Merge branch 'ak/corrected-commit-date'

The commit-graph learned to use corrected commit dates instead of
the generation number to help topological revision traversal.

* ak/corrected-commit-date:
  doc: add corrected commit date info
  commit-reach: use corrected commit dates in paint_down_to_common()
  commit-graph: use generation v2 only if entire chain does
  commit-graph: implement generation data chunk
  commit-graph: implement corrected commit date
  commit-graph: return 64-bit generation number
  commit-graph: add a slab to store topological levels
  t6600-test-reach: generalize *_three_modes
  commit-graph: consolidate fill_commit_graph_info
  revision: parse parent in indegree_walk_step()
  commit-graph: fix regression when computing Bloom filters

9 files changed, 330 insertions, 56 deletions

diff --git a/t/README b/t/README
index af706e0cd6..bc57006c04 100644
--- a/t/README
+++ b/t/README
@@ -387,6 +387,9 @@ GIT_TEST_COMMIT_GRAPH=<boolean>, when true, forces the commit-graph to
 be written after every 'git commit' command, and overrides the
 'core.commitGraph' setting to true.
 
+GIT_TEST_COMMIT_GRAPH_NO_GDAT=<boolean>, when true, forces the
+commit-graph to be written without generation data chunk.
+
 GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS=<boolean>, when true, forces
 commit-graph write to compute and write changed path Bloom filters for
 every 'git commit-graph write', as if the `--changed-paths` option was
diff --git a/t/helper/test-read-graph.c b/t/helper/test-read-graph.c
index 5f585a1725..75927b2c81 100644
--- a/t/helper/test-read-graph.c
+++ b/t/helper/test-read-graph.c
@@ -33,6 +33,10 @@ int cmd__read_graph(int argc, const char **argv)
 		printf(" oid_lookup");
 	if (graph->chunk_commit_data)
 		printf(" commit_metadata");
+	if (graph->chunk_generation_data)
+		printf(" generation_data");
+	if (graph->chunk_generation_data_overflow)
+		printf(" generation_data_overflow");
 	if (graph->chunk_extra_edges)
 		printf(" extra_edges");
 	if (graph->chunk_bloom_indexes)
diff --git a/t/t4216-log-bloom.sh b/t/t4216-log-bloom.sh
index 0f16c4b9d5..50f206db55 100755
--- a/t/t4216-log-bloom.sh
+++ b/t/t4216-log-bloom.sh
@@ -43,11 +43,11 @@ test_expect_success 'setup test - repo, commits, commit graph, log outputs' '
 '
 
 graph_read_expect () {
-	NUM_CHUNKS=5
+	NUM_CHUNKS=6
 	cat >expect <<- EOF
 	header: 43475048 1 $(test_oid oid_version) $NUM_CHUNKS 0
 	num_commits: $1
-	chunks: oid_fanout oid_lookup commit_metadata bloom_indexes bloom_data
+	chunks: oid_fanout oid_lookup commit_metadata generation_data bloom_indexes bloom_data
 	EOF
 	test-tool read-graph >actual &&
 	test_cmp expect actual
diff --git a/t/t5000-tar-tree.sh b/t/t5000-tar-tree.sh
index 3ebb0d3b65..7204799a0b 100755
--- a/t/t5000-tar-tree.sh
+++ b/t/t5000-tar-tree.sh
@@ -431,15 +431,33 @@ test_expect_success TAR_HUGE,LONG_IS_64BIT 'system tar can read our huge size' '
 	test_cmp expect actual
 '
 
-test_expect_success TIME_IS_64BIT 'set up repository with far-future commit' '
+test_expect_success TIME_IS_64BIT 'set up repository with far-future (2^34 - 1) commit' '
+	rm -f .git/index &&
+	echo foo >file &&
+	git add file &&
+	GIT_COMMITTER_DATE="@17179869183 +0000" \
+		git commit -m "tempori parendum"
+'
+
+test_expect_success TIME_IS_64BIT 'generate tar with far-future mtime' '
+	git archive HEAD >future.tar
+'
+
+test_expect_success TAR_HUGE,TIME_IS_64BIT,TIME_T_IS_64BIT 'system tar can read our future mtime' '
+	echo 2514 >expect &&
+	tar_info future.tar | cut -d" " -f2 >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success TIME_IS_64BIT 'set up repository with far-far-future (2^36 + 1) commit' '
 	rm -f .git/index &&
 	echo content >file &&
 	git add file &&
-	GIT_COMMITTER_DATE="@68719476737 +0000" \
+	GIT_TEST_COMMIT_GRAPH=0 GIT_COMMITTER_DATE="@68719476737 +0000" \
 		git commit -m "tempori parendum"
 '
 
