fix: avoid throwing exception when using NetworkList without a NetworkManager (#2539)

Author: PitouGames

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -20,6 +20,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 - Making a `NetworkVariable` with an `INetworkSerializable` type that doesn't meet the `new()` constraint will now create a compile-time error instead of an editor crash (#2528)
 - Fixed the inspector throwing exceptions when attempting to render `NetworkVariable`s of enum types. (#2529)
 - Fixed an exception and error logging when two different objects are shown and hidden on the same frame (#2524)
+- Fixed usage of `NetworkList` throwing exception when used without a NetworkManager in scene. (#2539)
 
 ## Changed
 

com.unity.netcode.gameobjects/Runtime/NetworkVariable/Collections/NetworkList.cs

@@ -374,7 +374,7 @@ public IEnumerator<T> GetEnumerator()
         public void Add(T item)
         {
             // check write permissions
-            if (!CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
+            if (m_NetworkBehaviour && !CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
             {
                 throw new InvalidOperationException("Client is not allowed to write to this NetworkList");
             }
@@ -395,7 +395,7 @@ public void Add(T item)
         public void Clear()
         {
             // check write permissions
-            if (!CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
+            if (m_NetworkBehaviour && !CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
             {
                 throw new InvalidOperationException("Client is not allowed to write to this NetworkList");
             }
@@ -421,7 +421,7 @@ public bool Contains(T item)
         public bool Remove(T item)
         {
             // check write permissions
-            if (!CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
+            if (m_NetworkBehaviour && !CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
             {
                 throw new InvalidOperationException("Client is not allowed to write to this NetworkList");
             }
@@ -456,7 +456,7 @@ public int IndexOf(T item)
         public void Insert(int index, T item)
         {
             // check write permissions
-            if (!CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
+            if (m_NetworkBehaviour && !CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
             {
                 throw new InvalidOperationException("Client is not allowed to write to this NetworkList");
             }
@@ -485,7 +485,7 @@ public void Insert(int index, T item)
         public void RemoveAt(int index)
         {
             // check write permissions
-            if (!CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
+            if (m_NetworkBehaviour && !CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
             {
                 throw new InvalidOperationException("Client is not allowed to write to this NetworkList");
             }
@@ -508,7 +508,7 @@ public T this[int index]
             set
             {
                 // check write permissions
-                if (!CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
+                if (m_NetworkBehaviour && !CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId))
                 {
                     throw new InvalidOperationException("Client is not allowed to write to this NetworkList");
                 }