Hey everyone,
I need to reorder a four-song Apple Music application queue while keeping the same selected occurrence, playback time, and playing/paused state. I reproduced two distinct failures in a standalone app without persistence or synchronization. I do not yet know whether these failures have a common cause.
Device: iPhone 16 Pro, iOS 27.0.1 (24A446), built-in audio. Music authorization and catalog subscription checks succeed. Four distinct catalog songs resolve successfully in the Japanese storefront, in the order A, B, C, D. These letters are anonymized labels for the songs used in the measured runs; the actual catalog IDs are omitted from this public post. This does not establish that the issue occurs with every four-song selection. Repeat and shuffle are off.
- MusicKit reorder after a stable paused baseline
Install ApplicationMusicPlayer.Queue once, starting at song D. Play once, then pause after several seconds; verify all four entries and unchanged Current/time for over ten seconds. Move the non-Current prefix in one operation:
queue.entries.move(fromOffsets: IndexSet(integersIn: 0..<3), toOffset: 4)
Expected: [A,B,C,D*] becomes [D*,A,B,C], retaining Current and elapsed time. RemotePlayerService instead terminates with SIGABRT during queue modification. The exception stack includes _componentsForContentItemID: and _qfa_performInsertPlaybackContext:atPosition:afterContentItemID:sectionIdentifier:actions:completion:. The client then hangs in synchronous XPC connection establishment on main. This also occurred with all app-initiated post-move SDK reads suppressed; the service report predates the first scheduled read. A direct Current move 3→0 produced a matching service exception stack in a separate run.
- MediaPlayer alternative fails before any reorder
Using applicationQueuePlayer instead, set one MPMusicPlayerStoreQueueDescriptor for the same songs A–D with startItemID set to song D's actual catalog ID. Set repeat/shuffle off, activate an AVAudioSession playback/default session and call play once. Immediately call performQueueTransaction:completionHandler: with an empty transaction block. Completion is on main and error is nil. All queue access is synchronous inside that callback. The relevant Objective-C read order is:
id raw = queue.items;
NSUInteger currentIndex = player.indexOfNowPlayingItem;
id current = player.nowPlayingItem;
NSArray *items = raw; // raw was checked to be a nonnil NSArray
NSUInteger count = items.count;
for (NSUInteger i = 0; i < count; ++i) {
id item = [items objectAtIndex:i];
if (!item) { /* record index and end observation */ break; }
// Validate MPMediaItem and copy its nonempty playbackStoreID.
}
count was 4, currentIndex was 2, current was nonnil, and elements 0 and 1 validated. objectAtIndex:2 returned nil. No queue object escapes the callback. The guard ended the read with audio continuing and UI responsive. An earlier Swift queue.items.map observation crashed in Swift element dynamic casting. This newer result does not establish which song occupies returned index 2. There was no queue mutation or repeat read in this MediaPlayer trial.
Both startup sequences logged "ping did not pong"; the MusicKit reorder trial subsequently reached the stable paused baseline. I cannot rule out startup's contribution. I have not established the behavior on another device/OS.
Questions
- Is modifying entries the supported way to reorder the full application queue across Current while retaining its occurrence and continuous audio?
- For MediaPlayer, is a successful read-only transaction completion expected to provide a fully readable nonnull items array? Is there a documented readiness condition before enumeration that this sequence is missing?
- If MediaPlayer transactions are a suitable alternative, how should callers target duplicate occurrences (not just song IDs) for removal/insertion?
I can provide a minimal project and the two separate failure reports through Feedback Assistant. Which component and additional diagnostics would be most useful? No Feedback ID exists yet.