Avoid out of bounds when setting less media items than in playlist

Issue: androidx/media#86
#minor-release
PiperOrigin-RevId: 455182232

RELEASENOTES.md

@@ -185,6 +185,9 @@
         `MediaSession.Callback.onSetMediaUri`. The same functionality can be
         achieved by using `MediaController.setMediaItem` and
         `MediaSession.Callback.onAddMediaItems`.
+    *   Fix `IndexOutOfBoundsException` when setting less media items than in
+        the current playlist
+        ([#86](https://github.com/androidx/media/issues/86)).
 *   Data sources:
     *   Rename `DummyDataSource` to `PlaceholderDataSource`.
     *   Workaround OkHttp interrupt handling.

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

@@ -828,7 +828,7 @@ import org.checkerframework.checker.nullness.qual.NonNull;
         Collections.singletonList(mediaItem),
         /* startIndex= */ C.INDEX_UNSET,
         /* startPositionMs= */ C.TIME_UNSET,
-        /* resetToDefaultPosition= */ false);
+        /* resetToDefaultPosition= */ true);
   }
 
   @Override
@@ -887,7 +887,7 @@ import org.checkerframework.checker.nullness.qual.NonNull;
         mediaItems,
         /* startIndex= */ C.INDEX_UNSET,
         /* startPositionMs= */ C.TIME_UNSET,
-        /* resetToDefaultPosition= */ false);
+        /* resetToDefaultPosition= */ true);
   }
 
   @Override
@@ -1832,12 +1832,18 @@ import org.checkerframework.checker.nullness.qual.NonNull;
       throw new IllegalSeekPositionException(newTimeline, startIndex, startPositionMs);
     }
 
+    boolean correctedStartIndex = false;
     if (resetToDefaultPosition) {
       startIndex = newTimeline.getFirstWindowIndex(playerInfo.shuffleModeEnabled);
       startPositionMs = C.TIME_UNSET;
     } else if (startIndex == C.INDEX_UNSET) {
       startIndex = playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex;
       startPositionMs = playerInfo.sessionPositionInfo.positionInfo.positionMs;
+      if (startIndex >= newTimeline.getWindowCount()) {
+        correctedStartIndex = true;
+        startIndex = newTimeline.getFirstWindowIndex(playerInfo.shuffleModeEnabled);
+        startPositionMs = C.TIME_UNSET;
+      }
     }
     PositionInfo newPositionInfo;
     SessionPositionInfo newSessionPositionInfo;
@@ -1905,7 +1911,7 @@ import org.checkerframework.checker.nullness.qual.NonNull;
     // Mask the playback state.
     int maskingPlaybackState = newPlayerInfo.playbackState;
     if (startIndex != C.INDEX_UNSET && newPlayerInfo.playbackState != STATE_IDLE) {
-      if (newTimeline.isEmpty() || startIndex >= newTimeline.getWindowCount()) {
+      if (newTimeline.isEmpty() || correctedStartIndex) {
         // Setting an empty timeline or invalid seek transitions to ended.
         maskingPlaybackState = STATE_ENDED;
       } else {

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

@@ -36,6 +36,7 @@ import android.os.RemoteException;
 import androidx.media3.common.AudioAttributes;
 import androidx.media3.common.C;
 import androidx.media3.common.HeartRating;
+import androidx.media3.common.IllegalSeekPositionException;
 import androidx.media3.common.MediaItem;
 import androidx.media3.common.MediaLibraryInfo;
 import androidx.media3.common.MediaMetadata;
@@ -56,6 +57,7 @@ import androidx.media3.test.session.common.TestUtils;
 import androidx.test.core.app.ApplicationProvider;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import androidx.test.filters.LargeTest;
+import com.google.common.collect.ImmutableList;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
@@ -64,6 +66,7 @@ import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.atomic.AtomicReference;
 import org.junit.After;
+import org.junit.Assert;
 import org.junit.Before;
 import org.junit.ClassRule;
 import org.junit.Rule;
@@ -1055,4 +1058,95 @@ public class MediaControllerTest {
 
