pack-bitmap.c: gracefully fallback after opening pack/MIDX
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>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t5326-multi-pack-bitmaps.sh b/t/t5326-multi-pack-bitmaps.sh
index c092407..3c1ecc7 100755
--- a/t/t5326-multi-pack-bitmaps.sh
+++ b/t/t5326-multi-pack-bitmaps.sh
@@ -266,4 +266,23 @@
)
'
+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
