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From: "Abhishek Kumar via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: "Derrick Stolee" <stolee@gmail.com>,
	"Jakub Narębski" <jnareb@gmail.com>,
	"Taylor Blau" <me@ttaylor.com>,
	"Abhishek Kumar" <abhishekkumar8222@gmail.com>,
	"SZEDER Gábor" <szeder.dev@gmail.com>,
	"Abhishek Kumar" <abhishekkumar8222@gmail.com>,
	"Abhishek Kumar" <abhishekkumar8222@gmail.com>
Subject: [PATCH v6 08/11] commit-graph: implement generation data chunk
Date: Sat, 16 Jan 2021 18:11:15 +0000	[thread overview]
Message-ID: <6d0696ae216156e820a8d19ebbae00039a0f3509.1610820679.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.676.v6.git.1610820679.gitgitgadget@gmail.com>

From: Abhishek Kumar <abhishekkumar8222@gmail.com>

As discovered by Ævar, we cannot increment graph version to
distinguish between generation numbers v1 and v2 [1]. Thus, one of
pre-requistes before implementing generation number v2 was to
distinguish between graph versions in a backwards compatible manner.

We are going to introduce a new chunk called Generation DATa chunk (or
GDAT). GDAT will store corrected committer date offsets whereas CDAT
will still store topological level.

Old Git does not understand GDAT chunk and would ignore it, reading
topological levels from CDAT. New Git can parse GDAT and take advantage
of newer generation numbers, falling back to topological levels when
GDAT chunk is missing (as it would happen with a commit-graph written
by old Git).

We introduce a test environment variable 'GIT_TEST_COMMIT_GRAPH_NO_GDAT'
which forces commit-graph file to be written without generation data
chunk to emulate a commit-graph file written by old Git.

To minimize the space required to store corrrected commit date, Git
stores corrected commit date offsets into the commit-graph file, instea
of corrected commit dates. This saves us 4 bytes per commit, decreasing
the GDAT chunk size by half, but it's possible for the offset to
overflow the 4-bytes allocated for storage. As such overflows are and
should be exceedingly rare, we use the following overflow management
scheme:

We introduce a new commit-graph chunk, Generation Data OVerflow ('GDOV')
to store corrected commit dates for commits with offsets greater than
GENERATION_NUMBER_V2_OFFSET_MAX.

If the offset is greater than GENERATION_NUMBER_V2_OFFSET_MAX, we set
the MSB of the offset and the other bits store the position of corrected
commit date in GDOV chunk, similar to how Extra Edge List is maintained.

We test the overflow-related code with the following repo history:

           F - N - U
          /         \
U - N - U            N
         \          /
	  N - F - N

Where the commits denoted by U have committer date of zero seconds
since Unix epoch, the commits denoted by N have committer date of
1112354055 (default committer date for the test suite) seconds since
Unix epoch 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.

[1]: https://lore.kernel.org/git/87a7gdspo4.fsf@evledraar.gmail.com/

Signed-off-by: Abhishek Kumar <abhishekkumar8222@gmail.com>
---
 commit-graph.c                | 114 ++++++++++++++++++++++++++++++----
 commit-graph.h                |   3 +
 commit.h                      |   1 +
 t/README                      |   3 +
 t/helper/test-read-graph.c    |   4 ++
 t/t4216-log-bloom.sh          |   4 +-
 t/t5318-commit-graph.sh       |  79 +++++++++++++++++++----
 t/t5324-split-commit-graph.sh |  12 ++--
 t/t6600-test-reach.sh         |   6 ++
 t/test-lib-functions.sh       |   6 ++
 10 files changed, 200 insertions(+), 32 deletions(-)

diff --git a/commit-graph.c b/commit-graph.c
index a899f429093..7365958d9d3 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -38,11 +38,13 @@ void git_test_write_commit_graph_or_die(void)
 #define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
 #define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
 #define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */
+#define GRAPH_CHUNKID_GENERATION_DATA 0x47444154 /* "GDAT" */
+#define GRAPH_CHUNKID_GENERATION_DATA_OVERFLOW 0x47444f56 /* "GDOV" */
 #define GRAPH_CHUNKID_EXTRAEDGES 0x45444745 /* "EDGE" */
 #define GRAPH_CHUNKID_BLOOMINDEXES 0x42494458 /* "BIDX" */
 #define GRAPH_CHUNKID_BLOOMDATA 0x42444154 /* "BDAT" */
 #define GRAPH_CHUNKID_BASE 0x42415345 /* "BASE" */
-#define MAX_NUM_CHUNKS 7
+#define MAX_NUM_CHUNKS 9
 
