Definitely +1 on this.

SPHEREx has already adopted this convention, just as a point of context.

You beat me to it. I was going to work on some automated tools and Jenkins support, followed by a changeover maybe in the December holiday timeframe.

The problem is not the repos or the docs, it's the build tooling that assumes the name (96 hits in jenkins-dm-jobs, 3 in lsstsw, 1 in lsst_build, need to check all GitHub actions, etc.).

I support this.

Kian-Tat Lim Ah, my apologies for jumping the gun. December sounds good. 

Kian-Tat Lim I believe Github states that it redirects requests for master to main? Not sure whether that helps with the builds. 

Yes, it looks like that will help, except for this:

raw file URLs are not redirected.

which is I think relevant to newinstall.sh in particular.

Yes please!

I'm strongly in favor.

The problem at the moment is that we are developing a mix of repositories with master and repositories with main as people create new repositories, and the newly-created repositories do not do branch redirection because they never had an old master branch. I think this has some potential for confusion and, depending on the nature of the build system issues, possibly some difficulties there.

Given that, perhaps we should configure our GitHub orgs to use master by default for new repositories for now so that we don't proliferate two naming schemes until such time as we're ready to do the conversion, and then change the default branch for new repositories to main when we've cut over existing repositories?

The build system issues I'm worried about are around Science Pipelines, not other services or even trying-to-be-independent packages. For those, the default in both the lsst and lsst-dm orgs is still master.

I trust lsst-sqre can come up with its own transition plan (e.g. I can't [and don't particularly want to] look at the current default setting).

I don't think a DM RFC is binding on lsst-ts or lsst-ops. I think there may be fewer build system issues in those orgs as they're mostly using more modern tooling.

Ah, thank you, I had not realized the default branch was already set on those organizations (I should have checked). That resolves my concern.

As things stand right now:

• This has been discussed in various forums, I think it's clear there's support for the principle.
• Given the disruption of the implementation and various other timescales, implementation may not actually happen until December timeframe but that's the way with RFCs anyway
• Orgs that manage their own build chains (like lsst-sqre) can transition ahead of time if they wish. 

Comments at variance with the above still welcome until RFC closes. 

I support this, and I think that asking all the DM developers to help out on a concentrated day of action (if helpful) is reasonable. If conda-forge can make the mega-migration then we can too! (see recent updates at https://github.com/conda-forge/conda-forge.github.io/issues/1162 ).

Can I request for a transition period, say a month or two, where both `master` and `main` branch names co-exist and the change of the default branch happens around the middle of this period? By this, I don't mean two different branches, but one single branch with an alias. I'm thinking along the lines of this Stack Overflow answer: https://stackoverflow.com/a/17236679

Unfortunately, git symbolic-ref main refs/heads/main may allow master to stay pointing to where main does, but my experiments seem to show that it is not the equivalent of a real branch, and commands do not work identically: e.g. git checkout master gives "detached HEAD" state, and I suspect merges will also be problematic. Also, I believe that the symbolic ref is only local to a clone; it does not seem possible to make it mandatory for all new clones.

If you are concerned about muscle memory typing the wrong branch name, you might try to use git checkout - or git switch - instead. It's shorter, and quite often what you want.