-test_expect_success TIME_IS_64BIT 'generate tar with future mtime' '
+test_expect_success TIME_IS_64BIT 'generate tar with far-far-future mtime' '
 	git archive HEAD >future.tar
 '
 
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 2ed0c1544d..fa27df579a 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -76,7 +76,7 @@ graph_git_behavior 'no graph' full commits/3 commits/1
 graph_read_expect() {
 	OPTIONAL=""
 	NUM_CHUNKS=3
-	if test ! -z $2
+	if test ! -z "$2"
 	then
 		OPTIONAL=" $2"
 		NUM_CHUNKS=$((3 + $(echo "$2" | wc -w)))
@@ -103,14 +103,14 @@ test_expect_success 'exit with correct error on bad input to --stdin-commits' '
 	# valid commit and tree OID
 	git rev-parse HEAD HEAD^{tree} >in &&
 	git commit-graph write --stdin-commits <in &&
-	graph_read_expect 3
+	graph_read_expect 3 generation_data
 '
 
 test_expect_success 'write graph' '
 	cd "$TRASH_DIRECTORY/full" &&
 	git commit-graph write &&
 	test_path_is_file $objdir/info/commit-graph &&
-	graph_read_expect "3"
+	graph_read_expect "3" generation_data
 '
 
 test_expect_success POSIXPERM 'write graph has correct permissions' '
@@ -219,7 +219,7 @@ test_expect_success 'write graph with merges' '
 	cd "$TRASH_DIRECTORY/full" &&
 	git commit-graph write &&
 	test_path_is_file $objdir/info/commit-graph &&
-	graph_read_expect "10" "extra_edges"
+	graph_read_expect "10" "generation_data extra_edges"
 '
 
 graph_git_behavior 'merge 1 vs 2' full merge/1 merge/2
@@ -254,7 +254,7 @@ test_expect_success 'write graph with new commit' '
 	cd "$TRASH_DIRECTORY/full" &&
 	git commit-graph write &&
 	test_path_is_file $objdir/info/commit-graph &&
-	graph_read_expect "11" "extra_edges"
+	graph_read_expect "11" "generation_data extra_edges"
 '
 
 graph_git_behavior 'full graph, commit 8 vs merge 1' full commits/8 merge/1
@@ -264,7 +264,7 @@ test_expect_success 'write graph with nothing new' '
 	cd "$TRASH_DIRECTORY/full" &&
 	git commit-graph write &&
 	test_path_is_file $objdir/info/commit-graph &&
-	graph_read_expect "11" "extra_edges"
+	graph_read_expect "11" "generation_data extra_edges"
 '
 
 graph_git_behavior 'cleared graph, commit 8 vs merge 1' full commits/8 merge/1
@@ -274,7 +274,7 @@ test_expect_success 'build graph from latest pack with closure' '
 	cd "$TRASH_DIRECTORY/full" &&
 	cat new-idx | git commit-graph write --stdin-packs &&
 	test_path_is_file $objdir/info/commit-graph &&
-	graph_read_expect "9" "extra_edges"
+	graph_read_expect "9" "generation_data extra_edges"
 '
 
 graph_git_behavior 'graph from pack, commit 8 vs merge 1' full commits/8 merge/1
@@ -287,7 +287,7 @@ test_expect_success 'build graph from commits with closure' '
 	git rev-parse merge/1 >>commits-in &&
 	cat commits-in | git commit-graph write --stdin-commits &&
 	test_path_is_file $objdir/info/commit-graph &&
-	graph_read_expect "6"
+	graph_read_expect "6" "generation_data"
 '
 
 graph_git_behavior 'graph from commits, commit 8 vs merge 1' full commits/8 merge/1
@@ -297,7 +297,7 @@ test_expect_success 'build graph from commits with append' '
 	cd "$TRASH_DIRECTORY/full" &&
 	git rev-parse merge/3 | git commit-graph write --stdin-commits --append &&
 	test_path_is_file $objdir/info/commit-graph &&
-	graph_read_expect "10" "extra_edges"
+	graph_read_expect "10" "generation_data extra_edges"
 '
 
