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| author | Taylor Blau <me@ttaylorr.com> | 2024-05-29 18:55:19 -0400 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2024-05-30 13:43:50 -0700 |
| commit | 23532be8e9c05ac231884e7ee3e4e151639f53bc (patch) | |
| tree | 75f3c4f0b57c0fde3e00b44d11d83e859c903c36 | |
| parent | 3e4a232f6e3bd3b7dd920bb07b21cf1c8b4e1a7f (diff) | |
| download | git-23532be8e9c05ac231884e7ee3e4e151639f53bc.tar.gz | |
midx-write.c: tolerate `--preferred-pack` without bitmaps
When passing a preferred pack to the MIDX write machinery, we ensure
that the given preferred pack is non-empty since 5d3cd09a808 (midx:
reject empty `--preferred-pack`'s, 2021-08-31).
However packs are only loaded (via `write_midx_internal()`, though a
subsequent patch will refactor this code out to its own function) when
the `MIDX_WRITE_REV_INDEX` flag is set.
So if a caller runs:
$ git multi-pack-index write --preferred-pack=...
with both (a) an existing MIDX, and (b) specifies a pack from that MIDX
as the preferred one, without passing `--bitmap`, then the check added
in 5d3cd09a808 will result in a segfault.
Note that packs loaded from disk which don't appear in an existing MIDX
do not trigger this issue, as those packs are loaded unconditionally. We
conditionally load packs from a MIDX since we tolerate MIDXs whose
packs do not resolve (i.e., via the MIDX write after removing
unreferenced packs via 'git multi-pack-index expire').
In practice, this isn't possible to trigger when running `git
multi-pack-index write` from `git repack`, as the latter always passes
`--stdin-packs`, which prevents us from loading an existing MIDX, as it
forces all packs to be read from disk.
But a future commit in this series will change that behavior to
unconditionally load an existing MIDX, even with `--stdin-packs`, making
this behavior trigger-able from 'repack' much more easily.
Prevent this from being an issue by removing the segfault altogether by
calling `prepare_midx_pack()` on packs loaded from an existing MIDX when
either the `MIDX_WRITE_REV_INDEX` flag is set *or* we specified a
`--preferred-pack`.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
| -rw-r--r-- | midx-write.c | 8 | ||||
| -rwxr-xr-x | t/t5319-multi-pack-index.sh | 23 |
2 files changed, 30 insertions, 1 deletions
diff --git a/midx-write.c b/midx-write.c index 65e69d2de7..fface1e93a 100644 --- a/midx-write.c +++ b/midx-write.c @@ -929,11 +929,17 @@ static int write_midx_internal(const char *object_dir, for (i = 0; i < ctx.m->num_packs; i++) { ALLOC_GROW(ctx.info, ctx.nr + 1, ctx.alloc); - if (flags & MIDX_WRITE_REV_INDEX) { + if (flags & MIDX_WRITE_REV_INDEX || + preferred_pack_name) { /* * If generating a reverse index, need to have * packed_git's loaded to compare their * mtimes and object count. + * + * If a preferred pack is specified, + * need to have packed_git's loaded to + * ensure the chosen preferred pack has + * a non-zero object count. */ if (prepare_midx_pack(the_repository, ctx.m, i)) { error(_("could not load pack")); diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh index dd09134db0..10d2a6bf92 100755 --- a/t/t5319-multi-pack-index.sh +++ b/t/t5319-multi-pack-index.sh @@ -350,6 +350,29 @@ test_expect_success 'preferred packs must be non-empty' ' ) ' +test_expect_success 'preferred pack from existing MIDX without bitmaps' ' + git init preferred-without-bitmaps && + ( + cd preferred-without-bitmaps && + + test_commit one && + pack="$(git pack-objects --all $objdir/pack/pack </dev/null)" && + + git multi-pack-index write && + + # make another pack so that the subsequent MIDX write + # has something to do + test_commit two && + git repack -d && + + # write a new MIDX without bitmaps reusing the singular + # pack from the existing MIDX as the preferred pack in + # the new MIDX + git multi-pack-index write --preferred-pack=pack-$pack.pack + ) + +' + test_expect_success 'verify multi-pack-index success' ' git multi-pack-index verify --object-dir=$objdir ' |