Add allows ref struct constraint to TBufferWriter for .NET 9+

src/MemoryPack.Core/Compression/BrotliCompressor.cs

@@ -195,7 +195,9 @@ public async ValueTask CopyToAsync(Stream stream, int bufferSize = 65535, Cancel
     }
 
     public void CopyTo<TBufferWriter>(ref MemoryPackWriter<TBufferWriter> memoryPackWriter)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>
 #else
         where TBufferWriter : class, IBufferWriter<byte>
@@ -253,7 +255,9 @@ static int CompressCore<TBufferWriter>(ref BrotliEncoder encoder, ReadOnlySpan<b
     }
 
     static int CompressCore<TBufferWriter>(ref BrotliEncoder encoder, ReadOnlySpan<byte> source, ref MemoryPackWriter<TBufferWriter> destBufferWriter, int? initialLength, bool isFinalBlock)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>
 #else
         where TBufferWriter : class, IBufferWriter<byte>

src/MemoryPack.Core/Formatters/CollectionFormatters.cs

@@ -55,7 +55,9 @@ public static class ListFormatter
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void SerializePackable<T, TBufferWriter>(ref MemoryPackWriter<TBufferWriter> writer, List<T?>? value)
             where T : IMemoryPackable<T>
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+            where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
             where TBufferWriter : IBufferWriter<byte>
 #else
             where TBufferWriter : class, IBufferWriter<byte>

src/MemoryPack.Core/Formatters/CultureInfoFormatter.cs

@@ -1,4 +1,4 @@
-using System.Globalization;
+using System.Globalization;
 using MemoryPack.Internal;
 
 namespace MemoryPack.Formatters;
@@ -27,4 +27,4 @@ public override void Deserialize(ref MemoryPackReader reader, scoped ref Culture
             value = CultureInfo.GetCultureInfo(str);
         }
     }
-}
+}

src/MemoryPack.Core/Formatters/DynamicUnionFormatter.cs

@@ -39,7 +39,7 @@ public override void Deserialize(ref MemoryPackReader reader, scoped ref T? valu
             value = default;
             return;
         }
-        
+
         if (tagToType.TryGetValue(tag, out var type))
         {
             object? v = value;

src/MemoryPack.Core/Formatters/InterfaceCollectionFormatters.cs

@@ -42,7 +42,9 @@ file static class InterfaceCollectionFormatterUtils
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TrySerializeOptimized<TBufferWriter, TCollection, TElement>(ref MemoryPackWriter<TBufferWriter> writer, [NotNullWhen(false)] scoped ref TCollection? value)
             where TCollection : IEnumerable<TElement>
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+            where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
             where TBufferWriter : IBufferWriter<byte>
 #else
             where TBufferWriter : class, IBufferWriter<byte>
@@ -75,7 +77,9 @@ public static bool TrySerializeOptimized<TBufferWriter, TCollection, TElement>(r
 
         public static void SerializeCollection<TBufferWriter, TCollection, TElement>(ref MemoryPackWriter<TBufferWriter> writer, scoped ref TCollection? value)
             where TCollection : ICollection<TElement>
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+            where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
             where TBufferWriter : IBufferWriter<byte>
 #else
             where TBufferWriter : class, IBufferWriter<byte>
@@ -94,7 +98,9 @@ public static void SerializeCollection<TBufferWriter, TCollection, TElement>(ref
 
         public static void SerializeReadOnlyCollection<TBufferWriter, TCollection, TElement>(ref MemoryPackWriter<TBufferWriter> writer, scoped ref TCollection? value)
             where TCollection : IReadOnlyCollection<TElement>
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+            where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
             where TBufferWriter : IBufferWriter<byte>
 #else
             where TBufferWriter : class, IBufferWriter<byte>

src/MemoryPack.Core/Formatters/KeyValuePairFormatter.cs

@@ -12,7 +12,9 @@ public static class KeyValuePairFormatter
     [Preserve]
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static void Serialize<TKey, TValue, TBufferWriter>(IMemoryPackFormatter<TKey> keyFormatter, IMemoryPackFormatter<TValue> valueFormatter, ref MemoryPackWriter<TBufferWriter> writer, KeyValuePair<TKey?, TValue?> value)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>
 #else
         where TBufferWriter : class, IBufferWriter<byte>