 graph_git_behavior 'append graph, commit 8 vs merge 1' full commits/8 merge/1
@@ -307,7 +307,7 @@ test_expect_success 'build graph using --reachable' '
 	cd "$TRASH_DIRECTORY/full" &&
 	git commit-graph write --reachable &&
 	test_path_is_file $objdir/info/commit-graph &&
-	graph_read_expect "11" "extra_edges"
+	graph_read_expect "11" "generation_data extra_edges"
 '
 
 graph_git_behavior 'append graph, commit 8 vs merge 1' full commits/8 merge/1
@@ -328,7 +328,7 @@ test_expect_success 'write graph in bare repo' '
 	cd "$TRASH_DIRECTORY/bare" &&
 	git commit-graph write &&
 	test_path_is_file $baredir/info/commit-graph &&
-	graph_read_expect "11" "extra_edges"
+	graph_read_expect "11" "generation_data extra_edges"
 '
 
 graph_git_behavior 'bare repo with graph, commit 8 vs merge 1' bare commits/8 merge/1
@@ -454,8 +454,9 @@ test_expect_success 'warn on improper hash version' '
 
 test_expect_success 'git commit-graph verify' '
 	cd "$TRASH_DIRECTORY/full" &&
-	git rev-parse commits/8 | git commit-graph write --stdin-commits &&
-	git commit-graph verify >output
+	git rev-parse commits/8 | GIT_TEST_COMMIT_GRAPH_NO_GDAT=1 git commit-graph write --stdin-commits &&
+	git commit-graph verify >output &&
+	graph_read_expect 9 extra_edges
 '
 
 NUM_COMMITS=9
@@ -741,4 +742,56 @@ test_expect_success 'corrupt commit-graph write (missing tree)' '
 	)
 '
 
+# We test the overflow-related code with the following repo history:
+#
+#               4:F - 5:N - 6:U
+#              /                \
+# 1:U - 2:N - 3:U                M:N
+#              \                /
+#               7:N - 8:F - 9:N
+#
+# Here the commits denoted by U have committer date of zero seconds
+# since Unix epoch, the commits denoted by N have committer date
+# starting from 1112354055 seconds since Unix epoch (default committer
+# date for the test suite), and the commits denoted by F have committer
+# date of (2 ^ 31 - 2) seconds since Unix epoch.
+#
+# The largest offset observed is 2 ^ 31, just large enough to overflow.
+#
+
+test_expect_success 'set up and verify repo with generation data overflow chunk' '
+	objdir=".git/objects" &&
+	UNIX_EPOCH_ZERO="@0 +0000" &&
+	FUTURE_DATE="@2147483646 +0000" &&
+	test_oid_cache <<-EOF &&
+	oid_version sha1:1
+	oid_version sha256:2
+	EOF
+	cd "$TRASH_DIRECTORY" &&
+	mkdir repo &&
+	cd repo &&
+	git init &&
+	test_commit --date "$UNIX_EPOCH_ZERO" 1 &&
+	test_commit 2 &&
+	test_commit --date "$UNIX_EPOCH_ZERO" 3 &&
+	git commit-graph write --reachable &&
+	graph_read_expect 3 generation_data &&
+	test_commit --date "$FUTURE_DATE" 4 &&
+	test_commit 5 &&
+	test_commit --date "$UNIX_EPOCH_ZERO" 6 &&
+	git branch left &&
+	git reset --hard 3 &&
+	test_commit 7 &&
+	test_commit --date "$FUTURE_DATE" 8 &&
+	test_commit 9 &&
+	git branch right &&
+	git reset --hard 3 &&
+	test_merge M left right &&
+	git commit-graph write --reachable &&
+	graph_read_expect 10 "generation_data generation_data_overflow" &&
+	git commit-graph verify
+'
+
+graph_git_behavior 'generation data overflow chunk repo' repo left right
+
 test_done
diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh
index 4d3842b83b..8e90f3423b 100755
--- a/t/t5324-split-commit-graph.sh
+++ b/t/t5324-split-commit-graph.sh
@@ -13,11 +13,11 @@ test_expect_success 'setup repo' '
 	infodir=".git/objects/info" &&
 	graphdir="$infodir/commit-graphs" &&
 	test_oid_cache <<-EOM
-	shallow sha1:1760
-	shallow sha256:2064
+	shallow sha1:2132
+	shallow sha256:2436
 
