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

[Jeff King <peff@peff.net>]

On Tue, Jun 12, 2012 at 01:30:07PM -0400, Nicolas Pitre wrote:

> > > To make it "safe", the cruft packs would have to be searchable for 
> > > object retrieval, but not during object creation.  That nuance would 
> > > affect the core code in subtle ways and I'm not sure if that would be 
> > > worth it ... just for the safe handling of cruft.
> > 
> > Why is that? If you do a "repack -Ad", then any referenced objects will
> > have been retrieved and put into the new all-in-one pack. At that point,
> > by deleting the cruft pack, you are guaranteed to be deleting only
> > objects that are either unreferenced, or are duplicated in another pack.
> 
> Now what if you fetch and a bunch of objects are already found in your 
> cruft pack?  Right now, we search for the existence of any object before 
> creating them, and if the cruft packs are searchable then such objects 
> won't get uncruftified.

Then those objects will remain in the cruft pack. Which is why, as I
said, it is not generally safe to just delete a cruft pack. However,
when you do a full repack, those objects will be copied into the new
pack (because they are referenced). Which is why I am claiming that it
is safe to remove cruft packs at that point.

-Peff