commit-graph: use parse_options_concat()

Make use of the parse_options_concat() so we don't need to copy/paste
common options like --object-dir.

This is inspired by a similar change to "checkout" in 2087182272
(checkout: split options[] array in three pieces, 2019-03-29), and the
same pattern in the multi-pack-index command, see
60ca94769c (builtin/multi-pack-index.c: split sub-commands,
2021-03-30).

A minor behavior change here is that now we're going to list both
--object-dir and --progress first, before we'd list --progress along
with other options.

Co-authored-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/commit-graph.c

@@ -46,6 +46,20 @@ static struct opts_commit_graph {
 	int enable_changed_paths;
 } opts;
 
+static struct option common_opts[] = {
+	OPT_STRING(0, "object-dir", &opts.obj_dir,
+		   N_("dir"),
+		   N_("the object directory to store the graph")),
+	OPT_BOOL(0, "progress", &opts.progress,
+		 N_("force progress reporting")),
+	OPT_END()
+};
+
+static struct option *add_common_options(struct option *to)
+{
+	return parse_options_concat(common_opts, to);
+}
+
 static struct object_directory *find_odb(struct repository *r,
 					 const char *obj_dir)
 {
@@ -79,20 +93,17 @@ static int graph_verify(int argc, const char **argv)
 	int flags = 0;
 
 	static struct option builtin_commit_graph_verify_options[] = {
-		OPT_STRING(0, "object-dir", &opts.obj_dir,
-			   N_("dir"),
-			   N_("the object directory to store the graph")),
 		OPT_BOOL(0, "shallow", &opts.shallow,
 			 N_("if the commit-graph is split, only verify the tip file")),
-		OPT_BOOL(0, "progress", &opts.progress, N_("force progress reporting")),
 		OPT_END(),
 	};
+	struct option *options = add_common_options(builtin_commit_graph_verify_options);
 
 	trace2_cmd_mode("verify");
 
 	opts.progress = isatty(2);
 	argc = parse_options(argc, argv, NULL,
-			     builtin_commit_graph_verify_options,
+			     options,
 			     builtin_commit_graph_verify_usage, 0);
 
 	if (!opts.obj_dir)
@@ -109,6 +120,7 @@ static int graph_verify(int argc, const char **argv)
 		die_errno(_("Could not open commit-graph '%s'"), graph_name);
 
 	FREE_AND_NULL(graph_name);
+	FREE_AND_NULL(options);
 
 	if (open_ok)
 		graph = load_commit_graph_one_fd_st(the_repository, fd, &st, odb);
@@ -209,9 +221,6 @@ static int graph_write(int argc, const char **argv)
 	struct progress *progress = NULL;
 
 	static struct option builtin_commit_graph_write_options[] = {
-		OPT_STRING(0, "object-dir", &opts.obj_dir,
-			N_("dir"),
-			N_("the object directory to store the graph")),
 		OPT_BOOL(0, "reachable", &opts.reachable,
 			N_("start walk at all refs")),
 		OPT_BOOL(0, "stdin-packs", &opts.stdin_packs,
@@ -222,7 +231,6 @@ static int graph_write(int argc, const char **argv)
 			N_("include all commits already in the commit-graph file")),
 		OPT_BOOL(0, "changed-paths", &opts.enable_changed_paths,
 			N_("enable computation for changed paths")),
-		OPT_BOOL(0, "progress", &opts.progress, N_("force progress reporting")),
 		OPT_CALLBACK_F(0, "split", &write_opts.split_flags, NULL,
 			N_("allow writing an incremental commit-graph file"),
 			PARSE_OPT_OPTARG | PARSE_OPT_NONEG,
@@ -238,6 +246,7 @@ static int graph_write(int argc, const char **argv)
 			0, write_option_max_new_filters),
 		OPT_END(),
 	};
+	struct option *options = add_common_options(builtin_commit_graph_write_options);
 
 	opts.progress = isatty(2);
 	opts.enable_changed_paths = -1;
@@ -251,7 +260,7 @@ static int graph_write(int argc, const char **argv)
 	git_config(git_commit_graph_write_config, &opts);
 
 	argc = parse_options(argc, argv, NULL,
-			     builtin_commit_graph_write_options,
+			     options,
 			     builtin_commit_graph_write_usage, 0);
 
 	if (opts.reachable + opts.stdin_packs + opts.stdin_commits > 1)
@@ -307,6 +316,7 @@ static int graph_write(int argc, const char **argv)
 		result = 1;
 
 cleanup:
+	FREE_AND_NULL(options);
 	string_list_clear(&pack_indexes, 0);
 	strbuf_release(&buf);
 	return result;
@@ -314,12 +324,7 @@ cleanup:
 
 int cmd_commit_graph(int argc, const char **argv, const char *prefix)
 {
-	static struct option builtin_commit_graph_options[] = {
+	struct option *builtin_commit_graph_options = common_opts;
-		OPT_STRING(0, "object-dir", &opts.obj_dir,
-			N_("dir"),
-			N_("the object directory to store the graph")),
-		OPT_END(),
-	};
 
 	git_config(git_default_config, NULL);
 	argc = parse_options(argc, argv, prefix,