From 6d354747acf9f76200355b79907c1f370d29e8d6 Mon Sep 17 00:00:00 2001 From: Arthur Schreiber Date: Tue, 18 Oct 2016 08:20:41 +0200 Subject: [PATCH] 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. --- src/merge.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/src/merge.c b/src/merge.c index 6934aa731..2a8fc7fa6 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(