java.lang.ArrayIndexOutOfBoundsException: length=0; index=0 on live streams with preroll advert when stop player #3423

// Required libs:
// androidx.media3:media3-test-utils: 1.11.1
// androidx.media3:media3-test-utils-robolectric:1.11.1
// androidx.media3:media3-exoplayer-hls:1.11.1
@RunWith(RobolectricTestRunner::class)
class LiveAdStopAnalyticsCrashTest {

    private companion object {
        const val LIVE_URL = "https://demo.unified-streaming.com/k8s/live/scte35.isml/.m3u8"
        const val VOD_URL = "https://test-streams.mux.dev/x36xhzz/x36xhzz.m3u8"
        const val AD_URL = "https://storage.googleapis.com/exoplayer-test-media-1/mp4/android-screens-10s.mp4"

        val PREROLL_ONLY_AD_STATE = AdPlaybackState(1234, 0L).withAdCount(0, 1)
        val PREROLL_MEDIA_ITEM = MediaItem.fromUri(AD_URL)
    }

    private class SimpleAdsLoader : AdsLoader {
        private var listener: AdsLoader.EventListener? = null
        private var adPlaybackState: AdPlaybackState? = null

        override fun start(s: AdsMediaSource, d: DataSpec, adsId: Any, v: AdViewProvider, l: AdsLoader.EventListener) {
            listener = l
            adPlaybackState = PREROLL_ONLY_AD_STATE
            l.onAdPlaybackState(adPlaybackState!!)
        }

        fun showAdNow() {
            adPlaybackState = adPlaybackState!!.withAvailableAdMediaItem(0, 0, PREROLL_MEDIA_ITEM)
            listener!!.onAdPlaybackState(adPlaybackState!!)
        }

        override fun stop(s: AdsMediaSource, l: AdsLoader.EventListener) = Unit
        override fun setPlayer(p: Player?) = Unit
        override fun release() = Unit
        override fun setSupportedContentTypes(vararg c: Int) = Unit
        override fun handlePrepareComplete(s: AdsMediaSource, g: Int, i: Int) = Unit
        override fun handlePrepareError(s: AdsMediaSource, g: Int, i: Int, e: IOException) = Unit
    }

    /** Lets the player run in real time (the test plays real streams over the network). */
    private fun ExoPlayer.runFor(millis: Long) {
        val end = System.currentTimeMillis() + millis
        while (System.currentTimeMillis() < end) {
            shadowOf(Looper.getMainLooper()).idleFor(Duration.ofMillis(50))
            Thread.sleep(50)
        }
    }

    private fun ExoPlayer.waitUntilStreamIsLoaded() {
        val window = Timeline.Window()
        val deadline = System.currentTimeMillis() + 20_000
        while (currentTimeline.isEmpty || currentTimeline.getWindow(0, window).isPlaceholder) {
            check(System.currentTimeMillis() < deadline) { "stream was not loaded" }
            runFor(50)
        }
    }

    private fun userClosesPlayerDuringAd(streamUrl: String) {
        val context = RuntimeEnvironment.getApplication()
        val adsLoader = SimpleAdsLoader()

        // 1. Create the player
        val player = TestExoPlayerBuilder(context)
            .setClock(Clock.DEFAULT)
            .setMediaSourceFactory(DefaultMediaSourceFactory(context).setLocalAdInsertionComponents({ adsLoader }, AdViewProvider { null }))
            .build()

        // !! Critical - use listener impl which calls DefaultPlaybackSessionManager inside
        player.addAnalyticsListener(PlaybackStatsListener(/* keepHistory= */ false, /* callback= */ null))

        // 2. Put a stream (live or regular video) with ads support into the player and start it
        player.setMediaItem(
            MediaItem.Builder()
                .setUri(streamUrl)
                .setAdsConfiguration(MediaItem.AdsConfiguration.Builder(Uri.parse("https://example.com/ad-tag")).build())
                .build()
        )
        player.prepare()
        player.play()
        player.waitUntilStreamIsLoaded()
        player.runFor(10)

        // 3. The app inserts an ad, the ad starts, the user watches it for 1 second
        adsLoader.showAdNow()
        TestPlayerRunHelper.run(player).untilPlayingAdIs(true)
        player.runFor(1000)
        assertTrue("the ad must still be playing", player.isPlayingAd)

        // 4. The user gets angry and closes the player
        player.stop()
        player.runFor(300)

        // 5. Example side effect on leaving player: volume is changed
        player.volume = 0.0f

        // 6. Host app still working...
        player.runFor(500) // <- crash for the live stream

        player.release()
    }

    // Will fail
    @Test
    fun liveStream_userClosesPlayerDuringAd() = userClosesPlayerDuringAd(LIVE_URL)

    // Will success
    @Test
    fun regularVideo_userClosesPlayerDuringAd() = userClosesPlayerDuringAd(VOD_URL)
}