Remove `@Nullable` from some `Dash/Hls/SsMediaSource.Factory` methods

The null-behaviour of these methods creates a minimization footgun,
because **any** call to these setters will prevent R8 from removing
the default implementation (even if it's never used by the app) - this
is because R8 can't tell the default implementation is only used if the
parameter is `null`.

Follow-up to https://github.com/androidx/media/commit/07302a23bd5894d57514c68b2db499ac46726e77

PiperOrigin-RevId: 450395941

RELEASENOTES.md

@@ -74,10 +74,27 @@
     *   Parse channel count from DTS `AudioChannelConfiguration` elements. This
         re-enables audio passthrough for DTS streams
         ([#10159](https://github.com/google/ExoPlayer/issues/10159)).
+    *   Disallow passing `null` to
+        `DashMediaSource.Factory.setCompositeSequenceableLoaderFactory`.
+        Instances of `DefaultCompositeSequenceableLoaderFactory` can be passed
+        explicitly if required.
 *   HLS:
     *   Fallback to chunkful preparation if the playlist CODECS attribute does
         not contain the audio codec
         ([#10065](https://github.com/google/ExoPlayer/issues/10065)).
+    *   Disallow passing `null` to
+        `HlsMediaSource.Factory.setCompositeSequenceableLoaderFactory`,
+        `HlsMediaSource.Factory.setPlaylistParserFactory`, and
+        `HlsMediaSource.Factory.setPlaylistTrackerFactory`. Instances of
+        `DefaultCompositeSequenceableLoaderFactory`,
+        `DefaultHlsPlaylistParserFactory`, or a reference to
+        `DefaultHlsPlaylistTracker.FACTORY` can be passed explicitly if
+        required.
+*   Smooth Streaming:
+    *   Disallow passing `null` to
+        `SsMediaSource.Factory.setCompositeSequenceableLoaderFactory`. Instances
+        of `DefaultCompositeSequenceableLoaderFactory` can be passed explicitly
+        if required.
 *   RTSP:
     *   Add RTP reader for MPEG4
         ([#35](https://github.com/androidx/media/pull/35)).

libraries/exoplayer_dash/src/main/java/androidx/media3/exoplayer/dash/DashMediaSource.java

@@ -218,11 +218,13 @@ public final class DashMediaSource extends BaseMediaSource {
      * @return This factory, for convenience.
      */
     public Factory setCompositeSequenceableLoaderFactory(
-        @Nullable CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory) {
+        CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory) {
       this.compositeSequenceableLoaderFactory =
-          compositeSequenceableLoaderFactory != null
-              ? compositeSequenceableLoaderFactory
-              : new DefaultCompositeSequenceableLoaderFactory();
+          checkNotNull(
+              compositeSequenceableLoaderFactory,
+              "DashMediaSource.Factory#setCompositeSequenceableLoaderFactory no longer handles null"
+                  + " by instantiating a new DefaultCompositeSequenceableLoaderFactory. Explicitly"
+                  + " construct and pass an instance in order to retain the old behavior.");
       return this;
     }
 

libraries/exoplayer_hls/src/main/java/androidx/media3/exoplayer/hls/HlsMediaSource.java

@@ -189,41 +189,40 @@ public final class HlsMediaSource extends BaseMediaSource
     }
 
     /**
-     * Sets the factory from which playlist parsers will be obtained. The default value is a {@link
-     * DefaultHlsPlaylistParserFactory}.
+     * Sets the factory from which playlist parsers will be obtained.
      *
      * @param playlistParserFactory An {@link HlsPlaylistParserFactory}.
      * @return This factory, for convenience.
      */
-    public Factory setPlaylistParserFactory(
-        @Nullable HlsPlaylistParserFactory playlistParserFactory) {
+    public Factory setPlaylistParserFactory(HlsPlaylistParserFactory playlistParserFactory) {
       this.playlistParserFactory =
-          playlistParserFactory != null
-              ? playlistParserFactory
-              : new DefaultHlsPlaylistParserFactory();
+          checkNotNull(
+              playlistParserFactory,
+              "HlsMediaSource.Factory#setPlaylistParserFactory no longer handles null by"
+                  + " instantiating a new DefaultHlsPlaylistParserFactory. Explicitly"
+                  + " construct and pass an instance in order to retain the old behavior.");
       return this;
     }
 
