This will merge the extensions into the deployment branch of mediawiki core, rather than branching and cloning 100+ submodules each week. Changes to the extensions would be merged into the relevant deployment branches of mediawiki/core. Branches can be used in the extensions to track deployed changes, but this wouldn't be necessary since the core deployment branch would be tracking the deployed changes.
- Branching of extensions could be simplified.
- Extension developers / maintainers control the branching and tagging of their code, no auto-generated branches cluttering up the repos.
- One view of deployed code - the git history of the deployment branches clearly shows the history of what changed in core as well as the extensions.
- Hotfixes to either core or the extensions show up as squashed merges into the deployed branch in one linear history.
- Easier patch management for security patches as all patches could be continuously maintained, rebased on top of the deployed branch. Eliminates a significant patch management overhead for release engineering.
- This also eliminates significant risk of human error in the process.
- The process of branching for deployment on Wednesday will be significantly faster: between patch management simplification and faster branching, I expect to save somewhere between 30-60 minutes every week.
- swat deployments should be easier as well. Instead of cherry-picking a patch and then updating the submodule pointer in a separate commit, you would just propose the patch to the deployed branch directly and you wouldn't need a separate submodule bump commit.
I'm not entirely sure how to make the transition to the new setup, or how to get people familiarized with it and comfortable with sub-repos. To start with I need to publish my example repo so that interested parties can see what the git history looks like with this arrangement. After that I don't really know what the next step is going to be, suggestions are welcomed.