-	base sha1:1376
-	base sha256:1496
+	base sha1:1408
+	base sha256:1528
 
 	oid_version sha1:1
 	oid_version sha256:2
@@ -31,9 +31,9 @@ graph_read_expect() {
 		NUM_BASE=$2
 	fi
 	cat >expect <<- EOF
-	header: 43475048 1 $(test_oid oid_version) 3 $NUM_BASE
+	header: 43475048 1 $(test_oid oid_version) 4 $NUM_BASE
 	num_commits: $1
-	chunks: oid_fanout oid_lookup commit_metadata
+	chunks: oid_fanout oid_lookup commit_metadata generation_data
 	EOF
 	test-tool read-graph >output &&
 	test_cmp expect output
@@ -453,4 +453,185 @@ test_expect_success 'prevent regression for duplicate commits across layers' '
 	git -C dup commit-graph verify
 '
 
+NUM_FIRST_LAYER_COMMITS=64
+NUM_SECOND_LAYER_COMMITS=16
+NUM_THIRD_LAYER_COMMITS=7
+NUM_FOURTH_LAYER_COMMITS=8
+NUM_FIFTH_LAYER_COMMITS=16
+SECOND_LAYER_SEQUENCE_START=$(($NUM_FIRST_LAYER_COMMITS + 1))
+SECOND_LAYER_SEQUENCE_END=$(($SECOND_LAYER_SEQUENCE_START + $NUM_SECOND_LAYER_COMMITS - 1))
+THIRD_LAYER_SEQUENCE_START=$(($SECOND_LAYER_SEQUENCE_END + 1))
+THIRD_LAYER_SEQUENCE_END=$(($THIRD_LAYER_SEQUENCE_START + $NUM_THIRD_LAYER_COMMITS - 1))
+FOURTH_LAYER_SEQUENCE_START=$(($THIRD_LAYER_SEQUENCE_END + 1))
+FOURTH_LAYER_SEQUENCE_END=$(($FOURTH_LAYER_SEQUENCE_START + $NUM_FOURTH_LAYER_COMMITS - 1))
+FIFTH_LAYER_SEQUENCE_START=$(($FOURTH_LAYER_SEQUENCE_END + 1))
+FIFTH_LAYER_SEQUENCE_END=$(($FIFTH_LAYER_SEQUENCE_START + $NUM_FIFTH_LAYER_COMMITS - 1))
+
+# Current split graph chain:
+#
+#     16 commits (No GDAT)
+# ------------------------
+#     64 commits (GDAT)
+#
+test_expect_success 'setup repo for mixed generation commit-graph-chain' '
+	graphdir=".git/objects/info/commit-graphs" &&
+	test_oid_cache <<-EOF &&
+	oid_version sha1:1
+	oid_version sha256:2
+	EOF
+	git init mixed &&
+	(
+		cd mixed &&
+		git config core.commitGraph true &&
+		git config gc.writeCommitGraph false &&
+		for i in $(test_seq $NUM_FIRST_LAYER_COMMITS)
+		do
+			test_commit $i &&
+			git branch commits/$i || return 1
+		done &&
+		git commit-graph write --reachable --split &&
+		graph_read_expect $NUM_FIRST_LAYER_COMMITS &&
+		test_line_count = 1 $graphdir/commit-graph-chain &&
+		for i in $(test_seq $SECOND_LAYER_SEQUENCE_START $SECOND_LAYER_SEQUENCE_END)
+		do
+			test_commit $i &&
+			git branch commits/$i || return 1
+		done &&
+		GIT_TEST_COMMIT_GRAPH_NO_GDAT=1 git commit-graph write --reachable --split=no-merge &&
+		test_line_count = 2 $graphdir/commit-graph-chain &&
+		test-tool read-graph >output &&
+		cat >expect <<-EOF &&
+		header: 43475048 1 $(test_oid oid_version) 4 1
+		num_commits: $NUM_SECOND_LAYER_COMMITS
+		chunks: oid_fanout oid_lookup commit_metadata
+		EOF
+		test_cmp expect output &&
+		git commit-graph verify &&
+		cat $graphdir/commit-graph-chain
+	)
+'
+
+# The new layer will be added without generation data chunk as it was not
+# present on the layer underneath it.
+#
+#      7 commits (No GDAT)
+# ------------------------
+#     16 commits (No GDAT)
+# ------------------------
+#     64 commits (GDAT)
+#
+test_expect_success 'do not write generation data chunk if not present on existing tip' '
+	git clone mixed mixed-no-gdat &&
+	(
+		cd mixed-no-gdat &&
+		for i in $(test_seq $THIRD_LAYER_SEQUENCE_START $THIRD_LAYER_SEQUENCE_END)
+		do
+			test_commit $i &&
+			git branch commits/$i || return 1
+		done &&
+		git commit-graph write --reachable --split=no-merge &&
+		test_line_count = 3 $graphdir/commit-graph-chain &&
+		test-tool read-graph >output &&
+		cat >expect <<-EOF &&
+		header: 43475048 1 $(test_oid oid_version) 4 2
