This is like get_merge_bases() but it works for multiple heads, like
show-branch --merge-base.
Signed-off-by: Miklos Vajna <vmiklos@xxxxxxxxxxxxxx>
---
On Wed, Jun 11, 2008 at 04:51:49PM -0700, Junio C Hamano <gitster@xxxxxxxxx> wrote:
> Why is passing "cleanup" through to get_merge_bases() safe, even when you
> are running it more than once?
>
> get_merge_bases() uses PARENT1, PARENT2 and other flags internally, and
> the information necessary to clean them efficiently (i.e. the set of
> commits that could be smudged with these flags due to its operation) is
> known only to it _after it finishes_. You cannot even say "previous run
> did not clean things up, so please clean-up before starting this round"
> upfront. That is why we have clean-up loops at the _end_ of the function
> after it finishes computing what it wants to return.
>
> The only reason clean-up is optional to the function is because there are
> one-shot callers such as "git merge-base" that do not want to pay penalty
> for cleaning up (the only time you do not have to tell it to clean up is
> when you know the invocation is the _last_ invocation of the function, iow
> there is no later invocation that will be harmed by leftover flags).
Yes, you have reason, cleanup in get_octopus_merge_bases() should not be
optional. Here is an updated patch that does not have this problem.
(Also available in my working branch where I fixed up 9/10 and 10/10 to
reflect this change.)
commit.c | 27 +++++++++++++++++++++++++++
commit.h | 1 +
2 files changed, 28 insertions(+), 0 deletions(-)
diff --git a/commit.c b/commit.c
index bbf9c75..6052ca3 100644
--- a/commit.c
+++ b/commit.c
@@ -600,6 +600,33 @@ static struct commit_list *merge_bases(struct commit *one, struct commit *two)
return result;
}
+struct commit_list *get_octopus_merge_bases(struct commit_list *in)
+{
+ struct commit_list *i, *j, *k, *ret = NULL;
+ struct commit_list **pptr = &ret;
+
+ for (i = in; i; i = i->next) {
+ if (!ret)
+ pptr = &commit_list_insert(i->item, pptr)->next;
+ else {
+ struct commit_list *new = NULL, *end = NULL;
+
+ for (j = ret; j; j = j->next) {
+ struct commit_list *bases;
+ bases = get_merge_bases(i->item, j->item, 1);
+ if (!new)
+ new = bases;
+ else
+ end->next = bases;
+ for (k = bases; k; k = k->next)
+ end = k;
+ }
+ ret = new;
+ }
+ }
+ return ret;
+}
+
struct commit_list *get_merge_bases(struct commit *one,
struct commit *two, int cleanup)
{
diff --git a/commit.h b/commit.h
index 7f8c5ee..dcec7fb 100644
--- a/commit.h
+++ b/commit.h
@@ -121,6 +121,7 @@ int read_graft_file(const char *graft_file);
struct commit_graft *lookup_commit_graft(const unsigned char *sha1);
extern struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2, int cleanup);
+extern struct commit_list *get_octopus_merge_bases(struct commit_list *in);
extern int register_shallow(const unsigned char *sha1);
extern int unregister_shallow(const unsigned char *sha1);
--
1.5.6.rc2.dirty
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