        }