put ensurePublisherConnected into a try {} catch {} (#891)

* put ensurePublisherConnected into a try {} catch {}

* fix the build

Author: xianshijing-lk

livekit-android-sdk/src/main/java/io/livekit/android/room/RTCEngine.kt

@@ -694,7 +694,11 @@ internal constructor(
 
     @CheckResult
     internal suspend fun sendData(dataPacket: LivekitModels.DataPacket): Result<Unit> {
-        ensurePublisherConnected(dataPacket.kind)
+        try {
+            ensurePublisherConnected(dataPacket.kind)
+        } catch (e: Exception) {
+            return Result.failure(e)
+        }
 
         fun sendDataImpl(dataPacket: LivekitModels.DataPacket): Result<Unit> {
             try {

livekit-android-test/src/test/java/io/livekit/android/room/participant/LocalParticipantMockE2ETest.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023-2025 LiveKit, Inc.
+ * Copyright 2023-2026 LiveKit, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,6 +26,7 @@ import io.livekit.android.events.ParticipantEvent
 import io.livekit.android.events.RoomEvent
 import io.livekit.android.room.DefaultsManager
 import io.livekit.android.room.RTCEngine
+import io.livekit.android.room.RoomException
 import io.livekit.android.room.track.LocalVideoTrack
 import io.livekit.android.room.track.LocalVideoTrackOptions
 import io.livekit.android.room.track.ScreenSharePresets
@@ -879,4 +880,19 @@ class LocalParticipantMockE2ETest : MockE2ETest() {
 
         assertTrue(headerPacket.user.payload.toByteArray().contentEquals(data))
     }
+
+    @Test
+    fun publishDataReturnsFailureWhenPublisherChannelIsMissing() = runTest {
+        connect()
+
+        val rtcEngine = component.rtcEngine()
+        val reliableDataChannelField = RTCEngine::class.java.getDeclaredField("reliableDataChannel")
+        reliableDataChannelField.isAccessible = true
+        reliableDataChannelField.set(rtcEngine, null)
+
+        val result = room.localParticipant.publishData("hello".toByteArray())
+
+        assertTrue(result.isFailure)
+        assertTrue(result.exceptionOrNull() is RoomException.ConnectException)
+    }
 }