[PATCH v2] repack: do not rebuild packs on --dry-run
- From
Siddharth Shrimali <r.siddharth.shrimali@gmail.com>
- Date
- Oct 10, 2026, 21:00 UTC
- Message-ID
- <20261010210050.76064-1-r.siddharth.shrimali@gmail.com>
- In-Reply-To
- <20261008062521.25505-1-r.siddharth.shrimali@gmail.com>
"git repack --drop-filtered --dry-run" is documented to list the objects that would be dropped "without rebuilding any pack or deleting anything", but it does both.
This is a bug in cmd_repack(): after printing the candidates, the --dry-run block falls through into the regular repack code. repack_promisor_objects() writes a new promisor pack, and with -d, existing_packs_remove_redundant() deletes the old packs.
The existing guard only skips the implied "delete_redundant = 1", so it does not stop an explicit -d, and it does not stop the new pack from being written either.
This has been broken since --dry-run was introduced in 1e746b00aa (builtin/repack: add --drop-filtered and --dry-run options). The --dry-run block never returned early, so a dry run has always gone on to do a regular repack. It was not broken by a later change.
Fix it by returning right after the candidates are listed, and add a test that checks the pack directory is unchanged with and without -d.
Reported-by: Coy Geek <coygeek@gmail.com> Helped-by: D. Ben Knoble <ben.knoble@gmail.com> Signed-off-by: Siddharth Shrimali <r.siddharth.shrimali@gmail.com> --- Bug report: https://lore.kernel.org/git/CACgTecOm+=vbf50tZNXhcYvRi1ZTsQwbjVoJAbQqs2CmXdJCxg@mail.gmail.com/
Changes since v1: - reworded the comment - documented the bug in the log message
builtin/repack.c | 7 +++++++ t/t7706-repack-drop-filtered.sh | 19 +++++++++++++++++++ 2 files changed, 26 insertions(+)
diff --git a/builtin/repack.c b/builtin/repack.c index c4360382c1..7797972642 100644 --- a/builtin/repack.c +++ b/builtin/repack.c @@ -387,14 +387,21 @@ int cmd_repack(int argc, if (dry_run) { struct oidset_iter iter; const struct object_id *oid; oidset_iter_init(&drop_oids, &iter); while ((oid = oidset_iter_next(&iter))) printf("%s\n", oid_to_hex(oid)); + + /* + * Only list the candidates to be dropped; skip + * the actual repack + */ + ret = 0; + goto cleanup; } } if (delete_redundant && repo->repository_format_precious_objects) die(_("cannot delete packs in a precious-objects repo")); die_for_incompatible_opt3(unpack_unreachable || (pack_everything & LOOSEN_UNREACHABLE), "-A", diff --git a/t/t7706-repack-drop-filtered.sh b/t/t7706-repack-drop-filtered.sh index cb36115834..a1c475e4ec 100755 --- a/t/t7706-repack-drop-filtered.sh +++ b/t/t7706-repack-drop-filtered.sh @@ -131,14 +131,33 @@ test_expect_success '--dry-run does not remove the filtered objects' ' git -C repo -c repack.writeBitmaps=false \ repack --drop-filtered --filter=blob:limit=1k --dry-run -a >out && # Candidate blob must still be present after a dry run. git -C repo cat-file -e "$BIG" ' +test_expect_success '--dry-run leaves the pack directory untouched' ' + BIG=$(cat big_oid) && + packdir=repo/.git/objects/pack && + + for opt in "" -d + do + ls $packdir >before && + + git -C repo -c repack.writeBitmaps=false \ + repack --drop-filtered --filter=blob:limit=1k \ + --dry-run -a $opt >out && + + ls $packdir >after && + test_cmp before after && + test_grep "$BIG" out && + git -C repo cat-file -e "$BIG" || return 1 + done +' + test_expect_success '--drop-filtered removes the promisor blob locally' ' BIG=$(cat big_oid) && SMALL=$(cat small_oid) && git -C repo -c repack.writeBitmaps=false \ repack --drop-filtered --filter=blob:limit=1k -a &&
-- 2.56.0