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authorJunio C Hamano <junkio@cox.net>2005-11-11 01:21:54 (GMT)
committerJunio C Hamano <junkio@cox.net>2005-11-11 18:52:30 (GMT)
commited9a540b2b351ea305e26bb0d9028f21c976b67c (patch)
treec19318a20552a25360f54fcc3b4890fbe23d37de /merge-base.c
parent592ee97d8fffa2318960074057e044709163abf7 (diff)
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merge-base: fully contaminate the well.
The discussion on the list demonstrated a pathological case where an ancestor of a merge-base can be left interesting. This commit introduces a postprocessing phase to fix it. Signed-off-by: Junio C Hamano <junkio@cox.net>
Diffstat (limited to 'merge-base.c')
-rw-r--r--merge-base.c78
1 files changed, 77 insertions, 1 deletions
diff --git a/merge-base.c b/merge-base.c
index 286bf0e..43a6818 100644
--- a/merge-base.c
+++ b/merge-base.c
@@ -80,6 +80,45 @@ static struct commit *interesting(struct commit_list *list)
* Now, list does not have any interesting commit. So we find the newest
* commit from the result list that is not marked uninteresting. Which is
* commit B.
+ *
+ *
+ * Another pathological example how this thing can fail to mark an ancestor
+ * of a merge base as UNINTERESTING without the postprocessing phase.
+ *
+ * 2
+ * H
+ * 1 / \
+ * G A \
+ * |\ / \
+ * | B \
+ * | \ \
+ * \ C F
+ * \ \ /
+ * \ D /
+ * \ | /
+ * \| /
+ * E
+ *
+ * list A B C D E F G H
+ * G1 H2 - - - - - - 1 2
+ * H2 E1 B1 - 1 - - 1 - 1 2
+ * F2 E1 B1 A2 2 1 - - 1 2 1 2
+ * E3 B1 A2 2 1 - - 3 2 1 2
+ * B1 A2 2 1 - - 3 2 1 2
+ * C1 A2 2 1 1 - 3 2 1 2
+ * D1 A2 2 1 1 1 3 2 1 2
+ * A2 2 1 1 1 3 2 1 2
+ * B3 2 3 1 1 3 2 1 2
+ * C7 2 3 7 1 3 2 1 2
+ *
+ * At this point, unfortunately, everybody in the list is
+ * uninteresting, so we fail to complete the following two
+ * steps to fully marking uninteresting commits.
+ *
+ * D7 2 3 7 7 3 2 1 2
+ * E7 2 3 7 7 7 2 1 2
+ *
+ * and we end up showing E as an interesting merge base.
*/
static int show_all = 0;
@@ -88,6 +127,7 @@ static int merge_base(struct commit *rev1, struct commit *rev2)
{
struct commit_list *list = NULL;
struct commit_list *result = NULL;
+ struct commit_list *tmp = NULL;
if (rev1 == rev2) {
printf("%s\n", sha1_to_hex(rev1->object.sha1));
@@ -104,9 +144,10 @@ static int merge_base(struct commit *rev1, struct commit *rev2)
while (interesting(list)) {
struct commit *commit = list->item;
- struct commit_list *tmp = list, *parents;
+ struct commit_list *parents;
int flags = commit->object.flags & 7;
+ tmp = list;
list = list->next;
free(tmp);
if (flags == 3) {
@@ -130,6 +171,41 @@ static int merge_base(struct commit *rev1, struct commit *rev2)
if (!result)
return 1;
+ /*
+ * Postprocess to fully contaminate the well.
+ */
+ for (tmp = result; tmp; tmp = tmp->next) {
+ struct commit *c = tmp->item;
+ /* Reinject uninteresting ones to list,
+ * so we can scan their parents.
+ */
+ if (c->object.flags & UNINTERESTING)
+ commit_list_insert(c, &list);
+ }
+ while (list) {
+ struct commit *c = list->item;
+ struct commit_list *parents;
+
+ tmp = list;
+ list = list->next;
+ free(tmp);
+
+ /* Anything taken out of the list is uninteresting, so
+ * mark all its parents uninteresting. We do not
+ * parse new ones (we already parsed all the relevant
+ * ones).
+ */
+ parents = c->parents;
+ while (parents) {
+ struct commit *p = parents->item;
+ parents = parents->next;
+ if (!(p->object.flags & UNINTERESTING)) {
+ p->object.flags |= UNINTERESTING;
+ commit_list_insert(p, &list);
+ }
+ }
+ }
+
while (result) {
struct commit *commit = result->item;
result = result->next;