Re: [PATCH 1/2] pack-revindex: drop hash table

> The main entry point to the pack-revindex code is
> find_pack_revindex(). This calls revindex_for_pack(), which
> lazily computes and caches the revindex for the pack.
>
> We store the cache in a very simple hash table. It's created
> by init_pack_revindex(), which inserts an entry for every
> packfile we know about, and we never grow or shrink the
> hash. If we ever need the revindex for a pack that isn't in
> the hash, we die() with an internal error.
>
> This can lead to a race, because we may load more packs
> after having called init_pack_revindex(). For example,
> imagine we have one process which needs to look at the
> revindex for a variety of objects (e.g., cat-file's
> "%(objectsize:disk)" format).  Simultaneously, git-gc is
> running, which is doing a `git repack -ad` is running. We
> might hit a sequence like: