Only use result.sendError where supported by legacy media library

`MediaLibraryServiceLegacyStub` handles various edge cases by calling
`result.sendError(null)` with the intention to send back an error to
the legacy browser [1].

`MediaBrowserServiceCompat` of the legacy media1 Compat library has an
inner base class `Result` that has a default implementation of
`onErrorSent` that throws an `UnsupportedOperationException` [2].
However, most anonymous inner classes for `Result` created in
`MediaBrowserServiceCompat` do not override `onErrorSent` [3].

Hence Media3 must not call `sendError` in these cases. Instead we call
`sendResult(null)` according to what the default implementation of
the callbacks in `MediaBrowserServiceCompat` do ([4] as an example).

Issue: androidx/media#78
Issue: androidx/media#334

[1] https://github.com/androidx/media/blob/release/libraries/session/src/main/java/androidx/media3/session/MediaLibraryServiceLegacyStub.java#L200
[2] https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:media/media/src/main/java/androidx/media/MediaBrowserServiceCompat.java;l=872
[3] https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:media/media/src/main/java/androidx/media/MediaBrowserServiceCompat.java;l=578-604?q=MediaBrowserServiceCompat&ss=androidx
[4] https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:media/media/src/main/java/androidx/media/MediaBrowserServiceCompat.java;l=1395

PiperOrigin-RevId: 551210137

RELEASENOTES.md

@@ -111,6 +111,10 @@
         do this in `MediaSession.Callback.onConnect` by using an
         `AcceptedResultBuilder` to make sure the custom layout is available to
         the controller when connection completes.
+    *   Fix cases where `MediaLibraryServiceLegacyStub` sent an error to a
+        `Result` that didn't support this which produced an
+        `UnsuportedOperationException`
+        ([#78](https://github.com/androidx/media/issues/78)).
 *   UI:
     *   Add a `Player.Listener` implementation for Wear OS devices that handles
         playback suppression due to

libraries/session/src/main/java/androidx/media3/session/MediaLibraryServiceLegacyStub.java

@@ -197,12 +197,12 @@ import java.util.concurrent.atomic.AtomicReference;
       @Nullable Bundle options) {
     @Nullable ControllerInfo controller = getCurrentController();
     if (controller == null) {
-      result.sendError(/* extras= */ null);
+      result.sendResult(/* result= */ null);
       return;
     }
     if (TextUtils.isEmpty(parentId)) {
       Log.w(TAG, "onLoadChildren(): Ignoring empty parentId from " + controller);
-      result.sendError(/* extras= */ null);
+      result.sendResult(/* result= */ null);
       return;
     }
     result.detach();
@@ -212,7 +212,7 @@ import java.util.concurrent.atomic.AtomicReference;
           if (!getConnectedControllersManager()
               .isSessionCommandAvailable(
                   controller, SessionCommand.COMMAND_CODE_LIBRARY_GET_CHILDREN)) {
-            result.sendError(/* extras= */ null);
+            result.sendResult(/* result= */ null);
             return;
           }
           if (options != null) {
@@ -260,12 +260,12 @@ import java.util.concurrent.atomic.AtomicReference;
   public void onLoadItem(String itemId, Result<MediaBrowserCompat.MediaItem> result) {
     @Nullable ControllerInfo controller = getCurrentController();
     if (controller == null) {
-      result.sendError(/* extras= */ null);
+      result.sendResult(/* result= */ null);
       return;
     }
     if (TextUtils.isEmpty(itemId)) {
       Log.w(TAG, "Ignoring empty itemId from " + controller);
-      result.sendError(/* extras= */ null);
+      result.sendResult(/* result= */ null);
       return;
     }
     result.detach();
@@ -275,7 +275,7 @@ import java.util.concurrent.atomic.AtomicReference;
           if (!getConnectedControllersManager()
               .isSessionCommandAvailable(
                   controller, SessionCommand.COMMAND_CODE_LIBRARY_GET_ITEM)) {
-            result.sendError(/* extras= */ null);
+            result.sendResult(/* result= */ null);
             return;
           }
           ListenableFuture<LibraryResult<MediaItem>> future =
@@ -291,12 +291,12 @@ import java.util.concurrent.atomic.AtomicReference;
       String query, @Nullable Bundle extras, Result<List<MediaBrowserCompat.MediaItem>> result) {
     @Nullable ControllerInfo controller = getCurrentController();
     if (controller == null) {
-      result.sendError(/* extras= */ null);
+      result.sendResult(/* result= */ null);
       return;
     }
     if (TextUtils.isEmpty(query)) {
       Log.w(TAG, "Ignoring empty query from " + controller);
-      result.sendError(/* extras= */ null);
+      result.sendResult(/* result= */ null);
       return;
     }
     if (!(controller.getControllerCb() instanceof BrowserLegacyCb)) {
@@ -308,7 +308,7 @@ import java.util.concurrent.atomic.AtomicReference;
         () -> {
           if (!getConnectedControllersManager()
               .isSessionCommandAvailable(controller, SessionCommand.COMMAND_CODE_LIBRARY_SEARCH)) {
-            result.sendError(/* extras= */ null);
+            result.sendResult(/* result= */ null);
             return;
           }
           BrowserLegacyCb cb = (BrowserLegacyCb) checkStateNotNull(controller.getControllerCb());
@@ -389,7 +389,7 @@ import java.util.concurrent.atomic.AtomicReference;
             result.sendResult(mediaItem);
           } catch (CancellationException | ExecutionException | InterruptedException e) {
             Log.w(TAG, "Library operation failed", e);
-            result.sendError(/* extras= */ null);
+            result.sendResult(/* result= */ null);
           }
         },
         MoreExecutors.directExecutor());
@@ -408,7 +408,7 @@ import java.util.concurrent.atomic.AtomicReference;
                     : MediaUtils.truncateListBySize(mediaItems, TRANSACTION_SIZE_LIMIT_IN_BYTES));
           } catch (CancellationException | ExecutionException | InterruptedException e) {
             Log.w(TAG, "Library operation failed", e);
-            result.sendError(/* extras= */ null);
+            result.sendResult(/* result= */ null);
           }
         },
         MoreExecutors.directExecutor());

libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaBrowserCompatWithMediaLibraryServiceTest.java

@@ -54,6 +54,7 @@ import static androidx.media3.test.session.common.MediaBrowserConstants.SEARCH_R
 import static androidx.media3.test.session.common.MediaBrowserConstants.SEARCH_RESULT_COUNT;
 import static androidx.media3.test.session.common.TestUtils.LONG_TIMEOUT_MS;
 import static androidx.media3.test.session.common.TestUtils.NO_RESPONSE_TIMEOUT_MS;
+import static androidx.media3.test.session.common.TestUtils.SERVICE_CONNECTION_TIMEOUT_MS;
 import static androidx.media3.test.session.common.TestUtils.TIMEOUT_MS;
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
@@ -210,6 +211,29 @@ public class MediaBrowserCompatWithMediaLibraryServiceTest
     assertThat(latch.await(TIMEOUT_MS, MILLISECONDS)).isTrue();
   }
 
+  @Test
+  public void getItem_commandGetItemNotAvailable_reportsNull() throws Exception {
+    Bundle rootHints = new Bundle();
+    rootHints.putInt(
+        MockMediaLibraryService.CONNECTION_HINTS_KEY_REMOVE_COMMAND_CODE,
+        SessionCommand.COMMAND_CODE_LIBRARY_GET_ITEM);
+    connectAndWait(rootHints);
+    CountDownLatch latch = new CountDownLatch(1);
+    List<MediaItem> capturedMediaItems = new ArrayList<>();
+    browserCompat.getItem(
+        MEDIA_ID_GET_BROWSABLE_ITEM,
+        new ItemCallback() {
+          @Override
+          public void onItemLoaded(MediaItem item) {
+            capturedMediaItems.add(item);
+            latch.countDown();
+          }
+        });
+
+    assertThat(latch.await(TIMEOUT_MS, MILLISECONDS)).isTrue();
+    assertThat(capturedMediaItems).containsExactly((Object) null);
+  }
+
   @Test
   public void getChildren() throws Exception {
     String testParentId = PARENT_ID;
@@ -415,6 +439,34 @@ public class MediaBrowserCompatWithMediaLibraryServiceTest
     assertThat(latch.await(TIMEOUT_MS, MILLISECONDS)).isTrue();
   }
 
+  @Test
+  public void getChildren_commandGetChildrenNotAvailable_reportsError() throws Exception {
+    Bundle rootHints = new Bundle();
+    rootHints.putInt(
+        MockMediaLibraryService.CONNECTION_HINTS_KEY_REMOVE_COMMAND_CODE,
+        SessionCommand.COMMAND_CODE_LIBRARY_GET_CHILDREN);
+    handler.postAndSync(
+        () -> {
+          browserCompat =
+              new MediaBrowserCompat(context, getServiceComponent(), connectionCallback, rootHints);
+        });
+    browserCompat.connect();
+    assertThat(connectionCallback.connectedLatch.await(SERVICE_CONNECTION_TIMEOUT_MS, MILLISECONDS))
+        .isTrue();
+    CountDownLatch errorLatch = new CountDownLatch(1);
+
+    browserCompat.subscribe(
+        PARENT_ID,
+        new MediaBrowserCompat.SubscriptionCallback() {
+          @Override
+          public void onError(String parentId) {
+            errorLatch.countDown();
+          }
+        });
+
+    assertThat(errorLatch.await(TIMEOUT_MS, MILLISECONDS)).isTrue();
+  }
+
   @Test
   public void search() throws Exception {
     String testQuery = SEARCH_QUERY;
@@ -511,6 +563,35 @@ public class MediaBrowserCompatWithMediaLibraryServiceTest
     assertThat(latch.await(TIMEOUT_MS, MILLISECONDS)).isTrue();
   }
 
