From 3cd685e93d1b597f8c0dda8f3c1ca5184bb5d9f5 Mon Sep 17 00:00:00 2001
From: Benedikt Reinartz <filmor@gmail.com>
Date: Tue, 1 Oct 2024 20:14:14 +0200
Subject: [PATCH] Use the BinaryFormatter only on .NET FW and Mono

---
 .../StateSerialization/MethodSerialization.cs |  4 ++
 .../StateSerialization/NoopFormatter.cs       | 14 -------
 src/runtime/StateSerialization/RuntimeData.cs | 40 ++++++++++++-------
 3 files changed, 30 insertions(+), 28 deletions(-)
 delete mode 100644 src/runtime/StateSerialization/NoopFormatter.cs

diff --git a/src/embed_tests/StateSerialization/MethodSerialization.cs b/src/embed_tests/StateSerialization/MethodSerialization.cs
index 80b7a08ee..b240d7ecf 100644
--- a/src/embed_tests/StateSerialization/MethodSerialization.cs
+++ b/src/embed_tests/StateSerialization/MethodSerialization.cs
@@ -33,6 +33,10 @@ static T SerializationRoundtrip<T>(T item)
     {
         using var buf = new MemoryStream();
         var formatter = RuntimeData.CreateFormatter();
+
+        if (formatter == null)
+            Assert.Inconclusive("Failed to create formatter for state serialization");
+
         formatter.Serialize(buf, item);
         buf.Position = 0;
         return (T)formatter.Deserialize(buf);
diff --git a/src/runtime/StateSerialization/NoopFormatter.cs b/src/runtime/StateSerialization/NoopFormatter.cs
deleted file mode 100644
index f05b7ebb2..000000000
--- a/src/runtime/StateSerialization/NoopFormatter.cs
+++ /dev/null
@@ -1,14 +0,0 @@
-using System;
-using System.IO;
-using System.Runtime.Serialization;
-
-namespace Python.Runtime;
-
-public class NoopFormatter : IFormatter {
-    public object Deserialize(Stream s) => throw new NotImplementedException();
-    public void Serialize(Stream s, object o) {}
-
-    public SerializationBinder? Binder { get; set; }
-    public StreamingContext Context { get; set; }
-    public ISurrogateSelector? SurrogateSelector { get; set; }
-}
diff --git a/src/runtime/StateSerialization/RuntimeData.cs b/src/runtime/StateSerialization/RuntimeData.cs
index 8eda9ce0b..584e43f8b 100644
--- a/src/runtime/StateSerialization/RuntimeData.cs
+++ b/src/runtime/StateSerialization/RuntimeData.cs
@@ -16,21 +16,23 @@ namespace Python.Runtime
     public static class RuntimeData
     {
 
-        public readonly static Func<IFormatter> DefaultFormatterFactory = () =>
+        public readonly static Func<IFormatter?> DefaultFormatterFactory = () =>
         {
             try
             {
-                return new BinaryFormatter();
-            }
-            catch
-            {
-                return new NoopFormatter();
+                var fw = RuntimeInformation.FrameworkDescription;
+                if (fw.StartsWith(".NET Framework") || fw.StartsWith("Mono"))
+                {
+                    return new BinaryFormatter();
+                }
             }
+            catch {}
+            return null;
         };
 
-        private static Func<IFormatter> _formatterFactory { get; set; } = DefaultFormatterFactory;
+        private static Func<IFormatter?> _formatterFactory { get; set; } = DefaultFormatterFactory;
 
-        public static Func<IFormatter> FormatterFactory
+        public static Func<IFormatter?> FormatterFactory
         {
             get => _formatterFactory;
             set
@@ -82,6 +84,14 @@ static void ClearCLRData ()
 
         internal static void Stash()
         {
+            ClearCLRData();
+
+            IFormatter? formatter = CreateFormatter();
+
+            if (formatter == null)
+                // No formatter defined, exit early
+                return;
+
             var runtimeStorage = new PythonNetState
             {
                 Metatype = MetaType.SaveRuntimeData(),
@@ -91,7 +101,6 @@ internal static void Stash()
                 SharedObjects = SaveRuntimeDataObjects(),
             };
 
-            IFormatter formatter = CreateFormatter();
             var ms = new MemoryStream();
             formatter.Serialize(ms, runtimeStorage);
 
@@ -102,11 +111,10 @@ internal static void Stash()
             Marshal.WriteIntPtr(mem, (IntPtr)ms.Length);
             Marshal.Copy(data, 0, mem + IntPtr.Size, (int)ms.Length);
 
-            ClearCLRData();
-
             using NewReference capsule = PyCapsule_New(mem, IntPtr.Zero, IntPtr.Zero);
             int res = PySys_SetObject("clr_data", capsule.BorrowOrThrow());
             PythonException.ThrowIfIsNotZero(res);
+
             PostStashHook?.Invoke();
         }
 
@@ -124,6 +132,12 @@ internal static void RestoreRuntimeData()
 
         private static void RestoreRuntimeDataImpl()
         {
+            IFormatter? formatter = CreateFormatter();
+
+            if (formatter == null)
+                // No formatter defined, exit early
+                return;
+
             PreRestoreHook?.Invoke();
             BorrowedReference capsule = PySys_GetObject("clr_data");
             if (capsule.IsNull)
@@ -135,7 +149,6 @@ private static void RestoreRuntimeDataImpl()
             byte[] data = new byte[length];
             Marshal.Copy(mem + IntPtr.Size, data, 0, length);
             var ms = new MemoryStream(data);
-            var formatter = CreateFormatter();
             var storage = (PythonNetState)formatter.Deserialize(ms);
 
             PyCLRMetaType = MetaType.RestoreRuntimeData(storage.Metatype);
@@ -373,9 +386,8 @@ public static MemoryStream GetSerializationData(string key)
             return new MemoryStream(buffer, writable:false);
         }
 
-        internal static IFormatter CreateFormatter()
+        internal static IFormatter? CreateFormatter()
         {
-
             if (FormatterType != null)
             {
                 return (IFormatter)Activator.CreateInstance(FormatterType);