+		num_commits: $NUM_THIRD_LAYER_COMMITS
+		chunks: oid_fanout oid_lookup commit_metadata
+		EOF
+		test_cmp expect output &&
+		git commit-graph verify
+	)
+'
+
+# Number of commits in each layer of the split-commit graph before merge:
+#
+#      8 commits (No GDAT)
+# ------------------------
+#      7 commits (No GDAT)
+# ------------------------
+#     16 commits (No GDAT)
+# ------------------------
+#     64 commits (GDAT)
+#
+# The top two layers are merged and do not have generation data chunk as layer below them does
+# not have generation data chunk.
+#
+#     15 commits (No GDAT)
+# ------------------------
+#     16 commits (No GDAT)
+# ------------------------
+#     64 commits (GDAT)
+#
+test_expect_success 'do not write generation data chunk if the topmost remaining layer does not have generation data chunk' '
+	git clone mixed-no-gdat mixed-merge-no-gdat &&
+	(
+		cd mixed-merge-no-gdat &&
+		for i in $(test_seq $FOURTH_LAYER_SEQUENCE_START $FOURTH_LAYER_SEQUENCE_END)
+		do
+			test_commit $i &&
+			git branch commits/$i || return 1
+		done &&
+		git commit-graph write --reachable --split --size-multiple 1 &&
+		test_line_count = 3 $graphdir/commit-graph-chain &&
+		test-tool read-graph >output &&
+		cat >expect <<-EOF &&
+		header: 43475048 1 $(test_oid oid_version) 4 2
+		num_commits: $(($NUM_THIRD_LAYER_COMMITS + $NUM_FOURTH_LAYER_COMMITS))
+		chunks: oid_fanout oid_lookup commit_metadata
+		EOF
+		test_cmp expect output &&
+		git commit-graph verify
+	)
+'
+
+# Number of commits in each layer of the split-commit graph before merge:
+#
+#     16 commits (No GDAT)
+# ------------------------
+#     15 commits (No GDAT)
+# ------------------------
+#     16 commits (No GDAT)
+# ------------------------
+#     64 commits (GDAT)
+#
+# The top three layers are merged and has generation data chunk as the topmost remaining layer
+# has generation data chunk.
+#
+#     47 commits (GDAT)
+# ------------------------
+#     64 commits (GDAT)
+#
+test_expect_success 'write generation data chunk if topmost remaining layer has generation data chunk' '
+	git clone mixed-merge-no-gdat mixed-merge-gdat &&
+	(
+		cd mixed-merge-gdat &&
+		for i in $(test_seq $FIFTH_LAYER_SEQUENCE_START $FIFTH_LAYER_SEQUENCE_END)
+		do
+			test_commit $i &&
+			git branch commits/$i || return 1
+		done &&
+		git commit-graph write --reachable --split --size-multiple 1 &&
+		test_line_count = 2 $graphdir/commit-graph-chain &&
+		test-tool read-graph >output &&
+		cat >expect <<-EOF &&
+		header: 43475048 1 $(test_oid oid_version) 5 1
+		num_commits: $(($NUM_SECOND_LAYER_COMMITS + $NUM_THIRD_LAYER_COMMITS + $NUM_FOURTH_LAYER_COMMITS + $NUM_FIFTH_LAYER_COMMITS))
+		chunks: oid_fanout oid_lookup commit_metadata generation_data
+		EOF
+		test_cmp expect output
+	)
+'
+
+test_expect_success 'write generation data chunk when commit-graph chain is replaced' '
+	git clone mixed mixed-replace &&
+	(
+		cd mixed-replace &&
+		git commit-graph write --reachable --split=replace &&
+		test_path_is_file $graphdir/commit-graph-chain &&
+		test_line_count = 1 $graphdir/commit-graph-chain &&
+		verify_chain_files_exist $graphdir &&
+		graph_read_expect $(($NUM_FIRST_LAYER_COMMITS + $NUM_SECOND_LAYER_COMMITS)) &&
+		git commit-graph verify
+	)
+'
+
 test_done
diff --git a/t/t6404-recursive-merge.sh b/t/t6404-recursive-merge.sh
index c7ab7048f5..eaf48e941e 100755
--- a/t/t6404-recursive-merge.sh
+++ b/t/t6404-recursive-merge.sh
@@ -18,6 +18,8 @@ GIT_COMMITTER_DATE="2006-12-12 23:28:00 +0100"
 export GIT_COMMITTER_DATE
 
