1 files changed, 322 insertions, 3 deletions
diff --git a/t/t4216-log-bloom.sh b/t/t4216-log-bloom.sh
index 2ba0324a69..3f163dc396 100755
--- a/t/t4216-log-bloom.sh
+++ b/t/t4216-log-bloom.sh
@@ -82,7 +82,23 @@ test_bloom_filters_used () {
 test_bloom_filters_not_used () {
 	log_args=$1
 	setup "$log_args" &&
-	! grep -q "statistics:{\"filter_not_present\":" "$TRASH_DIRECTORY/trace.perf" &&
+
+	if grep -q "statistics:{\"filter_not_present\":" "$TRASH_DIRECTORY/trace.perf"
+	then
+		# if the Bloom filter system is initialized, ensure that no
+		# filters were used
+		data="statistics:{"
+		# unusable filters (e.g., those computed with a
+		# different value of commitGraph.changedPathsVersion)
+		# are counted in the filter_not_present bucket, so any
+		# value is OK there.
+		data="$data\"filter_not_present\":[0-9][0-9]*,"
+		data="$data\"maybe\":0,"
+		data="$data\"definitely_not\":0,"
+		data="$data\"false_positive\":0}"
+
+		grep -q "$data" "$TRASH_DIRECTORY/trace.perf"
+	fi &&
 	test_cmp log_wo_bloom log_w_bloom
 }
 
@@ -163,7 +179,7 @@ test_expect_success 'setup - add commit-graph to the chain with Bloom filters' '
 
 test_bloom_filters_used_when_some_filters_are_missing () {
 	log_args=$1
-	bloom_trace_prefix="statistics:{\"filter_not_present\":3,\"maybe\":6,\"definitely_not\":9"
+	bloom_trace_prefix="statistics:{\"filter_not_present\":3,\"maybe\":6,\"definitely_not\":10"
 	setup "$log_args" &&
 	grep -q "$bloom_trace_prefix" "$TRASH_DIRECTORY/trace.perf" &&
 	test_cmp log_wo_bloom log_w_bloom
@@ -206,6 +222,10 @@ test_filter_trunc_large () {
 	grep "\"key\":\"filter-trunc-large\",\"value\":\"$1\"" $2
 }
 
+test_filter_upgraded () {
+	grep "\"key\":\"filter-upgraded\",\"value\":\"$1\"" $2
+}
+
 test_expect_success 'correctly report changes over limit' '
 	git init limits &&
 	(
@@ -405,8 +425,307 @@ test_expect_success 'Bloom generation backfills empty commits' '
 	)
 '
 
+graph=.git/objects/info/commit-graph
+graphdir=.git/objects/info/commit-graphs
+chain=$graphdir/commit-graph-chain
+
+test_expect_success 'setup for mixed Bloom setting tests' '
+	repo=mixed-bloom-settings &&
+
+	git init $repo &&
+	for i in one two three
+	do
+		test_commit -C $repo $i file || return 1
+	done
+'
+
+test_expect_success 'ensure Bloom filters with incompatible settings are ignored' '
+	# Compute Bloom filters with "unusual" settings.
+	git -C $repo rev-parse one >in &&
+	GIT_TEST_BLOOM_SETTINGS_NUM_HASHES=3 git -C $repo commit-graph write \
+		--stdin-commits --changed-paths --split <in &&
+	layer=$(head -n 1 $repo/$chain) &&
+
+	# A commit-graph layer without Bloom filters "hides" the layers
+	# below ...
+	git -C $repo rev-parse two >in &&
+	git -C $repo commit-graph write --stdin-commits --no-changed-paths \
+		--split=no-merge <in &&
+
+	# Another commit-graph layer that has Bloom filters, but with
+	# standard settings, and is thus incompatible with the base
+	# layer written above.
+	git -C $repo rev-parse HEAD >in &&
+	git -C $repo commit-graph write --stdin-commits --changed-paths \
+		--split=no-merge <in &&
+
+	test_line_count = 3 $repo/$chain &&
+
+	# Ensure that incompatible Bloom filters are ignored.
+	git -C $repo -c core.commitGraph=false log --oneline --no-decorate -- file \
+		>expect 2>err &&
+	git -C $repo log --oneline --no-decorate -- file >actual 2>err &&
+	test_cmp expect actual &&
+	grep "disabling Bloom filters for commit-graph layer .$layer." err
+'
+
+test_expect_success 'merge graph layers with incompatible Bloom settings' '
+	# Ensure that incompatible Bloom filters are ignored when
+	# merging existing layers.
