fix: fixing use of GO/NI/NB inside Constructor

Assets/Mirage/Weaver/Processors/PropertySiteProcessor.cs

@@ -5,7 +5,9 @@
 
 namespace Mirage.Weaver
 {
-    // todo add docs for what this type does
+    /// <summary>
+    /// Replaces SyncVar fields with their property getter/setting
+    /// </summary>
     public class PropertySiteProcessor
     {
         // setter functions that replace [SyncVar] member variable references. dict<field, replacement>
@@ -19,10 +21,22 @@ public void Process(ModuleDefinition moduleDef)
             CodePass.ForEachInstruction(moduleDef, WeavedMethods, ProcessInstruction);
         }
 
-        private static bool WeavedMethods(MethodDefinition md) =>
-                        md.Name != ".cctor" &&
-                        md.Name != NetworkBehaviourProcessor.ProcessedFunctionName &&
-                        !md.IsConstructor;
+        private static bool WeavedMethods(MethodDefinition md)
+        {
+            if (md.Name == ".cctor")
+                return false;
+            if (md.Name == NetworkBehaviourProcessor.ProcessedFunctionName)
+                return false;
+
+            // dont use network get/set inside unity consturctors
+            // this is because they will try to set dirtyBit and throw unity errors
+            if (md.DeclaringType.IsDerivedFrom<UnityEngine.Object>() && md.IsConstructor)
+                return false;
+
+            // note: Constructor for non-unity types should be safe to use, for example get/set a sync var on a NB from without a struct
+
+            return true;
+        }
 
         private Instruction ProcessInstruction(MethodDefinition md, Instruction instr, SequencePoint sequencePoint)
         {

Assets/Tests/Runtime/Syncing/SyncVarFieldReplaceTest.cs

@@ -0,0 +1,92 @@
+using Cysharp.Threading.Tasks;
+using NUnit.Framework;
+
+namespace Mirage.Tests.Runtime.Syncing
+{
+    public class SyncVarFieldReplaceTest : ServerSetup
+    {
+        private NetworkIdentity _target1;
+        private NetworkIdentity _target2;
+        private MockPlayer component;
+
+        protected override UniTask LateSetup()
+        {
+            _target1 = CreateNetworkIdentity();
+            serverObjectManager.Spawn(_target1, 1);
+
+            _target2 = CreateNetworkIdentity();
+            serverObjectManager.Spawn(_target2, 1);
+
+            component = CreateBehaviour<MockPlayer>();
+            component.target = _target1;
+            serverObjectManager.Spawn(component.Identity, 2);
+
+            return base.LateSetup();
+        }
+
+        [Test]
+        public void CanGetSyncVarFromMethod()
+        {
+            var mock = new MockCSharpClass();
+            mock.GetTarget(component);
+            Assert.That(mock.netid, Is.Not.Zero.And.EqualTo(component.target.NetId));
+        }
+
+        [Test]
+        public void CanSetSyncVarFromMethod()
+        {
+            var mock = new MockCSharpClass();
+            mock.SetTarget(component, _target2);
+            Assert.That(component.target, Is.EqualTo(_target2));
+        }
+        [Test]
+        public void CanGetSyncVarFromConstructor()
+        {
+            var mock = new MockCSharpClass(component);
+            Assert.That(mock.netid, Is.Not.Zero.And.EqualTo(component.target.NetId));
+        }
+
+        [Test]
+        public void CanSetSyncVarFromConstructor()
+        {
+            var mock = new MockCSharpClass(component, _target2);
+            Assert.That(component.target, Is.EqualTo(_target2));
+        }
+
+
+        public class MockCSharpClass
+        {
+            public uint netid;
+            private MockPlayer player;
+
+            public MockCSharpClass() { }
+            public MockCSharpClass(MockPlayer myPlayer)
+            {
+                // tests getting syncvar from constructor of c# only class
+                if (myPlayer.target != null)
+                    netid = myPlayer.target.NetId;
+
+                player = myPlayer;
+            }
+
+            public MockCSharpClass(MockPlayer myPlayer, NetworkIdentity target)
+            {
+                // tests setting syncvar from constructor of c# only class
+                myPlayer.target = target;
+            }
+
+            public void GetTarget(MockPlayer myPlayer)
+            {
+                if (myPlayer.target != null)
+                {
+                    netid = myPlayer.target.NetId;
+                }
+            }
+
+            public void SetTarget(MockPlayer myPlayer, NetworkIdentity target)
+            {
+                myPlayer.target = target;
+            }
+        }
+    }
+}