Django: Stable FormSet Ordering Fix

Today we're diving into a focused but important stability improvement in Django's model formsets. Rodrigo Vieira tackled issue #37004 with a clean solution that ensures stable ordering in BaseModelFormSet queries, bringing consistency across Django's serialization components. It's a small change with big implications for reliability.

Duration: PT4M6S

Episode overview

This episode is a short developer briefing from Django.

It explains recent repository work in plain language.

  • Show: Django
  • Published: 2026-04-02T10:00:33Z
  • Audio duration: PT4M6S

Transcript excerpt

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Hey there, Django developers! Welcome back to another episode. I'm so glad you're here with me today - grab your favorite cup of coffee because we've got a really interesting story about one of those fixes that might seem small on the surface but actually makes a huge difference for stability.

So picture this: you're working with model formsets in Django, and sometimes you notice that the ordering of your data isn't quite as predictable as you'd expect. Maybe you've run into situations where the same queryset returns items in slightly different orders between requests, and you're scratching your head…

Let's jump into our merged pull request. Rodrigo Vieira stepped up with PR #21036 to tackle issue #37004, and I love the approach they took here. The problem was that BaseModelFormSet's get_queryset method wasn't guaranteeing stable ordering, which could lead to inconsistent behavior that's really hard to debug.

Now here's what I find really elegant about Rodrigo's solution - instead of reinventing the wheel, they looked at how Django was already solving this exact problem elsewhere in the codebase. The serializers module had already implemented a pattern using…

The actual code change…

Wh…

Nearby episodes from Django

  1. Documentation Cleanup
  2. Weekly Recap - Security Fixes and Bug Resolutions
  3. Spring Cleaning and Bug Squashing
  4. Security & Widget Polish Day
  5. Community First - Making Pre-Release Testing Accessible
  6. Spring Cleaning and Stability Fixes
  7. Documentation Day - Fixing Infinite Loops and Database Mysteries
  8. Small Fixes, Big Impact