From f714906c48119413fbf864b0bc00589e9088e523 Mon Sep 17 00:00:00 2001
From: Jeff Chang <chengjeff@google.com>
Date: Thu, 14 Jan 2021 16:38:02 +0800
Subject: [PATCH] Avoid creating new instance when started for result with
 singleInstance/singleTask
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The activity with launchMode "singleTask" and "singleInstance" can
exist in multiple instances. It contradicts with developers
documentation and breaks the purpose of these modes. The conditions
for searching the reusable tasks always ignore the start-for-result
case result in singleInstance/singleTask instances being created.

List the problems :

1. singleInstance activity stays in the caller’s task if it was
   started via startActivityForResult(). The activity should
   always get launched into its own task. It should always be
   the single and only member of its task.

2. Multiple singleInstance/singleTask activities are created and stay
   in the different tasks.

The CL updates the condition for searching the reusable task which
avoids the new instance being created.

Bug: 122967919
Bug: 148047668
Test: atest IntentTests
Change-Id: I721cfcaac0759327ae81f430d52d81f1c8145262
---
 .../core/java/com/android/server/wm/ActivityStarter.java   | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/services/core/java/com/android/server/wm/ActivityStarter.java b/services/core/java/com/android/server/wm/ActivityStarter.java
index c6ed16ce1f4dd..8ed15197bb867 100644
--- a/services/core/java/com/android/server/wm/ActivityStarter.java
+++ b/services/core/java/com/android/server/wm/ActivityStarter.java
@@ -1814,8 +1814,7 @@ class ActivityStarter {
     }
 
     private Task computeTargetTask() {
-        if (mStartActivity.resultTo == null && mInTask == null && !mAddingToTask
-                && (mLaunchFlags & FLAG_ACTIVITY_NEW_TASK) != 0) {
+        if (mInTask == null && !mAddingToTask && (mLaunchFlags & FLAG_ACTIVITY_NEW_TASK) != 0) {
             // A new task should be created instead of using existing one.
             return null;
         } else if (mSourceRecord != null) {
@@ -2512,7 +2511,9 @@ class ActivityStarter {
         // If bring to front is requested, and no result is requested and we have not been given
         // an explicit task to launch in to, and we can find a task that was started with this
         // same component, then instead of launching bring that one to the front.
-        putIntoExistingTask &= mInTask == null && mStartActivity.resultTo == null;
+        putIntoExistingTask &= !isLaunchModeOneOf(LAUNCH_SINGLE_INSTANCE, LAUNCH_SINGLE_TASK)
+                ? (mInTask == null && mStartActivity.resultTo == null)
+                : (mInTask == null);
         ActivityRecord intentActivity = null;
         if (putIntoExistingTask) {
             if (LAUNCH_SINGLE_INSTANCE == mLaunchMode) {