From: qeesung via GitGitGadget Date: Fri, 18 Sep 2026 03:03:30 GMT Subject: [PATCH v2 0/5] repack: don't lose objects to a ".keep" that appears mid-run Message-ID: In-Reply-To: A concurrent push or fetch can make "git repack -d" delete a pack whose objects were never copied anywhere, and exit 0. We hit this in production: a ref pointing at a commit that no longer exists, on git 2.43, and it reproduces on master. What happens: * repack scans for ".keep" files and decides which packs to delete, then spawns pack-objects with --honor-pack-keep, which scans again; * in between, an index-pack --keep finishes -- a push migrating its quarantine, or a fetch -- and installs a ".keep" next to a pack that repack has already decided to delete; * pack-objects sees that ".keep" and leaves the pack's objects out; repack deletes the pack by its earlier list, with force_delete. The fix is to stop the two processes from scanning separately: hand pack-objects the snapshot repack took at startup (5/5). Patches 1-4 are what 5/5 needs to be safe: * 1/5: under --stdin-packs=follow, a --keep-pack pack stops the traversal like a "^" pack; on-disk ".keep" packs never did. * 2/5: the cruft walk goes by a stale kept-pack cache, which --honor-pack-keep happened to mask. Pre-existing, reproducible today. * 3/5: look --keep-pack names up in a sorted list; it gets long. * 4/5: --keep-pack-from-file, since a repository can have more kept packs than fit on a command line (32K characters on Windows). Every fix comes with a test that fails without it; the race itself is reproduced in t7703 by having a ".keep" appear as pack-objects starts. The full suite passes, and the series merges cleanly into next and seen. Changes since v1: * Dropped 1/6 (odb: don't remove a ".keep" we never installed). Justin Tobler is going to fix the receive-pack side properly, by having the ODB transaction create the ".keep" itself at commit time rather than reading back what index-pack wrote: https://lore.kernel.org/git/aql8Wt2q9RnQpjEC@jtobler--20250820-SHC54/ * The remaining patches are unchanged apart from renumbering. Qin ShiCheng (5): pack-objects: keep --keep-pack open when following pack-objects: reset kept-pack cache for cruft walk pack-objects: sort --keep-pack list for lookup pack-objects: add --keep-pack-from-file repack: tell pack-objects which packs are kept Documentation/git-pack-objects.adoc | 8 +++ builtin/pack-objects.c | 71 ++++++++++++++++++----- builtin/repack.c | 15 +++++ odb/source-packed.h | 3 +- packfile.c | 9 ++- packfile.h | 7 +++ repack-filtered.c | 3 - repack.c | 34 ++++++++++- repack.h | 17 +++++- t/t5329-pack-objects-cruft.sh | 40 +++++++++++++ t/t5331-pack-objects-stdin.sh | 87 +++++++++++++++++++++++++++++ t/t7700-repack.sh | 43 ++++++++++++++ t/t7703-repack-geometric.sh | 72 ++++++++++++++++++++++++ 13 files changed, 386 insertions(+), 23 deletions(-) base-commit: 3cb9185f65410273787f74333cc027d2ea5daada Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2219%2Fqeesung%2Frepack-kept-packs-snapshot-v2 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2219/qeesung/repack-kept-packs-snapshot-v2 Pull-Request: https://github.com/gitgitgadget/git/pull/2219 Range-diff vs v1: 1: 932e8e425a < -: ---------- odb: don't remove a ".keep" we never installed 2: 9349ea48b0 = 1: 8cf72312c5 pack-objects: keep --keep-pack open when following 3: a1b85c0a25 = 2: 77aec8941f pack-objects: reset kept-pack cache for cruft walk 4: 38070935dc = 3: b76e06a467 pack-objects: sort --keep-pack list for lookup 5: f8e27b7aac = 4: 20a051cfb6 pack-objects: add --keep-pack-from-file 6: a18e354e73 = 5: 4684fd8552 repack: tell pack-objects which packs are kept -- gitgitgadget