Fix multiuser race in FeatureFlagsClassicDebug constructor.

Under HSUM, the constructor may be called while the system is still
running as user 0. In this case, we register the iGET_FLAGS receiver
under user 0. However, the flippin app runs as user 10 so will then
see an empty response to it's GET_FLAGS ordered broadcast and crash.

This change installs a callback to capture the system switching
from user 0 to user 10 (or indeed, any subsequent user switch) and
ensure re-registers the receiver so it's running in the correct user.

Bug: 345443431
Flag: com.android.systemui.classic_flags_multi_user
Test: Manually verified; atest -c com.android.systemui.flags.FeatureFlagsClassicDebugTest
Change-Id: If8b5273963e67ab23fb10a9ad930fa9fa7b09590

2 files changed, 43 insertions, 14 deletions

diff --git a/packages/SystemUI/multivalentTests/src/com/android/systemui/flags/FeatureFlagsClassicDebugTest.kt b/packages/SystemUI/multivalentTests/src/com/android/systemui/flags/FeatureFlagsClassicDebugTest.kt
index 3388a785a26a..20cd8608d204 100644
--- a/packages/SystemUI/multivalentTests/src/com/android/systemui/flags/FeatureFlagsClassicDebugTest.kt
+++ b/packages/SystemUI/multivalentTests/src/com/android/systemui/flags/FeatureFlagsClassicDebugTest.kt
@@ -28,11 +28,13 @@ import androidx.test.filters.SmallTest
 import com.android.systemui.Flags.FLAG_SYSUI_TEAMFOOD
 import com.android.systemui.SysuiTestCase
 import com.android.systemui.settings.FakeUserTracker
+import com.android.systemui.util.concurrency.FakeExecutor
 import com.android.systemui.util.mockito.any
 import com.android.systemui.util.mockito.eq
 import com.android.systemui.util.mockito.nullable
 import com.android.systemui.util.mockito.withArgCaptor
 import com.android.systemui.util.settings.GlobalSettings
+import com.android.systemui.util.time.FakeSystemClock
 import com.google.common.truth.Truth.assertThat
 import java.io.PrintWriter
 import java.io.Serializable
@@ -68,6 +70,7 @@ class FeatureFlagsClassicDebugTest : SysuiTestCase() {
     @Mock private lateinit var systemProperties: SystemPropertiesHelper
     @Mock private lateinit var resources: Resources
     @Mock private lateinit var restarter: Restarter
+    private lateinit var fakeExecutor: FakeExecutor
     private lateinit var userTracker: FakeUserTracker
     private val flagMap = mutableMapOf<String, Flag<*>>()
     private lateinit var broadcastReceiver: BroadcastReceiver
@@ -83,6 +86,7 @@ class FeatureFlagsClassicDebugTest : SysuiTestCase() {
         flagMap.put(teamfoodableFlagA.name, teamfoodableFlagA)
         flagMap.put(releasedFlagB.name, releasedFlagB)
 
+        fakeExecutor = FakeExecutor(FakeSystemClock())
         userTracker = FakeUserTracker(onCreateCurrentUserContext = { mockContext })
 
         mFeatureFlagsClassicDebug =
@@ -95,7 +99,8 @@ class FeatureFlagsClassicDebugTest : SysuiTestCase() {
                 serverFlagReader,
                 flagMap,
                 restarter,
-                userTracker
+                userTracker,
+                fakeExecutor,
             )
         mFeatureFlagsClassicDebug.init()
         verify(flagManager).onSettingsChangedAction = any()
@@ -325,14 +330,14 @@ class FeatureFlagsClassicDebugTest : SysuiTestCase() {
         // trying to erase an id not in the map does nothing
         broadcastReceiver.onReceive(
             mockContext,
-            Intent(FlagManager.ACTION_SET_FLAG).putExtra(FlagManager.EXTRA_NAME, "")
+            Intent(FlagManager.ACTION_SET_FLAG).putExtra(FlagManager.EXTRA_NAME, ""),
         )
         verifyNoMoreInteractions(flagManager, globalSettings)
 
         // valid id with no value puts empty string in the setting
         broadcastReceiver.onReceive(
             mockContext,
-            Intent(FlagManager.ACTION_SET_FLAG).putExtra(FlagManager.EXTRA_NAME, "1")
+            Intent(FlagManager.ACTION_SET_FLAG).putExtra(FlagManager.EXTRA_NAME, "1"),
         )
         verifyPutData("1", "", numReads = 0)
     }
@@ -415,7 +420,7 @@ class FeatureFlagsClassicDebugTest : SysuiTestCase() {
         serverFlagReader.setFlagValue(
             teamfoodableFlagA.namespace,
             teamfoodableFlagA.name,
-            !teamfoodableFlagA.default
+            !teamfoodableFlagA.default,
         )
         verify(restarter, never()).restartSystemUI(anyString())
     }
@@ -428,7 +433,7 @@ class FeatureFlagsClassicDebugTest : SysuiTestCase() {
         serverFlagReader.setFlagValue(
             teamfoodableFlagA.namespace,
             teamfoodableFlagA.name,
-            !teamfoodableFlagA.default
+            !teamfoodableFlagA.default,
         )
         verify(restarter).restartSystemUI(anyString())
     }
@@ -441,7 +446,7 @@ class FeatureFlagsClassicDebugTest : SysuiTestCase() {
         serverFlagReader.setFlagValue(
             teamfoodableFlagA.namespace,
             teamfoodableFlagA.name,
-            teamfoodableFlagA.default
+            teamfoodableFlagA.default,
         )
         verify(restarter, never()).restartSystemUI(anyString())
     }
diff --git a/packages/SystemUI/src/com/android/systemui/flags/FeatureFlagsClassicDebug.java b/packages/SystemUI/src/com/android/systemui/flags/FeatureFlagsClassicDebug.java
index 303f91688575..911331b8bff1 100644
--- a/packages/SystemUI/src/com/android/systemui/flags/FeatureFlagsClassicDebug.java
+++ b/packages/SystemUI/src/com/android/systemui/flags/FeatureFlagsClassicDebug.java
@@ -42,7 +42,7 @@ import androidx.annotation.Nullable;
 
