DownloadHelper.getDownloadRequest() crashes with IndexOutOfBoundsException in HlsMediaPeriod.getStreamKeys() for HLS streams with a demuxed audio rendition and no subtitles #3333

Version

Media3 1.10.1

More version details

No response

Devices that reproduce the issue

• Pixel 6 running Android 17 (build CP31.260618.005)

Devices that do not reproduce the issue

None found.

Reproducible in the demo app?

Yes

Reproduction steps

The only change needed to the demo app is adding one entry to its media list.

1. Check out the 1.10.1 tag of this repository.
2. Add the following sample to the HLS group in demos/main/src/main/assets/media.exolist.json:

   {
     "name": "Repro: demuxed audio, no subtitles",
     "uri": "https://storage.googleapis.com/shaka-demo-assets/bbb-dark-truths-hls/hls.m3u8"
   }

3. ./gradlew :demo:assembleNoDecoderExtensionsDebug and install the APK.
4. In the demo app, expand HLS and tap the download icon next to the new sample.
5. In the track-selection dialog, leave the defaults (VIDEO = 自動 / Auto, AUDIO = default) and press OK.

The app crashes immediately, before any segment is downloaded.

Expected result

DownloadHelper.getDownloadRequest() returns a DownloadRequest whose streamKeys cover the selected video
variant and the selected audio rendition, and the download starts.

Actual result

The app crashes:

FATAL EXCEPTION: main
Process: androidx.media3.demo.main, PID: 8815
java.lang.IndexOutOfBoundsException: index (0) must be less than size (0)
	at com.google.common.base.Preconditions.checkElementIndex(Preconditions.java:1372)
	at com.google.common.base.Preconditions.checkElementIndex(Preconditions.java:1354)
	at com.google.common.collect.RegularImmutableList.get(RegularImmutableList.java:84)
	at androidx.media3.exoplayer.hls.HlsMediaPeriod.getStreamKeys(HlsMediaPeriod.java:289)
	at androidx.media3.exoplayer.offline.DownloadHelper.getDownloadRequestBuilder(DownloadHelper.java:939)
	at androidx.media3.exoplayer.offline.DownloadHelper.getDownloadRequest(DownloadHelper.java:891)
	at androidx.media3.exoplayer.offline.DownloadHelper.getDownloadRequest(DownloadHelper.java:860)
	at androidx.media3.demo.main.DownloadTracker$StartDownloadDialogHelper.buildDownloadRequest(DownloadTracker.java:368)
	at androidx.media3.demo.main.DownloadTracker$StartDownloadDialogHelper.onTracksSelected(DownloadTracker.java:250)
	at androidx.media3.demo.main.TrackSelectionDialog.lambda$createForTracksAndParameters$0(TrackSelectionDialog.java:161)
	...

Media

https://storage.googleapis.com/shaka-demo-assets/bbb-dark-truths-hls/hls.m3u8

Bug Report

• You will email the zip file produced by adb bugreport to android-media-github@google.com after filing this issue.