 test_expect_success 'setup tests' '
+	GIT_TEST_COMMIT_GRAPH=0 &&
+	export GIT_TEST_COMMIT_GRAPH &&
 	echo 1 >a1 &&
 	git add a1 &&
 	GIT_AUTHOR_DATE="2006-12-12 23:00:00" git commit -m 1 a1 &&
@@ -69,7 +71,7 @@ test_expect_success 'setup tests' '
 '
 
 test_expect_success 'combined merge conflicts' '
-	test_must_fail env GIT_TEST_COMMIT_GRAPH=0 git merge -m final G
+	test_must_fail git merge -m final G
 '
 
 test_expect_success 'result contains a conflict' '
@@ -85,6 +87,7 @@ test_expect_success 'result contains a conflict' '
 '
 
 test_expect_success 'virtual trees were processed' '
+	# TODO: fragile test, relies on ambigious merge-base resolution
 	git ls-files --stage >out &&
 
 	cat >expect <<-EOF &&
diff --git a/t/t6600-test-reach.sh b/t/t6600-test-reach.sh
index f807276337..e2d33a8a4c 100755
--- a/t/t6600-test-reach.sh
+++ b/t/t6600-test-reach.sh
@@ -55,10 +55,13 @@ test_expect_success 'setup' '
 	git show-ref -s commit-5-5 | git commit-graph write --stdin-commits &&
 	mv .git/objects/info/commit-graph commit-graph-half &&
 	chmod u+w commit-graph-half &&
+	GIT_TEST_COMMIT_GRAPH_NO_GDAT=1 git commit-graph write --reachable &&
+	mv .git/objects/info/commit-graph commit-graph-no-gdat &&
+	chmod u+w commit-graph-no-gdat &&
 	git config core.commitGraph true
 '
 
-run_three_modes () {
+run_all_modes () {
 	test_when_finished rm -rf .git/objects/info/commit-graph &&
 	"$@" <input >actual &&
 	test_cmp expect actual &&
@@ -67,11 +70,14 @@ run_three_modes () {
 	test_cmp expect actual &&
 	cp commit-graph-half .git/objects/info/commit-graph &&
 	"$@" <input >actual &&
+	test_cmp expect actual &&
+	cp commit-graph-no-gdat .git/objects/info/commit-graph &&
+	"$@" <input >actual &&
 	test_cmp expect actual
 }
 
-test_three_modes () {
-	run_three_modes test-tool reach "$@"
+test_all_modes () {
+	run_all_modes test-tool reach "$@"
 }
 
 test_expect_success 'ref_newer:miss' '
@@ -80,7 +86,7 @@ test_expect_success 'ref_newer:miss' '
 	B:commit-4-9
 	EOF
 	echo "ref_newer(A,B):0" >expect &&
-	test_three_modes ref_newer
+	test_all_modes ref_newer
 '
 
 test_expect_success 'ref_newer:hit' '
@@ -89,7 +95,7 @@ test_expect_success 'ref_newer:hit' '
 	B:commit-2-3
 	EOF
 	echo "ref_newer(A,B):1" >expect &&
-	test_three_modes ref_newer
+	test_all_modes ref_newer
 '
 
 test_expect_success 'in_merge_bases:hit' '
@@ -98,7 +104,7 @@ test_expect_success 'in_merge_bases:hit' '
 	B:commit-8-8
 	EOF
 	echo "in_merge_bases(A,B):1" >expect &&
-	test_three_modes in_merge_bases
+	test_all_modes in_merge_bases
 '
 
 test_expect_success 'in_merge_bases:miss' '
@@ -107,7 +113,7 @@ test_expect_success 'in_merge_bases:miss' '
 	B:commit-5-9
 	EOF
 	echo "in_merge_bases(A,B):0" >expect &&
-	test_three_modes in_merge_bases
+	test_all_modes in_merge_bases
 '
 
 test_expect_success 'in_merge_bases_many:hit' '
@@ -117,7 +123,7 @@ test_expect_success 'in_merge_bases_many:hit' '
 	X:commit-5-7
 	EOF
 	echo "in_merge_bases_many(A,X):1" >expect &&
-	test_three_modes in_merge_bases_many
+	test_all_modes in_merge_bases_many
 '
 
