Replace reflection-based code

Author: bkoelman

src/JsonApiDotNetCore.OpenApi/ActionDescriptorExtensions.cs

@@ -20,10 +20,7 @@ public static MethodInfo GetActionMethod(this ActionDescriptor descriptor)
     {
         ArgumentGuard.NotNull(descriptor);
 
-        IFilterMetadata? filterMetadata = descriptor.FilterDescriptors.Select(filterDescriptor => filterDescriptor.Filter)
-            .OfType<TFilterMetaData>().FirstOrDefault();
-
-        return (TFilterMetaData?)filterMetadata;
+        return descriptor.FilterDescriptors.Select(filterDescriptor => filterDescriptor.Filter).OfType<TFilterMetaData>().FirstOrDefault();
     }
 
     public static ControllerParameterDescriptor? GetBodyParameterDescriptor(this ActionDescriptor descriptor)

src/JsonApiDotNetCore.OpenApi/JsonApiActionDescriptorCollectionProvider.cs

@@ -1,4 +1,3 @@
-using System.Reflection;
 using JsonApiDotNetCore.Middleware;
 using JsonApiDotNetCore.OpenApi.JsonApiMetadata;
 using Microsoft.AspNetCore.Mvc;
@@ -154,14 +153,7 @@ private static void UpdateBodyParameterDescriptor(ActionDescriptor endpoint, Typ
         }
 
         requestBodyDescriptor.ParameterType = documentType;
-        ParameterInfo replacementParameterInfo = requestBodyDescriptor.ParameterInfo.WithParameterType(documentType);
-
-        if (parameterName != null)
-        {
-            replacementParameterInfo = replacementParameterInfo.WithName(parameterName);
-        }
-
-        requestBodyDescriptor.ParameterInfo = replacementParameterInfo;
+        requestBodyDescriptor.ParameterInfo = new ParameterInfoWrapper(requestBodyDescriptor.ParameterInfo, documentType, parameterName);
     }
 
     private static ActionDescriptor Clone(ActionDescriptor descriptor)

src/JsonApiDotNetCore.OpenApi/ParameterInfoExtensions.cs

@@ -0,0 +1,78 @@
+using System.Reflection;
+
+namespace JsonApiDotNetCore.OpenApi;
+
+/// <summary>
+/// Used for parameters in action method expansion. Changes the parameter name and type, while still using all metadata of the underlying non-expanded
+/// parameter.
+/// </summary>
+internal sealed class ParameterInfoWrapper : ParameterInfo
+{
+    private readonly ParameterInfo _innerParameter;
+
+    public override ParameterAttributes Attributes => _innerParameter.Attributes;
+    public override IEnumerable<CustomAttributeData> CustomAttributes => _innerParameter.CustomAttributes;
+    public override object? DefaultValue => _innerParameter.DefaultValue;
+    public override bool HasDefaultValue => _innerParameter.HasDefaultValue;
+    public override MemberInfo Member => _innerParameter.Member;
+    public override int MetadataToken => _innerParameter.MetadataToken;
+    public override string? Name { get; }
+    public override Type ParameterType { get; }
+    public override int Position => _innerParameter.Position;
+    public override object? RawDefaultValue => _innerParameter.RawDefaultValue;
+
+    public ParameterInfoWrapper(ParameterInfo innerParameter, Type overriddenParameterType, string? overriddenName)
+    {
+        ArgumentGuard.NotNull(innerParameter);
+        ArgumentGuard.NotNull(overriddenParameterType);
+
+        _innerParameter = innerParameter;
+        ParameterType = overriddenParameterType;
+        Name = overriddenName;
+    }
+
+    public override object[] GetCustomAttributes(bool inherit)
+    {
+        return _innerParameter.GetCustomAttributes(inherit);
+    }
+
+    public override object[] GetCustomAttributes(Type attributeType, bool inherit)
+    {
+        return _innerParameter.GetCustomAttributes(attributeType, inherit);
+    }
+
+    public override bool IsDefined(Type attributeType, bool inherit)
+    {
+        return _innerParameter.IsDefined(attributeType, inherit);
+    }
+
+    public override bool Equals(object? obj)
+    {
+        return _innerParameter.Equals(obj);
+    }
+
+    public override int GetHashCode()
+    {
+        return _innerParameter.GetHashCode();
+    }
+
+    public override string ToString()
+    {
+        return _innerParameter.ToString();
+    }
+
+    public override IList<CustomAttributeData> GetCustomAttributesData()
+    {
+        return _innerParameter.GetCustomAttributesData();
+    }
+
+    public override Type[] GetOptionalCustomModifiers()
+    {
+        return _innerParameter.GetOptionalCustomModifiers();
+    }
+
+    public override Type[] GetRequiredCustomModifiers()
+    {
+        return _innerParameter.GetRequiredCustomModifiers();
+    }
+}