Commit 6d354747acf9f76200355b79907c1f370d29e8d6
2016-10-18T08:20:41
Perf: Don't perform merge operations for trivial merges. When one side of a merge is treesame to the ancestor, we can take the other side and skip all the expensive merge operations. This optimization can only be performed when the generation of REUC extension data is skipped.
diff --git a/src/merge.c b/src/merge.c
index 6934aa7..2a8fc7f 100644
--- a/src/merge.c
+++ b/src/merge.c
@@ -2018,6 +2018,26 @@ int git_merge_trees(
git_iterator_options iter_opts = GIT_ITERATOR_OPTIONS_INIT;
int error;
+ assert(out && repo);
+
+ /* if one side is treesame to the ancestor, take the other side */
+ if (ancestor_tree && merge_opts && (merge_opts->flags & GIT_MERGE_SKIP_REUC)) {
+ const git_tree *result = NULL;
+ const git_oid *ancestor_tree_id = git_tree_id(ancestor_tree);
+
+ if (our_tree && !git_oid_cmp(ancestor_tree_id, git_tree_id(our_tree)))
+ result = their_tree;
+ else if (their_tree && !git_oid_cmp(ancestor_tree_id, git_tree_id(their_tree)))
+ result = our_tree;
+
+ if (result) {
+ if ((error = git_index_new(out)) == 0)
+ error = git_index_read_tree(*out, result);
+
+ return error;
+ }
+ }
+
iter_opts.flags = GIT_ITERATOR_DONT_IGNORE_CASE;
if ((error = git_iterator_for_tree(