playback: report whether queue edits were applied

app/src/main/kotlin/com/subtracks/playback/PlaybackController.kt

@@ -423,8 +423,9 @@ class PlaybackController(
     suspend fun removeAt(
         position: Long,
         resetVersion: Long? = null,
-    ) {
-        val requestedVersion = resetVersion ?: snapshot?.resetVersion ?: return
+    ): Boolean {
+        val requestedVersion = resetVersion ?: snapshot?.resetVersion ?: return false
+        var applied = false
         queueRepository.withMutationLock {
             val snapshot = this@PlaybackController.snapshot ?: return@withMutationLock
             if (snapshot.resetVersion != requestedVersion) return@withMutationLock
@@ -436,6 +437,7 @@ class PlaybackController(
             if (snapshot.shuffled && !snapshot.isUpNext(position)) return@withMutationLock
             if (snapshot.size == 1L) {
                 if (!removeAt(snapshot, position)) return@withMutationLock
+                applied = true
                 if (detachedWindow && currentPosition() == null) {
                     val updated = readSnapshot()
                     this@PlaybackController.snapshot = updated
@@ -471,6 +473,7 @@ class PlaybackController(
             val wasUpNext = snapshot.isUpNext(current)
             val removed = if (position == current) null else queueItemAt(snapshot, position)
             if (!removeAt(snapshot, position)) return@withMutationLock
+            applied = true
             var updated = readSnapshot()
             this@PlaybackController.snapshot = updated
             windowJob?.cancel()
@@ -576,15 +579,17 @@ class PlaybackController(
             queueRepository.setCursor(target)
             refresh(target)
         }
+        return applied
     }
 
     suspend fun move(
         from: Long,
         to: Long,
         resetVersion: Long? = null,
-    ) {
-        if (from == to) return
-        val requestedVersion = resetVersion ?: snapshot?.resetVersion ?: return
+    ): Boolean {
+        if (from == to) return false
+        val requestedVersion = resetVersion ?: snapshot?.resetVersion ?: return false
+        var applied = false
         queueRepository.withMutationLock {
             val snapshot = this@PlaybackController.snapshot ?: return@withMutationLock
             if (snapshot.resetVersion != requestedVersion) return@withMutationLock
@@ -596,6 +601,7 @@ class PlaybackController(
             val upNext = snapshot.upNext.map { it.entry }
             val wasUpNext = snapshot.isUpNext(current)
             if (!move(snapshot, from, to)) return@withMutationLock
+            applied = true
             val updated = readSnapshot()
             this@PlaybackController.snapshot = updated
             // The current track still exists, so derive its new position from the edit instead of
@@ -669,6 +675,7 @@ class PlaybackController(
             queueRepository.setCursor(target)
             refresh(target)
         }
+        return applied
     }
 
     suspend fun undo() =

app/src/test/kotlin/com/subtracks/playback/PlaybackControllerTest.kt

@@ -1899,7 +1899,7 @@ class PlaybackControllerTest {
                 ?.id == "s1"
         }
 
-        runBlocking { controller.removeAt(3) }
+        assertTrue(runBlocking { controller.removeAt(3) })
         await { handle.itemCount == 4 }
 
         assertEquals(
@@ -1920,7 +1920,7 @@ class PlaybackControllerTest {
                 ?.id == "s1"
         }
 
-        runBlocking { controller.move(0, 2) }
+        assertTrue(runBlocking { controller.move(0, 2) })
         await { controller.state.value.position == 2L }
 
         assertEquals(listOf("s2", "s3", "s1", "s4"), handle.items.map { it.id })
@@ -1931,6 +1931,23 @@ class PlaybackControllerTest {
         )
     }
 
+    @Test
+    fun staleMoveAndRemovalReturnFalseWithoutChangingTheQueue() {
+        seedAlbum(3, sourceId = 1)
+        controller.playAlbum(1, "al1", 0)
+        await {
+            controller.state.value.item
+                ?.id == "s1"
+        }
+        val before = resolvedIds()
+        val staleVersion = runBlocking { queues.snapshot().resetVersion } + 1
+
+        assertFalse(runBlocking { controller.move(0, 1, staleVersion) })
+        assertFalse(runBlocking { controller.removeAt(1, staleVersion) })
+
+        assertEquals(before, resolvedIds())
+    }
+
     @Test
     fun movingALaterTrackBeforeTheCurrentShiftsTheCursor() {
         seedAlbum(4, sourceId = 1)
@@ -4005,7 +4022,7 @@ class PlaybackControllerTest {
         runBlocking { queues.resetChangedOrigins(setOf(QueueOrigin(QueueKind.Playlist, 1, "p1")), point) }
         await { handle.items.map { it.id } == listOf("s3", "s4", "s5") }
 
-        runBlocking { controller.removeAt(3) }
+        assertTrue(runBlocking { controller.removeAt(3) })
 
         assertEquals(listOf("s3", "s4"), handle.items.map { it.id })
         assertEquals("s3", handle.currentItem?.id)