The rationale is described in https://code.djangoproject.com/ticket/19671.
On Tuesday, October 13, 2015 at 7:06:16 AM UTC-7, Mike Herring wrote: > > Doc here: > > https://docs.djangoproject.com/en/1.8/ref/models/fields/#django.db.models.ManyToManyField > > ManyToManyField does not support validators. > > > Is there a particular reason that ManyToManyField doesn't support > validators? I would like to add a validator to require the user to select > at least 3 options, but it seems the field simply doesn't run validators. I > attempted to add one in like this: > > from django.core.exceptions import ValidationError > > def validate_three(value): > > if len(value) < 3: > > raise ValidationError("Must choose three related posts") > > > BlogPost._meta.get_field('related_posts').validators.append(validate_three) > > But when it validates the field later, it says that self.validators == [] > -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/f4a3970a-d432-4140-a897-3ee9885ab0e7%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
