string_list_clear(&subjects, 0);
 }
 
-static void do_fmt_merge_msg_title(struct strbuf *out,
+static void fmt_merge_msg_title(struct strbuf *out,
        const char *current_branch) {
        int i = 0;
        char *sep = "";
                strbuf_addf(out, " into %s\n", current_branch);
 }
 
-static int do_fmt_merge_msg(int merge_title, struct strbuf *in,
-       struct strbuf *out, int shortlog_len) {
+int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
+                 struct fmt_merge_msg_opts *opts)
+{
        int i = 0, pos = 0;
        unsigned char head_sha1[20];
        const char *current_branch;
                        die ("Error in line %d: %.*s", i, len, p);
        }
 
-       if (merge_title && srcs.nr)
-               do_fmt_merge_msg_title(out, current_branch);
+       if (opts->add_title && srcs.nr)
+               fmt_merge_msg_title(out, current_branch);
 
-       if (shortlog_len) {
+       if (opts->shortlog_len) {
                struct commit *head;
                struct rev_info rev;
 
 
                for (i = 0; i < origins.nr; i++)
                        shortlog(origins.items[i].string, origins.items[i].util,
-                                       head, &rev, shortlog_len, out);
+                                head, &rev, opts->shortlog_len, out);
        }
        if (out->len && out->buf[out->len-1] != '\n')
                strbuf_addch(out, '\n');
        return 0;
 }
 
-int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
-                 int merge_title, int shortlog_len) {
-       return do_fmt_merge_msg(merge_title, in, out, shortlog_len);
-}
-
 int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 {
        const char *inpath = NULL;
        FILE *in = stdin;
        struct strbuf input = STRBUF_INIT, output = STRBUF_INIT;
        int ret;
+       struct fmt_merge_msg_opts opts;
 
        git_config(fmt_merge_msg_config, NULL);
        argc = parse_options(argc, argv, prefix, options, fmt_merge_msg_usage,
 
        if (message)
                strbuf_addstr(&output, message);
-       ret = fmt_merge_msg(&input, &output,
-                           message ? 0 : 1,
-                           shortlog_len);
 
+       memset(&opts, 0, sizeof(opts));
+       opts.add_title = !message;
+       opts.shortlog_len = shortlog_len;
+
+       ret = fmt_merge_msg(&input, &output, &opts);
        if (ret)
                return ret;
        write_in_full(STDOUT_FILENO, output.buf, output.len);
 
                        merge_name(argv[i], &merge_names);
 
                if (!have_message || shortlog_len) {
-                       fmt_merge_msg(&merge_names, &merge_msg, !have_message,
-                                     shortlog_len);
+                       struct fmt_merge_msg_opts opts;
+                       memset(&opts, 0, sizeof(opts));
+                       opts.add_title = !have_message;
+                       opts.shortlog_len = shortlog_len;
+
+                       fmt_merge_msg(&merge_names, &merge_msg, &opts);
                        if (merge_msg.len)
                                strbuf_setlen(&merge_msg, merge_msg.len - 1);
                }