Re: Keeping unreachable objects in a separate pack instead of loose?

[Nicolas Pitre <nico@fluxnic.net>]

On Tue, 12 Jun 2012, Jeff King wrote:

> So the race window depends on the time it takes "git prune" to run.
> 
> I wonder if git-prune could do a double-check of the refs. Something
> like:
> 
>   1. calculate reachability on all refs
> 
>   2. read list of objects to prune, and make a list of unreachable ones
> 
>   3. calculate reachability again (which should be very cheap, because
>      you can stop when you get to an object you have already seen)
> 
>   4. Drop any objects found in (3) from the list in (2), and delete
>      items from your list
> 
> But I think that still has a race where objects are created before
> step 2, but are not actually referenced until after step 3. I think
> doing it safely may actually require a repo-wide prune lock.

Yeah... that's what I was thinking too.  Maybe we're making our life 
overly miserable by trying to avoid any locking here.


Nicolas