static int all, edit_flag, also, interactive, only, amend, signoff;
 static int quiet, verbose, no_verify, allow_empty, dry_run, renew_authorship;
 static int no_post_rewrite, allow_empty_message;
-static char *untracked_files_arg, *force_date;
+static char *untracked_files_arg, *force_date, *ignore_submodule_arg;
 /*
  * The default commit message cleanup mode will remove the lines
  * beginning with # (shell comments) and leading and trailing
        if (!pathspec || !*pathspec) {
                fd = hold_locked_index(&index_lock, 1);
                refresh_cache_or_die(refresh_flags);
-               if (write_cache(fd, active_cache, active_nr) ||
-                   commit_locked_index(&index_lock))
-                       die("unable to write new_index file");
+               if (active_cache_changed) {
+                       if (write_cache(fd, active_cache, active_nr) ||
+                           commit_locked_index(&index_lock))
+                               die("unable to write new_index file");
+               } else {
+                       rollback_lock_file(&index_lock);
+               }
                commit_style = COMMIT_AS_IS;
                return get_index_file();
        }
                  PARSE_OPT_OPTARG, NULL, (intptr_t)"all" },
                OPT_BOOLEAN(0, "ignored", &show_ignored_in_status,
                            "show ignored files"),
+               { OPTION_STRING, 0, "ignore-submodules", &ignore_submodule_arg, "when",
+                 "ignore changes to submodules, optional when: all, dirty, untracked. (Default: all)",
+                 PARSE_OPT_OPTARG, NULL, (intptr_t)"all" },
                OPT_END(),
        };
 
 
        fd = hold_locked_index(&index_lock, 0);
        if (0 <= fd) {
-               if (!write_cache(fd, active_cache, active_nr))
+               if (active_cache_changed &&
+                   !write_cache(fd, active_cache, active_nr))
                        commit_locked_index(&index_lock);
-               rollback_lock_file(&index_lock);
+               else
+                       rollback_lock_file(&index_lock);
        }
 
        s.is_initial = get_sha1(s.reference, sha1) ? 1 : 0;
        s.in_merge = in_merge;
+       s.ignore_submodule_arg = ignore_submodule_arg;
        wt_status_collect(&s);
 
        if (s.relative_paths)
                break;
        case STATUS_FORMAT_LONG:
                s.verbose = verbose;
+               s.ignore_submodule_arg = ignore_submodule_arg;
                wt_status_print(&s);
                break;
        }