src/MemoryPack.Core/IMemoryPackFormatter.cs

@@ -8,7 +8,9 @@ public interface IMemoryPackFormatter
 {
     [Preserve]
     void Serialize<TBufferWriter>(ref MemoryPackWriter<TBufferWriter> writer, scoped ref object? value)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct;
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>;
 #else
         where TBufferWriter : class, IBufferWriter<byte>;
@@ -22,7 +24,9 @@ public interface IMemoryPackFormatter<T>
 {
     [Preserve]
     void Serialize<TBufferWriter>(ref MemoryPackWriter<TBufferWriter> writer, scoped ref T? value)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct;
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>;
 #else
         where TBufferWriter : class, IBufferWriter<byte>;
@@ -36,7 +40,9 @@ public abstract class MemoryPackFormatter<T> : IMemoryPackFormatter<T>, IMemoryP
 {
     [Preserve]
     public abstract void Serialize<TBufferWriter>(ref MemoryPackWriter<TBufferWriter> writer, scoped ref T? value)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct;
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>;
 #else
         where TBufferWriter : class, IBufferWriter<byte>;

src/MemoryPack.Core/IMemoryPackable.cs

@@ -22,8 +22,11 @@ public interface IMemoryPackable<T> : IMemoryPackFormatterRegister
 {
     // note: serialize parameter should be `ref readonly` but current lang spec can not.
     // see proposal https://github.com/dotnet/csharplang/issues/6010
-
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+    static abstract void Serialize<TBufferWriter>(ref MemoryPackWriter<TBufferWriter> writer, scoped ref T? value)
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct;
+    static abstract void Deserialize(ref MemoryPackReader reader, scoped ref T? value);
+#elif NET7_0_OR_GREATER
     static abstract void Serialize<TBufferWriter>(ref MemoryPackWriter<TBufferWriter> writer, scoped ref T? value)
         where TBufferWriter : IBufferWriter<byte>;
     static abstract void Deserialize(ref MemoryPackReader reader, scoped ref T? value);

src/MemoryPack.Core/Internal/ReusableLinkedArrayBufferWriter.cs

@@ -165,7 +165,9 @@ public byte[] ToArrayAndReset()
     }
 
     public void WriteToAndReset<TBufferWriter>(ref MemoryPackWriter<TBufferWriter> writer)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>
 #else
         where TBufferWriter : class, IBufferWriter<byte>

src/MemoryPack.Core/MemoryPack.Core.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFrameworks>net7.0;net8.0;netstandard2.1</TargetFrameworks>
+        <TargetFrameworks>net7.0;net8.0;net9.0;netstandard2.1</TargetFrameworks>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>
         <AllowUnsafeBlocks>True</AllowUnsafeBlocks>

src/MemoryPack.Core/MemoryPackFormatterProvider.cs

@@ -372,7 +372,9 @@ public ErrorMemoryPackFormatter(Type type, string message)
     }
 
     public void Serialize<TBufferWriter>(ref MemoryPackWriter<TBufferWriter> writer, scoped ref object? value)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>
 #else
         where TBufferWriter : class, IBufferWriter<byte>

src/MemoryPack.Core/MemoryPackReader.cs

@@ -796,7 +796,7 @@ public unsafe void DangerousReadUnmanagedSpan<T>(scoped ref Span<T> value)
         var byteCount = length * Unsafe.SizeOf<T>();
         ref var src = ref GetSpanReference(byteCount);
 
