[PATCH v3 4/6] commit-graph: add --version=<n> option

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <dstolee@microsoft.com>

Allow the commit-graph builtin to specify the file format version
using the '--version=<n>' option. Specify the version exactly in
the verification tests as using a different version would change
the offsets used in those tests.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 Documentation/git-commit-graph.txt |  3 +++
 builtin/commit-graph.c             | 13 ++++++++-----
 t/t5318-commit-graph.sh            |  2 +-
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt
index 624470e198..1d1cc70de4 100644
--- a/Documentation/git-commit-graph.txt
+++ b/Documentation/git-commit-graph.txt
@@ -51,6 +51,9 @@ or `--stdin-packs`.)
 +
 With the `--append` option, include all commits that are present in the
 existing commit-graph file.
++
+With the `--version=<n>` option, specify the file format version. Used
+only for testing.
 
 'read'::
 
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index 7d9185dfc2..e766dd076e 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -10,7 +10,7 @@ static char const * const builtin_commit_graph_usage[] = {
 	N_("git commit-graph [--object-dir <objdir>]"),
 	N_("git commit-graph read [--object-dir <objdir>]"),
 	N_("git commit-graph verify [--object-dir <objdir>]"),
-	N_("git commit-graph write [--object-dir <objdir>] [--append] [--reachable|--stdin-packs|--stdin-commits]"),
+	N_("git commit-graph write [--object-dir <objdir>] [--append] [--reachable|--stdin-packs|--stdin-commits] [--version=<n>]"),
 	NULL
 };
 
@@ -25,7 +25,7 @@ static const char * const builtin_commit_graph_read_usage[] = {
 };
 
 static const char * const builtin_commit_graph_write_usage[] = {
-	N_("git commit-graph write [--object-dir <objdir>] [--append] [--reachable|--stdin-packs|--stdin-commits]"),
+	N_("git commit-graph write [--object-dir <objdir>] [--append] [--reachable|--stdin-packs|--stdin-commits] [--version=<n>]"),
 	NULL
 };
 
@@ -35,6 +35,7 @@ static struct opts_commit_graph {
 	int stdin_packs;
 	int stdin_commits;
 	int append;
+	int version;
 } opts;
 
 
@@ -156,6 +157,8 @@ static int graph_write(int argc, const char **argv)
 			N_("start walk at commits listed by stdin")),
 		OPT_BOOL(0, "append", &opts.append,
 			N_("include all commits already in the commit-graph file")),
+		OPT_INTEGER(0, "version", &opts.version,
+			N_("specify the file format version")),
 		OPT_END(),
 	};
 
@@ -168,12 +171,12 @@ static int graph_write(int argc, const char **argv)
 	if (!opts.obj_dir)
 		opts.obj_dir = get_object_directory();
 	if (opts.append)
-		flags |= COMMIT_GRAPH_APPEND;
+		flags |= COMMIT_GRAPH_APPEND;	
 
 	read_replace_refs = 0;
 
 	if (opts.reachable)
-		return write_commit_graph_reachable(opts.obj_dir, flags, 0);
+		return write_commit_graph_reachable(opts.obj_dir, flags, opts.version);
 
 	string_list_init(&lines, 0);
 	if (opts.stdin_packs || opts.stdin_commits) {
@@ -193,7 +196,7 @@ static int graph_write(int argc, const char **argv)
 	result = write_commit_graph(opts.obj_dir,
 				    pack_indexes,
 				    commit_hex,
-				    flags, 0);
+				    flags, opts.version);
 
 	UNLEAK(lines);
 	return result;
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index e80c1cac02..4eb5a09ef3 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -328,7 +328,7 @@ test_expect_success 'replace-objects invalidates commit-graph' '
 
 test_expect_success 'git commit-graph verify' '
 	cd "$TRASH_DIRECTORY/full" &&
-	git rev-parse commits/8 | git commit-graph write --stdin-commits &&
+	git rev-parse commits/8 | git commit-graph write --stdin-commits --version=1 &&
 	git commit-graph verify >output
 '
 
-- 
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