commit-graph: implement "--additive" option

Teach git-commit-graph to add all commits from the existing
commit-graph file to the file about to be written. This should be
used when adding new commits without performing garbage collection.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index 57a5728a33..62ac26e444 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -8,7 +8,7 @@
 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 write [--object-dir <objdir>] [--stdin-packs|--stdin-commits]"),
+	N_("git commit-graph write [--object-dir <objdir>] [--additive] [--stdin-packs|--stdin-commits]"),
 	NULL
 };
 
@@ -18,7 +18,7 @@ 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>] [--stdin-packs|--stdin-commits]"),
+	N_("git commit-graph write [--object-dir <objdir>] [--additive] [--stdin-packs|--stdin-commits]"),
 	NULL
 };
 
@@ -26,6 +26,7 @@ static struct opts_commit_graph {
 	const char *obj_dir;
 	int stdin_packs;
 	int stdin_commits;
+	int additive;
 } opts;
 
 static int graph_read(int argc, const char **argv)
@@ -94,6 +95,8 @@ static int graph_write(int argc, const char **argv)
 			N_("scan packfiles listed by stdin for commits")),
 		OPT_BOOL(0, "stdin-commits", &opts.stdin_commits,
 			N_("start walk at commits listed by stdin")),
+		OPT_BOOL(0, "additive", &opts.additive,
+			N_("include all commits already in the commit-graph file")),
 		OPT_END(),
 	};
 
@@ -131,7 +134,8 @@ static int graph_write(int argc, const char **argv)
 			   pack_indexes,
 			   packs_nr,
 			   commit_hex,
-			   commits_nr);
+			   commits_nr,
+			   opts.additive);
 
 	return 0;
 }