replace_parents(&buf, argc - 1, &argv[1]);
 
+       if (remove_signature(&buf)) {
+               warning(_("the original commit '%s' has a gpg signature."), old_ref);
+               warning(_("the signature will be removed in the replacement commit!"));
+       }
+
        if (write_sha1_file(buf.buf, buf.len, commit_type, new))
                die(_("could not write replacement commit for: '%s'"), old_ref);
 
 
        return saw_signature;
 }
 
+int remove_signature(struct strbuf *buf)
+{
+       const char *line = buf->buf;
+       const char *tail = buf->buf + buf->len;
+       int in_signature = 0;
+       const char *sig_start = NULL;
+       const char *sig_end = NULL;
+
+       while (line < tail) {
+               const char *next = memchr(line, '\n', tail - line);
+               next = next ? next + 1 : tail;
+
+               if (in_signature && line[0] == ' ')
+                       sig_end = next;
+               else if (starts_with(line, gpg_sig_header) &&
+                        line[gpg_sig_header_len] == ' ') {
+                       sig_start = line;
+                       sig_end = next;
+                       in_signature = 1;
+               } else {
+                       if (*line == '\n')
+                               /* dump the whole remainder of the buffer */
+                               next = tail;
+                       in_signature = 0;
+               }
+               line = next;
+       }
+
+       if (sig_start)
+               strbuf_remove(buf, sig_start - buf->buf, sig_end - sig_start);
+
+       return sig_start != NULL;
+}
+
 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
 {
        struct merge_remote_desc *desc;
 
 
 extern int parse_signed_commit(const struct commit *commit,
                               struct strbuf *message, struct strbuf *signature);
+extern int remove_signature(struct strbuf *buf);
+
 extern void print_commit_list(struct commit_list *list,
                              const char *format_cur,
                              const char *format_last);