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

[Sam Vilain <sam@vilain.net>]

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.