fix: replacing const with attribute (#1076)

const does not behave well with some types like enums

Assets/Mirage/Runtime/Serialization/WeaverAttributes.cs

@@ -1,5 +1,25 @@
 using System;
 
+namespace Mirage.Serialization.Internal.Codegen
+{
+    /// <summary>
+    /// Used by weaver
+    /// <para>
+    /// Weavers Adds to types that have readers generared for them. Checked by other asmdefs so they dont generate their own readers
+    /// </para>
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Method)]
+    public sealed class WeaverReaderGeneratedAttribute : Attribute { }
+
+    /// <summary>
+    /// Used by weaver
+    /// <para>
+    /// Weavers Adds to types that have writers generared for them. Checked by other asmdefs so they dont generate their own writers
+    /// </para>
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Method)]
+    public sealed class WeaverWriterGeneratedAttribute : Attribute { }
+}
 namespace Mirage.Serialization
 {
     // weaver doesn't need constructor parameters to be used, so we can have constructor without fields/properties

Assets/Mirage/Weaver/Extensions.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Linq;
 using Mono.Cecil;
+using ConstructorInfo = System.Reflection.ConstructorInfo;
 
 namespace Mirage.Weaver
 {
@@ -278,6 +279,13 @@ public static bool HasCustomAttribute(this ICustomAttributeProvider attributePro
             return attributeProvider.CustomAttributes.Any(attr => attr.AttributeType.Is(t));
         }
 
+        public static void AddCustomAttribute(this ICustomAttributeProvider attributeProvider, ModuleDefinition module, Type t)
+        {
+            ConstructorInfo constructor = t.GetConstructor(new Type[0]);
+            var customAttribute = new CustomAttribute(module.ImportReference(constructor));
+            attributeProvider.CustomAttributes.Add(customAttribute);
+        }
+
         public static T GetField<T>(this CustomAttribute ca, string field, T defaultValue)
         {
             foreach (CustomAttributeNamedArgument customField in ca.Fields)

Assets/Mirage/Weaver/Serialization/Readers.cs

@@ -14,7 +14,7 @@ public class Readers : SerializeFunctionBase
         public Readers(ModuleDefinition module, IWeaverLogger logger) : base(module, logger) { }
 
         protected override string FunctionTypeLog => "read function";
-        protected override string GeneratedLabel => "__MirageReaderGenerated";
+        protected override Type GeneratedAttribute => typeof(Mirage.Serialization.Internal.Codegen.WeaverReaderGeneratedAttribute);
         protected override Expression<Action> ArrayExpression => () => CollectionExtensions.ReadArray<byte>(default);
         protected override Expression<Action> ListExpression => () => CollectionExtensions.ReadList<byte>(default);
         protected override Expression<Action> SegmentExpression => () => CollectionExtensions.ReadArraySegment<byte>(default);

Assets/Mirage/Weaver/Serialization/Writers.cs

@@ -13,7 +13,7 @@ public class Writers : SerializeFunctionBase
         public Writers(ModuleDefinition module, IWeaverLogger logger) : base(module, logger) { }
 
         protected override string FunctionTypeLog => "write function";
-        protected override string GeneratedLabel => "__MirageWirterGenerated";
+        protected override Type GeneratedAttribute => typeof(Mirage.Serialization.Internal.Codegen.WeaverWriterGeneratedAttribute);
         protected override Expression<Action> ArrayExpression => () => CollectionExtensions.WriteArray<byte>(default, default);
         protected override Expression<Action> ListExpression => () => CollectionExtensions.WriteList<byte>(default, default);
         protected override Expression<Action> SegmentExpression => () => CollectionExtensions.WriteArraySegment<byte>(default, default);

Assets/Mirage/Weaver/SerializeFunctionBase.cs

@@ -22,7 +22,7 @@ public abstract class SerializeFunctionBase
         /// <summary>
         /// Name for const that will tell other asmdef's that type has already generated function
         /// </summary>
-        protected abstract string GeneratedLabel { get; }
+        protected abstract Type GeneratedAttribute { get; }
 
         protected SerializeFunctionBase(ModuleDefinition module, IWeaverLogger logger)
         {
@@ -63,10 +63,14 @@ private void MarkAsGenerated(TypeReference typeReference)
         private void MarkAsGenerated(TypeDefinition typeDefinition)
         {
             // if in this module, then mark as generated
-            if (typeDefinition.Module == module)
-            {
-                typeDefinition.SetConst(GeneratedLabel, true);
-            }
+            if (typeDefinition.Module != module)
+                return;
+
+            // dont add twice
+            if (typeDefinition.HasCustomAttribute(GeneratedAttribute))
+                return;
+
+            typeDefinition.AddCustomAttribute(module, GeneratedAttribute);
         }
 
         /// <summary>
@@ -80,7 +84,7 @@ private bool HasGeneratedFunctionInAnotherModule(TypeReference typeReference)
             if (def.Module == module)
                 return false;
 
-            return def.GetConst<bool>(GeneratedLabel);
+            return def.HasCustomAttribute(GeneratedAttribute);
         }
 
         /// <summary>

Assets/Tests/Runtime/Serialization/RpcWithTypeInAnotherAssembly.cs → Assets/Tests/Runtime/Serialization/GeneratedFunctionsInOtherAssembly.cs

@@ -31,7 +31,7 @@ public void SendValue_None(MessageWithNoWriter value)
         }
     }
 
-    public class RpcWithTypeInAnotherAssembly : ClientServerSetup<RpcWithTypeInAnotherAssemblyBehaviour>
+    public class GeneratedFunctionsInOtherAssembly : ClientServerSetup<RpcWithTypeInAnotherAssemblyBehaviour>
     {
         [UnityTest]
         [Description("This has custom writer in other Assembly, we need to make sure we use it")]