From 8ac1c4a0f9e3e38e8ef28164e4340c0a6009f363 Mon Sep 17 00:00:00 2001
From: Patrick Williams <pdwilliams@google.com>
Date: Tue, 21 Mar 2023 15:16:27 -0500
Subject: [PATCH] Copy transaction in applyTransactionOnDraw

This prevents a race where the transaction is copied in the RenderThread
while simultaneously applied in another thread.

Bug: 273911227
Test: presubmits
Change-Id: I6d5345ae0c5d998010e0d3c3f33813190b1ea8de
---
 core/java/android/view/ViewRootImpl.java | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index d1f9fbded0031..152fa08d2a9d2 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -11365,9 +11365,13 @@ public final class ViewRootImpl implements ViewParent,
         if (mRemoved || !isHardwareEnabled()) {
             t.apply();
         } else {
+            // Copy and clear the passed in transaction for thread safety. The new transaction is
+            // accessed on the render thread.
+            var localTransaction = new Transaction();
+            localTransaction.merge(t);
             mHasPendingTransactions = true;
             registerRtFrameCallback(frame -> {
-                mergeWithNextTransaction(t, frame);
+                mergeWithNextTransaction(localTransaction, frame);
             });
         }
         return true;