Prevent NPE by return empty list

Bug: 329502978
Test: atest ProxyAccessibilityServiceConnectionTest

Flag: EXEMPT simple bug fix
Change-Id: I93f876e324044311780fba6ebeeb53f174d5056b
(cherry picked from commit fbc3ca8ea7fe504f4f0a6743dfb4649eb59b960d)

2 files changed, 17 insertions, 10 deletions

diff --git a/services/accessibility/java/com/android/server/accessibility/ProxyAccessibilityServiceConnection.java b/services/accessibility/java/com/android/server/accessibility/ProxyAccessibilityServiceConnection.java
index 6aa4702ec7d5..b77b2bef57a2 100644
--- a/services/accessibility/java/com/android/server/accessibility/ProxyAccessibilityServiceConnection.java
+++ b/services/accessibility/java/com/android/server/accessibility/ProxyAccessibilityServiceConnection.java
@@ -126,7 +126,7 @@ public class ProxyAccessibilityServiceConnection extends AccessibilityServiceCon
      * @param infos the list of enabled and installed services.
      */
     @Override
-    public void setInstalledAndEnabledServices(List<AccessibilityServiceInfo> infos) {
+    public void setInstalledAndEnabledServices(@NonNull List<AccessibilityServiceInfo> infos) {
         final long identity = Binder.clearCallingIdentity();
         try {
             synchronized (mLock) {
@@ -216,9 +216,11 @@ public class ProxyAccessibilityServiceConnection extends AccessibilityServiceCon
     }
 
     @Override
+    @NonNull
     public List<AccessibilityServiceInfo> getInstalledAndEnabledServices() {
         synchronized (mLock) {
-            return mInstalledAndEnabledServices;
+            return mInstalledAndEnabledServices != null
+                    ? mInstalledAndEnabledServices : Collections.emptyList();
         }
     }
 
diff --git a/services/tests/servicestests/src/com/android/server/accessibility/ProxyAccessibilityServiceConnectionTest.java b/services/tests/servicestests/src/com/android/server/accessibility/ProxyAccessibilityServiceConnectionTest.java
index 6ac3658bc3b4..3d0db71ba17f 100644
--- a/services/tests/servicestests/src/com/android/server/accessibility/ProxyAccessibilityServiceConnectionTest.java
+++ b/services/tests/servicestests/src/com/android/server/accessibility/ProxyAccessibilityServiceConnectionTest.java
@@ -24,6 +24,13 @@ import static android.accessibilityservice.AccessibilityServiceInfo.FLAG_REQUEST
 
 import static androidx.test.platform.app.InstrumentationRegistry.getInstrumentation;
 
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.junit.Assert.assertThrows;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
 import android.accessibilityservice.AccessibilityServiceInfo;
 import android.accessibilityservice.AccessibilityTrace;
 import android.content.ComponentName;
@@ -33,13 +40,6 @@ import android.graphics.Color;
 import android.os.Handler;
 import android.view.accessibility.AccessibilityEvent;
 
-import static com.google.common.truth.Truth.assertThat;
-
-import static org.junit.Assert.assertThrows;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.when;
-
 import com.android.server.wm.WindowManagerInternal;
 
 import org.junit.Before;
@@ -225,7 +225,7 @@ public class ProxyAccessibilityServiceConnectionTest {
     }
 
     @Test
-    public void testDisableSelf_setIllegalOperationExceptionThrown_() {
+    public void testDisableSelf_setIllegalOperationExceptionThrown() {
         UnsupportedOperationException thrown =
                 assertThrows(
                         UnsupportedOperationException.class,
@@ -233,4 +233,9 @@ public class ProxyAccessibilityServiceConnectionTest {
 
         assertThat(thrown).hasMessageThat().contains("disableSelf is not supported");
     }
+
+    @Test
+    public void getInstalledAndEnabledServices_noServices_returnEmpty() {
+        assertThat(mProxyConnection.getInstalledAndEnabledServices()).isEmpty();
+    }
 }