fix: player prefab spawning not honoring when spawnwithobservers is disabled (#3077)

* fix

When SpawnWithObservers is disabled on player prefab, the instantiated instance should only spawn on the authority side.
For client-server this will always be the server/host.
For distributed authority this will always be the owner.

* test

Validation test for the SpawnWithObservers regression bug.

* update

updating changelog entry

Author: NoelStephensUnity

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -13,6 +13,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 ### Fixed
 
 - Fixed issue where applying the position and/or rotation to the `NetworkManager.ConnectionApprovalResponse` when connection approval and auto-spawn player prefab were enabled would not apply the position and/or rotation when the player prefab was instantiated. (#3078)
+- Fixed issue where `NetworkObject.SpawnWithObservers` was not being honored when spawning the player prefab. (#3077)
 - Fixed issue with the client count not being correct on the host or server side when a client disconnects itself from a session. (#3075)
 
 ### Changed

com.unity.netcode.gameobjects/Runtime/Core/NetworkObject.cs

@@ -1613,7 +1613,12 @@ internal void SpawnInternal(bool destroyWithScene, ulong ownerClientId, bool pla
             }
             else if (NetworkManager.DistributedAuthorityMode && !NetworkManager.DAHost)
             {
-                NetworkManager.SpawnManager.SendSpawnCallForObject(NetworkManager.ServerClientId, this);
+                // If spawning with observers or if not spawning with observers but the observer count is greater than 1 (i.e. owner/authority creating),
+                // then we want to send a spawn notification.
+                if (SpawnWithObservers || !SpawnWithObservers && Observers.Count > 1)
+                {
+                    NetworkManager.SpawnManager.SendSpawnCallForObject(NetworkManager.ServerClientId, this);
+                }
             }
             else
             {
@@ -3053,10 +3058,15 @@ internal static NetworkObject AddSceneObject(in SceneObject sceneObject, FastBuf
                         }
                     }
 
-                    // Add all known players to the observers list if they don't already exist
-                    foreach (var player in networkManager.SpawnManager.PlayerObjects)
+                    // Only add all other players as observers if we are spawning with observers,
+                    // otherwise user controls via NetworkShow.
+                    if (networkObject.SpawnWithObservers)
                     {
-                        networkObject.Observers.Add(player.OwnerClientId);
+                        // Add all known players to the observers list if they don't already exist
+                        foreach (var player in networkManager.SpawnManager.PlayerObjects)
+                        {
+                            networkObject.Observers.Add(player.OwnerClientId);
+                        }
                     }
                 }
             }

com.unity.netcode.gameobjects/Runtime/Spawning/NetworkSpawnManager.cs

@@ -72,11 +72,22 @@ private void AddPlayerObject(NetworkObject playerObject)
                     return;
                 }
             }
+
             foreach (var player in m_PlayerObjects)
             {
-                player.Observers.Add(playerObject.OwnerClientId);
-                playerObject.Observers.Add(player.OwnerClientId);
+                // If the player's SpawnWithObservers is not set then do not add the new player object's owner as an observer.
+                if (player.SpawnWithObservers)
+                {
+                    player.Observers.Add(playerObject.OwnerClientId);
+                }
+
+                // If the new player object's SpawnWithObservers is not set then do not add this player as an observer to the new player object.
+                if (playerObject.SpawnWithObservers)
+                {
+                    playerObject.Observers.Add(player.OwnerClientId);
+                }
             }
+
             m_PlayerObjects.Add(playerObject);
             if (!m_PlayerObjectsTable.ContainsKey(playerObject.OwnerClientId))
             {

com.unity.netcode.gameobjects/TestHelpers/Runtime/NetcodeIntegrationTest.cs

@@ -545,9 +545,14 @@ protected IEnumerator CreateAndStartNewClient()
         private bool AllPlayerObjectClonesSpawned(NetworkManager joinedClient)
         {
             m_InternalErrorLog.Clear();
+            // If we are not checking for spawned players then exit early with a success
+            if (!ShouldCheckForSpawnedPlayers())
+            {
+                return true;
+            }
+
             // Continue to populate the PlayerObjects list until all player object (local and clone) are found
             ClientNetworkManagerPostStart(joinedClient);
-
             var playerObjectRelative = m_ServerNetworkManager.SpawnManager.PlayerObjects.Where((c) => c.OwnerClientId == joinedClient.LocalClientId).FirstOrDefault();
             if (playerObjectRelative == null)
             {