+	>trace2.txt &&
+	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
+		git -C $repo commit-graph write --reachable --changed-paths 2>err &&
+	grep "disabling Bloom filters for commit-graph layer .$layer." err &&
+	grep "{\"hash_version\":1,\"num_hashes\":7,\"bits_per_entry\":10,\"max_changed_paths\":512" trace2.txt &&
+
+	test_path_is_file $repo/$graph &&
+	test_dir_is_empty $repo/$graphdir &&
+
+	git -C $repo -c core.commitGraph=false log --oneline --no-decorate -- \
+		file >expect &&
+	trace_out="$(pwd)/trace.perf" &&
+	GIT_TRACE2_PERF="$trace_out" \
+		git -C $repo log --oneline --no-decorate -- file >actual 2>err &&
+
+	test_cmp expect actual &&
+	grep "statistics:{\"filter_not_present\":0," trace.perf &&
+	test_must_be_empty err
+'
+
+# chosen to be the same under all Unicode normalization forms
+CENT=$(printf "\302\242")
+
+test_expect_success 'ensure Bloom filter with incompatible versions are ignored' '
+	rm "$repo/$graph" &&
+
+	git -C $repo log --oneline --no-decorate -- $CENT >expect &&
+
+	# Compute v1 Bloom filters for commits at the bottom.
+	git -C $repo rev-parse HEAD^ >in &&
+	git -C $repo commit-graph write --stdin-commits --changed-paths \
+		--split <in &&
+
+	# Compute v2 Bloomfilters for the rest of the commits at the top.
+	git -C $repo rev-parse HEAD >in &&
+	git -C $repo -c commitGraph.changedPathsVersion=2 commit-graph write \
+		--stdin-commits --changed-paths --split=no-merge <in &&
+
+	test_line_count = 2 $repo/$chain &&
+
+	git -C $repo log --oneline --no-decorate -- $CENT >actual 2>err &&
+	test_cmp expect actual &&
+
+	layer="$(head -n 1 $repo/$chain)" &&
+	cat >expect.err <<-EOF &&
+	warning: disabling Bloom filters for commit-graph layer $SQ$layer$SQ due to incompatible settings
+	EOF
+	test_cmp expect.err err &&
+
+	# Merge the two layers with incompatible bloom filter versions,
+	# ensuring that the v2 filters are used.
+	>trace2.txt &&
+	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
+		git -C $repo -c commitGraph.changedPathsVersion=2 commit-graph write --reachable --changed-paths 2>err &&
+	grep "disabling Bloom filters for commit-graph layer .$layer." err &&
+	grep "{\"hash_version\":2,\"num_hashes\":7,\"bits_per_entry\":10,\"max_changed_paths\":512" trace2.txt
+'
+
+get_first_changed_path_filter () {
+	test-tool read-graph bloom-filters >filters.dat &&
+	head -n 1 filters.dat
+}
+
+test_expect_success 'set up repo with high bit path, version 1 changed-path' '
+	git init highbit1 &&
+	test_commit -C highbit1 c1 "$CENT" &&
+	git -C highbit1 commit-graph write --reachable --changed-paths
+'
+
+test_expect_success 'setup check value of version 1 changed-path' '
+	(
+		cd highbit1 &&
+		echo "52a9" >expect &&
+		get_first_changed_path_filter >actual
+	)
+'
+
+# expect will not match actual if char is unsigned by default. Write the test
+# in this way, so that a user running this test script can still see if the two
+# files match. (It will appear as an ordinary success if they match, and a skip
+# if not.)
+if test_cmp highbit1/expect highbit1/actual
+then
+	test_set_prereq SIGNED_CHAR_BY_DEFAULT
+fi
+test_expect_success SIGNED_CHAR_BY_DEFAULT 'check value of version 1 changed-path' '
+	# Only the prereq matters for this test.
+	true
+'
+
+test_expect_success 'setup make another commit' '
+	# "git log" does not use Bloom filters for root commits - see how, in
+	# revision.c, rev_compare_tree() (the only code path that eventually calls
+	# get_bloom_filter()) is only called by try_to_simplify_commit() when the commit
+	# has one parent. Therefore, make another commit so that we perform the tests on
+	# a non-root commit.
