1 files changed, 437 insertions, 0 deletions
diff --git a/t/t5326-multi-pack-bitmaps.sh b/t/t5326-multi-pack-bitmaps.sh
new file mode 100755
index 0000000..0882cbb
--- /dev/null
+++ b/t/t5326-multi-pack-bitmaps.sh
@@ -0,0 +1,437 @@
+#!/bin/sh
+
+test_description='exercise basic multi-pack bitmap functionality'
+. ./test-lib.sh
+. "${TEST_DIRECTORY}/lib-bitmap.sh"
+
+# We'll be writing our own midx and bitmaps, so avoid getting confused by the
+# automatic ones.
+GIT_TEST_MULTI_PACK_INDEX=0
+GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0
+
+# This test exercise multi-pack bitmap functionality where the object order is
+# stored and read from a special chunk within the MIDX, so use the default
+# behavior here.
+sane_unset GIT_TEST_MIDX_WRITE_REV
+sane_unset GIT_TEST_MIDX_READ_RIDX
+
+bitmap_reuse_tests() {
+	from=$1
+	to=$2
+	writeLookupTable=false
+
+	for i in $3-${$#}
+	do
+		case $i in
+		"pack.writeBitmapLookupTable") writeLookupTable=true;;
+		esac
+	done
+
+	test_expect_success "setup pack reuse tests ($from -> $to)" '
+		rm -fr repo &&
+		git init repo &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+			test_commit_bulk 16 &&
+			git tag old-tip &&
+
+			git config core.multiPackIndex true &&
+			if test "MIDX" = "$from"
+			then
+				git repack -Ad &&
+				git multi-pack-index write --bitmap
+			else
+				git repack -Adb
+			fi
+		)
+	'
+
+	test_expect_success "build bitmap from existing ($from -> $to)" '
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+			test_commit_bulk --id=further 16 &&
+			git tag new-tip &&
+
+			if test "MIDX" = "$to"
+			then
+				git repack -d &&
+				git multi-pack-index write --bitmap
+			else
+				git repack -Adb
+			fi
+		)
+	'
+
+	test_expect_success "verify resulting bitmaps ($from -> $to)" '
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+			git for-each-ref &&
+			git rev-list --test-bitmap refs/tags/old-tip &&
+			git rev-list --test-bitmap refs/tags/new-tip
+		)
+	'
+}
+
+test_midx_bitmap_cases () {
+	writeLookupTable=false
+	writeBitmapLookupTable=
+
+	for i in "$@"
+	do
+		case $i in
+		"pack.writeBitmapLookupTable")
+			writeLookupTable=true
+			writeBitmapLookupTable="$i"
+			;;
+		esac
+	done
+
+	test_expect_success 'setup test_repository' '
+		rm -rf * .git &&
+		git init &&
+		git config pack.writeBitmapLookupTable '"$writeLookupTable"'
+	'
+
+	midx_bitmap_core
+
+	bitmap_reuse_tests 'pack' 'MIDX' "$writeBitmapLookupTable"
+	bitmap_reuse_tests 'MIDX' 'pack' "$writeBitmapLookupTable"
+	bitmap_reuse_tests 'MIDX' 'MIDX' "$writeBitmapLookupTable"
+
+	test_expect_success 'missing object closure fails gracefully' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			test_commit loose &&
+			test_commit packed &&
+
+			# Do not pass "--revs"; we want a pack without the "loose"
+			# commit.
+			git pack-objects $objdir/pack/pack <<-EOF &&
+			$(git rev-parse packed)
+			EOF
+
+			test_must_fail git multi-pack-index write --bitmap 2>err &&
+			grep "doesn.t have full closure" err &&
+			test_path_is_missing $midx
+		)
+	'
+
+	midx_bitmap_partial_tests
+
+	test_expect_success 'removing a MIDX clears stale bitmaps' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+			test_commit base &&
+			git repack &&
+			git multi-pack-index write --bitmap &&
+
+			# Write a MIDX and bitmap; remove the MIDX but leave the bitmap.