 #define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16)
 
@@ -61,6 +63,8 @@ void git_test_write_commit_graph_or_die(void)
 #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
 			+ GRAPH_FANOUT_SIZE + the_hash_algo->rawsz)
 
+#define CORRECTED_COMMIT_DATE_OFFSET_OVERFLOW (1ULL << 31)
+
 /* Remember to update object flag allocation in object.h */
 #define REACHABLE       (1u<<15)
 
@@ -394,6 +398,20 @@ struct commit_graph *parse_commit_graph(struct repository *r,
 				graph->chunk_commit_data = data + chunk_offset;
 			break;
 
+		case GRAPH_CHUNKID_GENERATION_DATA:
+			if (graph->chunk_generation_data)
+				chunk_repeated = 1;
+			else
+				graph->chunk_generation_data = data + chunk_offset;
+			break;
+
+		case GRAPH_CHUNKID_GENERATION_DATA_OVERFLOW:
+			if (graph->chunk_generation_data_overflow)
+				chunk_repeated = 1;
+			else
+				graph->chunk_generation_data_overflow = data + chunk_offset;
+			break;
+
 		case GRAPH_CHUNKID_EXTRAEDGES:
 			if (graph->chunk_extra_edges)
 				chunk_repeated = 1;
@@ -754,8 +772,8 @@ static void fill_commit_graph_info(struct commit *item, struct commit_graph *g,
 {
 	const unsigned char *commit_data;
 	struct commit_graph_data *graph_data;
-	uint32_t lex_index;
-	uint64_t date_high, date_low;
+	uint32_t lex_index, offset_pos;
+	uint64_t date_high, date_low, offset;
 
 	while (pos < g->num_commits_in_base)
 		g = g->base_graph;
@@ -773,7 +791,19 @@ static void fill_commit_graph_info(struct commit *item, struct commit_graph *g,
 	date_low = get_be32(commit_data + g->hash_len + 12);
 	item->date = (timestamp_t)((date_high << 32) | date_low);
 
-	graph_data->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
+	if (g->chunk_generation_data) {
+		offset = (timestamp_t)get_be32(g->chunk_generation_data + sizeof(uint32_t) * lex_index);
+
+		if (offset & CORRECTED_COMMIT_DATE_OFFSET_OVERFLOW) {
+			if (!g->chunk_generation_data_overflow)
+				die(_("commit-graph requires overflow generation data but has none"));
+
+			offset_pos = offset ^ CORRECTED_COMMIT_DATE_OFFSET_OVERFLOW;
+			graph_data->generation = get_be64(g->chunk_generation_data_overflow + 8 * offset_pos);
+		} else
+			graph_data->generation = item->date + offset;
+	} else
+		graph_data->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 
 	if (g->topo_levels)
 		*topo_level_slab_at(g->topo_levels, item) = get_be32(commit_data + g->hash_len + 8) >> 2;
@@ -945,6 +975,7 @@ struct write_commit_graph_context {
 	struct oid_array oids;
 	struct packed_commit_list commits;
 	int num_extra_edges;
+	int num_generation_data_overflows;
 	unsigned long approx_nr_objects;
 	struct progress *progress;
 	int progress_done;
@@ -963,7 +994,8 @@ struct write_commit_graph_context {
 		 report_progress:1,
 		 split:1,
 		 changed_paths:1,
-		 order_by_pack:1;
+		 order_by_pack:1,
+		 write_generation_data:1;
 
 	struct topo_level_slab *topo_levels;
 	const struct commit_graph_opts *opts;
@@ -1123,6 +1155,45 @@ static int write_graph_chunk_data(struct hashfile *f,
 	return 0;
 }
 