     /**
-     * Sets the {@link HlsPlaylistTracker} factory. The default value is {@link
-     * DefaultHlsPlaylistTracker#FACTORY}.
+     * Sets the {@link HlsPlaylistTracker} factory.
      *
      * @param playlistTrackerFactory A factory for {@link HlsPlaylistTracker} instances.
      * @return This factory, for convenience.
      */
-    public Factory setPlaylistTrackerFactory(
-        @Nullable HlsPlaylistTracker.Factory playlistTrackerFactory) {
+    public Factory setPlaylistTrackerFactory(HlsPlaylistTracker.Factory playlistTrackerFactory) {
       this.playlistTrackerFactory =
-          playlistTrackerFactory != null
-              ? playlistTrackerFactory
-              : DefaultHlsPlaylistTracker.FACTORY;
+          checkNotNull(
+              playlistTrackerFactory,
+              "HlsMediaSource.Factory#setPlaylistTrackerFactory no longer handles null by"
+                  + " defaulting to DefaultHlsPlaylistTracker.FACTORY. Explicitly"
+                  + " pass a reference to this instance in order to retain the old behavior.");
       return this;
     }
 
     /**
      * Sets the factory to create composite {@link SequenceableLoader}s for when this media source
-     * loads data from multiple streams (video, audio etc...). The default is an instance of {@link
-     * DefaultCompositeSequenceableLoaderFactory}.
+     * loads data from multiple streams (video, audio etc...).
      *
      * @param compositeSequenceableLoaderFactory A factory to create composite {@link
      *     SequenceableLoader}s for when this media source loads data from multiple streams (video,
@@ -231,11 +230,13 @@ public final class HlsMediaSource extends BaseMediaSource
      * @return This factory, for convenience.
      */
     public Factory setCompositeSequenceableLoaderFactory(
-        @Nullable CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory) {
+        CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory) {
       this.compositeSequenceableLoaderFactory =
-          compositeSequenceableLoaderFactory != null
-              ? compositeSequenceableLoaderFactory
-              : new DefaultCompositeSequenceableLoaderFactory();
+          checkNotNull(
+              compositeSequenceableLoaderFactory,
+              "HlsMediaSource.Factory#setCompositeSequenceableLoaderFactory no longer handles null"
+                  + " by instantiating a new DefaultCompositeSequenceableLoaderFactory. Explicitly"
+                  + " construct and pass an instance in order to retain the old behavior.");
       return this;
     }
 

libraries/exoplayer_smoothstreaming/src/main/java/androidx/media3/exoplayer/smoothstreaming/SsMediaSource.java

@@ -175,8 +175,7 @@ public final class SsMediaSource extends BaseMediaSource
 
     /**
      * Sets the factory to create composite {@link SequenceableLoader}s for when this media source
-     * loads data from multiple streams (video, audio etc.). The default is an instance of {@link
-     * DefaultCompositeSequenceableLoaderFactory}.
+     * loads data from multiple streams (video, audio etc.).
      *
      * @param compositeSequenceableLoaderFactory A factory to create composite {@link
      *     SequenceableLoader}s for when this media source loads data from multiple streams (video,
@@ -184,11 +183,13 @@ public final class SsMediaSource extends BaseMediaSource
      * @return This factory, for convenience.
      */
     public Factory setCompositeSequenceableLoaderFactory(
-        @Nullable CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory) {
+        CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory) {
       this.compositeSequenceableLoaderFactory =
-          compositeSequenceableLoaderFactory != null
-              ? compositeSequenceableLoaderFactory
-              : new DefaultCompositeSequenceableLoaderFactory();
+          checkNotNull(
+              compositeSequenceableLoaderFactory,
+              "SsMediaSource.Factory#setCompositeSequenceableLoaderFactory no longer handles null"
+                  + " by instantiating a new DefaultCompositeSequenceableLoaderFactory. Explicitly"
+                  + " construct and pass an instance in order to retain the old behavior.");
       return this;
     }