I previously proposed that we define a new type of project in phabricator.wikimedia.org specifically for repository meta-data (see T128161: Proposal: New project type for repository metadata)
These meta-tag projects have type tag a name starting with #meta-
My intent is that meta-tags are used as meta-data on repositories, and referenced the corresponding herald rules. They are not intended for use in maniphest task tagging and I want to explicitly bypass the expectation that each #meta-* project needs to be discussed before creation.
What I failed to make explicit in the previous discussion is that there will be a need to create many more meta tags to trigger many different actions related to continuous-integration and release automation.
Why we need meta-tag projects
Projects are the universal meta-data in phabricator. They are flexible and easy to use and almost every object in phabricator can be tagged with projects to add meaning or behavior.
When Release-Engineering-Team is working on prototyping CI configuration in phabricator, it's a significant burden to discuss each tag before we can start using it. Herald rules need to be set up for all of our git repositories and there are more than 1500 repositories already in Diffusion. Rather than configuring one herald rule for each repo the proper way to do this is to make a few herald rules for the various groups of related repositories and tag the repositories with meta-data to trigger the rules. It's much more efficient and manageable - the alternative would be completely unworkable with so many repositories. We should not have to edit 833 different herald rules in order to adjust access policies or add a new CI job to mediawiki extensions.
Our current project creation guidelines are overly rigid and heavily focused on "task management." It's unfortunate that they are called 'projects' in phabricator, since projects are really a lot more generic than the name implies. They are used for a lot more than just organizing projects and tasks.
Unless there are serious objections then I would like to amend the project creation guidelines to explicitly allow for creation of #meta- tags without discussing each one beforehand.