Re: [PATCH 5/6] Teach "fsck" not to follow subproject links

Linus Torvalds wrote:

It can be a nice space optimization, and yes, if there really is a lot of 
shared state, it can make it much cheaper to do some of the checks, but 
right now we have absolutely *no* way for fsck to then do the reachability 
check, because there is no way to tell fsck where all the refs are (since 
now the refs come in from multiple repositories!)
  

Well, not if the refs are only gitlinks because there is no checkout.

So the individual objects get cheaper to fsck (no need to fsck shared 
objects over and over again), but the reachability gets much harder to 
fsck.

It's not an insurmountable problem, or even necessarily a very large one, 
but it boils down to one very basic issue:

 - nobody seems to actually *use* the shared object directory model!

The thing is, with pack-files and alternates directories, a lot of the 
original reasons for shared object directories simply don't exist..

I think that's just the chicken-and-egg problem. Once this happens I
think we'll see people aggregating all sorts of related repositories
with this feature, and possibly making much richer histories by tracking
portions of their trees as subprojects rather than just a subdirectory.

Sam.