sequencer: use argv_array in reset_merge

Avoid using magic numbers for array size and index under `reset_merge`
function. Use `argv_array` instead. This will make code shorter and
easier to extend.

Signed-off-by: Rohit Ashiwal <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: r1walz

sequencer.c

@@ -2734,13 +2734,18 @@ static int rollback_is_safe(void)
 
 static int reset_merge(const struct object_id *oid)
 {
-	const char *argv[4];	/* reset --merge <arg> + NULL */
+	int ret;
+	struct argv_array argv = ARGV_ARRAY_INIT;
 
-	argv[0] = "reset";
-	argv[1] = "--merge";
-	argv[2] = oid_to_hex(oid);
-	argv[3] = NULL;
-	return run_command_v_opt(argv, RUN_GIT_CMD);
+	argv_array_pushl(&argv, "reset", "--merge", NULL);
+
+	if (!is_null_oid(oid))
+		argv_array_push(&argv, oid_to_hex(oid));
+
+	ret = run_command_v_opt(argv.argv, RUN_GIT_CMD);
+	argv_array_clear(&argv);
+
+	return ret;
 }
 
 static int rollback_single_pick(struct repository *r)