t5326: move tests to t/lib-bitmap.sh

In t5326, we have a handful of tests that we would like to run twice:
once using the MIDX's new `RIDX` chunk as the source of the
reverse-index cache, and once using the separate `.rev` file.

But because these tests mutate the state of the underlying repository,
and then make assumptions about those mutations occurring in a certain
sequence, simply running the tests twice in the same repository is
awkward.

Instead, extract the core of interesting tests into t/lib-bitmap.sh to
prepare for them to be run twice, each in a separate test script. This
means that they can each operate on a separate repository, removing any
concerns about mutating state.

For now, this patch is a strict cut-and-paste of some tests from t5326.
The tests which did not move are not interesting with respect to the
source of their reverse index data.

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>

1 files changed, 177 insertions, 0 deletions

diff --git a/t/lib-bitmap.sh b/t/lib-bitmap.sh
index 21d0392dda..48a8730a13 100644
--- a/t/lib-bitmap.sh
+++ b/t/lib-bitmap.sh
@@ -1,6 +1,9 @@
 # Helpers for scripts testing bitmap functionality; see t5310 for
 # example usage.
 
+objdir=.git/objects
+midx=$objdir/pack/multi-pack-index
+
 # Compare a file containing rev-list bitmap traversal output to its non-bitmap
 # counterpart. You can't just use test_cmp for this, because the two produce
 # subtly different output:
@@ -264,3 +267,177 @@ have_delta () {
 midx_checksum () {
 	test-tool read-midx --checksum "$1"
 }
+
+# midx_pack_source <obj>
+midx_pack_source () {
+	test-tool read-midx --show-objects .git/objects | grep "^$1 " | cut -f2
+}
+
+test_rev_exists () {
+	commit="$1"
+
+	test_expect_success 'reverse index exists' '
+		GIT_TRACE2_EVENT=$(pwd)/event.trace \
+			git rev-list --test-bitmap "$commit" &&
+
+		test_path_is_file $midx-$(midx_checksum $objdir).rev &&
+		grep "\"category\":\"load_midx_revindex\",\"key\":\"source\",\"value\":\"rev\"" event.trace
+	'
+}
+
+midx_bitmap_core () {
+	setup_bitmap_history
+
+	test_expect_success 'create single-pack midx with bitmaps' '
+		git repack -ad &&
+		git multi-pack-index write --bitmap &&
+		test_path_is_file $midx &&
+		test_path_is_file $midx-$(midx_checksum $objdir).bitmap
+	'
+
+	test_rev_exists HEAD
+
+	basic_bitmap_tests
+
+	test_expect_success 'create new additional packs' '
+		for i in $(test_seq 1 16)
+		do
+			test_commit "$i" &&
+			git repack -d || return 1
+		done &&
+
+		git checkout -b other2 HEAD~8 &&
+		for i in $(test_seq 1 8)
+		do
+			test_commit "side-$i" &&
+			git repack -d || return 1
+		done &&
+		git checkout second
+	'
+
+	test_expect_success 'create multi-pack midx with bitmaps' '
+		git multi-pack-index write --bitmap &&
+
+		ls $objdir/pack/pack-*.pack >packs &&
+		test_line_count = 25 packs &&
+
+		test_path_is_file $midx &&
+		test_path_is_file $midx-$(midx_checksum $objdir).bitmap
+	'
+
+	test_rev_exists HEAD
+
+	basic_bitmap_tests
+
+	test_expect_success '--no-bitmap is respected when bitmaps exist' '
+		git multi-pack-index write --bitmap &&
+
+		test_commit respect--no-bitmap &&
+		git repack -d &&
+
+		test_path_is_file $midx &&
+		test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+
+		git multi-pack-index write --no-bitmap &&
+
+		test_path_is_file $midx &&
+		test_path_is_missing $midx-$(midx_checksum $objdir).bitmap &&
+		test_path_is_missing $midx-$(midx_checksum $objdir).rev
+	'
+
+	test_expect_success 'setup midx with base from later pack' '
+		# Write a and b so that "a" is a delta on top of base "b", since Git
+		# prefers to delete contents out of a base rather than add to a shorter
+		# object.
+		test_seq 1 128 >a &&
+		test_seq 1 130 >b &&
+
+		git add a b &&
+		git commit -m "initial commit" &&
+
+		a=$(git rev-parse HEAD:a) &&
+		b=$(git rev-parse HEAD:b) &&
+
+		# In the first pack, "a" is stored as a delta to "b".
+		p1=$(git pack-objects .git/objects/pack/pack <<-EOF
+		$a
+		$b
+		EOF
+		) &&
+
+		# In the second pack, "a" is missing, and "b" is not a delta nor base to
+		# any other object.
+		p2=$(git pack-objects .git/objects/pack/pack <<-EOF
+		$b
+		$(git rev-parse HEAD)
+		$(git rev-parse HEAD^{tree})
+		EOF
+		) &&
+
+		git prune-packed &&
+		# Use the second pack as the preferred source, so that "b" occurs
+		# earlier in the MIDX object order, rendering "a" unusable for pack
+		# reuse.
+		git multi-pack-index write --bitmap --preferred-pack=pack-$p2.idx &&
+
+		have_delta $a $b &&
+		test $(midx_pack_source $a) != $(midx_pack_source $b)
+	'
+
+	rev_list_tests 'full bitmap with backwards delta'
+
+	test_expect_success 'clone with bitmaps enabled' '
+		git clone --no-local --bare . clone-reverse-delta.git &&
+		test_when_finished "rm -fr clone-reverse-delta.git" &&
+
+		git rev-parse HEAD >expect &&
+		git --git-dir=clone-reverse-delta.git rev-parse HEAD >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success 'changing the preferred pack does not corrupt bitmaps' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+
+			test_commit A &&
+			test_commit B &&
+
+			git rev-list --objects --no-object-names HEAD^ >A.objects &&
+			git rev-list --objects --no-object-names HEAD^.. >B.objects &&
+
+			A=$(git pack-objects $objdir/pack/pack <A.objects) &&
+			B=$(git pack-objects $objdir/pack/pack <B.objects) &&
+
+			cat >indexes <<-EOF &&
+			pack-$A.idx
+			pack-$B.idx
+			EOF
+
+			git multi-pack-index write --bitmap --stdin-packs \
+				--preferred-pack=pack-$A.pack <indexes &&
+			git rev-list --test-bitmap A &&
+
+			git multi-pack-index write --bitmap --stdin-packs \
+				--preferred-pack=pack-$B.pack <indexes &&
+			git rev-list --test-bitmap A
+		)
+	'
+}
+
+midx_bitmap_partial_tests () {
+	test_expect_success 'setup partial bitmaps' '
+		test_commit packed &&
+		git repack &&
+		test_commit loose &&
+		git multi-pack-index write --bitmap 2>err &&
+		test_path_is_file $midx &&
+		test_path_is_file $midx-$(midx_checksum $objdir).bitmap
+	'
+
+	test_rev_exists HEAD~
+
+	basic_bitmap_tests HEAD~
+}