Re: Bug: Branch Deletion Doesn't Clean Up

[Mike Hommey <mh@glandium.org>]

On Thu, Feb 04, 2016 at 02:55:00AM -0500, Jeff King wrote:
> [resend; sorry, I forgot to cc Michael on the first one]
> 
> On Thu, Jan 07, 2016 at 02:24:41PM -0500, Karl Moskowski wrote:
> 
> > The problem is, deleting a branch whose name contains slashes doesn’t
> > delete the directories in .git/refs/heads/.
> 
> Yes. Git's model is to leave the directories in place, and remove them
> only when they get in the way of creating another ref. In theory, the
> effect is the same as deleting the directories proactively.
> 
> But as you noticed, it does funny things with case-preserving
> filesystems. It also can cause performance problems if you have a very
> large number of empty directories (because git has to open each of them
> just to find out they're empty).
> 
> We can into the latter case at GitHub. Michael Haggerty (cc'd) worked up
> some patches recently for this, but I don't now if they're yet polished
> enough to send upstream.
> 
> > It seems like git branch -d ascend the hierarchy (up to
> > .git/refs/heads/), deleting any empty directories.
> 
> Yes, though it needs to be coupled with making the branch-creation
> process more robust to races (since we might create "refs/heads/foo" in
> order to make "refs/heads/foo/bar" while somebody else is deleting it to
> get rid of "refs/heads/foo/baz").

Can't we come up with a system that would update packed-refs directly
instead of creating files?

Mike