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From: Elijah Newren <newren@gmail.com>
To: git@vger.kernel.org
Cc: Elijah Newren <newren@gmail.com>
Subject: [PATCH 10/20] merge-ort: avoid recursing into identical trees
Date: Thu, 29 Oct 2020 20:41:21 -0700	[thread overview]
Message-ID: <20201030034131.1479968-11-newren@gmail.com> (raw)
In-Reply-To: <20201030034131.1479968-1-newren@gmail.com>

When all three trees have the same oid, there is no need to recurse into
these trees to find that all files within them happen to match.  We can
just record any one of the trees as the resolution of merging that
particular path.

Immediately resolving trees for other types of trivial tree merges (such
as one side matches the merge base, or the two sides match each other)
would prevent us from detecting renames for some paths, and thus prevent
us from doing three-way content merges for those paths whose renames we
did not detect.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-ort.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/merge-ort.c b/merge-ort.c
index 60e2b78e2d..2a402e18ed 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -202,6 +202,20 @@ static int collect_merge_info_callback(int n,
 	fullpath = xmalloc(len+1);
 	make_traverse_path(fullpath, len+1, info, p->path, p->pathlen);
 
+	/*
+	 * If mbase, side1, and side2 all match, we can resolve early.  Even
+	 * if these are trees, there will be no renames or anything
+	 * underneath.
+	 */
+	if (side1_matches_mbase && side2_matches_mbase) {
+		/* mbase, side1, & side2 all match; use mbase as resolution */
+		setup_path_info(opt, &pi, dirname, info->pathlen, fullpath,
+				names, names+0, mbase_null, 0,
+				filemask, dirmask, 1);
+		strmap_put(&opti->paths, pi.string, pi.util);
+		return mask;
+	}
+
 	/*
 	 * Record information about the path so we can resolve later in
 	 * process_entries.
-- 
2.29.1.56.ga287c268e6.dirty


  parent reply	other threads:[~2020-10-30  3:42 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-30  3:41 [PATCH 00/20] fundamentals of merge-ort implementation Elijah Newren
2020-10-30  3:41 ` [PATCH 01/20] merge-ort: setup basic internal data structures Elijah Newren
2020-10-30  3:41 ` [PATCH 02/20] merge-ort: add some high-level algorithm structure Elijah Newren
2020-10-30  3:41 ` [PATCH 03/20] merge-ort: port merge_start() from merge-recursive Elijah Newren
2020-10-30  3:41 ` [PATCH 04/20] merge-ort: use histogram diff Elijah Newren
2020-10-30  3:41 ` [PATCH 05/20] merge-ort: add an err() function similar to one from merge-recursive Elijah Newren
2020-10-30  3:41 ` [PATCH 06/20] merge-ort: implement a very basic collect_merge_info() Elijah Newren
2020-10-30  3:41 ` [PATCH 07/20] merge-ort: avoid repeating fill_tree_descriptor() on the same tree Elijah Newren
2020-10-30  3:41 ` [PATCH 08/20] merge-ort: compute a few more useful fields for collect_merge_info Elijah Newren
2020-10-30  3:41 ` [PATCH 09/20] merge-ort: record stage and auxiliary info for every path Elijah Newren
2020-10-30  3:41 ` Elijah Newren [this message]
2020-10-30  3:41 ` [PATCH 11/20] merge-ort: add a preliminary simple process_entries() implementation Elijah Newren
2020-10-30  3:41 ` [PATCH 12/20] merge-ort: have process_entries operate in a defined order Elijah Newren
2020-10-30  3:41 ` [PATCH 13/20] merge-ort: step 1 of tree writing -- record basenames, modes, and oids Elijah Newren
2020-10-30  3:41 ` [PATCH 14/20] merge-ort: step 2 of tree writing -- function to create tree object Elijah Newren
2020-10-30  3:41 ` [PATCH 15/20] merge-ort: step 3 of tree writing -- handling subdirectories as we go Elijah Newren
2020-10-30  3:41 ` [PATCH 16/20] merge-ort: basic outline for merge_switch_to_result() Elijah Newren
2020-10-30  3:41 ` [PATCH 17/20] merge-ort: add implementation of checkout() Elijah Newren
2020-10-30  3:41 ` [PATCH 18/20] tree: enable cmp_cache_name_compare() to be used elsewhere Elijah Newren
2020-10-30  3:41 ` [PATCH 19/20] merge-ort: add implementation of record_unmerged_index_entries() Elijah Newren
2020-10-30  3:41 ` [PATCH 20/20] merge-ort: free data structures in merge_finalize() Elijah Newren
2020-10-30  3:58 ` [PATCH 00/20] fundamentals of merge-ort implementation Elijah Newren
  -- strict thread matches above, loose matches on Subject: below --
2020-11-29  7:43 Elijah Newren via GitGitGadget
2020-11-29  7:43 ` [PATCH 10/20] merge-ort: avoid recursing into identical trees Elijah Newren via GitGitGadget

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