Broken: GenericInlineModelAdmin and two ForeignKey
|Reported by:||Owned by:||nobody|
|Has patch:||no||Needs documentation:||no|
|Needs tests:||no||Patch needs improvement:||no|
A scenario that I would not call exotic at all:
from django.contrib.contenttypes import generic from django.contrib.contenttypes.models import ContentType from django.db import models class Whatever(models.Model): something = models.CharField(max_length=254) class Person(models.Model): name = models.CharField(max_length=254) class Action(models.Model): content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') task = models.CharField(max_length=254) accountable = models.ForeignKey(Person, related_name='actions_accountable_for', null=True, blank=True) assigned_to = models.ForeignKey(Person, related_name='actions_assigned_to', null=True, blank=True) due_date = models.DateField(null=True, blank=True) completed_date = models.DateField(null=True, blank=True)
So I want to attach an "Action" (something that needs to be done) to various other things (generic relation), and it has a Person being accountable and a Person that's assigned to it. They have a different related_name so all good.
from django.contrib import admin from django.contrib.contenttypes.generic import GenericStackedInline from models import Action, Whatever class ActionInline(GenericStackedInline): model = Action class WhateverAdmin(admin.ModelAdmin): inlines = [ActionInline] admin.site.register(Whatever, WhateverAdmin)
That throws the exception
<class 'myproject.myapp.models.Action'> has more than 1 ForeignKey to <class 'myproject.myapp.models.Person'>
This happens in admin.validation.validate_inline() triggered by "admin.site.register(Whatever, WhateverAdmin)".
I don't get it. The related_name are different, and the foreign key for the inline is a GenericForeignKey. I thought maybe I just have to satisfy that (buggy?) validation and set 'fk_name' in ActionInline to one of the two (as the GenericStackedInline won't be using it anyway). But then I get:
fk_name 'accountable' is not a ForeignKey to <class 'myproject.myapp.models.Whatever'>
Sure it's not. But it's not the relevant foreign key for this inline - the generic foreign key is. Is this a bug? How can I get around this?
The documentation states I can use a GenericInlineModelAdmin
It also says that if an inline has two ForeignKeys to the same model, "fk_name" needs to be specified
That seems to assume that the two ForeignKeys are used in the inline for that foreign model.
What's also freaky is that with settings.DEBUG=True the Exception is thrown but with DEBUG=False the change_form is rendered without complaints (and seemingly working).