This series implements the final component of multi-pack reachability bitmaps:
the ability to write them from `git repack`.
The gist is that it is currently impossible to write a MIDX based on the result
of a `git repack` without the possibility that an existing MIDX may go away.
That's because `git repack` may have deleted a pack that was included in the
MIDX (either because it was rolled up when doing a `--geometric` repack, or the
repack was done all-into-one), and MIDXs cannot refer to deleted packs.
To solve this, `git repack` is taught a new option to write a MIDX between the
critical section: right after the new packs are written and moved into place,
but right before any old packs are deleted.
Unfortunately, there is quite a bit of auxiliary tooling we need to implement
before this is possible. The series is laid out like so:
- The first two patches lay the ground work for and expose `git
multi-pack-index --stdin-packs`, which allows callers to write a MIDX
containing only certain packs.
- The next patch implements preliminary support for `--refs-snapshot`, which
allows the MIDX bitmap selection code to reference the prior state of
reference tips, preventing a race.
- The next two patches prepare the `repack` builtin to write a MIDX, and the
following patch actually implements `--write-midx`.
- The final two patches make sure the MIDX generated has an appropriately
chosen preferred pack, and that the refs-snapshot is provided.
It is based on `tb/multi-pack-bitmaps`. Thanks in advance for your review!
Taylor Blau (8):
midx: expose 'write_midx_file_only()' publicly
builtin/multi-pack-index.c: support --stdin-packs mode
midx: preliminary support for `--refs-snapshot`
builtin/repack.c: keep track of existing packs unconditionally
builtin/repack.c: extract showing progress to a variable
builtin/repack.c: support writing a MIDX while repacking
builtin/repack.c: make largest pack preferred
builtin/repack.c: pass `--refs-snapshot` when writing bitmaps
Documentation/git-multi-pack-index.txt | 19 ++
Documentation/git-repack.txt | 18 +-
builtin/multi-pack-index.c | 35 +++-
builtin/repack.c | 251 ++++++++++++++++++++++---
midx.c | 102 ++++++++--
midx.h | 4 +-
pack-bitmap.c | 2 +-
pack-bitmap.h | 1 +
t/helper/test-read-midx.c | 25 ++-
t/lib-midx.sh | 8 +
t/t5319-multi-pack-index.sh | 15 ++
t/t5326-multi-pack-bitmaps.sh | 82 ++++++++
t/t7700-repack.sh | 96 ++++++++++
t/t7703-repack-geometric.sh | 23 +++
14 files changed, 630 insertions(+), 51 deletions(-)
create mode 100644 t/lib-midx.sh
--
2.33.0.96.g73915697e6
