DASH: empty <SegmentTimeline/> crashes track selection with IndexOutOfBoundsException (regression 1.9.x → 1.10.x) #3326

Version

Media3 1.10.1

More version details

Regression introduced between 1.9.4 (works) and 1.10.0/1.10.1 (crashes).
Root cause traced back to commit f066180c8de61fb8be4746f3d7f5237ee3969f1e
("Refactor DASH initial discontinuity handling", PiperOrigin-RevId: 871747537, Issue: #3057).
Still present (unchanged code) on release-1.11.0-alpha01 and release-1.11.0-beta01.

Devices that reproduce the issue

device independent

Devices that do not reproduce the issue

device independent

Reproducible in the demo app?

Not tested

Reproduction steps

1. Start playback of a multi‑period DASH stream (e.g. server‑side ad insertion) with a subtitle
   track enabled in the track selector.
2. Have the source deliver a Period whose subtitle AdaptationSet Representation uses a
   SegmentTemplate with an empty <SegmentTimeline/>, typically emitted at an ad→content transition
   while segments are not yet listed.
3. When that Period is prepared and its tracks are selected, the player crashes.

Expected result

The player should tolerate a valid‑but‑empty segment index (as Media3 1.9.4 did — playback continues) instead of throwing.

Actual result

Playback stops with ExoPlaybackException: Unexpected runtime error /
ERROR_CODE_UNSPECIFIED caused by IndexOutOfBoundsException during period preparation:

androidx.media3.exoplayer.ExoPlaybackException: Unexpected runtime error
Caused by: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
    at java.util.ArrayList.get(ArrayList.java:437)
    at androidx.media3.exoplayer.dash.manifest.SegmentBase$SingleSegmentBase... 
    at androidx.media3.exoplayer.dash.DashMediaPeriod.buildSampleStream(DashMediaPeriod.java:858)
    at androidx.media3.exoplayer.dash.DashMediaPeriod.selectNewStreams(DashMediaPeriod.java:477)
    at androidx.media3.exoplayer.dash.DashMediaPeriod.selectTracks(DashMediaPeriod.java:293)
    at androidx.media3.exoplayer.source.MaskingMediaPeriod.selectTracks(MaskingMediaPeriod.java:189)
    at androidx.media3.exoplayer.MediaPeriodQueue.getMediaPeriodInfoForContent(MediaPeriodQueue.java:1249)
    at androidx.media3.exoplayer.ExoPlayerImplInternal.handleLoadingPeriodPrepared(ExoPlayerImplInternal.java:3093)
    at androidx.media3.exoplayer.ExoPlayerImplInternal.handlePeriodPrepared(ExoPlayerImplInternal.java:3074)
    at androidx.media3.exoplayer.ExoPlayerImplInternal.handleMessage(ExoPlayerImplInternal.java:815)

Media

no test stream available. I will send an example for a manifest together with a bugreport via mail

Bug Report

• You will email the zip file produced by adb bugreport to [email protected] after filing this issue.