     assertThat(mediaMetadata).isEqualTo(testMediaMetadata);
   }
+
+  @Test
+  public void
+      setMediaItems_setLessMediaItemsThanCurrentMediaItemIndex_masksCurrentMediaItemIndexAndStateCorrectly()
+          throws Exception {
+    MediaController controller = controllerTestRule.createController(remoteSession.getToken());
+    List<MediaItem> threeItemsList =
+        ImmutableList.of(
+            MediaItem.fromUri("http://www.google.com/1"),
+            MediaItem.fromUri("http://www.google.com/2"),
+            MediaItem.fromUri("http://www.google.com/3"));
+    List<MediaItem> twoItemsList =
+        ImmutableList.of(
+            MediaItem.fromUri("http://www.google.com/1"),
+            MediaItem.fromUri("http://www.google.com/2"));
+
+    int[] currentMediaIndexAndState =
+        threadTestRule
+            .getHandler()
+            .postAndSync(
+                () -> {
+                  controller.setMediaItems(threeItemsList);
+                  controller.prepare();
+                  controller.seekTo(/* mediaItemIndex= */ 2, /* positionMs= */ C.TIME_UNSET);
+                  controller.setMediaItems(twoItemsList);
+                  return new int[] {
+                    controller.getCurrentMediaItemIndex(), controller.getPlaybackState()
+                  };
+                });
+
+    assertThat(currentMediaIndexAndState[0]).isEqualTo(0);
+    assertThat(currentMediaIndexAndState[1]).isEqualTo(Player.STATE_BUFFERING);
+  }
+
+  @Test
+  public void
+      setMediaItems_setLessMediaItemsThanCurrentMediaItemIndexResetPositionFalse_masksCurrentMediaItemIndexAndStateCorrectly()
+          throws Exception {
+    MediaController controller = controllerTestRule.createController(remoteSession.getToken());
+    List<MediaItem> threeItemsList =
+        ImmutableList.of(
+            MediaItem.fromUri("http://www.google.com/1"),
+            MediaItem.fromUri("http://www.google.com/2"),
+            MediaItem.fromUri("http://www.google.com/3"));
+    List<MediaItem> twoItemsList =
+        ImmutableList.of(
+            MediaItem.fromUri("http://www.google.com/1"),
+            MediaItem.fromUri("http://www.google.com/2"));
+
+    int[] currentMediaItemIndexAndState =
+        threadTestRule
+            .getHandler()
+            .postAndSync(
+                () -> {
+                  controller.setMediaItems(threeItemsList);
+                  controller.prepare();
+                  controller.seekTo(/* mediaItemIndex= */ 2, /* positionMs= */ C.TIME_UNSET);
+                  controller.setMediaItems(twoItemsList, /* resetPosition= */ false);
+                  return new int[] {
+                    controller.getCurrentMediaItemIndex(), controller.getPlaybackState()
+                  };
+                });
+
+    assertThat(currentMediaItemIndexAndState[0]).isEqualTo(0);
+    assertThat(currentMediaItemIndexAndState[1]).isEqualTo(Player.STATE_ENDED);
+  }
+
+  @Test
+  public void setMediaItems_startIndexTooLarge_throwIllegalSeekPositionException()
+      throws Exception {
+    MediaController controller = controllerTestRule.createController(remoteSession.getToken());
+    List<MediaItem> threeItemsList =
+        ImmutableList.of(
+            MediaItem.fromUri("http://www.google.com/1"),
+            MediaItem.fromUri("http://www.google.com/2"),
+            MediaItem.fromUri("http://www.google.com/3"));
+
+    Assert.assertThrows(
+        IllegalSeekPositionException.class,
+        () ->
+            threadTestRule
+                .getHandler()
+                .postAndSync(
+                    () -> {
+                      controller.setMediaItems(
+                          threeItemsList,
+                          /* startIndex= */ 99,
+                          /* startPositionMs= */ C.TIME_UNSET);
+                      return controller.getCurrentMediaItemIndex();
+                    }));
+  }
 }