From 5b8be42fa1c476c36b66adb6be20165188b2ae99 Mon Sep 17 00:00:00 2001
From: olly <olly@google.com>
Date: Mon, 21 Jun 2021 23:42:35 +0100
Subject: [PATCH] HLS: Fix issue where a live event doesn't transition to
 STATE_ENDED

The problem occurs when the primary media playlist URL switches
from one whose latest snapshot has not yet got the ended tag, to
one whose latest snapshot already has the ended tag. In this case:

- We trigger a redundant load of the ended playlist.
- When the redundant load completes,
  MediaPlaylistBundle.processLoadedPlaylist detects that the
  playlist is unchanged from the one it already has, and so
  doesn't call onPlaylistUpdated.
- PrimaryPlaylistListener.onPrimaryPlaylistRefreshed is never
  called with the new primary. Hence the externally visible primary
  is still the one that hasn't ended. HlsMediaSource therefore thinks
  the event hasn't ended, which in turn prevents the player from
  transitioning to the ended state.

This commit detects when the new primary already has the ended tag.
In this case, we call onPrimaryPlaylistRefreshed directly and remove
the unnecessary playlist load.

Issue: #9067
#minor-release
PiperOrigin-RevId: 380680532
---
 RELEASENOTES.md                                     |  3 +++
 .../hls/playlist/DefaultHlsPlaylistTracker.java     | 13 ++++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index 9c7a68cec6e..2c1cfde1ead 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -20,6 +20,9 @@
         ([#4083](https://github.com/google/ExoPlayer/issues/4083)). Such content
         is malformed and should be re-encoded.
 *   HLS:
+    *   Fix issue where playback of a live event could become stuck rather than
+        transitioning to `STATE_ENDED` when the event ends
+        ([#9067](https://github.com/google/ExoPlayer/issues/9067)).
     *   Fix issue where a new initialization segment, as specified by an
         `EXT-X-MAP` tag in a media playlist, would not be loaded when
         encountered during playback
diff --git a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/DefaultHlsPlaylistTracker.java b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/DefaultHlsPlaylistTracker.java
index 2a69f5c6af3..9ad1cb59349 100644
--- a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/DefaultHlsPlaylistTracker.java
+++ b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/DefaultHlsPlaylistTracker.java
@@ -339,9 +339,16 @@ private void maybeSetPrimaryUrl(Uri url) {
       return;
     }
     primaryMediaPlaylistUrl = url;
-    playlistBundles
-        .get(primaryMediaPlaylistUrl)
-        .loadPlaylistInternal(getRequestUriForPrimaryChange(url));
+    MediaPlaylistBundle newPrimaryBundle = playlistBundles.get(primaryMediaPlaylistUrl);
+    @Nullable HlsMediaPlaylist newPrimarySnapshot = newPrimaryBundle.playlistSnapshot;
+    if (newPrimarySnapshot != null && newPrimarySnapshot.hasEndTag) {
+      primaryMediaPlaylistSnapshot = newPrimarySnapshot;
+      primaryPlaylistListener.onPrimaryPlaylistRefreshed(newPrimarySnapshot);
+    } else {
+      // The snapshot for the new primary media playlist URL may be stale. Defer updating the
+      // primary snapshot until after we've refreshed it.
+      newPrimaryBundle.loadPlaylistInternal(getRequestUriForPrimaryChange(url));
+    }
   }
 
   private Uri getRequestUriForPrimaryChange(Uri newPrimaryPlaylistUri) {