This is a short-ish series I wrote today while thinking through an idea that Peff and I were talking about yesterday that allows us to avoid MIDX'ing any cruft pack(s) in a repository when repacking. The core of the idea is to introduce a variant of the '--stdin-packs' option in 'pack-objects'. The existing behavior is to create a pack whose contents is the set difference between the specified included and exclude packs. The new mode (which I'm calling --stdin-packs=follow) tweaks the namehash traversal we do at the end of --stdin-packs to also pick up and pack objects which were reachable from commits in the above set difference, but don't appear in the included or excluded pack. If you repack consistently using this strategy, you can guarantee that the union of geometrically-repacked packs are closed under reachability without having to keep track of any cruft pack(s) in the MIDX. I'm pretty sure that this is all sound, having played with it for the better part of the day and not being able to come up with any counter-examples. I'm sending this as an RFC because I'm not sure if there's an obvious case that I am missing that makes this whole idea bogus. Code-review is welcome, but I think at this stage it may be more useful to center the discussion around whether or not the idea makes sense first. Thanks in advance :-). Taylor Blau (8): pack-objects: use standard option incompatibility functions pack-objects: limit scope in 'add_object_entry_from_pack()' pack-objects: factor out handling '--stdin-packs' pack-objects: declare 'rev_info' for '--stdin-packs' earlier pack-objects: perform name-hash traversal for unpacked objects pack-objects: introduce '--stdin-packs=follow' repack: keep track of existing MIDX'd packs repack: exclude cruft pack(s) from the MIDX where possible Documentation/git-pack-objects.adoc | 8 +- builtin/pack-objects.c | 193 +++++++++++++++++----------- builtin/repack.c | 97 +++++++++++--- t/t5331-pack-objects-stdin.sh | 103 ++++++++++++++- t/t7704-repack-cruft.sh | 70 ++++++++++ 5 files changed, 376 insertions(+), 95 deletions(-) base-commit: 485f5f863615e670fd97ae40af744e14072cfe18 -- 2.49.0.229.g19b69c1246
