Re: bug: git-repack -a -d produces broken pack on NFS

[Linus Torvalds <torvalds@osdl.org>]

On Thu, 27 Apr 2006, Junio C Hamano wrote:

> Linus Torvalds <torvalds@osdl.org> writes:
> 
> > That said, the pack-file should all be written with the "sha1write()" 
> > interface, which is very careful indeed.
> >
> > I wonder if the _pack-file_ itself might be ok, and the problem is an 
> > index file corruption. For some reason we check the index file first, 
> > which is insane. We should check that the pack-file matches its _own_ SHA1 
> > first, and check the index file second.
> 
> We need to check both, so I fail to see why the order matters.

It's insane to do any _cross_-file checking before you've even verified 
that the files themselves are valid.

Another way of saying the same thing: checking whether the SHA1 of the 
pack-file matches the index file is pointless before you've verified that 
the SHA1 itself is valid.

Basically, if the pack-file is corrupt, you want to know that. You don't 
want to know that it's SHA1 doesn't match the index file - that's a 
"secondary" issue to the fact that the SHA1 wasn't correct in the first 
place.

Right now, if the pack-file is corrupt, it doesn't actually tell us so. It 
says that it doesn't match the index file. Which is likely wrong - it 
probably _does_ match the index file, but it's been corrupted.

See the difference?

			Linus