Add fail-fast null checks to the stable Player API

This will help developers self-diagnose issues like Issue: google/ExoPlayer#10392
where the NPE occurs far from the original null value because a field
gets assigned to null.

This change aims to ensure that every stable method on Player,
ExoPlayer and ExoPlayer.Builder that takes a non-null type will fail
with an NPE before returning.

#minor-release

PiperOrigin-RevId: 461846580
(cherry picked from commit e1fde5d530a43b64f6e0603843ccafe7692e8453)

libraries/common/src/main/java/androidx/media3/common/BasePlayer.java

@@ -21,7 +21,7 @@ import static java.lang.Math.min;
 import androidx.annotation.Nullable;
 import androidx.media3.common.util.UnstableApi;
 import androidx.media3.common.util.Util;
-import java.util.Collections;
+import com.google.common.collect.ImmutableList;
 import java.util.List;
 
 /** Abstract base {@link Player} which implements common implementation independent methods. */
@@ -36,17 +36,17 @@ public abstract class BasePlayer implements Player {
 
   @Override
   public final void setMediaItem(MediaItem mediaItem) {
-    setMediaItems(Collections.singletonList(mediaItem));
+    setMediaItems(ImmutableList.of(mediaItem));
   }
 
   @Override
   public final void setMediaItem(MediaItem mediaItem, long startPositionMs) {
-    setMediaItems(Collections.singletonList(mediaItem), /* startWindowIndex= */ 0, startPositionMs);
+    setMediaItems(ImmutableList.of(mediaItem), /* startIndex= */ 0, startPositionMs);
   }
 
   @Override
   public final void setMediaItem(MediaItem mediaItem, boolean resetPosition) {
-    setMediaItems(Collections.singletonList(mediaItem), resetPosition);
+    setMediaItems(ImmutableList.of(mediaItem), resetPosition);
   }
 
   @Override
@@ -56,12 +56,12 @@ public abstract class BasePlayer implements Player {
 
   @Override
   public final void addMediaItem(int index, MediaItem mediaItem) {
-    addMediaItems(index, Collections.singletonList(mediaItem));
+    addMediaItems(index, ImmutableList.of(mediaItem));
   }
 
   @Override
   public final void addMediaItem(MediaItem mediaItem) {
-    addMediaItems(Collections.singletonList(mediaItem));
+    addMediaItems(ImmutableList.of(mediaItem));
   }
 
   @Override

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/ExoPlayer.java

@@ -16,6 +16,7 @@
 package androidx.media3.exoplayer;
 
 import static androidx.media3.common.util.Assertions.checkArgument;
+import static androidx.media3.common.util.Assertions.checkNotNull;
 import static androidx.media3.common.util.Assertions.checkState;
 
 import android.content.Context;
@@ -542,6 +543,7 @@ public interface ExoPlayer extends Player {
           context,
           () -> renderersFactory,
           () -> new DefaultMediaSourceFactory(context, new DefaultExtractorsFactory()));
+      checkNotNull(renderersFactory);
     }
 
     /**
@@ -560,6 +562,7 @@ public interface ExoPlayer extends Player {
     @UnstableApi
     public Builder(Context context, MediaSource.Factory mediaSourceFactory) {
       this(context, () -> new DefaultRenderersFactory(context), () -> mediaSourceFactory);
+      checkNotNull(mediaSourceFactory);
     }
 
     /**
@@ -583,6 +586,8 @@ public interface ExoPlayer extends Player {
         RenderersFactory renderersFactory,
         MediaSource.Factory mediaSourceFactory) {
       this(context, () -> renderersFactory, () -> mediaSourceFactory);
+      checkNotNull(renderersFactory);
+      checkNotNull(mediaSourceFactory);
     }
 
     /**
@@ -617,6 +622,11 @@ public interface ExoPlayer extends Player {
           () -> loadControl,
           () -> bandwidthMeter,
           (clock) -> analyticsCollector);
+      checkNotNull(renderersFactory);
+      checkNotNull(mediaSourceFactory);
+      checkNotNull(trackSelector);
+      checkNotNull(bandwidthMeter);
+      checkNotNull(analyticsCollector);
     }
 