+			stale_bitmap=$midx-$(midx_checksum $objdir).bitmap &&
+			rm $midx &&
+
+			# Then write a new MIDX.
+			test_commit new &&
+			git repack &&
+			git multi-pack-index write --bitmap &&
+
+			test_path_is_file $midx &&
+			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+			test_path_is_missing $stale_bitmap
+		)
+	'
+
+	test_expect_success 'pack.preferBitmapTips' '
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			test_commit_bulk --message="%s" 103 &&
+
+			git log --format="%H" >commits.raw &&
+			sort <commits.raw >commits &&
+
+			git log --format="create refs/tags/%s %H" HEAD >refs &&
+			git update-ref --stdin <refs &&
+
+			git multi-pack-index write --bitmap &&
+			test_path_is_file $midx &&
+			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+
+			test-tool bitmap list-commits | sort >bitmaps &&
+			comm -13 bitmaps commits >before &&
+			test_line_count = 1 before &&
+
+			perl -ne "printf(\"create refs/tags/include/%d \", $.); print" \
+				<before | git update-ref --stdin &&
+
+			rm -fr $midx-$(midx_checksum $objdir).bitmap &&
+			rm -fr $midx &&
+
+			git -c pack.preferBitmapTips=refs/tags/include \
+				multi-pack-index write --bitmap &&
+			test-tool bitmap list-commits | sort >bitmaps &&
+			comm -13 bitmaps commits >after &&
+
+			! test_cmp before after
+		)
+	'
+
+	test_expect_success 'writing a bitmap with --refs-snapshot' '
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			test_commit one &&
+			test_commit two &&
+
+			git rev-parse one >snapshot &&
+
+			git repack -ad &&
+
+			# First, write a MIDX which see both refs/tags/one and
+			# refs/tags/two (causing both of those commits to receive
+			# bitmaps).
+			git multi-pack-index write --bitmap &&
+
+			test_path_is_file $midx &&
+			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+
+			test-tool bitmap list-commits | sort >bitmaps &&
+			grep "$(git rev-parse one)" bitmaps &&
+			grep "$(git rev-parse two)" bitmaps &&
+
+			rm -fr $midx-$(midx_checksum $objdir).bitmap &&
+			rm -fr $midx &&
+
+			# Then again, but with a refs snapshot which only sees
+			# refs/tags/one.
+			git multi-pack-index write --bitmap --refs-snapshot=snapshot &&
+
+			test_path_is_file $midx &&
+			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+
+			test-tool bitmap list-commits | sort >bitmaps &&
+			grep "$(git rev-parse one)" bitmaps &&
+			! grep "$(git rev-parse two)" bitmaps
+		)
+	'
+
+	test_expect_success 'write a bitmap with --refs-snapshot (preferred tips)' '
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			test_commit_bulk --message="%s" 103 &&
+
+			git log --format="%H" >commits.raw &&
+			sort <commits.raw >commits &&
+
+			git log --format="create refs/tags/%s %H" HEAD >refs &&
+			git update-ref --stdin <refs &&
+
+			git multi-pack-index write --bitmap &&
+			test_path_is_file $midx &&
+			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+
+			test-tool bitmap list-commits | sort >bitmaps &&
+			comm -13 bitmaps commits >before &&
+			test_line_count = 1 before &&
+
+			(
+				grep -vf before commits.raw &&
+				# mark missing commits as preferred
+				sed "s/^/+/" before
+			) >snapshot &&
+
+			rm -fr $midx-$(midx_checksum $objdir).bitmap &&
+			rm -fr $midx &&
+
+			git multi-pack-index write --bitmap --refs-snapshot=snapshot &&
+			test-tool bitmap list-commits | sort >bitmaps &&
+			comm -13 bitmaps commits >after &&
+
+			! test_cmp before after
+		)
+	'
+
+	test_expect_success 'hash-cache values are propagated from pack bitmaps' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			test_commit base &&
+			test_commit base2 &&
+			git repack -adb &&
+
+			test-tool bitmap dump-hashes >pack.raw &&
+			test_file_not_empty pack.raw &&
+			sort pack.raw >pack.hashes &&
+
+			test_commit new &&
+			git repack &&
+			git multi-pack-index write --bitmap &&
+
+			test-tool bitmap dump-hashes >midx.raw &&
+			sort midx.raw >midx.hashes &&
+
+			# ensure that every namehash in the pack bitmap can be found in
+			# the midx bitmap (i.e., that there are no oid-namehash pairs
+			# unique to the pack bitmap).
