Django Admin readonly custom widget - Ticket #30577

This project demonstrates a breaking change in Django's main branch related to rendering of widgets in Django admin with read_only attribute.

In Django ticket #30577 for custom rendering of readonly fields in Django admin, it was suggested to set read_only = True on the widget. This utilized the workaround present for ReadOnlyPasswordHashWidget to force Django to use custom widget for rendering the readonly field.

In PR #19063, this workaround for the ReadOnlyPasswordHashWidget was removed, breaking the rendering of readonly fields.

What This Project Demonstrates

This project shows the difference in behavior between:

• Django 5.2: Custom widgets work correctly for view-only users
• Django main branch: Custom widgets are ignored, falling back to default rendering

Note

The project includes SQLite database which contains required objects for demonstration. The focus is on the staffuser who has view-only permissions for the JsonDataModel.

Testing Instructions

Step 1: Test with Django 5.2 (Working Behavior)

1. Ensure Django 5.2 is installed:

   pip install Django==5.2.4

2. Run the project:

   python manage.py migrate
   python manage.py runserver

3. Test the staffuser experience:

   • Visit: http://127.0.0.1:8000/admin/jsonapp/jsondatamodel/3/change/
   • Login with: staffuser / Django@123
   • Expected Result: JSON is displayed with proper indentation in a disabled textarea using the custom ReadOnlyIndentedJSONWidget

Step 2: Test with Django Main Branch (Broken Behavior)

1. Install Django from main branch:

   pip install git+https://github.com/django/django.git

2. Run the same project:

   python manage.py runserver

3. Test the staffuser experience again:

   • Login with: staffuser / Django@123
   • Navigate to "JSON Data" and open any object
   • Actual Result: Custom widget is ignored, JSON is displayed using default readonly rendering (likely as plain text without formatting)

Key Difference

• Django 5.2: Custom ReadOnlyIndentedJSONWidget is used → JSON displayed with proper formatting
• Django Main: Custom widget ignored → Default readonly rendering used → Poor user experience