com.unity.netcode.gameobjects/Tests/Runtime/PlayerObjectTests.cs

@@ -11,7 +11,7 @@ namespace Unity.Netcode.RuntimeTests
     [TestFixture(HostOrServer.Server)]
     internal class PlayerObjectTests : NetcodeIntegrationTest
     {
-        protected override int NumberOfClients => 1;
+        protected override int NumberOfClients => 2;
 
         protected GameObject m_NewPlayerToSpawn;
 
@@ -52,4 +52,72 @@ public IEnumerator SpawnAndReplaceExistingPlayerObject()
             Assert.False(s_GlobalTimeoutHelper.TimedOut, "Timed out waiting for client-side player object to change!");
         }
     }
+
+    /// <summary>
+    /// Validate that when auto-player spawning but SpawnWithObservers is disabled,
+    /// the player instantiated is only spawned on the authority side.
+    /// </summary>
+    [TestFixture(HostOrServer.DAHost)]
+    [TestFixture(HostOrServer.Host)]
+    [TestFixture(HostOrServer.Server)]
+    internal class PlayerSpawnNoObserversTest : NetcodeIntegrationTest
+    {
+        protected override int NumberOfClients => 2;
+
+        public PlayerSpawnNoObserversTest(HostOrServer hostOrServer) : base(hostOrServer) { }
+
+        protected override bool ShouldCheckForSpawnedPlayers()
+        {
+            return false;
+        }
+
+        protected override void OnCreatePlayerPrefab()
+        {
+            var playerNetworkObject = m_PlayerPrefab.GetComponent<NetworkObject>();
+            playerNetworkObject.SpawnWithObservers = false;
+            base.OnCreatePlayerPrefab();
+        }
+
+        [UnityTest]
+        public IEnumerator SpawnWithNoObservers()
+        {
+            yield return s_DefaultWaitForTick;
+
+            if (!m_DistributedAuthority)
+            {
+                // Make sure clients did not spawn their player object on any of the clients including the owner.
+                foreach (var client in m_ClientNetworkManagers)
+                {
+                    foreach (var playerObject in m_ServerNetworkManager.SpawnManager.PlayerObjects)
+                    {
+                        Assert.IsFalse(client.SpawnManager.SpawnedObjects.ContainsKey(playerObject.NetworkObjectId), $"Client-{client.LocalClientId} spawned player object for Client-{playerObject.NetworkObjectId}!");
+                    }
+                }
+            }
+            else
+            {
+                // For distributed authority, we want to make sure the player object is only spawned on the authority side and all non-authority instances did not spawn it.
+                var playerObjectId = m_ServerNetworkManager.LocalClient.PlayerObject.NetworkObjectId;
+                foreach (var client in m_ClientNetworkManagers)
+                {
+                    Assert.IsFalse(client.SpawnManager.SpawnedObjects.ContainsKey(playerObjectId), $"Client-{client.LocalClientId} spawned player object for Client-{m_ServerNetworkManager.LocalClientId}!");
+                }
+
+                foreach (var clientPlayer in m_ClientNetworkManagers)
+                {
+                    playerObjectId = clientPlayer.LocalClient.PlayerObject.NetworkObjectId;
+                    Assert.IsFalse(m_ServerNetworkManager.SpawnManager.SpawnedObjects.ContainsKey(playerObjectId), $"Client-{m_ServerNetworkManager.LocalClientId} spawned player object for Client-{clientPlayer.LocalClientId}!");
+                    foreach (var client in m_ClientNetworkManagers)
+                    {
+                        if (clientPlayer == client)
+                        {
+                            continue;
+                        }
+                        Assert.IsFalse(client.SpawnManager.SpawnedObjects.ContainsKey(playerObjectId), $"Client-{client.LocalClientId} spawned player object for Client-{clientPlayer.LocalClientId}!");
+                    }
+                }
+
+            }
+        }
+    }
 }