Breaking changes in a MediaWiki library can require quick resolution in a project that uses the library, or cause unexpected breakage. This recently happened with the Codex 0.1.0-alpha.8 release, which contained breaking changes in multiple components. Although breaking changes should be expected when using a library in alpha, we should consider how to ease this burden.

Is there any precedent for maintaining at least the previous version of a library in MediaWiki and allowing skins/extensions to pin that version? This would give project maintainers some space to make updates related to breaking changes. Of course, this could lead to loading more than one version of the library on a single page, which may be unacceptable from a performance standpoint.

Let's consider whether something like this is possible. If not, we should at least amend our processes for alpha/beta releases to ensure teams have warning of imminent breaking changes.

Acceptance criteria

• Discuss whether this is feasible, or if there are alternate technical solutions
• Otherwise, develop a clear process for announcing alpha/beta releases to give teams warning when breaking changes are coming