+static int write_graph_chunk_generation_data(struct hashfile *f,
+					      struct write_commit_graph_context *ctx)
+{
+	int i, num_generation_data_overflows = 0;
+
+	for (i = 0; i < ctx->commits.nr; i++) {
+		struct commit *c = ctx->commits.list[i];
+		timestamp_t offset = commit_graph_data_at(c)->generation - c->date;
+		display_progress(ctx->progress, ++ctx->progress_cnt);
+
+		if (offset > GENERATION_NUMBER_V2_OFFSET_MAX) {
+			offset = CORRECTED_COMMIT_DATE_OFFSET_OVERFLOW | num_generation_data_overflows;
+			num_generation_data_overflows++;
+		}
+
+		hashwrite_be32(f, offset);
+	}
+
+	return 0;
+}
+
+static int write_graph_chunk_generation_data_overflow(struct hashfile *f,
+						       struct write_commit_graph_context *ctx)
+{
+	int i;
+	for (i = 0; i < ctx->commits.nr; i++) {
+		struct commit *c = ctx->commits.list[i];
+		timestamp_t offset = commit_graph_data_at(c)->generation - c->date;
+		display_progress(ctx->progress, ++ctx->progress_cnt);
+
+		if (offset > GENERATION_NUMBER_V2_OFFSET_MAX) {
+			hashwrite_be32(f, offset >> 32);
+			hashwrite_be32(f, (uint32_t) offset);
+		}
+	}
+
+	return 0;
+}
+
 static int write_graph_chunk_extra_edges(struct hashfile *f,
 					 struct write_commit_graph_context *ctx)
 {
@@ -1386,6 +1457,9 @@ static void compute_generation_numbers(struct write_commit_graph_context *ctx)
 				if (current->date && current->date > max_corrected_commit_date)
 					max_corrected_commit_date = current->date - 1;
 				commit_graph_data_at(current)->generation = max_corrected_commit_date + 1;
+
+				if (commit_graph_data_at(current)->generation - current->date > GENERATION_NUMBER_V2_OFFSET_MAX)
+					ctx->num_generation_data_overflows++;
 			}
 		}
 	}
@@ -1719,6 +1793,21 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 	chunks[2].id = GRAPH_CHUNKID_DATA;
 	chunks[2].size = (hashsz + 16) * ctx->commits.nr;
 	chunks[2].write_fn = write_graph_chunk_data;
+
+	if (git_env_bool(GIT_TEST_COMMIT_GRAPH_NO_GDAT, 0))
+		ctx->write_generation_data = 0;
+	if (ctx->write_generation_data) {
+		chunks[num_chunks].id = GRAPH_CHUNKID_GENERATION_DATA;
+		chunks[num_chunks].size = sizeof(uint32_t) * ctx->commits.nr;
+		chunks[num_chunks].write_fn = write_graph_chunk_generation_data;
+		num_chunks++;
+	}
+	if (ctx->num_generation_data_overflows) {
+		chunks[num_chunks].id = GRAPH_CHUNKID_GENERATION_DATA_OVERFLOW;
+		chunks[num_chunks].size = sizeof(timestamp_t) * ctx->num_generation_data_overflows;
+		chunks[num_chunks].write_fn = write_graph_chunk_generation_data_overflow;
+		num_chunks++;
+	}
 	if (ctx->num_extra_edges) {
 		chunks[num_chunks].id = GRAPH_CHUNKID_EXTRAEDGES;
 		chunks[num_chunks].size = 4 * ctx->num_extra_edges;
@@ -2139,6 +2228,8 @@ int write_commit_graph(struct object_directory *odb,
 	ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
 	ctx->opts = opts;
 	ctx->total_bloom_filter_data_size = 0;
+	ctx->write_generation_data = 1;
+	ctx->num_generation_data_overflows = 0;
 
 	bloom_settings.bits_per_entry = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_BITS_PER_ENTRY",
 						      bloom_settings.bits_per_entry);
@@ -2445,16 +2536,17 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
 			continue;
 
