From 420b58a7cba42e642f7eab0d1bc92f9d912a9864 Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Mon, 9 Oct 2017 20:01:49 +0100
Subject: [PATCH] Check alternates when comparing to the common ancestor

This is the actual bugfix.
---
 src/renderers/shared/shared/ReactTreeTraversal.js | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/renderers/shared/shared/ReactTreeTraversal.js b/src/renderers/shared/shared/ReactTreeTraversal.js
index efe4da50e77a6..d483881530bda 100644
--- a/src/renderers/shared/shared/ReactTreeTraversal.js
+++ b/src/renderers/shared/shared/ReactTreeTraversal.js
@@ -119,6 +119,10 @@ function traverseEnterLeave(from, to, fn, argFrom, argTo) {
     if (from === common) {
       break;
     }
+    const alternate = from.alternate;
+    if (alternate !== null && alternate === common) {
+      break;
+    }
     pathFrom.push(from);
     from = getParent(from);
   }
@@ -130,6 +134,10 @@ function traverseEnterLeave(from, to, fn, argFrom, argTo) {
     if (to === common) {
       break;
     }
+    const alternate = to.alternate;
+    if (alternate !== null && alternate === common) {
+      break;
+    }
     pathTo.push(to);
     to = getParent(to);
   }