Re: [RFC PATCH] multi-pack-index: allow operating without pack files

On Mon, 2021-08-23 at 00:05 -0400, Taylor Blau wrote:

We're going to run into problems much earlier than that, though: the
MIDX needs to load information about objects from packs in order to
break ties when multiple copies of the same object exist in multiple
packs (according to that pack's mtime).

Huh, I guess I never ran into a need - we make sure in bup that each
object only exists once, that's kind of the point :)

I guess we could break ties by "lower hash of the pack" instead of
"mtime"? It doesn't really matter how they're broken, as long as it's
consistent?

Arguably, mtime is not a good measure anyway, since the same repo
elsewhere would have different mtimes.

So I'm not sure how we would even write a MIDX without physical packs on
disk that we can open and stat, let along how we would teach Git to
handle a situation where packs that did exist when writing a MIDX went
away when we tried to read from the same MIDX later on.

It handles that just fine on the read side.

johannes