C#: Remove VariantSpanDisposer and use constants in stackalloc

- Remove `VariantSpanDisposer`, no need to dispose of the Variant Spans
since we are now borrowing the Variants instead of copying them.
- Remove `VariantSpanExtensions.Cleared` that was only used so the
Span was initialized for `VariantSpanDisposer` to know what to dispose.
- Fix stackalloc Spans to use constant VarArgsSpanThreshold
and avoid bound checks.

5 files changed, 10 insertions, 50 deletions

diff --git a/modules/mono/editor/bindings_generator.cpp b/modules/mono/editor/bindings_generator.cpp
index 82b5f478e1..9185506776 100644
--- a/modules/mono/editor/bindings_generator.cpp
+++ b/modules/mono/editor/bindings_generator.cpp
@@ -2542,15 +2542,13 @@ Error BindingsGenerator::_generate_cs_native_calls(const InternalCall &p_icall,
 					 << INDENT2 "int total_length = " << real_argc_str << " + vararg_length;\n";
 
 			r_output << INDENT2 "Span<godot_variant.movable> varargs_span = vararg_length <= VarArgsSpanThreshold ?\n"
-					 << INDENT3 "stackalloc godot_variant.movable[VarArgsSpanThreshold].Cleared() :\n"
+					 << INDENT3 "stackalloc godot_variant.movable[VarArgsSpanThreshold] :\n"
 					 << INDENT3 "new godot_variant.movable[vararg_length];\n";
 
 			r_output << INDENT2 "Span<IntPtr> " C_LOCAL_PTRCALL_ARGS "_span = total_length <= VarArgsSpanThreshold ?\n"
 					 << INDENT3 "stackalloc IntPtr[VarArgsSpanThreshold] :\n"
 					 << INDENT3 "new IntPtr[total_length];\n";
 
-			r_output << INDENT2 "using var variantSpanDisposer = new VariantSpanDisposer(varargs_span);\n";
-
 			r_output << INDENT2 "fixed (godot_variant.movable* varargs = &MemoryMarshal.GetReference(varargs_span))\n"
 					 << INDENT2 "fixed (IntPtr* " C_LOCAL_PTRCALL_ARGS " = "
 								"&MemoryMarshal.GetReference(" C_LOCAL_PTRCALL_ARGS "_span))\n"
diff --git a/modules/mono/glue/GodotSharp/GodotSharp/Core/Bridge/ScriptManagerBridge.cs b/modules/mono/glue/GodotSharp/GodotSharp/Core/Bridge/ScriptManagerBridge.cs
index d83cf43eb2..d6fad391b6 100644
--- a/modules/mono/glue/GodotSharp/GodotSharp/Core/Bridge/ScriptManagerBridge.cs
+++ b/modules/mono/glue/GodotSharp/GodotSharp/Core/Bridge/ScriptManagerBridge.cs
@@ -827,7 +827,7 @@ namespace Godot.Bridge
                 {
                     // Weird limitation, hence the need for aux:
                     // "In the case of pointer types, you can use a stackalloc expression only in a local variable declaration to initialize the variable."
-                    var aux = stackalloc godotsharp_property_info[length];
+                    var aux = stackalloc godotsharp_property_info[stackMaxLength];
                     interopProperties = aux;
                 }
                 else
@@ -947,7 +947,7 @@ namespace Godot.Bridge
                 {
                     // Weird limitation, hence the need for aux:
                     // "In the case of pointer types, you can use a stackalloc expression only in a local variable declaration to initialize the variable."
-                    var aux = stackalloc godotsharp_property_def_val_pair[length];
+                    var aux = stackalloc godotsharp_property_def_val_pair[stackMaxLength];
                     interopDefaultValues = aux;
                 }
                 else
diff --git a/modules/mono/glue/GodotSharp/GodotSharp/Core/Callable.cs b/modules/mono/glue/GodotSharp/GodotSharp/Core/Callable.cs
index f9309ca13e..23b0aa9204 100644
--- a/modules/mono/glue/GodotSharp/GodotSharp/Core/Callable.cs
+++ b/modules/mono/glue/GodotSharp/GodotSharp/Core/Callable.cs
@@ -77,7 +77,7 @@ namespace Godot
             _trampoline = trampoline;
         }
 
-        private const int VarArgsSpanThreshold = 5;
+        private const int VarArgsSpanThreshold = 10;
 
         /// <summary>
         /// Calls the method represented by this <see cref="Callable"/>.
@@ -92,15 +92,13 @@ namespace Godot
             int argc = args.Length;
 
