Re: Fix interesting git-rev-list corner case
- From
Linus Torvalds <torvalds@osdl.org>
- Date
- Jul 30, 2005, 22:10 UTC
- Message-ID
- <Pine.LNX.4.58.0507301507390.29650@g5.osdl.org>
- In-Reply-To
- <Pine.LNX.4.58.0507301428300.29650@g5.osdl.org>
On Sat, 30 Jul 2005, Linus Torvalds wrote:
Show 5 quoted lines
> > Yup, it's git-merge-base, and it is confused by the same thing that > confused git-rev-list. > > Thanks, I'll fix it.
Hmm.. Here's a tentative fix. I'm not really happy with it, and maybe somebody else can come up with a better one. I think this one ends up being quite a bit more expensive than the old one (it will look up _all_ common parents that have a child that isn't common, and then select the newest one of the bunch), but I haven't really thought it through very much.
I bet there is a smarter way to do this, but this _should_ fix the problem Peter sees. Peter?
Linus ---
diff --git a/merge-base.c b/merge-base.c --- a/merge-base.c +++ b/merge-base.c @@ -2,54 +2,50 @@ #include "cache.h" #include "commit.h" -static struct commit *process_list(struct commit_list **list_p, int this_mark, - int other_mark) -{ - struct commit *item = (*list_p)->item; - - if (item->object.flags & other_mark) { - return item; - } else { - pop_most_recent_commit(list_p, this_mark); - } - return NULL; -} - static struct commit *common_ancestor(struct commit *rev1, struct commit *rev2) { - struct commit_list *rev1list = NULL; - struct commit_list *rev2list = NULL; + struct commit_list *list = NULL; + struct commit_list *result = NULL; - commit_list_insert(rev1, &rev1list); - rev1->object.flags |= 0x1; - commit_list_insert(rev2, &rev2list); - rev2->object.flags |= 0x2; + if (rev1 == rev2) + return rev1; parse_commit(rev1); parse_commit(rev2); - while (rev1list || rev2list) { - struct commit *ret; - if (!rev1list) { - // process 2 - ret = process_list(&rev2list, 0x2, 0x1); - } else if (!rev2list) { - // process 1 - ret = process_list(&rev1list, 0x1, 0x2); - } else if (rev1list->item->date < rev2list->item->date) { - // process 2 - ret = process_list(&rev2list, 0x2, 0x1); - } else { - // process 1 - ret = process_list(&rev1list, 0x1, 0x2); + rev1->object.flags |= 1; + rev2->object.flags |= 2; + insert_by_date(rev1, &list); + insert_by_date(rev2, &list); + + while (list) { + struct commit *commit = list->item; + struct commit_list *tmp = list, *parents; + int flags = commit->object.flags & 3; + + list = list->next; + free(tmp); + switch (flags) { + case 3: + insert_by_date(commit, &result); + continue; + case 0: + die("git-merge-base: commit without either parent?"); } - if (ret) { - free_commit_list(rev1list); - free_commit_list(rev2list); - return ret; + parents = commit->parents; + while (parents) { + struct commit *p = parents->item; + parents = parents->next; + if ((p->object.flags & flags) == flags) + continue; + parse_commit(p); + p->object.flags |= flags; + insert_by_date(p, &list); } } - return NULL; + if (!result) + return NULL; + return result->item; } int main(int argc, char **argv) @@ -64,6 +60,8 @@ int main(int argc, char **argv) } rev1 = lookup_commit_reference(rev1key); rev2 = lookup_commit_reference(rev2key); + if (!rev1 || !rev2) + return 1; ret = common_ancestor(rev1, rev2); if (!ret) return 1;