 		/*
-		 * If one of our parents has generation GENERATION_NUMBER_V1_MAX, then
-		 * our generation is also GENERATION_NUMBER_V1_MAX. Decrement to avoid
-		 * extra logic in the following condition.
+		 * If we are using topological level and one of our parents has
+		 * generation GENERATION_NUMBER_V1_MAX, then our generation is
+		 * also GENERATION_NUMBER_V1_MAX. Decrement to avoid extra logic
+		 * in the following condition.
 		 */
-		if (max_generation == GENERATION_NUMBER_V1_MAX)
+		if (!g->chunk_generation_data && max_generation == GENERATION_NUMBER_V1_MAX)
 			max_generation--;
 
 		generation = commit_graph_generation(graph_commit);
-		if (generation != max_generation + 1)
-			graph_report(_("commit-graph generation for commit %s is %"PRItime" != %"PRItime),
+		if (generation < max_generation + 1)
+			graph_report(_("commit-graph generation for commit %s is %"PRItime" < %"PRItime),
 				     oid_to_hex(&cur_oid),
 				     generation,
 				     max_generation + 1);
diff --git a/commit-graph.h b/commit-graph.h
index 2e9aa7824ee..19a02001fde 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -6,6 +6,7 @@
 #include "oidset.h"
 
 #define GIT_TEST_COMMIT_GRAPH "GIT_TEST_COMMIT_GRAPH"
+#define GIT_TEST_COMMIT_GRAPH_NO_GDAT "GIT_TEST_COMMIT_GRAPH_NO_GDAT"
 #define GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE "GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE"
 #define GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS "GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS"
 
@@ -68,6 +69,8 @@ struct commit_graph {
 	const uint32_t *chunk_oid_fanout;
 	const unsigned char *chunk_oid_lookup;
 	const unsigned char *chunk_commit_data;
+	const unsigned char *chunk_generation_data;
+	const unsigned char *chunk_generation_data_overflow;
 	const unsigned char *chunk_extra_edges;
 	const unsigned char *chunk_base_graphs;
 	const unsigned char *chunk_bloom_indexes;
diff --git a/commit.h b/commit.h
index 742d96c41e8..eff94f3f7c2 100644
--- a/commit.h
+++ b/commit.h
@@ -14,6 +14,7 @@
 #define GENERATION_NUMBER_INFINITY ((1ULL << 63) - 1)
 #define GENERATION_NUMBER_V1_MAX 0x3FFFFFFF
 #define GENERATION_NUMBER_ZERO 0
+#define GENERATION_NUMBER_V2_OFFSET_MAX ((1ULL << 31) - 1)
 
 struct commit_list {
 	struct commit *item;
diff --git a/t/README b/t/README
index c730a707705..8a121487279 100644
--- a/t/README
+++ b/t/README
@@ -393,6 +393,9 @@ 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 5f585a17256..75927b2c81d 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 d11040ce41c..dbde0161882 100755
--- a/t/t4216-log-bloom.sh
+++ b/t/t4216-log-bloom.sh
@@ -40,11 +40,11 @@ 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/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 2ed0c1544da..fa27df579a5 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 4d3842b83b9..587757b62d9 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
diff --git a/t/t6600-test-reach.sh b/t/t6600-test-reach.sh
index af10f0dc090..e2d33a8a4c4 100755
--- a/t/t6600-test-reach.sh
+++ b/t/t6600-test-reach.sh
@@ -55,6 +55,9 @@ 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
 '
 
@@ -67,6 +70,9 @@ run_all_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
 }
 
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 999982fe4a9..3ad712c3acc 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -202,6 +202,12 @@ test_commit () {
 		--signoff)
 			signoff="$1"
 			;;
+		--date)
+			notick=yes
+			GIT_COMMITTER_DATE="$2"
+			GIT_AUTHOR_DATE="$2"
+			shift
+			;;
 		-C)
 			indir="$2"
 			shift
-- 
gitgitgadget


  parent reply	other threads:[~2021-01-16 18:14 UTC|newest]

