Taylor Blau <me@xxxxxxxxxxxx> writes:
> verbatim reuse (c.f., `write_reused_pack_verbatim()`).
Unlike "e.g." and "i.e.", I think these should all be "cf." (there
are many others).
> + This patch handles the "preferred" pack (c.f., the section
> + "multi-pack-index reverse indexes" in
> + Documentation/technical/pack-format.txt) specially, since pack-objects
> + depends on reusing exact chunks of that pack verbatim in
> + reuse_partial_packfile_from_bitmap(). So if that pack cannot be loaded,
> + the utility of a bitmap is significantly diminished.
It explains why we care about the "preferred" pack, which is a nice
clarification. It hints that the other packs do not matter as much,
and it is clearly stated that how they are handled is ...
> + Similar to dc1daacdcc, we could technically just add this check in
> + reuse_partial_packfile_from_bitmap(), since it's possible to use a MIDX
> + .bitmap without needing to open any of its packs. But it's simpler to do
> + the check as early as possible, covering all direct uses of the
> + preferred pack. Note that doing this check early requires us to call
> + prepare_midx_pack() early, too, so move the relevant part of that loop
> + from load_reverse_index() into open_midx_bitmap_1().
> +
> + Subsequent patches handle the non-preferred packs in a slightly
> + different fashion.
... left for later steps.
Excellent write-up.
> Signed-off-by: Taylor Blau <me@xxxxxxxxxxxx>
>
> @@ pack-bitmap.c: static int open_midx_bitmap_1(struct bitmap_index *bitmap_git,
> +
> + preferred = bitmap_git->midx->packs[midx_preferred_pack(bitmap_git)];
> + if (!is_pack_valid(preferred)) {
> -+ close(fd);
> + warning(_("preferred pack (%s) is invalid"),
> + preferred->pack_name);
> + goto cleanup;
> 2: 9adf6e1341 < -: ---------- builtin/pack-objects.c: ensure pack validity from MIDX bitmap objects
> -: ---------- > 2: 2719d33f32 builtin/pack-objects.c: avoid redundant NULL check
> -: ---------- > 3: cdc3265ec2 builtin/pack-objects.c: ensure included `--stdin-packs` exist
> -: ---------- > 4: 3fc3a95517 builtin/pack-objects.c: ensure pack validity from MIDX bitmap objects