+  @Test
+  public void search_commandSearchNotAvailable_reportsError() throws Exception {
+    String testQuery = SEARCH_QUERY;
+    int page = 4;
+    int pageSize = 10;
+    Bundle testExtras = new Bundle();
+    testExtras.putString(testQuery, testQuery);
+    testExtras.putInt(MediaBrowserCompat.EXTRA_PAGE, page);
+    testExtras.putInt(MediaBrowserCompat.EXTRA_PAGE_SIZE, pageSize);
+    Bundle rootHints = new Bundle();
+    rootHints.putInt(
+        MockMediaLibraryService.CONNECTION_HINTS_KEY_REMOVE_COMMAND_CODE,
+        SessionCommand.COMMAND_CODE_LIBRARY_SEARCH);
+    connectAndWait(rootHints);
+    CountDownLatch latch = new CountDownLatch(1);
+
+    browserCompat.search(
+        testQuery,
+        testExtras,
+        new SearchCallback() {
+          @Override
+          public void onError(String query, Bundle extras) {
+            latch.countDown();
+          }
+        });
+
+    assertThat(latch.await(TIMEOUT_MS, MILLISECONDS)).isTrue();
+  }
+
   @Test
   public void search_error() throws Exception {
     String testQuery = SEARCH_QUERY_ERROR;
@@ -607,8 +688,9 @@ public class MediaBrowserCompatWithMediaLibraryServiceTest
   @Test
   public void rootBrowserHints_searchNotSupported_reportsSearchNotSupported() throws Exception {
     Bundle connectionHints = new Bundle();
-    connectionHints.putBoolean(
+    connectionHints.putInt(
-        MockMediaLibraryService.CONNECTION_HINTS_KEY_REMOVE_COMMAND_CODE_LIBRARY_SEARCH, true);
+        MockMediaLibraryService.CONNECTION_HINTS_KEY_REMOVE_COMMAND_CODE,
+        SessionCommand.COMMAND_CODE_LIBRARY_SEARCH);
     connectAndWait(connectionHints);
 
     boolean isSearchSupported =

libraries/test_session_current/src/main/java/androidx/media3/session/MockMediaLibraryService.java

@@ -89,12 +89,12 @@ public class MockMediaLibraryService extends MediaLibraryService {
       "CONNECTION_HINTS_CUSTOM_LIBRARY_ROOT";
 
   /**
-   * Key used in connection hints to instruct the mock service to remove {@link
+   * Key used in connection hints to instruct the mock service to remove a {@link SessionCommand}
-   * SessionCommand#COMMAND_CODE_LIBRARY_SEARCH} from the available commands in {@link
+   * identified by its command code from the available commands in {@link
    * MediaSession.Callback#onConnect(MediaSession, ControllerInfo)}.
    */
-  public static final String CONNECTION_HINTS_KEY_REMOVE_COMMAND_CODE_LIBRARY_SEARCH =
+  public static final String CONNECTION_HINTS_KEY_REMOVE_COMMAND_CODE =
-      "CONNECTION_HINTS_KEY_REMOVE_SEARCH_SESSION_COMMAND";
+      "CONNECTION_HINTS_KEY_REMOVE_COMMAND_CODE";
 
   private static final String TEST_IMAGE_PATH = "media/png/non-motion-photo-shortened.png";
 
@@ -198,11 +198,11 @@ public class MockMediaLibraryService extends MediaLibraryService {
       SessionCommands.Builder builder = connectionResult.availableSessionCommands.buildUpon();
       builder.add(new SessionCommand(CUSTOM_ACTION, /* extras= */ Bundle.EMPTY));
       builder.add(new SessionCommand(CUSTOM_ACTION_ASSERT_PARAMS, /* extras= */ Bundle.EMPTY));
-      if (controller
+      Bundle connectionHints = controller.getConnectionHints();
-          .getConnectionHints()
+      int commandCodeToRemove =
-          .getBoolean(
+          connectionHints.getInt(CONNECTION_HINTS_KEY_REMOVE_COMMAND_CODE, /* defaultValue= */ -1);
-              CONNECTION_HINTS_KEY_REMOVE_COMMAND_CODE_LIBRARY_SEARCH, /* defaultValue= */ false)) {
+      if (commandCodeToRemove != -1) {
-        builder.remove(SessionCommand.COMMAND_CODE_LIBRARY_SEARCH);
+        builder.remove(commandCodeToRemove);
       }
       return MediaSession.ConnectionResult.accept(
           /* availableSessionCommands= */ builder.build(),