Thread overview: 211+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-28  9:13 [PATCH 0/6] [GSoC] Implement Corrected Commit Date Abhishek Kumar via GitGitGadget
2020-07-28  9:13 ` [PATCH 1/6] commit-graph: fix regression when computing bloom filter Abhishek Kumar via GitGitGadget
2020-07-28 15:28   ` Taylor Blau
2020-07-30  5:24     ` Abhishek Kumar
2020-08-04  0:46   ` Jakub Narębski
2020-08-04  0:56     ` Taylor Blau
2020-08-04 10:10       ` Jakub Narębski
2020-08-04  7:55     ` Jakub Narębski
2020-07-28  9:13 ` [PATCH 2/6] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2020-07-28 13:00   ` Derrick Stolee
2020-07-28 15:30     ` Taylor Blau
2020-08-05 23:16   ` Jakub Narębski
2020-07-28  9:13 ` [PATCH 3/6] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2020-07-28 13:14   ` Derrick Stolee
2020-07-28 15:19     ` René Scharfe
2020-07-28 15:58       ` Derrick Stolee
2020-07-28 16:01     ` Taylor Blau
2020-07-30  6:07     ` Abhishek Kumar
2020-07-28  9:13 ` [PATCH 4/6] commit-graph: consolidate compare_commits_by_gen Abhishek Kumar via GitGitGadget
2020-07-28 16:03   ` Taylor Blau
2020-07-28  9:13 ` [PATCH 5/6] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2020-07-28 16:12   ` Taylor Blau
2020-07-30  6:52     ` Abhishek Kumar
2020-07-28  9:13 ` [PATCH 6/6] commit-graph: implement corrected commit date offset Abhishek Kumar via GitGitGadget
2020-07-28 15:55   ` Derrick Stolee
2020-07-28 16:23     ` Taylor Blau
2020-07-30  7:27     ` Abhishek Kumar
2020-07-28 14:54 ` [PATCH 0/6] [GSoC] Implement Corrected Commit Date Taylor Blau
2020-07-30  7:47   ` Abhishek Kumar
2020-07-28 16:35 ` Derrick Stolee
2020-08-09  2:53 ` [PATCH v2 00/10] " Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 01/10] commit-graph: fix regression when computing bloom filter Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 02/10] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 03/10] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 04/10] commit-graph: consolidate compare_commits_by_gen Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 05/10] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2020-08-10 16:28     ` Derrick Stolee
2020-08-11 11:03       ` Abhishek Kumar
2020-08-11 12:27         ` Derrick Stolee
2020-08-11 18:58           ` Taylor Blau
2020-08-09  2:53   ` [PATCH v2 06/10] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 07/10] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2020-08-10 14:23     ` Derrick Stolee
2020-08-14  4:59       ` Abhishek Kumar
2020-08-14 12:24         ` Derrick Stolee
2020-08-09  2:53   ` [PATCH v2 08/10] commit-graph: handle mixed generation commit chains Abhishek Kumar via GitGitGadget
2020-08-10 16:42     ` Derrick Stolee
2020-08-11 11:36       ` Abhishek Kumar
2020-08-11 12:43         ` Derrick Stolee
2020-08-09  2:53   ` [PATCH v2 09/10] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 10/10] doc: add corrected commit date info Abhishek Kumar via GitGitGadget
2020-08-10 16:47   ` [PATCH v2 00/10] [GSoC] Implement Corrected Commit Date Derrick Stolee
2020-08-15 16:39   ` [PATCH v3 00/11] " Abhishek Kumar via GitGitGadget
2020-08-15 16:39     ` [PATCH v3 01/11] commit-graph: fix regression when computing bloom filter Abhishek Kumar via GitGitGadget
2020-08-17 22:30       ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 02/11] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2020-08-18 14:18       ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 03/11] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2020-08-19 17:54       ` Jakub Narębski
2020-08-21  4:11         ` Abhishek Kumar
2020-08-25 11:11           ` Jakub Narębski
2020-09-01 11:35             ` Abhishek Kumar
2020-08-15 16:39     ` [PATCH v3 04/11] commit-graph: consolidate compare_commits_by_gen Abhishek Kumar via GitGitGadget
2020-08-17 13:22       ` Derrick Stolee
2020-08-21 11:05       ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 05/11] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2020-08-21 13:14       ` Jakub Narębski
2020-08-25  5:04         ` Abhishek Kumar
2020-08-25 12:18           ` Jakub Narębski
2020-09-01 12:06             ` Abhishek Kumar
2020-09-03 13:42               ` Jakub Narębski
2020-09-05 17:21                 ` Abhishek Kumar
2020-09-13 15:39                   ` Jakub Narębski
2020-09-28 21:48                     ` Jakub Narębski
2020-10-05  5:25                       ` Abhishek Kumar
