[PATCH v3 9/9] pack-bitmap.c: gracefully fallback after opening pack/MIDX
- From
Taylor Blau <me@ttaylorr.com>
- Date
- Jan 4, 2022, 18:16 UTC
- Message-ID
- <9707d5ea4433d9a5c7f8581dbb2d8a05f410efd3.1641320129.git.me@ttaylorr.com>
- In-Reply-To
- <cover.1641320129.git.me@ttaylorr.com>
When opening a MIDX/pack-bitmap, we call open_midx_bitmap_1() or open_pack_bitmap_1() respectively in a loop over the set of MIDXs/packs. By design, these functions are supposed to be called over every pack and MIDX, since only one of them should have a valid bitmap.
Ordinarily we return '0' from these two functions in order to indicate that we successfully loaded a bitmap To signal that we couldn't load a bitmap corresponding to the MIDX/pack (either because one doesn't exist, or because there was an error with loading it), we can return '-1'. In either case, the callers each enumerate all MIDXs/packs to ensure that at most one bitmap per-kind is present.
But when we fail to load a bitmap that does exist (for example, loading a MIDX bitmap without finding a corresponding reverse index), we'll return -1 but leave the 'midx' field non-NULL. So when we fallback to loading a pack bitmap, we'll complain that the bitmap we're trying to populate already is "opened", even though it isn't.
Rectify this by setting the '->pack' and '->midx' field back to NULL as appropriate. Two tests are added: one to ensure that the MIDX-to-pack bitmap fallback works, and another to ensure we still complain when there are multiple pack bitmaps in a repository.
Signed-off-by: Taylor Blau <me@ttaylorr.com> --- pack-bitmap.c | 4 ++++ t/t5310-pack-bitmaps.sh | 28 ++++++++++++++++++++++++++++ t/t5326-multi-pack-bitmaps.sh | 19 +++++++++++++++++++ 3 files changed, 51 insertions(+)
diff --git a/pack-bitmap.c b/pack-bitmap.c index f772d3cb7f..9c666cdb8b 100644 --- a/pack-bitmap.c +++ b/pack-bitmap.c @@ -358,7 +358,9 @@ static int open_midx_bitmap_1(struct bitmap_index *bitmap_git, cleanup: munmap(bitmap_git->map, bitmap_git->map_size); bitmap_git->map_size = 0; + bitmap_git->map_pos = 0; bitmap_git->map = NULL; + bitmap_git->midx = NULL; return -1; } @@ -405,6 +407,8 @@ static int open_pack_bitmap_1(struct bitmap_index *bitmap_git, struct packed_git munmap(bitmap_git->map, bitmap_git->map_size); bitmap_git->map = NULL; bitmap_git->map_size = 0; + bitmap_git->map_pos = 0; + bitmap_git->pack = NULL; return -1; } diff --git a/t/t5310-pack-bitmaps.sh b/t/t5310-pack-bitmaps.sh index d05ab716f6..f775fc1ce6 100755 --- a/t/t5310-pack-bitmaps.sh +++ b/t/t5310-pack-bitmaps.sh @@ -397,4 +397,32 @@ test_expect_success 'pack.preferBitmapTips' ' ) ' +test_expect_success 'complains about multiple pack bitmaps' ' + rm -fr repo && + git init repo && + test_when_finished "rm -fr repo" && + ( + cd repo && + + test_commit base && + + git repack -adb && + bitmap="$(ls .git/objects/pack/pack-*.bitmap)" && + mv "$bitmap" "$bitmap.bak" && + + test_commit other && + git repack -ab && + + mv "$bitmap.bak" "$bitmap" && + + find .git/objects/pack -type f -name "*.pack" >packs && + find .git/objects/pack -type f -name "*.bitmap" >bitmaps && + test_line_count = 2 packs && + test_line_count = 2 bitmaps && + + git rev-list --use-bitmap-index HEAD 2>err && + grep "ignoring extra bitmap file" err + ) +' + test_done diff --git a/t/t5326-multi-pack-bitmaps.sh b/t/t5326-multi-pack-bitmaps.sh index c0924074c4..3c1ecc7e25 100755 --- a/t/t5326-multi-pack-bitmaps.sh +++ b/t/t5326-multi-pack-bitmaps.sh @@ -266,4 +266,23 @@ test_expect_success 'hash-cache values are propagated from pack bitmaps' ' ) ' +test_expect_success 'graceful fallback when missing reverse index' ' + rm -fr repo && + git init repo && + test_when_finished "rm -fr repo" && + ( + cd repo && + + test_commit base && + + # write a pack and MIDX bitmap containing base + git repack -adb && + git multi-pack-index write --bitmap && + + GIT_TEST_MIDX_READ_RIDX=0 \ + git rev-list --use-bitmap-index HEAD 2>err && + ! grep "ignoring extra bitmap file" err + ) +' + test_done
-- 2.34.1.25.gb3157a20e6