     private Builder(
@@ -641,7 +651,7 @@ public interface ExoPlayer extends Player {
         Supplier<LoadControl> loadControlSupplier,
         Supplier<BandwidthMeter> bandwidthMeterSupplier,
         Function<Clock, AnalyticsCollector> analyticsCollectorFunction) {
-      this.context = context;
+      this.context = checkNotNull(context);
       this.renderersFactorySupplier = renderersFactorySupplier;
       this.mediaSourceFactorySupplier = mediaSourceFactorySupplier;
       this.trackSelectorSupplier = trackSelectorSupplier;
@@ -690,6 +700,7 @@ public interface ExoPlayer extends Player {
     @UnstableApi
     public Builder setRenderersFactory(RenderersFactory renderersFactory) {
       checkState(!buildCalled);
+      checkNotNull(renderersFactory);
       this.renderersFactorySupplier = () -> renderersFactory;
       return this;
     }
@@ -703,6 +714,7 @@ public interface ExoPlayer extends Player {
      */
     public Builder setMediaSourceFactory(MediaSource.Factory mediaSourceFactory) {
       checkState(!buildCalled);
+      checkNotNull(mediaSourceFactory);
       this.mediaSourceFactorySupplier = () -> mediaSourceFactory;
       return this;
     }
@@ -717,6 +729,7 @@ public interface ExoPlayer extends Player {
     @UnstableApi
     public Builder setTrackSelector(TrackSelector trackSelector) {
       checkState(!buildCalled);
+      checkNotNull(trackSelector);
       this.trackSelectorSupplier = () -> trackSelector;
       return this;
     }
@@ -731,6 +744,7 @@ public interface ExoPlayer extends Player {
     @UnstableApi
     public Builder setLoadControl(LoadControl loadControl) {
       checkState(!buildCalled);
+      checkNotNull(loadControl);
       this.loadControlSupplier = () -> loadControl;
       return this;
     }
@@ -745,6 +759,7 @@ public interface ExoPlayer extends Player {
     @UnstableApi
     public Builder setBandwidthMeter(BandwidthMeter bandwidthMeter) {
       checkState(!buildCalled);
+      checkNotNull(bandwidthMeter);
       this.bandwidthMeterSupplier = () -> bandwidthMeter;
       return this;
     }
@@ -760,6 +775,7 @@ public interface ExoPlayer extends Player {
     @UnstableApi
     public Builder setLooper(Looper looper) {
       checkState(!buildCalled);
+      checkNotNull(looper);
       this.looper = looper;
       return this;
     }
@@ -774,6 +790,7 @@ public interface ExoPlayer extends Player {
     @UnstableApi
     public Builder setAnalyticsCollector(AnalyticsCollector analyticsCollector) {
       checkState(!buildCalled);
+      checkNotNull(analyticsCollector);
       this.analyticsCollectorFunction = (clock) -> analyticsCollector;
       return this;
     }
@@ -809,7 +826,7 @@ public interface ExoPlayer extends Player {
      */
     public Builder setAudioAttributes(AudioAttributes audioAttributes, boolean handleAudioFocus) {
       checkState(!buildCalled);
-      this.audioAttributes = audioAttributes;
+      this.audioAttributes = checkNotNull(audioAttributes);
       this.handleAudioFocus = handleAudioFocus;
       return this;
     }
@@ -935,7 +952,7 @@ public interface ExoPlayer extends Player {
     @UnstableApi
     public Builder setSeekParameters(SeekParameters seekParameters) {
       checkState(!buildCalled);
-      this.seekParameters = seekParameters;
+      this.seekParameters = checkNotNull(seekParameters);
       return this;
     }
 
@@ -1037,7 +1054,7 @@ public interface ExoPlayer extends Player {
     @UnstableApi
     public Builder setLivePlaybackSpeedControl(LivePlaybackSpeedControl livePlaybackSpeedControl) {
       checkState(!buildCalled);
-      this.livePlaybackSpeedControl = livePlaybackSpeedControl;
+      this.livePlaybackSpeedControl = checkNotNull(livePlaybackSpeedControl);
       return this;
     }
 

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/ExoPlayerImpl.java

@@ -1484,14 +1484,13 @@ import java.util.concurrent.TimeoutException;
   @Override
   public void addAnalyticsListener(AnalyticsListener listener) {
     // Don't verify application thread. We allow calls to this method from any thread.
-    checkNotNull(listener);
-    analyticsCollector.addListener(listener);
+    analyticsCollector.addListener(checkNotNull(listener));
   }
 
   @Override
   public void removeAnalyticsListener(AnalyticsListener listener) {
     // Don't verify application thread. We allow calls to this method from any thread.
-    analyticsCollector.removeListener(listener);
+    analyticsCollector.removeListener(checkNotNull(listener));
   }
 
   @Override
@@ -1602,8 +1601,7 @@ import java.util.concurrent.TimeoutException;
   @Override
   public void addListener(Listener listener) {
     // Don't verify application thread. We allow calls to this method from any thread.
-    checkNotNull(listener);
-    listeners.add(listener);
+    listeners.add(checkNotNull(listener));
   }
 
   @Override