Lately I’ve wanted branches (heads) to have a corresponding tail which points to the base commit that the branch sits on top of (like the commit on `main` when you created the branch).[1] Because branches get rebased all the time and eventually you have six commits out in the Æther somewhere and you have to think twice about where it even starts. And yeah you can probably think for a few seconds and recall that you have worked with John and not Jimmy on this branch so the seventh commit backwards that belongs to Jimmy must be the commit base. Or Git can tell you that the seventh commit belongs to `main` already. But why should you have to expend any effort?
You can optionally include the base commit when you send out “patches” to a mailing list.[2] Because it might not have been obvious that you based your changes on:
- The latest release
- The main development branch
- Some integration branch (probably an error)
You also need to keep the “base” in mind when you use `git range-diff` because that tool takes two ranges lik `main..previous` and `main..current`. And sometimes you can rely on just using `main..` and letting Git figure it out but in my experience passing an explicit value sometimes works better.
`git range-diff` is a super-cool but perhaps niche tool. But you basically have to use it on review round number 2 and higher when you are sending changes to the Git project.
[1] This has been discussed before and there was a patch series that implemented it. But that was basically a POC and done in the spirit of “this is useless IMO but here’s how you could do it”... and the implementation didn’t factor in all the shenanigans that you can do with `reset` and `rebase` so it couldn’t have been merged as-is. (Although to be fair: the bar was not set to work perfectly with any kind of branch reset etc., which I suspect is impossible in any case.)
[2] Patches after all are just commit messages plus the patches themselves and don’t tell you what they are based on.