#12780: Provide a hook for compound form/formset validation in ModelAdmin
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Reporter: mrts | Owner: Ramez Issac
Type: New feature | Status: assigned
Component: contrib.admin | Version: dev
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Changes (by Natalia Bidart):
* cc: Carlton Gibson, Natalia Bidart, Mariusz Felisiak (added)
Comment:
In order to properly review the PR, I've been investigating solutions for
this ticket, and as I mentioned in
[[https://github.com/django/django/pull/16777|PR #16777]], I think there
is currently enough flexibility in overriding the inline's formset so that
any custom validation involving both the parent form/instance and the
formset themselves can be done there. Following the example referenced in
the ticket description use case, in order to block `Clip` instances to be
approved without a matching `ClipDescription` in the same language, the
customization would look similar to this:
{{{
# models.py
from django.db import models
LANGS = ['de', 'en', 'es', 'fr', 'it']
class Clip(models.Model):
is_approved = models.BooleanField(default=False)
language = models.CharField(choices=[(i, i) for i in LANGS],
max_length=2)
class ClipDescription(models.Model):
clip = models.ForeignKey(Clip, on_delete=models.CASCADE)
text = models.TextField()
language = models.CharField(choices=[(i, i) for i in LANGS],
max_length=2)
}}}
{{{
# admin.py
from django import forms
from django.contrib import admin
from django.core.exceptions import ValidationError
from .models import Clip, ClipDescription
class InlineFormset(forms.models.BaseInlineFormSet):
def clean(self):
languages = {
f.cleaned_data['language']
for f in self.forms
if 'language' in f.cleaned_data
# This next line filters out inline objects that did exist
# but will be deleted if we let this form validate --
# obviously we don't want to count those if our goal is to
# enforce a condition of related objects.
and not f.cleaned_data.get('DELETE', False)
}
if (
self.instance.is_approved
and self.instance.language not in languages
):
raise ValidationError(
'A Clip cannot be approved without a description in the
same language'
)
class ClipDescriptionInline(admin.TabularInline):
model = ClipDescription
formset = InlineFormset
class ClipAdmin(admin.ModelAdmin):
inlines = [
ClipDescriptionInline,
]
admin.site.register(Clip, ClipAdmin)
}}}
In summary, I'm proposing to close this issue as invalid/wontfix, but I'd
live to know what others think first.
--
Ticket URL: <https://code.djangoproject.com/ticket/12780#comment:13>
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