Django Autocomplete Light - FK Field Results not Forwarding

Question

I'm following along in the DAL documentation to add a filtered field to my form, but the forwarding isn't working to connect one field to the other:

Forms.py

class PurchaseForm(forms.ModelForm):

    commodity = forms.ModelChoiceField(
        queryset=Commodity.objects.all(),
        widget=autocomplete.ModelSelect2(url='commodity-autocomplete'),
        required=False,
    )

    class Meta:
        model = Purchase
        fields = ["variety"]
        widgets = {
            'variety': autocomplete.ModelSelect2(url='variety-autocomplete', forward=['commodity'],   
        }

Views.py

class VarietyAutocompleteView(autocomplete.Select2QuerySetView):
    def get_queryset(self):
        qs = Variety.objects.all()

        commodity = self.forwarded.get('commodity', None)
        print("Commodity:" + str(commodity))
        if commodity:
            qs = qs.filter(commodity=commodity)

        if self.q:
            qs = qs.filter(name__istartswith=self.q)

        return qs

I'd like my Variety choices to be filtered by their foreign key relationship to Commodity objects. Both autocomplete fields are working on their own just fine, but the choice from the commodity field is not being forwarded to the VarietyAutocompleteView (my print command prints Commodity:None). Is this perhaps because I am passing a foreign key object? Or have I set this up incorrectly somehow?

Answer 1

I'll add for anyone else like me who is thinking "yeah, but I still really don't want to change" - that in practice the line:

 'variety': autocomplete.ModelSelect2(url='variety-autocomplete', forward=['commodity'])

Really did not work for me either, but changing it to something like:

 'variety': autocomplete.ModelSelect2(url='variety-autocomplete', forward=('commodity', ))

Did work. Notice that it's a tuple so you need to have a "," there to make it work, as it's supposed to be an iterable value.

I didn't dig much further into why an array is part of the docs and yet doesn't work, but that was the critical change that make my variant work.

Also - I was using a formset (so there were prefixes) and that proved to not be a problem.