Fix Unity static state resetting for generic types

sdks/csharp/src/SpacetimeDBClient.cs

@@ -135,6 +135,12 @@ public abstract class DbConnectionBase<DbConnection, Tables, Reducer> : IDbConne
         where DbConnection : DbConnectionBase<DbConnection, Tables, Reducer>, new()
         where Tables : RemoteTablesBase
     {
+        /// <remarks>
+        /// This isn't reset since [RuntimeInitializeOnLoadMethod] methods cannot be in generic types
+        /// We assume that the user will reset this if needed; Unity will give an error about this field not being reset.
+        /// One way we can get around this in the future is using <see href="https://docs.unity3d.com/6000.5/Documentation/ScriptReference/Unity.Scripting.LifecycleManagement.AutoStaticsCleanupAttribute.html">AutoStaticsCleanup</see> 
+        /// But that requires Unity 6.5
+        /// <remarks>
         internal static bool IsTesting { get; set; } = false;
 
         public static DbConnectionBuilder<DbConnection> Builder() => new();
@@ -292,23 +298,6 @@ internal struct ParsedMessage
 
         private static readonly Status Committed = new Status.Committed(default);
 
-#if UNITY_5_3_OR_NEWER
-        /// <summary>
-        /// Resets the static instance to prevent data persistence when Enter Play Mode Options (Disable Domain Reloading) is active.
-        /// RuntimeInitializeOnLoadMethod is used since it is supported in older versions of Unity.
-        /// AutoStaticsCleanup and NoAutoStaticsCleanup is only supported in Unity 6+
-        /// </summary>
-        /// <remarks>
-        /// See the <see href="https://docs.unity3d.com/6000.5/Documentation/Manual/domain-reloading.html">Unity Domain Reloading Manual</see> 
-        /// and the <see href="https://docs.unity3d.com/6000.5/Documentation/ScriptReference/RuntimeInitializeOnLoadMethodAttribute.html">RuntimeInitializeOnLoadMethodAttribute API Docs</see> for details.
-        /// </remarks>
-        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
-        private static void ResetStaticFields()
-        {
-            IsTesting = false;
-        }
-#endif
-
         /// <summary>
         /// Get a description of a message suitable for storing in the tracker metadata.
         /// </summary>

sdks/csharp/src/Table.cs

@@ -187,6 +187,22 @@ public RemoteTableHandleBase(IDbConnection conn, bool isEventTable = false) : ba
         {
             IsEventTable = isEventTable;
         }
+
+#if UNITY_5_3_OR_NEWER
+        /// <summary>
+        /// Resets the static instance to prevent data persistence when Enter Play Mode Options (Disable Domain Reloading) is active.
+        /// RuntimeInitializeOnLoadMethod can't be used here since this is a generic class, so we have to handle it ourselves.
+        /// AutoStaticsCleanup and NoAutoStaticsCleanup is only supported in Unity 6+
+        /// </summary>
+        /// <remarks>
+        /// See the <see href="https://docs.unity3d.com/6000.5/Documentation/Manual/domain-reloading.html">Unity Domain Reloading Manual</see> 
+        /// and the <see href="https://docs.unity3d.com/6000.5/Documentation/ScriptReference/RuntimeInitializeOnLoadMethodAttribute.html">RuntimeInitializeOnLoadMethodAttribute API Docs</see> for details.
+        /// </remarks>
+        static RemoteTableHandleBase()
+        {
+            RemoteTableHandleStaticReset.Register(() => _serializer = null);
+        }
+#endif
 
         // This method needs to be overridden by autogen.
         protected virtual object? GetPrimaryKey(Row row) => null;
@@ -245,24 +261,6 @@ private static IReadWrite<Row> Serializer
             }
         }
 
-
-#if UNITY_5_3_OR_NEWER
-        /// <summary>
-        /// Resets the static instance to prevent data persistence when Enter Play Mode Options (Disable Domain Reloading) is active.
-        /// RuntimeInitializeOnLoadMethod is used since it is supported in older versions of Unity.
-        /// AutoStaticsCleanup and NoAutoStaticsCleanup is only supported in Unity 6+
-        /// </summary>
-        /// <remarks>
-        /// See the <see href="https://docs.unity3d.com/6000.5/Documentation/Manual/domain-reloading.html">Unity Domain Reloading Manual</see> 
-        /// and the <see href="https://docs.unity3d.com/6000.5/Documentation/ScriptReference/RuntimeInitializeOnLoadMethodAttribute.html">RuntimeInitializeOnLoadMethodAttribute API Docs</see> for details.
-        /// </remarks>
-        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
-        private static void ResetStaticFields()
-        {
-            _serializer = null;
-        }
-#endif
-
         // The function to use for decoding a type value.
         Row DecodeValue(BinaryReader reader) => Serializer.Read(reader);
 
@@ -683,5 +681,37 @@ public abstract class RemoteEventTableHandle<EventContext, Row> : RemoteTableHan
     {
         protected RemoteEventTableHandle(IDbConnection conn) : base(conn, isEventTable: true) { }
     }
+
+#if UNITY_5_3_OR_NEWER
+    /// <summary>
+    /// Provides a mechanism for registering and invoking static reset callbacks
+    /// during Unity's subsystem registration phase.
+    /// This is because Unity's RuntimeInitializeOnLoadMethod can't be used in generic classes
+    /// One way we can get around this in the future is using <see href="https://docs.unity3d.com/6000.5/Documentation/ScriptReference/Unity.Scripting.LifecycleManagement.AutoStaticsCleanupAttribute.html">AutoStaticsCleanup</see> 
+    /// But that requires Unity 6.5
+    /// </summary>
+    /// <remarks>
+    /// Our generic static constructor doesn't necessarily execute for every table type before Unity's SubsystemRegistration callback runs
+    /// So this will only reset types that have already been initialized/registered. Which should be okay.
+    /// </remarks>
+    internal static class RemoteTableHandleStaticReset
+    {
+        private static readonly List<Action> Resets = new();
+
+        internal static void Register(Action reset)
+        {
+            Resets.Add(reset);
+        }
+
+        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
+        private static void Reset()
+        {
+            foreach (var reset in Resets)
+            {
+                reset();
+            }
+        }
+    }
+#endif
 }
 #nullable disable