From 706d0f00955e85991bbacdd96cce46a031cf7c50 Mon Sep 17 00:00:00 2001
From: davidliu <davidliu@deviange.net>
Date: Tue, 4 Aug 2026 21:54:30 +0900
Subject: [PATCH] Fix custom RTCConfigurations not picking up server-provided
 ice servers when needed

---
 .changeset/tricky-grapes-compare.md           |  5 +++
 .../java/io/livekit/android/room/RTCEngine.kt |  9 +++--
 .../android/room/RTCEngineMockE2ETest.kt      | 33 +++++++++++++++++++
 3 files changed, 42 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/tricky-grapes-compare.md

diff --git a/.changeset/tricky-grapes-compare.md b/.changeset/tricky-grapes-compare.md
new file mode 100644
index 00000000..3dedf82d
--- /dev/null
+++ b/.changeset/tricky-grapes-compare.md
@@ -0,0 +1,5 @@
+---
+"client-sdk-android": patch
+---
+
+Fix custom RTCConfigurations not picking up server-provided ice servers when user-provided list is empty
diff --git a/livekit-android-sdk/src/main/java/io/livekit/android/room/RTCEngine.kt b/livekit-android-sdk/src/main/java/io/livekit/android/room/RTCEngine.kt
index b43c3cf3..e0e64e7d 100644
--- a/livekit-android-sdk/src/main/java/io/livekit/android/room/RTCEngine.kt
+++ b/livekit-android-sdk/src/main/java/io/livekit/android/room/RTCEngine.kt
@@ -998,14 +998,13 @@ internal constructor(
 
             // Only use server-provided servers if user doesn't provide any.
             if (mergedServers.isEmpty()) {
-                iceServers.forEach { server ->
-                    if (!mergedServers.contains(server)) {
-                        mergedServers.add(server)
-                    }
-                }
+                mergedServers.addAll(serverIceServers)
             }
 
             iceServers = mergedServers
+            sdpSemantics = PeerConnection.SdpSemantics.UNIFIED_PLAN
+            continualGatheringPolicy =
+                PeerConnection.ContinualGatheringPolicy.GATHER_CONTINUALLY
         }
             ?: RTCConfiguration(serverIceServers).apply {
                 sdpSemantics = PeerConnection.SdpSemantics.UNIFIED_PLAN
diff --git a/livekit-android-test/src/test/java/io/livekit/android/room/RTCEngineMockE2ETest.kt b/livekit-android-test/src/test/java/io/livekit/android/room/RTCEngineMockE2ETest.kt
index 19a9d1c6..6225fb1e 100644
--- a/livekit-android-test/src/test/java/io/livekit/android/room/RTCEngineMockE2ETest.kt
+++ b/livekit-android-test/src/test/java/io/livekit/android/room/RTCEngineMockE2ETest.kt
@@ -17,6 +17,7 @@
 package io.livekit.android.room
 
 import com.google.protobuf.ByteString
+import io.livekit.android.ConnectOptions
 import io.livekit.android.room.track.TrackException
 import io.livekit.android.test.MockE2ETest
 import io.livekit.android.test.events.FlowCollector
@@ -84,6 +85,38 @@ class RTCEngineMockE2ETest : MockE2ETest() {
         assertEquals(sentIceServers, subPeerConnection.rtcConfig.iceServers)
     }
 
+    @Test
+    fun customRtcConfigWithEmptyIceServersUsesServerIceServers() = runTest {
+        val connectJob = async {
+            room.connect(
+                url = TestData.EXAMPLE_URL,
+                token = "token",
+                options = ConnectOptions(
+                    rtcConfig = PeerConnection.RTCConfiguration(emptyList()).apply {
+                        iceTransportsType = PeerConnection.IceTransportsType.RELAY
+                    },
+                ),
+            )
+        }
+        prepareSignal(TestData.JOIN)
+        connectJob.await()
+        connectPeerConnection()
+
+        val subPeerConnection = getSubscriberPeerConnection()
+        assertEquals(PeerConnection.IceTransportsType.RELAY, subPeerConnection.rtcConfig.iceTransportsType)
+        val sentIceServers = TestData.JOIN.join.iceServersList
+            .map { it.toWebrtc() }
+        assertEquals(sentIceServers, subPeerConnection.rtcConfig.iceServers)
+        assertEquals(
+            PeerConnection.SdpSemantics.UNIFIED_PLAN,
+            subPeerConnection.rtcConfig.sdpSemantics,
+        )
+        assertEquals(
+            PeerConnection.ContinualGatheringPolicy.GATHER_CONTINUALLY,
+            subPeerConnection.rtcConfig.continualGatheringPolicy,
+        )
+    }
+
     @Test
     fun roomConnectDoesNotHangOnWebSocketFailure() = runTest {
         val connectJob = async {