-        if (value == null || value.Length != length)
+        if (value.IsEmpty || value.Length != length)
         {
             value = AllocateUninitializedArray<T>(length);
         }

src/MemoryPack.Core/MemoryPackSerializer.Deserialize.cs

@@ -15,7 +15,7 @@ public static T? Deserialize<
 #if NET5_0_OR_GREATER
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
 #endif
-        T>(ReadOnlySpan<byte> buffer, MemoryPackSerializerOptions? options = default)
+    T>(ReadOnlySpan<byte> buffer, MemoryPackSerializerOptions? options = default)
     {
         T? value = default;
         Deserialize(buffer, ref value, options);
@@ -26,7 +26,7 @@ public static int Deserialize<
 #if NET5_0_OR_GREATER
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
 #endif
-        T>(ReadOnlySpan<byte> buffer, ref T? value, MemoryPackSerializerOptions? options = default)
+    T>(ReadOnlySpan<byte> buffer, ref T? value, MemoryPackSerializerOptions? options = default)
     {
         if (!RuntimeHelpers.IsReferenceOrContainsReferences<T>())
         {
@@ -62,7 +62,7 @@ public static T? Deserialize<
 #if NET5_0_OR_GREATER
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
 #endif
-        T>(in ReadOnlySequence<byte> buffer, MemoryPackSerializerOptions? options = default)
+    T>(in ReadOnlySequence<byte> buffer, MemoryPackSerializerOptions? options = default)
     {
         T? value = default;
         Deserialize<T>(buffer, ref value, options);
@@ -73,7 +73,7 @@ public static int Deserialize<
 #if NET5_0_OR_GREATER
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
 #endif
-        T>(in ReadOnlySequence<byte> buffer, ref T? value, MemoryPackSerializerOptions? options = default)
+    T>(in ReadOnlySequence<byte> buffer, ref T? value, MemoryPackSerializerOptions? options = default)
     {
         if (!RuntimeHelpers.IsReferenceOrContainsReferences<T>())
         {
@@ -144,7 +144,7 @@ public static async ValueTask<T?> DeserializeAsync<
 #if NET5_0_OR_GREATER
         [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)]
 #endif
-        T>(Stream stream, MemoryPackSerializerOptions? options = default, CancellationToken cancellationToken = default)
+    T>(Stream stream, MemoryPackSerializerOptions? options = default, CancellationToken cancellationToken = default)
     {
         if (stream is MemoryStream ms && ms.TryGetBuffer(out ArraySegment<byte> streamBuffer))
         {

src/MemoryPack.Core/MemoryPackSerializer.NonGenerics.cs

@@ -32,7 +32,9 @@ public static byte[] Serialize(Type type, object? value, MemoryPackSerializerOpt
     }
 
     public static unsafe void Serialize<TBufferWriter>(Type type, in TBufferWriter bufferWriter, object? value, MemoryPackSerializerOptions? options = default)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>
 #else
         where TBufferWriter : class, IBufferWriter<byte>
@@ -58,7 +60,9 @@ public static unsafe void Serialize<TBufferWriter>(Type type, in TBufferWriter b
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static void Serialize<TBufferWriter>(Type type, ref MemoryPackWriter<TBufferWriter> writer, object? value)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>
 #else
         where TBufferWriter : class, IBufferWriter<byte>

src/MemoryPack.Core/MemoryPackSerializer.Serialize.cs

@@ -86,7 +86,9 @@ public static byte[] Serialize<T>(in T? value, MemoryPackSerializerOptions? opti
     }
 
     public static unsafe void Serialize<T, TBufferWriter>(in TBufferWriter bufferWriter, in T? value, MemoryPackSerializerOptions? options = default)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>
 #else
         where TBufferWriter : class, IBufferWriter<byte>
@@ -154,7 +156,9 @@ public static unsafe void Serialize<T, TBufferWriter>(in TBufferWriter bufferWri
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static void Serialize<T, TBufferWriter>(ref MemoryPackWriter<TBufferWriter> writer, in T? value)
-#if NET7_0_OR_GREATER
+#if NET9_0_OR_GREATER
+        where TBufferWriter : IBufferWriter<byte>, allows ref struct
+#elif NET7_0_OR_GREATER
         where TBufferWriter : IBufferWriter<byte>
 #else
         where TBufferWriter : class, IBufferWriter<byte>