 test_expect_success 'in_merge_bases_many:miss' '
@@ -127,7 +133,7 @@ test_expect_success 'in_merge_bases_many:miss' '
 	X:commit-8-6
 	EOF
 	echo "in_merge_bases_many(A,X):0" >expect &&
-	test_three_modes in_merge_bases_many
+	test_all_modes in_merge_bases_many
 '
 
 test_expect_success 'in_merge_bases_many:miss-heuristic' '
@@ -137,7 +143,7 @@ test_expect_success 'in_merge_bases_many:miss-heuristic' '
 	X:commit-6-6
 	EOF
 	echo "in_merge_bases_many(A,X):0" >expect &&
-	test_three_modes in_merge_bases_many
+	test_all_modes in_merge_bases_many
 '
 
 test_expect_success 'is_descendant_of:hit' '
@@ -148,7 +154,7 @@ test_expect_success 'is_descendant_of:hit' '
 	X:commit-1-1
 	EOF
 	echo "is_descendant_of(A,X):1" >expect &&
-	test_three_modes is_descendant_of
+	test_all_modes is_descendant_of
 '
 
 test_expect_success 'is_descendant_of:miss' '
@@ -159,7 +165,7 @@ test_expect_success 'is_descendant_of:miss' '
 	X:commit-7-6
 	EOF
 	echo "is_descendant_of(A,X):0" >expect &&
-	test_three_modes is_descendant_of
+	test_all_modes is_descendant_of
 '
 
 test_expect_success 'get_merge_bases_many' '
@@ -174,7 +180,7 @@ test_expect_success 'get_merge_bases_many' '
 		git rev-parse commit-5-6 \
 			      commit-4-7 | sort
 	} >expect &&
-	test_three_modes get_merge_bases_many
+	test_all_modes get_merge_bases_many
 '
 
 test_expect_success 'reduce_heads' '
@@ -196,7 +202,7 @@ test_expect_success 'reduce_heads' '
 			      commit-2-8 \
 			      commit-1-10 | sort
 	} >expect &&
-	test_three_modes reduce_heads
+	test_all_modes reduce_heads
 '
 
 test_expect_success 'can_all_from_reach:hit' '
@@ -219,7 +225,7 @@ test_expect_success 'can_all_from_reach:hit' '
 	Y:commit-8-1
 	EOF
 	echo "can_all_from_reach(X,Y):1" >expect &&
-	test_three_modes can_all_from_reach
+	test_all_modes can_all_from_reach
 '
 
 test_expect_success 'can_all_from_reach:miss' '
@@ -241,7 +247,7 @@ test_expect_success 'can_all_from_reach:miss' '
 	Y:commit-8-5
 	EOF
 	echo "can_all_from_reach(X,Y):0" >expect &&
-	test_three_modes can_all_from_reach
+	test_all_modes can_all_from_reach
 '
 
 test_expect_success 'can_all_from_reach_with_flag: tags case' '
@@ -264,7 +270,7 @@ test_expect_success 'can_all_from_reach_with_flag: tags case' '
 	Y:commit-8-1
 	EOF
 	echo "can_all_from_reach_with_flag(X,_,_,0,0):1" >expect &&
-	test_three_modes can_all_from_reach_with_flag
+	test_all_modes can_all_from_reach_with_flag
 '
 
 test_expect_success 'commit_contains:hit' '
@@ -280,8 +286,8 @@ test_expect_success 'commit_contains:hit' '
 	X:commit-9-3
 	EOF
 	echo "commit_contains(_,A,X,_):1" >expect &&
-	test_three_modes commit_contains &&
-	test_three_modes commit_contains --tag
+	test_all_modes commit_contains &&
+	test_all_modes commit_contains --tag
 '
 
 test_expect_success 'commit_contains:miss' '
@@ -297,8 +303,8 @@ test_expect_success 'commit_contains:miss' '
 	X:commit-9-3
 	EOF
 	echo "commit_contains(_,A,X,_):0" >expect &&
-	test_three_modes commit_contains &&
-	test_three_modes commit_contains --tag
+	test_all_modes commit_contains &&
+	test_all_modes commit_contains --tag
 '
 
 test_expect_success 'rev-list: basic topo-order' '
@@ -310,7 +316,7 @@ test_expect_success 'rev-list: basic topo-order' '
 		commit-6-2 commit-5-2 commit-4-2 commit-3-2 commit-2-2 commit-1-2 \
 		commit-6-1 commit-5-1 commit-4-1 commit-3-1 commit-2-1 commit-1-1 \
 	>expect &&
-	run_three_modes git rev-list --topo-order commit-6-6
+	run_all_modes git rev-list --topo-order commit-6-6
 '
 