+	test_commit -C highbit1 anotherc1 "another$CENT"
+'
+
+test_expect_success 'version 1 changed-path used when version 1 requested' '
+	(
+		cd highbit1 &&
+		test_bloom_filters_used "-- another$CENT"
+	)
+'
+
+test_expect_success 'version 1 changed-path not used when version 2 requested' '
+	(
+		cd highbit1 &&
+		git config --add commitGraph.changedPathsVersion 2 &&
+		test_bloom_filters_not_used "-- another$CENT"
+	)
+'
+
+test_expect_success 'version 1 changed-path used when autodetect requested' '
+	(
+		cd highbit1 &&
+		git config --add commitGraph.changedPathsVersion -1 &&
+		test_bloom_filters_used "-- another$CENT"
+	)
+'
+
+test_expect_success 'when writing another commit graph, preserve existing version 1 of changed-path' '
+	test_commit -C highbit1 c1double "$CENT$CENT" &&
+	git -C highbit1 commit-graph write --reachable --changed-paths &&
+	(
+		cd highbit1 &&
+		git config --add commitGraph.changedPathsVersion -1 &&
+		echo "options: bloom(1,10,7) read_generation_data" >expect &&
+		test-tool read-graph >full &&
+		grep options full >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'set up repo with high bit path, version 2 changed-path' '
+	git init highbit2 &&
+	git -C highbit2 config --add commitGraph.changedPathsVersion 2 &&
+	test_commit -C highbit2 c2 "$CENT" &&
+	git -C highbit2 commit-graph write --reachable --changed-paths
+'
+
+test_expect_success 'check value of version 2 changed-path' '
+	(
+		cd highbit2 &&
+		echo "c01f" >expect &&
+		get_first_changed_path_filter >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'setup make another commit' '
+	# "git log" does not use Bloom filters for root commits - see how, in
+	# revision.c, rev_compare_tree() (the only code path that eventually calls
+	# get_bloom_filter()) is only called by try_to_simplify_commit() when the commit
+	# has one parent. Therefore, make another commit so that we perform the tests on
+	# a non-root commit.
+	test_commit -C highbit2 anotherc2 "another$CENT"
+'
+
+test_expect_success 'version 2 changed-path used when version 2 requested' '
+	(
+		cd highbit2 &&
+		test_bloom_filters_used "-- another$CENT"
+	)
+'
+
+test_expect_success 'version 2 changed-path not used when version 1 requested' '
+	(
+		cd highbit2 &&
+		git config --add commitGraph.changedPathsVersion 1 &&
+		test_bloom_filters_not_used "-- another$CENT"
+	)
+'
+
+test_expect_success 'version 2 changed-path used when autodetect requested' '
+	(
+		cd highbit2 &&
+		git config --add commitGraph.changedPathsVersion -1 &&
+		test_bloom_filters_used "-- another$CENT"
+	)
+'
+
+test_expect_success 'when writing another commit graph, preserve existing version 2 of changed-path' '
+	test_commit -C highbit2 c2double "$CENT$CENT" &&
+	git -C highbit2 commit-graph write --reachable --changed-paths &&
+	(
+		cd highbit2 &&
+		git config --add commitGraph.changedPathsVersion -1 &&
+		echo "options: bloom(2,10,7) read_generation_data" >expect &&
+		test-tool read-graph >full &&
+		grep options full >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'when writing commit graph, do not reuse changed-path of another version' '
+	git init doublewrite &&
+	test_commit -C doublewrite c "$CENT" &&
+
+	git -C doublewrite config --add commitGraph.changedPathsVersion 1 &&
+	>trace2.txt &&
+	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
+		git -C doublewrite commit-graph write --reachable --changed-paths &&
+	test_filter_computed 1 trace2.txt &&
+	test_filter_upgraded 0 trace2.txt &&
+
+	git -C doublewrite commit-graph write --reachable --changed-paths &&
+	for v in -2 3
+	do
+		git -C doublewrite config --add commitGraph.changedPathsVersion $v &&
+		git -C doublewrite commit-graph write --reachable --changed-paths 2>err &&
+		cat >expect <<-EOF &&
+		warning: attempting to write a commit-graph, but ${SQ}commitGraph.changedPathsVersion${SQ} ($v) is not supported
+		EOF
+		test_cmp expect err || return 1
+	done &&
+
+	git -C doublewrite config --add commitGraph.changedPathsVersion 2 &&
+	>trace2.txt &&
+	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
+		git -C doublewrite commit-graph write --reachable --changed-paths &&
+	test_filter_computed 1 trace2.txt &&
+	test_filter_upgraded 0 trace2.txt &&
+
+	(
+		cd doublewrite &&
+		echo "c01f" >expect &&
+		get_first_changed_path_filter >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'when writing commit graph, reuse changed-path of another version where possible' '
+	git init upgrade &&
+
+	test_commit -C upgrade base no-high-bits &&
+
+	git -C upgrade config --add commitGraph.changedPathsVersion 1 &&
+	>trace2.txt &&
+	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
+		git -C upgrade commit-graph write --reachable --changed-paths &&
+	test_filter_computed 1 trace2.txt &&
+	test_filter_upgraded 0 trace2.txt &&
+
+	git -C upgrade config --add commitGraph.changedPathsVersion 2 &&
+	>trace2.txt &&
+	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
+		git -C upgrade commit-graph write --reachable --changed-paths &&
+	test_filter_computed 0 trace2.txt &&
+	test_filter_upgraded 1 trace2.txt
+'
+
 corrupt_graph () {
-	graph=.git/objects/info/commit-graph &&
 	test_when_finished "rm -rf $graph" &&
 	git commit-graph write --reachable --changed-paths &&
 	corrupt_chunk_file $graph "$@"