Started today doing testing of syncing, and found some bugs and things it needs to do better. But was quickly sidetracked when I noticed that transferkey was making a commit to the git-annex branch for every file it transferred, which is too slow and bloats history too much.

To fix that actually involved fixing a long-standing annoyance; that read-only git-annex commands like whereis sometimes start off with "(Recording state in git)", when the journal contains some not yet committed changes to the git-annex branch. I had to carefully think through the cases to avoid those commits.

As I was working on that, I found a real nasty lurking bug in the git-annex branch handling. It's unlikely to happen unless annex.autocommit=false is set, but it could occur when two git-annex processes race one another just right too. The root of the bug is that git cat-file --batch does not always show changes made to the index after it started. I think it does in enough cases to have tricked me before, but in general it can't be trusted to report the current state of the index, but only some past state.

I was able to fix the bug, by ensuring that changes being made to the branch are always visible in either the journal or the branch -- never in the index alone.

---

Hopefully something less low-level tomorrow..!