 test_expect_success 'rev-list: first-parent topo-order' '
@@ -322,7 +328,7 @@ test_expect_success 'rev-list: first-parent topo-order' '
 		commit-6-2 \
 		commit-6-1 commit-5-1 commit-4-1 commit-3-1 commit-2-1 commit-1-1 \
 	>expect &&
-	run_three_modes git rev-list --first-parent --topo-order commit-6-6
+	run_all_modes git rev-list --first-parent --topo-order commit-6-6
 '
 
 test_expect_success 'rev-list: range topo-order' '
@@ -334,7 +340,7 @@ test_expect_success 'rev-list: range topo-order' '
 		commit-6-2 commit-5-2 commit-4-2 \
 		commit-6-1 commit-5-1 commit-4-1 \
 	>expect &&
-	run_three_modes git rev-list --topo-order commit-3-3..commit-6-6
+	run_all_modes git rev-list --topo-order commit-3-3..commit-6-6
 '
 
 test_expect_success 'rev-list: range topo-order' '
@@ -346,7 +352,7 @@ test_expect_success 'rev-list: range topo-order' '
 		commit-6-2 commit-5-2 commit-4-2 \
 		commit-6-1 commit-5-1 commit-4-1 \
 	>expect &&
-	run_three_modes git rev-list --topo-order commit-3-8..commit-6-6
+	run_all_modes git rev-list --topo-order commit-3-8..commit-6-6
 '
 
 test_expect_success 'rev-list: first-parent range topo-order' '
@@ -358,7 +364,7 @@ test_expect_success 'rev-list: first-parent range topo-order' '
 		commit-6-2 \
 		commit-6-1 commit-5-1 commit-4-1 \
 	>expect &&
-	run_three_modes git rev-list --first-parent --topo-order commit-3-8..commit-6-6
+	run_all_modes git rev-list --first-parent --topo-order commit-3-8..commit-6-6
 '
 
 test_expect_success 'rev-list: ancestry-path topo-order' '
@@ -368,7 +374,7 @@ test_expect_success 'rev-list: ancestry-path topo-order' '
 		commit-6-4 commit-5-4 commit-4-4 commit-3-4 \
 		commit-6-3 commit-5-3 commit-4-3 \
 	>expect &&
-	run_three_modes git rev-list --topo-order --ancestry-path commit-3-3..commit-6-6
+	run_all_modes git rev-list --topo-order --ancestry-path commit-3-3..commit-6-6
 '
 
 test_expect_success 'rev-list: symmetric difference topo-order' '
@@ -382,7 +388,7 @@ test_expect_success 'rev-list: symmetric difference topo-order' '
 		commit-3-8 commit-2-8 commit-1-8 \
 		commit-3-7 commit-2-7 commit-1-7 \
 	>expect &&
-	run_three_modes git rev-list --topo-order commit-3-8...commit-6-6
+	run_all_modes git rev-list --topo-order commit-3-8...commit-6-6
 '
 
 test_expect_success 'get_reachable_subset:all' '
@@ -402,7 +408,7 @@ test_expect_success 'get_reachable_subset:all' '
 			      commit-1-7 \
 			      commit-5-6 | sort
 	) >expect &&
-	test_three_modes get_reachable_subset
+	test_all_modes get_reachable_subset
 '
 
 test_expect_success 'get_reachable_subset:some' '
@@ -420,7 +426,7 @@ test_expect_success 'get_reachable_subset:some' '
 		git rev-parse commit-3-3 \
 			      commit-1-7 | sort
 	) >expect &&
-	test_three_modes get_reachable_subset
+	test_all_modes get_reachable_subset
 '
 
 test_expect_success 'get_reachable_subset:none' '
@@ -434,7 +440,7 @@ test_expect_success 'get_reachable_subset:none' '
 	Y:commit-2-8
 	EOF
 	echo "get_reachable_subset(X,Y)" >expect &&
-	test_three_modes get_reachable_subset
+	test_all_modes get_reachable_subset
 '
 
 test_done
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 07976af81c..05dc2cc6be 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -218,6 +218,12 @@ test_commit () {
 		--signoff)
 			signoff="$1"
 			;;
+		--date)
+			notick=yes
+			GIT_COMMITTER_DATE="$2"
+			GIT_AUTHOR_DATE="$2"
+			shift
+			;;
 		-C)
 			indir="$2"
 			shift