+			comm -23 pack.hashes midx.hashes >dropped.hashes &&
+			test_must_be_empty dropped.hashes
+		)
+	'
+
+	test_expect_success 'no .bitmap is written without any objects' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			empty="$(git pack-objects $objdir/pack/pack </dev/null)" &&
+			cat >packs <<-EOF &&
+			pack-$empty.idx
+			EOF
+
+			git multi-pack-index write --bitmap --stdin-packs \
+				<packs 2>err &&
+
+			grep "bitmap without any objects" err &&
+
+			test_path_is_file $midx &&
+			test_path_is_missing $midx-$(midx_checksum $objdir).bitmap
+		)
+	'
+
+	test_expect_success 'graceful fallback when missing reverse index' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			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_midx_bitmap_cases
+
+test_midx_bitmap_cases "pack.writeBitmapLookupTable"
+
+test_expect_success 'multi-pack-index write writes lookup table if enabled' '
+	rm -fr repo &&
+	git init repo &&
+	test_when_finished "rm -fr repo" &&
+	(
+		cd repo &&
+		test_commit base &&
+		git config pack.writeBitmapLookupTable true &&
+		git repack -ad &&
+		GIT_TRACE2_EVENT="$(pwd)/trace" \
+			git multi-pack-index write --bitmap &&
+		grep "\"label\":\"writing_lookup_table\"" trace
+	)
+'
+
+test_expect_success 'preferred pack change with existing MIDX bitmap' '
+	git init preferred-pack-with-existing &&
+	(
+		cd preferred-pack-with-existing &&
+
+		test_commit base &&
+		test_commit other &&
+
+		git rev-list --objects --no-object-names base >p1.objects &&
+		git rev-list --objects --no-object-names other >p2.objects &&
+
+		p1="$(git pack-objects "$objdir/pack/pack" \
+			--delta-base-offset <p1.objects)" &&
+		p2="$(git pack-objects "$objdir/pack/pack" \
+			--delta-base-offset <p2.objects)" &&
+
+		# Generate a MIDX containing the first two packs,
+		# marking p1 as preferred, and ensure that it can be
+		# successfully cloned.
+		git multi-pack-index write --bitmap \
+			--preferred-pack="pack-$p1.pack" &&
+		test_path_is_file $midx &&
+		test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+		git clone --no-local . clone1 &&
+
+		# Then generate a new pack which sorts ahead of any
+		# existing pack (by tweaking the pack prefix).
+		test_commit foo &&
+		git pack-objects --all --unpacked $objdir/pack/pack0 &&
+
+		# Generate a new MIDX which changes the preferred pack
+		# to a pack contained in the existing MIDX.
+		git multi-pack-index write --bitmap \
+			--preferred-pack="pack-$p2.pack" &&
+		test_path_is_file $midx &&
+		test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+
+		# When the above circumstances are met, the preferred
+		# pack should change appropriately and clones should
+		# (still) succeed.
+		git clone --no-local . clone2
+	)
+'
+
+test_expect_success 'tagged commits are selected for bitmapping' '
+	rm -fr repo &&
+	git init repo &&
+	test_when_finished "rm -fr repo" &&
+	(
+		cd repo &&
+
+		test_commit --annotate base &&
+		git repack -d &&
+
+		# Remove refs/heads/main which points at the commit directly,
+		# leaving only a reference to the annotated tag.
+		git branch -M main &&
+		git checkout base &&
+		git branch -d main &&
+
+		git multi-pack-index write --bitmap &&
+
+		git rev-parse HEAD >want &&
+		test-tool bitmap list-commits >actual &&
+		grep $(cat want) actual
+	)
+'
+
+test_done