SyncVarNetworkBehaviour ==, != overloads

Assets/Mirror/Runtime/SyncVarNetworkBehaviour.cs

@@ -7,6 +7,7 @@
 //
 // original Weaver code was broken because it didn't store by netId.
 using System;
+using System.Runtime.CompilerServices;
 
 namespace Mirror
 {
@@ -44,6 +45,34 @@ public SyncVarNetworkBehaviour(T value = null, Action<T, T> hook = null)
         // even if SyncField is readonly, it's still useful: SyncFieldNetworkBehaviour = target;
         public static implicit operator SyncVarNetworkBehaviour<T>(T value) => new SyncVarNetworkBehaviour<T>(value);
 
+        // NOTE: overloading all == operators blocks '== null' checks with an
+        // "ambiguous invocation" error. that's good. this way user code like
+        // "player.target == null" won't compile instead of silently failing!
+
+        // == operator for comparisons like Player.target==monster
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool operator ==(SyncVarNetworkBehaviour<T> a, SyncVarNetworkBehaviour<T> b) =>
+            a.Value == b.Value;
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool operator !=(SyncVarNetworkBehaviour<T> a, SyncVarNetworkBehaviour<T> b) => !(a == b);
+
+        // == operator for comparisons like Player.target==monster
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool operator ==(SyncVarNetworkBehaviour<T> a, NetworkBehaviour b) =>
+            a.Value == b;
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool operator !=(SyncVarNetworkBehaviour<T> a, NetworkBehaviour b) => !(a == b);
+
+        // == operator for comparisons like Player.target==monster
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool operator ==(NetworkBehaviour a, SyncVarNetworkBehaviour<T> b) =>
+            a == b.Value;
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool operator !=(NetworkBehaviour a, SyncVarNetworkBehaviour<T> b) => !(a == b);
+
         // wrap <NetworkIdentity> hook within base <uint> hook
         static Action<ulong, ulong> WrapHook(Action<T, T> hook) =>
             (oldValue, newValue) => { hook(ULongToNetworkBehaviour(oldValue), ULongToNetworkBehaviour(newValue)); };

Assets/Mirror/Tests/Editor/SyncVarNetworkBehaviourAbstractTests.cs

@@ -1,4 +1,5 @@
 using NUnit.Framework;
+using UnityEngine;
 
 namespace Mirror.Tests
 {
@@ -96,6 +97,37 @@ public void ImplicitFrom_SetsValue()
             Assert.That(field.Value, Is.EqualTo(component));
         }
 
+        [Test]
+        public void OperatorEquals()
+        {
+            // != null
+            SyncVarNetworkBehaviour<NetworkBehaviour> field = new SyncVarNetworkBehaviour<NetworkBehaviour>(component);
+
+            // NOTE: this throws a compilation error, which is good!
+            // we don't want users to do 'player.target == null'.
+            // better to not compile than to fail silently.
+            // Assert.That(field != null, Is.True);
+
+            // different SyncVar<T>, same .Value
+            SyncVarNetworkBehaviour<NetworkBehaviour> fieldSame = new SyncVarNetworkBehaviour<NetworkBehaviour>(component);
+            Assert.That(field == fieldSame, Is.True);
+            Assert.That(field != fieldSame, Is.False);
+
+            // different SyncVar<T>, different .Value
+            SyncVarNetworkBehaviour<NetworkBehaviour> fieldNull = new SyncVarNetworkBehaviour<NetworkBehaviour>(null);
+            Assert.That(field == fieldNull, Is.False);
+            Assert.That(field != fieldNull, Is.True);
+
+            // same NetworkBehaviour<NetworkBehaviour>
+            Assert.That(field == component, Is.True);
+            Assert.That(field != component, Is.False);
+
+            // different NetworkBehaviour<NetworkBehaviour>
+            EmptyBehaviour other = new GameObject().AddComponent<EmptyBehaviour>();
+            Assert.That(field == (NetworkBehaviour)other, Is.False); // NRE
+            Assert.That(field != (NetworkBehaviour)other, Is.True);
+        }
+
         // make sure the NetworkBehaviour hook works, even though base is uint.
         [Test]
         public void Hook()

Assets/Mirror/Tests/Editor/SyncVarNetworkBehaviourInheritedTests.cs

@@ -1,4 +1,5 @@
 using NUnit.Framework;
+using UnityEngine;
 
 namespace Mirror.Tests
 {
@@ -93,6 +94,37 @@ public void ImplicitFrom_SetsValue()
             Assert.That(field.Value, Is.EqualTo(component));
         }
 
+        [Test]
+        public void OperatorEquals()
+        {
+            // != null
+            SyncVarNetworkBehaviour<EmptyBehaviour> field = new SyncVarNetworkBehaviour<EmptyBehaviour>(component);
+
+            // NOTE: this throws a compilation error, which is good!
+            // we don't want users to do 'player.target == null'.
+            // better to not compile than to fail silently.
+            // Assert.That(field != null, Is.True);
+
+            // different SyncVar<T>, same .Value
+            SyncVarNetworkBehaviour<EmptyBehaviour> fieldSame = new SyncVarNetworkBehaviour<EmptyBehaviour>(component);
+            Assert.That(field == fieldSame, Is.True);
+            Assert.That(field != fieldSame, Is.False);
+
+            // different SyncVar<T>, different .Value
+            SyncVarNetworkBehaviour<EmptyBehaviour> fieldNull = new SyncVarNetworkBehaviour<EmptyBehaviour>(null);
+            Assert.That(field == fieldNull, Is.False);
+            Assert.That(field != fieldNull, Is.True);
+
+            // same NetworkBehaviour<EmptyBehaviour>
+            Assert.That(field == component, Is.True);
+            Assert.That(field != component, Is.False);
+
+            // different NetworkBehaviour<EmptyBehaviour>
+            CreateNetworked(out GameObject otherGo, out NetworkIdentity otherIdentity, out EmptyBehaviour otherComp);
+            Assert.That(field == otherComp, Is.False);
+            Assert.That(field != otherComp, Is.True);
+        }
+
         // make sure the NetworkBehaviour hook works, even though base is uint.
         [Test]
         public void Hook()