             Span<godot_variant.movable> argsStoreSpan = argc <= VarArgsSpanThreshold ?
-                stackalloc godot_variant.movable[VarArgsSpanThreshold].Cleared() :
+                stackalloc godot_variant.movable[VarArgsSpanThreshold] :
                 new godot_variant.movable[argc];
 
-            Span<IntPtr> argsSpan = argc <= 10 ?
-                stackalloc IntPtr[argc] :
+            Span<IntPtr> argsSpan = argc <= VarArgsSpanThreshold ?
+                stackalloc IntPtr[VarArgsSpanThreshold] :
                 new IntPtr[argc];
 
-            using var variantSpanDisposer = new VariantSpanDisposer(argsStoreSpan);
-
             fixed (godot_variant* varargs = &MemoryMarshal.GetReference(argsStoreSpan).DangerousSelfRef)
             fixed (IntPtr* argsPtr = &MemoryMarshal.GetReference(argsSpan))
             {
@@ -128,15 +126,13 @@ namespace Godot
             int argc = args.Length;
 
             Span<godot_variant.movable> argsStoreSpan = argc <= VarArgsSpanThreshold ?
-                stackalloc godot_variant.movable[VarArgsSpanThreshold].Cleared() :
+                stackalloc godot_variant.movable[VarArgsSpanThreshold] :
                 new godot_variant.movable[argc];
 
-            Span<IntPtr> argsSpan = argc <= 10 ?
-                stackalloc IntPtr[argc] :
+            Span<IntPtr> argsSpan = argc <= VarArgsSpanThreshold ?
+                stackalloc IntPtr[VarArgsSpanThreshold] :
                 new IntPtr[argc];
 
-            using var variantSpanDisposer = new VariantSpanDisposer(argsStoreSpan);
-
             fixed (godot_variant* varargs = &MemoryMarshal.GetReference(argsStoreSpan).DangerousSelfRef)
             fixed (IntPtr* argsPtr = &MemoryMarshal.GetReference(argsSpan))
             {
diff --git a/modules/mono/glue/GodotSharp/GodotSharp/Core/NativeInterop/VariantSpanHelpers.cs b/modules/mono/glue/GodotSharp/GodotSharp/Core/NativeInterop/VariantSpanHelpers.cs
deleted file mode 100644
index 46f31bbf4e..0000000000
--- a/modules/mono/glue/GodotSharp/GodotSharp/Core/NativeInterop/VariantSpanHelpers.cs
+++ /dev/null
@@ -1,33 +0,0 @@
-using System;
-
-namespace Godot.NativeInterop
-{
-    internal readonly ref struct VariantSpanDisposer
-    {
-        private readonly Span<godot_variant.movable> _variantSpan;
-
-        // IMPORTANT: The span element must be default initialized.
-        // Make sure call Clear() on the span if it was created with stackalloc.
-        public VariantSpanDisposer(Span<godot_variant.movable> variantSpan)
-        {
-            _variantSpan = variantSpan;
-        }
-
-        public void Dispose()
-        {
-            for (int i = 0; i < _variantSpan.Length; i++)
-                _variantSpan[i].DangerousSelfRef.Dispose();
-        }
-    }
-
-    internal static class VariantSpanExtensions
-    {
-        // Used to make sure we always initialize the span values to the default,
-        // as we need that in order to safely dispose all elements after.
-        public static Span<godot_variant.movable> Cleared(this Span<godot_variant.movable> span)
-        {
-            span.Clear();
-            return span;
-        }
-    }
-}
diff --git a/modules/mono/glue/GodotSharp/GodotSharp/GodotSharp.csproj b/modules/mono/glue/GodotSharp/GodotSharp/GodotSharp.csproj
index 85f7e36639..503e5abe37 100644
--- a/modules/mono/glue/GodotSharp/GodotSharp/GodotSharp.csproj
+++ b/modules/mono/glue/GodotSharp/GodotSharp/GodotSharp.csproj
@@ -101,7 +101,6 @@
     <Compile Include="Core\NativeInterop\InteropUtils.cs" />
     <Compile Include="Core\NativeInterop\NativeFuncs.extended.cs" />
     <Compile Include="Core\NativeInterop\NativeVariantPtrArgs.cs" />
-    <Compile Include="Core\NativeInterop\VariantSpanHelpers.cs" />
     <Compile Include="Core\NativeInterop\VariantUtils.cs" />
     <Compile Include="Core\NativeInterop\VariantUtils.generic.cs" />
     <Compile Include="Core\NodePath.cs" />