From 8e653c84066928d545518ee2109b6a84d5109ea8 Mon Sep 17 00:00:00 2001
From: Robert Carr <racarr@google.com>
Date: Wed, 13 May 2020 13:25:51 -0700
Subject: [PATCH] applySyncTransaction: Add to syncSet earlier

We need to add modified WindowContainers to the BLASTSync set
before applying any changes. Recall that while participating in
sync window containers stop using the Display global
pending-transaction and instead redirect their changes in to the
BLASTSync-transaction. If we add to the BLAST sync too late, some
changes could go in to the WM transaction while others go in to
the BLASTSync-transaction. This means the effects would not be
applied atomically.

Bug: 149946388
Bug: 155814541
Test: Expand PIP. No flash.
Change-Id: I9b9b8f2308098d045a44004e2cca6dcbf84efcd9
---
 .../android/server/wm/WindowOrganizerController.java   | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/services/core/java/com/android/server/wm/WindowOrganizerController.java b/services/core/java/com/android/server/wm/WindowOrganizerController.java
index c4cb4b5091d82..707a7898f8b6c 100644
--- a/services/core/java/com/android/server/wm/WindowOrganizerController.java
+++ b/services/core/java/com/android/server/wm/WindowOrganizerController.java
@@ -138,6 +138,13 @@ class WindowOrganizerController extends IWindowOrganizerController.Stub
                             Slog.e(TAG, "Attempt to operate on detached container: " + wc);
                             continue;
                         }
+                        // Make sure we add to the syncSet before performing
+                        // operations so we don't end up splitting effects between the WM
+                        // pending transaction and the BLASTSync transaction.
+                        if (syncId >= 0) {
+                            mBLASTSyncEngine.addToSyncSet(syncId, wc);
+                        }
+
                         int containerEffect = applyWindowContainerChange(wc, entry.getValue());
                         effects |= containerEffect;
 
@@ -146,9 +153,6 @@ class WindowOrganizerController extends IWindowOrganizerController.Stub
                                 && (containerEffect & TRANSACT_EFFECTS_CLIENT_CONFIG) != 0) {
                             haveConfigChanges.add(wc);
                         }
-                        if (syncId >= 0) {
-                            mBLASTSyncEngine.addToSyncSet(syncId, wc);
-                        }
                     }
                     // Hierarchy changes
                     final List<WindowContainerTransaction.HierarchyOp> hops = t.getHierarchyOps();