Editing ForeignKey in admin popup causes incorrect escaping for uuid field

[Zach Borboa]

Editing and saving a model's foreign key causes the related field to display incorrectly.

Displays something like "b71658a1\u002Df845\u002D4a44\u002D8085\u002D03034580ac72"
instead of "b71658a1-f845-4a44-8085-03034580ac72"

Screenshot: ​https://i.imgur.com/Q5lrfV2.png

Reproduce:

1. Create new project using python3

$ mkvirtualenv --python=$(which python3) myproject && cd myproject
$ django-admin startproject mysite && cd mysite
$ python manage.py startapp polls

2. Add polls to INSTALLED_APPS

3. Set polls/models.py

   import uuid
   from django.db import models
   
   class Question(models.Model):
       id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
       question_text = models.CharField(max_length=200)
   
       def __str__(self):
           return str(self.id)
   
   class Choice(models.Model):
       question = models.ForeignKey(Question)
       choice_text = models.CharField(max_length=200)
   

4. Set polls/admin.py

   from django.contrib import admin
   
   from .models import Choice
   from .models import Question
   
   admin.site.register(Choice)
   admin.site.register(Question)
   

5. Go to the admin add page for Choice ​http://127.0.0.1:8000/admin/polls/choice/add/
6. Click the plus sign ("+") next to the "Question:" label. Enter question text (like "test") and click save. The uuid is correctly displayed in the Question select box.
7. Click the pencil edit button next to the Question label. In the new popup window, click save. The uuid is no longer correctly displayed.

[Tim Graham]

Regression in 1.9 bisected to 845817b039fc059955bb1eafa5fd78565a49159d.

[Sasha Gaevsky]

Replying to timgraham:

Regression in 1.9 bisected to 845817b039fc059955bb1eafa5fd78565a49159d.

Just wondering if you tested in master branch.

[Tim Graham]

There's another regression when closing the popup on master if that's what you ran into. It's tracked in comment:6:ticket:25165

[Sasha Gaevsky]

Replying to timgraham:

There's another regression when closing the popup on master if that's what you ran into. It's tracked in comment:6:ticket:25165

Yes, that's exactly it.

Will it be fixed in terms of 25165 or new ticket will be opened?

[Tim Graham]

For now #25165 is reopened to fix the regressions it introduced.

[Sasha Gaevsky]

​PR

[Tim Graham <timograham@…>]

In a839d71d:

[1.9.x] Fixed #25997 -- Removed redundant escaping in admin's edit related model popup.

[Tim Graham <timograham@…>]

In ade54ff:

Refs #25165 -- Fixed JSON serialization for add/edit popup in the admin.

Forwardport of test in o839d71d8562abe0b245024e55ca1d02a45e58fd from stable/1.9.x
(refs #25997).

[Tim Graham <timograham@…>]

In 5052f79:

Added a test for adding a UUID pk object using the "Add related" admin popup.

Follow up to refs #25997 but this case wasn't broken.

[Tim Graham <timograham@…>]

In cb96d0c:

[1.9.x] Added a test for adding a UUID pk object using the "Add related" admin popup.

Follow up to refs #25997 but this case wasn't broken.

Backport of 5052f79df45d843d1e44dcc47152ed503220098f from master