MySQL

Django Evolution 2.2: Django 3.2-4.1 Support

Christian Hammond

Django Evolution 2.2 is a major feature release, offering new database features, improved compatibility, and several bug fixes.

Django Evolution is our alternative database migration library for Django, which supports a wide range of Django versions and optimized application of database changes. It targets self-managed applications, like Review Board, which may potentially go several releases between upgrades.

The highlights include:

  • Compatibility with Django 1.6 through 4.1, and Python 2.7 through 3.11
  • Support for conditions, expressions, opclasses, and field lists in Django’s Index classes.
  • Ability to change field types in ChangeField.
  • Improved settings for defining project-provided custom evolutions.
  • Bug fixes for MySQL compatibility, edge cases in SQL generation for indexes, and Python 3.10 compatibility.

The release notes cover the full list of changes in Django Evolution 2.2.

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Django Evolution 2.1.3: Evolution and compatibility fixes

Christian Hammond

Django Evolution 2.1.3 a small but important bug fix release that addresses issues with Python 3.10, mysqlclient, and evolving very old databases.

Compatibility Fixes

Python 3.10 removed some deprecated imports from collections, which Django 2.0 and older depend on. When using this combination of versions, Django Evolution will bring back those legacy imports, allowing Django to work again.

mysqlclient also received a similar fix. Django 1.11 and older depended on some unintentional functionality, which mysqlclient maintained until the 2.1 release. We now patch these versions of Django at runtime to continue working.

Upgrade Fixes

Two important issues affecting upgrades were addressed:

  1. Django Evolution no longer tries to apply evolutions to models that were just introduced. This was a regression from previous releases.
  2. When upgrading from very old databases, some state for a model’s unique_together index couldn’t be compared properly, causing issues applying some upgrades. The old format for this state is now taken into account during comparison.

Coming Up…

We’re preparing Django Evolution 2.2, which will support all versions of Django up through 4.0. This should be coming soon.

In the meantime, check out the release notes for the full changes, including other fixes in this release.

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