[PATCH v3 01/10] midx: fix segfault with no packs and invalid preferred pack
- From
Patrick Steinhardt <ps@pks.im>
- Date
- Apr 13, 2023, 11:16 UTC
- Message-ID
- <dd8145beade440e5444130d3a3189b2c5d15a911.1681384405.git.ps@pks.im>
- In-Reply-To
- <cover.1681384405.git.ps@pks.im>
When asked to write a multi-pack-index the user can specify a preferred pack that is used as a tie breaker when multiple packs contain the same objects. When this packfile cannot be found, we just pick the first pack that is getting tracked by the newly written multi-pack-index as a fallback.
Picking the fallback can fail in the case where we're asked to write a multi-pack-index with no packfiles at all: picking the fallback value will cause a segfault as we blindly index into the array of packfiles, which would be empty.
Fix this bug by resetting the preferred packfile index to `-1` before searching for the preferred pack. This fixes the segfault as we already check for whether the index is `> - 1`. If it is not, we simply don't pick a preferred packfile at all.
Helped-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Patrick Steinhardt <ps@pks.im> --- midx.c | 6 +++--- t/t5319-multi-pack-index.sh | 12 ++++++++++++ 2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/midx.c b/midx.c index 47989f7ea7..67eb617591 100644 --- a/midx.c +++ b/midx.c @@ -1328,17 +1328,17 @@ static int write_midx_internal(const char *object_dir, } if (preferred_pack_name) { - int found = 0; + ctx.preferred_pack_idx = -1; + for (i = 0; i < ctx.nr; i++) { if (!cmp_idx_or_pack_name(preferred_pack_name, ctx.info[i].pack_name)) { ctx.preferred_pack_idx = i; - found = 1; break; } } - if (!found) + if (ctx.preferred_pack_idx == -1) warning(_("unknown preferred pack: '%s'"), preferred_pack_name); } else if (ctx.nr && diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh index 499d5d4c78..0883c7c6bd 100755 --- a/t/t5319-multi-pack-index.sh +++ b/t/t5319-multi-pack-index.sh @@ -183,6 +183,18 @@ test_expect_success 'write midx with --stdin-packs' ' compare_results_with_midx "mixed mode (one pack + extra)" +test_expect_success 'write with no objects and preferred pack' ' + test_when_finished "rm -rf empty" && + git init empty && + test_must_fail git -C empty multi-pack-index write \ + --stdin-packs --preferred-pack=does-not-exist </dev/null 2>err && + cat >expect <<-EOF && + warning: unknown preferred pack: ${SQ}does-not-exist${SQ} + error: no pack files to index. + EOF + test_cmp expect err +' + test_expect_success 'write progress off for redirected stderr' ' git multi-pack-index --object-dir=$objdir write 2>err && test_line_count = 0 err
-- 2.40.0