- if (commit->parents->next)
- die ("Cannot %s a multi-parent commit.", me);
+ if (commit->parents->next) {
+ /* Reverting or cherry-picking a merge commit */
+ int cnt;
+ struct commit_list *p;
+
+ if (!mainline)
+ die("Commit %s is a merge but no -m option was given.",
+ sha1_to_hex(commit->object.sha1));
+
+ for (cnt = 1, p = commit->parents;
+ cnt != mainline && p;
+ cnt++)
+ p = p->next;
+ if (cnt != mainline || !p)
+ die("Commit %s does not have parent %d",
+ sha1_to_hex(commit->object.sha1), mainline);
+ parent = p->item;
+ } else if (0 < mainline)
+ die("Mainline was specified but commit %s is not a merge.",
+ sha1_to_hex(commit->object.sha1));
+ else
+ parent = commit->parents->item;
+