2020-08-15 16:39     ` [PATCH v3 06/11] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget
2020-08-21 18:43       ` Jakub Narębski
2020-08-25  6:14         ` Abhishek Kumar
2020-08-25  7:33           ` Jakub Narębski
2020-08-25  7:56             ` Jakub Narębski
2020-09-01 10:26               ` Abhishek Kumar
2020-09-03  9:25                 ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 07/11] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2020-08-22  0:05       ` Jakub Narębski
2020-08-25  6:49         ` Abhishek Kumar
2020-08-25 10:07           ` Jakub Narębski
2020-09-01 11:01             ` Abhishek Kumar
2020-08-15 16:39     ` [PATCH v3 08/11] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2020-08-22 13:09       ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 09/11] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget
2020-08-22 17:14       ` Jakub Narębski
2020-08-26  7:15         ` Abhishek Kumar
2020-08-26 10:38           ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 10/11] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2020-08-22 19:09       ` Jakub Narębski
2020-09-01 10:08         ` Abhishek Kumar
2020-09-03 19:11           ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 11/11] doc: add corrected commit date info Abhishek Kumar via GitGitGadget
2020-08-22 22:20       ` Jakub Narębski
2020-08-27  6:39         ` Abhishek Kumar
2020-08-27 12:43           ` Jakub Narębski
2020-08-27 13:15           ` Derrick Stolee
2020-09-01 13:01             ` Abhishek Kumar
2020-08-17  0:13     ` [PATCH v3 00/11] [GSoC] Implement Corrected Commit Date Jakub Narębski
     [not found]       ` <CANQwDwdKp7oKy9BeKdvKhwPUiq0R5MS8TCw-eWGCYCoMGv=G-g@mail.gmail.com>
2020-08-17  1:32         ` Fwd: " Taylor Blau
2020-08-17  7:56           ` Jakub Narębski
2020-08-18  6:12       ` Abhishek Kumar
2020-08-23 15:27       ` Jakub Narębski
2020-08-24  2:49         ` Abhishek Kumar
2020-10-07 14:09     ` [PATCH v4 00/10] " Abhishek Kumar via GitGitGadget
2020-10-07 14:09       ` [PATCH v4 01/10] commit-graph: fix regression when computing Bloom filters Abhishek Kumar via GitGitGadget
2020-10-24 23:16         ` Jakub Narębski
2020-10-25 20:58           ` Taylor Blau
2020-11-03  5:36             ` Abhishek Kumar
2020-10-07 14:09       ` [PATCH v4 02/10] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2020-10-24 23:41         ` Jakub Narębski
2020-10-07 14:09       ` [PATCH v4 03/10] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2020-10-25 10:52         ` Jakub Narębski
2020-10-27  6:33           ` Abhishek Kumar
2020-10-07 14:09       ` [PATCH v4 04/10] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2020-10-25 13:48         ` Jakub Narębski
2020-11-03  6:40           ` Abhishek Kumar
2020-10-07 14:09       ` [PATCH v4 05/10] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget
2020-10-25 22:17         ` Jakub Narębski
2020-10-07 14:09       ` [PATCH v4 06/10] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2020-10-27 18:53         ` Jakub Narębski
2020-11-03 11:44           ` Abhishek Kumar
2020-11-04 16:45             ` Jakub Narębski
2020-11-05 14:05               ` Philip Oakley
2020-11-05 18:22                 ` Junio C Hamano
2020-11-06 18:26                   ` Extending and updating gitglossary (was: Re: [PATCH v4 06/10] commit-graph: implement corrected commit date) Jakub Narębski
2020-11-06 19:33                     ` Extending and updating gitglossary Junio C Hamano
2020-11-08 17:23                     ` Extending and updating gitglossary (was: Re: [PATCH v4 06/10] commit-graph: implement corrected commit date) Philip Oakley
2020-11-10  1:35                       ` Extending and updating gitglossary Jakub Narębski
2020-11-10 14:04                         ` Philip Oakley
2020-11-10 23:52                           ` Jakub Narębski
2020-10-07 14:09       ` [PATCH v4 07/10] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2020-10-30 12:45         ` Jakub Narębski
2020-11-06 11:25           ` Abhishek Kumar
2020-11-06 17:56             ` Jakub Narębski
2020-10-07 14:09       ` [PATCH v4 08/10] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget
2020-11-01  0:55         ` Jakub Narębski
2020-11-12 10:01           ` Abhishek Kumar
2020-11-13  9:59             ` Jakub Narębski
2020-10-07 14:09       ` [PATCH v4 09/10] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2020-11-03 17:59         ` Jakub Narębski
