Django forms - how to dynamically alter field labels

Question

How do I dynamically alter field labels in forms in Django In the below code, the labels word in the def clean_passport function is 'greyed out', saying 'labels' not accessed

Also, 'document_type' is not submitted in the form, it is not included as a form field, but is in the model, and it is assigned a value in the view.... how do I access it, if I need to do customised form validation based on the value of document_type???

Or should I put the logic in the model, and change the field characteristics there? Again, how would I access the value of document_type of a record / object in the model? Can you do that, dynamically change field attributes on a database?

UPDATE

I think I may need to create 4 separate forms as a way around this, unless anyone has a more generalisable / flexible solution

FORM

class LegalDocumentUpdateForm(forms.ModelForm):

    # FORM META PARAMETERS
    class Meta:
        model = Legal_Document
        fields = ('name_on_document', 'number_on_document', 'issuing_country', 'issuance_date', 'expiry_date', 'document_location')
        labels = {
            'name_on_document': _("Name on Document*"),
            'number_on_document': _("Document Number"),
            'issuing_country': _("Issuing Country"),
            'issuance_date': _("Issuance Date"),
            'expiry_date': _("Expiry Date"),
            'document_location': _("Document Location*")
            }

    # SANITIZATION & VALIDATION CHECKS
    def clean(self):
        document_type = self.cleaned_data['document_type']
        # document_type is not submitted in the form, but is in the model, and preset in the view.... how do I access it, if I need to do form validation depending on the value of document_type???
        if document_type == 'Passport':
            number_on_document = self.cleaned_data['number_on_document']
            issuing_country = self.cleaned_data['issuing_country']
            expiry_date = self.cleaned_data['expiry_date']
            if number_on_document == None:
                raise forms.ValidationError(_("Please enter the Passport Number."))
            if issuing_country == None:
                raise forms.ValidationError(_("Please enter the Passport's Issuing Country."))
            if expiry_date == None:
                raise forms.ValidationError(_("Please enter the Passport's Expiry Date."))
            labels = {
                'name_on_document': _("Passport Full Name*"),
                'number_on_document': _("Passport Number*"),
                'issuing_country': _("Issuing Country*"),
                'expiry_date': _("Passport Expiry Date*"),
            }

MODEL

# LEGAL DOCUMENT MODEL
class Legal_Document(models.Model):

    class LegalDocumentTypes(models.TextChoices):
        PASSPORT = 'Passport', _('Passport')
        BIRTHCERT = 'Birth Certificate', _('Birth or Adoption Certificate')
        CERTOFREG = 'Certificate of Registration', _('Certificate of Registration or Naturalisation')
        NIPROOF = 'Proof of N.I.', _('Proof of N.I. Document')

    related_user            = models.OneToOneField(User, on_delete=models.CASCADE, null=False, default='')
    document_id             = models.BigAutoField(verbose_name='Document ID', primary_key=True, serialize=False, auto_created=True)
    document_type           = models.CharField(verbose_name='Document Type', max_length=27, choices=LegalDocumentTypes.choices, blank=False, null=False, default=LegalDocumentTypes.PASSPORT)
    name_on_document        = models.CharField(verbose_name='Name on Document', max_length=100, blank=False, null=False, default='')
    number_on_document      = models.CharField(verbose_name='Document Number', max_length=20, blank=True, null=False, default='')
    issuing_country         = CountryField(verbose_name='Issuing Country', max_length=100, blank=True, null=False, default='')
    issuance_date           = models.DateField(verbose_name='Issuance Date', blank=True, null=True)
    expiry_date             = models.DateField(verbose_name='Expiry Date', blank=True, null=True)
    document_location       = models.CharField(verbose_name='Document Location', max_length=30, blank=False, null=False, default='')

Answer 1

Each field has a label attribute which you can set.

E.g.

self.fields['name_on_document'].label = 'Whatever'

Maybe you can use that in the clean method. But I don't see the point as it won't be displayed unless there is an error in the form.