[PATCH 0/3] pack-objects: support bitmaps and delta-islands with `--path-walk`

[Taylor Blau <me@ttaylorr.com>]

Note to the maintainer:

 * This series is based on 'ds/path-walk-filters' with Patrick's
   'ps/clang-w-glibc-2.43-and-_Generic' merged in. The former has since
   graduated. These are the three remaining patches from my earlier RFC
   after Stolee's series incorporated the filter-related pieces.

Here is a trimmed-down reroll of my series to make `--path-walk` work
with reachability bitmaps and delta-islands. This series was originally
an RFC that was a companion to Stolee's recent patches to extend
`--filter` support to `--path-walk` [1].

Since the previous round, Stolee's series has graduated and incorporated
the filter-related patches from my earlier RFC [2]. What remains are the
three patches here that implement support for reachability bitmaps and
delta-islands under `--path-walk`.

 * The first patch allows `--path-walk` to use reachability bitmaps when
   they can answer the request, falling back to path-walk enumeration
   when they cannot. It also lets bitmap writing see the same commit
   candidates that the regular traversal would have shown to the bitmap
   selector.

 * The second patch is preparatory, and factors the
   delta-islands-specific tree-depth recording from `show_object()` into
   a helper.

 * The final patch teaches the path-walk callback to perform the same
   delta-islands side effects as the regular traversal: propagating
   island marks for commits, and recording tree depths for trees. This
   gives `resolve_tree_islands()` the same input in either enumeration
   mode, so the existing island checks can be reused unchanged.

Thanks in advance for your review!

[1]: https://lore.kernel.org/git/pull.2101.git.1777731354.gitgitgadget@gmail.com/
[2]: https://lore.kernel.org/git/cover.1777853408.git.me@ttaylorr.com/

Taylor Blau (3):
  pack-objects: support reachability bitmaps with `--path-walk`
  pack-objects: extract `record_tree_depth()` helper
  pack-objects: support `--delta-islands` with `--path-walk`

 Documentation/git-pack-objects.adoc | 12 ++---
 builtin/pack-objects.c              | 68 +++++++++++++++++++++--------
 t/t5310-pack-bitmaps.sh             | 36 +++++++++++++++
 t/t5320-delta-islands.sh            | 29 ++++++++++++
 4 files changed, 122 insertions(+), 23 deletions(-)


base-commit: 45a9ecee26839cc880fdd5e704339dd3cf4ffc26
-- 
2.54.0.22.ga642305e3c9