Striker (https://toolsadmin.wikimedia.org/) can link tools to Diffusion repositories, and even automatically create them on behalf of the tool’s administrator(s). By contrast, creating a new Gerrit repository for a tool requires administrative action, to be requested on https://www.mediawiki.org/wiki/Gerrit/New_repositories/Requests. If we want to stop using Differential (T191182), Striker should make it at least as easy to set up a source code repository on Gerrit as it currently does for Diffusion.
|T330844 Avoid to have too much different places (like Gerrit, GitHub, Differential, GitLab, ...) where code review may take place to help newcomers
|T342041 Remove custom src/customfields/DifferentialApplyPatchWithOnlyGitField.php
|T330797 Uninstall Differential (Phabricator application)
|T324131 Remove "Active Differential users" stats from monthly community_metrics.sh email
|T191182 Migrate active repositories in Phabricator Differential to GitLab
|T224676 Add Gerrit support to Striker (toolsadmin)
Marking as stalled and moving back to needs discussion because of the potential for Gitlab to replace Gerrit at this point as the official git hosting and code review platform for Wikimedia projects. Striker implemented Diffusion repos rather than Gerrit repos initially because at the time Diffusion was expected to eventually replace Gerrit as the canonical system. Ultimately I think all Striker managed repos should be in the same hosting system. I expect that to include a migration phase that moves all the existing things from Diffusion to somewhere. It seems like it would be a waste of effort to migrate them all to Gerrit and then turn around and migrate them to Gitlab.