[RFC/PATCH 2/3] simplify-merges: never remove all TREESAME parents
From: Kevin Bracey <hidden>
Date: 2016-06-15 22:57:01
Subsystem:
documentation, the rest · Maintainers:
Jonathan Corbet, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2016-06-15 · Re: [RFC/PATCH 2/3] simplify-merges: never remove all TREESAME parents · Junio C Hamano <hidden>
- 2016-06-15 · Re: [RFC/PATCH 2/3] simplify-merges: never remove all TREESAME parents · Kevin Bracey <hidden>
- 2016-06-15 · Re: [RFC/PATCH 2/3] simplify-merges: never remove all TREESAME parents · Junio C Hamano <hidden>
In the event of an odd merge, we may find ourselves TREESAME to apparently redundant parents. Prevent simplify_merges() from removing every TREESAME parent - in the event of such a merge it's useful to see where we came actually from came. Signed-off-by: Kevin Bracey <redacted> --- Documentation/rev-list-options.txt | 3 ++- revision.c | 24 ++++++++++++++++++++++++ 2 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 380db48..0832004 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt@@ -472,7 +472,8 @@ history according to the following rules: + * Replace each parent `P` of `C'` with its simplification `P'`. In the process, drop parents that are ancestors of other parents, and - remove duplicates. + remove duplicates, but take care to never drop all parents that + we are TREESAME to. + * If after this parent rewriting, `C'` is a root or merge commit (has zero or >1 parents), a boundary commit, or !TREESAME, it remains.
diff --git a/revision.c b/revision.c
index 176eb7b..4e27c9a 100644
--- a/revision.c
+++ b/revision.c@@ -2106,8 +2106,32 @@ static int remove_marked_parents(struct rev_info *revs, struct commit *commit) { struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object); struct commit_list **pp, *p; + struct commit *su = NULL, *sm = NULL; int n, removed = 0; + /* Prescan - look for both marked and unmarked TREESAME parents */ + for (p = commit->parents, n = 0; p; p = p->next, n++) { + if (ts->treesame[n]) { + if (p->item->object.flags & TMP_MARK) { + if (!sm) sm = p->item; + } + else { + if (!su) { + su = p->item; + break; + } + } + } + } + + /* If we are TREESAME to a marked-for-deletion parent, but not to any + * unmarked parents, unmark the first TREESAME parent. We don't want + * to remove our "real" parent in the event of an "-s ours" type + * merge. + */ + if (!su && sm) + sm->object.flags &= ~TMP_MARK; + pp = &commit->parents; n = 0; while ((p = *pp) != NULL) {
--
1.8.2.1.632.gd2b1879