Opened 8 years ago

Closed 7 years ago

Last modified 5 years ago

#9362 closed (fixed)

InlineAdminForm breaks content_type FK on model

Reported by: Carl Meyer Owned by: Carl Meyer
Component: contrib.admin Version: 1.0
Severity: Keywords:
Cc: Robin Breathe, Robert Triage Stage: Accepted
Has patch: yes Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: UI/UX:

Description

r8586 fixed "View on Site" links for admin inline formsets, by having InlineAdminForm.__init__ set a temporary "content_type_id" attribute on the inline-edited "original" instance to the content type id of its model, and then using that attribute in the template to link to the redirection.

This is all fine and dandy, except when the model being edited inline already has a "content_type" field which is a foreign key to ContentType (most likely because it has a generic foreign key). In this case, InlineAdminForm reassigns an already-existing "content_type_id" attribute to point to the wrong model entirely, breaking any behavior of the instance that depends on the generic foreign key.

This behavior can be seen with these test models:

from django.db import models
from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes import generic

class Parent(models.Model):
    name = models.CharField(max_length=50)

    def __unicode__(self):
        return self.name

class Teacher(models.Model):
    name = models.CharField(max_length=50)

    def __unicode__(self):
        return self.name

class Child(models.Model):
    name = models.CharField(max_length=50)
    teacher = models.ForeignKey(Teacher)

    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    parent = generic.GenericForeignKey()

    def __unicode__(self):
        return u'I am %s, a child of %s' % (self.name, self.parent)

With this admin configuration:

from django.contrib import admin
from models import Child, Teacher, Parent

class ChildInline(admin.TabularInline):
    model = Child
    extra = 1

class TeacherAdmin(admin.ModelAdmin):
    inlines = (ChildInline,)

admin.site.register(Teacher, TeacherAdmin)
admin.site.register(Parent)

In the admin, create a Parent named John, then create a Teacher named Sally, then add a Child named Joe using the inline formset for the Teacher. After saving the Child, where the new Child's unicode representation should be displayed as "I am Joe, a child of John", it will instead say "I am Joe, a child of I am Joe, a child of John". This is because InlineAdminForm has changed Joe's content_type_id from Parent to Child, so Joe's "parent" attribute is now pointing to himself.

(The reason for the Teacher model and FK in the above examples is to make it clear that this occurs with any ordinary InlineAdmin, not only with a GenericInlineAdmin).

The easy fix is to use a more obscure attribute name for the temporary "my content type" attribute needed for redirection. Technically it would still be possible to mistakenly overwrite an existing attribute, but much less likely than it is now.

Attachments (2)

9362_r9232.diff (4.4 KB) - added by Carl Meyer 8 years ago.
naive fix with regression test
9362_r10178.diff (4.5 KB) - added by Carl Meyer 8 years ago.

Download all attachments as: .zip

Change History (14)

Changed 8 years ago by Carl Meyer

Attachment: 9362_r9232.diff added

naive fix with regression test

comment:1 Changed 8 years ago by Carl Meyer

Has patch: set
Needs documentation: unset
Needs tests: unset
Patch needs improvement: unset

comment:2 Changed 8 years ago by Brian Rosner

Owner: changed from nobody to Brian Rosner
Status: newassigned
Triage Stage: UnreviewedAccepted

comment:3 Changed 8 years ago by Robin Breathe

Cc: Robin Breathe added

comment:4 Changed 8 years ago by Robert

Cc: Robert added

comment:5 Changed 8 years ago by Patrick Kranzlmueller

is it impolite to ask, whether or not this is going to be fixed ... and when?
the fix seems to be easy and the current behaviour is extremely annoying.

comment:6 Changed 8 years ago by Jacob

milestone: 1.1

comment:7 Changed 8 years ago by Carl Meyer

Owner: changed from Brian Rosner to Carl Meyer
Status: assignednew

comment:8 Changed 8 years ago by Carl Meyer

Better patch attached after discussion with brosner. Includes test.

Changed 8 years ago by Carl Meyer

Attachment: 9362_r10178.diff added

comment:9 Changed 7 years ago by Carl Meyer

Status: newassigned

comment:10 Changed 7 years ago by Russell Keith-Magee

Resolution: fixed
Status: assignedclosed

(In [10667]) Fixed #9362 -- Prevented inline forms from overwriting the content_type_id attribute on objets being inlined. Thanks to carljm for the report and patch.

comment:11 Changed 7 years ago by Russell Keith-Magee

(In [10671]) [1.0.X] Fixed #9362 -- Prevented inline forms from overwriting the content_type_id attribute on objets being inlined. Thanks to carljm for the report and patch.

Merge of r10667 from trunk.

comment:12 Changed 5 years ago by Jacob

milestone: 1.1

Milestone 1.1 deleted

Note: See TracTickets for help on using tickets.
Back to Top