Re: Since gc.autodetach=1 you can end up with auto-gc on every command with no user notification

> Someone at work came to me with the problem that they were getting the
> "Auto packing the repository in background for optimum performance"
> notice on every Git command that they ran.
>
> This problem is a combination of two things:
>
>  * Since Nguyễn's v1.9-rc0-2-g9f673f9 where we started running "git
> gc" in the background the user hasn't seen the "There are too many
> unreachable loose objects" message added back in v1.5.3.1-27-ga087cc9
>
>  * The checkout has a lot of loose objects. So even after "git prune
> --expire=2.week.ago" the .git/objects/17 directory has 317 objects.
> More than 27 in that directory trigger "git gc --auto".
>
> So it's partly a UI issue. Since the repacking is happening in the
> background the user never sees the message suggesting that they run
> "git prune".
>
> But perhaps the heuristic of "are there more than 27 objects in
> .git/objects/17" could be improved, but I don't know with what
> exactly.
>
> But having something fork a gc to the background on every fetch (and
> similar object-modifying operations) is quite sub-optimal.