 import com.android.systemui.dagger.SysUISingleton;
 import com.android.systemui.dagger.qualifiers.Main;
-import com.android.systemui.settings.UserContextProvider;
+import com.android.systemui.settings.UserTracker;
 import com.android.systemui.util.settings.GlobalSettings;
 
 import java.io.PrintWriter;
@@ -51,6 +51,7 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.TreeMap;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executor;
 import java.util.function.Consumer;
 
 import javax.inject.Inject;
@@ -74,7 +75,6 @@ public class FeatureFlagsClassicDebug implements FeatureFlagsClassic {
     static final String TAG = "SysUIFlags";
 
     private final FlagManager mFlagManager;
-    private final Context mContext;
     private final GlobalSettings mGlobalSettings;
     private final Resources mResources;
     private final SystemPropertiesHelper mSystemProperties;
@@ -84,6 +84,8 @@ public class FeatureFlagsClassicDebug implements FeatureFlagsClassic {
     private final Map<String, String> mStringFlagCache = new ConcurrentHashMap<>();
     private final Map<String, Integer> mIntFlagCache = new ConcurrentHashMap<>();
     private final Restarter mRestarter;
+    private final UserTracker mUserTracker;
+    private final Executor mMainExecutor;
 
     private final ServerFlagReader.ChangeListener mOnPropertiesChanged =
             new ServerFlagReader.ChangeListener() {
@@ -118,6 +120,18 @@ public class FeatureFlagsClassicDebug implements FeatureFlagsClassic {
                 }
             };
 
+    private final UserTracker.Callback mUserChangedCallback =
+            new UserTracker.Callback() {
+                @Override
+                public void onUserChanged(int newUser, @NonNull Context userContext) {
+                    mContext.unregisterReceiver(mReceiver);
+                    mContext = userContext;
+                    registerReceiver();
+                }
+            };
+
+    private Context mContext;
+
     @Inject
     public FeatureFlagsClassicDebug(
             FlagManager flagManager,
@@ -128,10 +142,11 @@ public class FeatureFlagsClassicDebug implements FeatureFlagsClassic {
             ServerFlagReader serverFlagReader,
             @Named(ALL_FLAGS) Map<String, Flag<?>> allFlags,
             Restarter restarter,
-            UserContextProvider userContextProvider) {
+            UserTracker userTracker,
+            @Main Executor executor) {
         mFlagManager = flagManager;
         if (classicFlagsMultiUser()) {
-            mContext = userContextProvider.createCurrentUserContext(context);
+            mContext = userTracker.createCurrentUserContext(context);
         } else {
             mContext = context;
         }
@@ -141,19 +156,28 @@ public class FeatureFlagsClassicDebug implements FeatureFlagsClassic {
         mServerFlagReader = serverFlagReader;
         mAllFlags = allFlags;
         mRestarter = restarter;
+        mUserTracker = userTracker;
+        mMainExecutor = executor;
     }
 
     /** Call after construction to setup listeners. */
     void init() {
-        IntentFilter filter = new IntentFilter();
-        filter.addAction(ACTION_SET_FLAG);
-        filter.addAction(ACTION_GET_FLAGS);
         mFlagManager.setOnSettingsChangedAction(
                 suppressRestart -> restartSystemUI(suppressRestart, "Settings changed"));
         mFlagManager.setClearCacheAction(this::removeFromCache);
+        registerReceiver();
+        if (classicFlagsMultiUser()) {
+            mUserTracker.addCallback(mUserChangedCallback, mMainExecutor);
+        }
+        mServerFlagReader.listenForChanges(mAllFlags.values(), mOnPropertiesChanged);
+    }
+
+    void registerReceiver() {
+        IntentFilter filter = new IntentFilter();
+        filter.addAction(ACTION_SET_FLAG);
+        filter.addAction(ACTION_GET_FLAGS);
         mContext.registerReceiver(mReceiver, filter, null, null,
                 Context.RECEIVER_EXPORTED_UNAUDITED);
-        mServerFlagReader.listenForChanges(mAllFlags.values(), mOnPropertiesChanged);
     }
 
     @Override