Hide refs/branchless/* refs by default from git log

[krobelus]

As reported in jonas/tig#1160, git log --decorate (which is the default for git log) will add opaque references to branchless commits.

I'm not sure if there is a way to hide those references. I imagine the commits need to be referenced somewhere to evade garbage collection. Maybe there are other ways around that..

[martinvonz]

I think you can simply add something like this to your git config:

[log]
        excludeDecoration = refs/branchless/*

I suppose git-branchless init could add that to the repo-level config. I haven't checked if that * is recursive or not, or if that matters for git-branchless.

[arxanas]

Yep, we need to have the references for GC purposes. In principle it would be possible to substantially reduce the number of references by taking advantage of the fact that a commit keeps all of its ancestors live, but it would be rather complicated, and I don't want to risk that kind of thing in something as important as preventing commits from being GCed.

I think it should work to add a log.excludeDecoration pattern as part of git-branchless init, like @martinvonz says. We only store references at the top-level of refs/branchless/, so the above pattern should be fine.