fix: Revert "NetworkIdentity.observers dictionary is always created, …

…but always empty on clients. Gets rid of all null checks." to fix server-only bug not allowing movement on client, e.g. in uMMORPG

This reverts commit e8d9d85.

Assets/Mirror/Editor/NetworkIdentityEditor.cs

@@ -70,7 +70,7 @@ public override void OnInspectorGUI()
 
             EditorGUILayout.Separator();
 
-            if (networkIdentity.observers.Count > 0)
+            if (networkIdentity.observers != null && networkIdentity.observers.Count > 0)
             {
                 showObservers = EditorGUILayout.Foldout(showObservers, "Observers");
                 if (showObservers)

Assets/Mirror/Editor/NetworkInformationPreview.cs

@@ -146,7 +146,7 @@ public override void OnPreviewGUI(Rect r, GUIStyle background)
                     lastY = behaviourRect.y;
                 }
 
-                if (identity.observers.Count > 0)
+                if (identity.observers != null && identity.observers.Count > 0)
                 {
                     Rect observerRect = new Rect(initialX, lastY + 10, 200, 20);
 

Assets/Mirror/Runtime/NetworkIdentity.cs

@@ -39,8 +39,8 @@ public bool isServer
         public bool isLocalPlayer { get; private set; }
         public bool hasAuthority { get; private set; }
 
-        // <connectionId, NetworkConnection>. always empty on clients.
-        public Dictionary<int, NetworkConnection> observers = new Dictionary<int, NetworkConnection>();
+        // <connectionId, NetworkConnection>
+        public Dictionary<int, NetworkConnection> observers;
 
         public uint netId { get; internal set; }
         public ulong sceneId => m_SceneId;
@@ -150,7 +150,7 @@ internal void SetNotLocalPlayer()
         // this is used when a connection is destroyed, since the "observers" property is read-only
         internal void RemoveObserverInternal(NetworkConnection conn)
         {
-            observers.Remove(conn.connectionId);
+            observers?.Remove(conn.connectionId);
         }
 
         void Awake()
@@ -401,7 +401,7 @@ internal void OnStartServer(bool allowNonZeroNetId)
             m_IsServer = true;
             hasAuthority = !localPlayerAuthority;
 
-            observers.Clear();
+            observers = new Dictionary<int, NetworkConnection>();
 
             // If the instance/net ID is invalid here then this is an object instantiated from a prefab and the server should assign a valid ID
             if (netId == 0)
@@ -778,15 +778,24 @@ internal void OnNetworkDestroy()
 
         internal void ClearObservers()
         {
-            foreach (NetworkConnection conn in observers.Values)
+            if (observers != null)
             {
-                conn.RemoveFromVisList(this, true);
+                foreach (NetworkConnection conn in observers.Values)
+                {
+                    conn.RemoveFromVisList(this, true);
+                }
+                observers.Clear();
             }
-            observers.Clear();
         }
 
         internal void AddObserver(NetworkConnection conn)
         {
+            if (observers == null)
+            {
+                Debug.LogError("AddObserver for " + gameObject + " observer list is null");
+                return;
+            }
+
             if (observers.ContainsKey(conn.connectionId))
             {
                 // if we try to add a connectionId that was already added, then
@@ -802,6 +811,9 @@ internal void AddObserver(NetworkConnection conn)
 
         public void RebuildObservers(bool initialize)
         {
+            if (observers == null)
+                return;
+
             bool changed = false;
             bool result = false;
             HashSet<NetworkConnection> oldObservers = new HashSet<NetworkConnection>(observers.Values);
@@ -1016,7 +1028,7 @@ internal void MirrorUpdate()
         {
             // SendToReady sends to all observers. no need to serialize if we
             // don't have any.
-            if (observers.Count == 0)
+            if (observers == null || observers.Count == 0)
                 return;
 
             // serialize all the dirty components and send (if any were dirty)

Assets/Mirror/Runtime/NetworkServer.cs

@@ -168,7 +168,7 @@ static bool SendToObservers(NetworkIdentity identity, short msgType, MessageBase
         {
             if (LogFilter.Debug) Debug.Log("Server.SendToObservers id:" + msgType);
 
-            if (identity != null)
+            if (identity != null && identity.observers != null)
             {
                 // pack message into byte[] once
                 byte[] bytes = MessagePacker.PackMessage((ushort)msgType, msg);
@@ -190,7 +190,7 @@ static bool SendToObservers(NetworkIdentity identity, short msgType, MessageBase
         {
             if (LogFilter.Debug) Debug.Log("Server.SendToObservers id:" + typeof(T));
 
-            if (identity != null)
+            if (identity != null && identity.observers != null)
             {
                 // pack message into byte[] once
                 byte[] bytes = MessagePacker.Pack(msg);
@@ -242,7 +242,7 @@ public static bool SendToReady(NetworkIdentity identity, short msgType, MessageB
         {
             if (LogFilter.Debug) Debug.Log("Server.SendToReady msgType:" + msgType);
 
-            if (identity != null)
+            if (identity != null && identity.observers != null)
             {
                 // pack message into byte[] once
                 byte[] bytes = MessagePacker.PackMessage((ushort)msgType, msg);
@@ -265,7 +265,7 @@ public static bool SendToReady(NetworkIdentity identity, short msgType, MessageB
         {
             if (LogFilter.Debug) Debug.Log("Server.SendToReady msgType:" + typeof(T));
 
-            if (identity != null)
+            if (identity != null && identity.observers != null)
             {
                 // pack message into byte[] once
                 byte[] bytes = MessagePacker.Pack(msg);