[0/4] pack-bitmap: permute existing namehash values

Message

Taylor Blau Sept. 7, 2021, 9:17 p.m. UTC

This short series depends on tb/multi-pack-bitmaps and is used to propagate
the hashcache between .bitmap files when generating multi-pack reachability
bitmaps.

The gist is that single pack bitmaps get the namehash values via the traversal
used to generate the pack, but there is no such traversal for MIDX bitmaps, and
thus the hash-cache extension (if we were to write it) would contain all zeros.

This series teaches the pack-bitmap code how to permute the hashcache values
from an existing bitmap into the new one. This doesn't keep the hashcache
up-to-date, but it at least prevents existing data from falling out when
generating a MIDX bitmap.

Taylor Blau (4):
  t/helper/test-bitmap.c: add 'dump-hashes' mode
  pack-bitmap.c: propagate namehash values from existing bitmaps
  midx.c: respect 'pack.writeBitmapHashcache' when writing bitmaps
  t5326: test propagating hashcache values

 Documentation/config/pack.txt |  4 ++++
 builtin/multi-pack-index.c    | 21 ++++++++++++++++++++
 midx.c                        |  6 +++++-
 midx.h                        |  1 +
 pack-bitmap.c                 | 36 +++++++++++++++++++++++++++++------
 pack-bitmap.h                 |  1 +
 t/helper/test-bitmap.c        | 10 +++++++++-
 t/t5326-multi-pack-bitmaps.sh | 32 +++++++++++++++++++++++++++++++
 8 files changed, 103 insertions(+), 8 deletions(-)