2020-11-03 18:19           ` Junio C Hamano
2020-11-20 10:33           ` Abhishek Kumar
2020-10-07 14:09       ` [PATCH v4 10/10] doc: add corrected commit date info Abhishek Kumar via GitGitGadget
2020-11-04  1:37         ` Jakub Narębski
2020-11-21  6:30           ` Abhishek Kumar
2020-11-04 23:37       ` [PATCH v4 00/10] [GSoC] Implement Corrected Commit Date Jakub Narębski
2020-11-22  5:31         ` Abhishek Kumar
2020-12-28 11:15       ` [PATCH v5 00/11] " Abhishek Kumar via GitGitGadget
2020-12-28 11:15         ` [PATCH v5 01/11] commit-graph: fix regression when computing Bloom filters Abhishek Kumar via GitGitGadget
2020-12-30  1:35           ` Derrick Stolee
2021-01-08  5:45             ` Abhishek Kumar
2021-01-05  9:45           ` SZEDER Gábor
2021-01-05  9:47             ` SZEDER Gábor
2021-01-08  5:51             ` Abhishek Kumar
2020-12-28 11:15         ` [PATCH v5 02/11] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 03/11] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 04/11] t6600-test-reach: generalize *_three_modes Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 05/11] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 06/11] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 07/11] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2020-12-30  1:53           ` Derrick Stolee
2021-01-10 12:21             ` Abhishek Kumar
2020-12-28 11:16         ` [PATCH v5 08/11] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 09/11] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget
2020-12-30  3:23           ` Derrick Stolee
2021-01-10 13:13             ` Abhishek Kumar
2021-01-11 12:43               ` Derrick Stolee
2020-12-28 11:16         ` [PATCH v5 10/11] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 11/11] doc: add corrected commit date info Abhishek Kumar via GitGitGadget
2020-12-30  4:35         ` [PATCH v5 00/11] [GSoC] Implement Corrected Commit Date Derrick Stolee
2021-01-10 14:06           ` Abhishek Kumar
2021-01-16 18:11         ` [PATCH v6 " Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 01/11] commit-graph: fix regression when computing Bloom filters Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 02/11] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 03/11] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 04/11] t6600-test-reach: generalize *_three_modes Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 05/11] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 06/11] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 07/11] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` Abhishek Kumar via GitGitGadget [this message]
2021-01-16 18:11           ` [PATCH v6 09/11] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 10/11] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 11/11] doc: add corrected commit date info Abhishek Kumar via GitGitGadget
2021-01-27  0:04             ` SZEDER Gábor
2021-01-30  5:29               ` Abhishek Kumar
2021-01-31  1:45                 ` Taylor Blau
2021-01-18 21:04           ` [PATCH v6 00/11] [GSoC] Implement Corrected Commit Date Derrick Stolee
2021-01-18 22:00             ` Taylor Blau
2021-01-23 12:11               ` Abhishek Kumar
2021-01-19  0:02             ` Junio C Hamano
2021-01-23 12:07             ` Abhishek Kumar
2021-02-01  6:58           ` [PATCH v7 " Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 01/11] commit-graph: fix regression when computing Bloom filters Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 02/11] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 03/11] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 04/11] t6600-test-reach: generalize *_three_modes Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 05/11] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 06/11] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 07/11] commit-graph: document generation number v2 Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 08/11] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 09/11] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 10/11] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 11/11] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2021-02-01 13:14             ` [PATCH v7 00/11] [GSoC] Implement Corrected Commit Date Derrick Stolee
2021-02-01 18:26               ` Junio C Hamano

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