From a0b13f309e1bceb6487bb4913bd8c80d93b870a8 Mon Sep 17 00:00:00 2001
From: Po-Chun Chang <31112892+birdychang@users.noreply.github.com>
Date: Thu, 11 May 2023 00:42:15 -0700
Subject: [PATCH] fix: skip traversal of pointers with the same cid (#109)

---
 diff.go          | 3 +++
 diff_parallel.go | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/diff.go b/diff.go
index 3af3d81..a4b7d29 100644
--- a/diff.go
+++ b/diff.go
@@ -80,6 +80,9 @@ func diffNode(ctx context.Context, pre, cur *Node, depth int) ([]*Change, error)
 
 			// both pointers are shards, recurse down the tree.
 			if prePointer.isShard() && curPointer.isShard() {
+				if prePointer.Link == curPointer.Link {
+					continue
+				}
 				preChild, err := prePointer.loadChild(ctx, pre.store, pre.bitWidth, pre.hash)
 				if err != nil {
 					return nil, err
diff --git a/diff_parallel.go b/diff_parallel.go
index 818cf07..44ebbf6 100644
--- a/diff_parallel.go
+++ b/diff_parallel.go
@@ -192,6 +192,9 @@ func (s *diffScheduler) work(ctx context.Context, todo *task, results chan *Chan
 		switch {
 		// both pointers are shards, recurse down the tree.
 		case prePointer.isShard() && curPointer.isShard():
+			if prePointer.Link == curPointer.Link {
+				return nil
+			}
 			preChild, err := prePointer.loadChild(ctx, pre.store, pre.bitWidth, pre.hash)
 			if err != nil {
 				return err