Implement RuntimeValidatableTypeInfoResolver with basic functionality

Co-authored-by: captainsafia <1857993+captainsafia@users.noreply.github.com>

Author: Copilot

src/Http/Http.Abstractions/src/Validation/RuntimeValidatableTypeInfoResolver.cs

@@ -0,0 +1,176 @@
+#pragma warning disable ASP0029 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Concurrent;
+using System.ComponentModel.DataAnnotations;
+using System.Diagnostics.CodeAnalysis;
+using System.IO.Pipelines;
+using System.Linq;
+using System.Reflection;
+using System.Security.Claims;
+
+namespace Microsoft.AspNetCore.Http.Validation;
+
+[RequiresUnreferencedCode("Uses unbounded Reflection to inspect property types.")]
+internal sealed class RuntimeValidatableTypeInfoResolver : IValidatableInfoResolver
+{
+    private static readonly ConcurrentDictionary<Type, IValidatableInfo?> _cache = new();
+
+    public bool TryGetValidatableTypeInfo(Type type, [NotNullWhen(true)] out IValidatableInfo? info)
+    {
+        info = _cache.GetOrAdd(type, static type => BuildValidatableTypeInfo(type, new HashSet<Type>()));
+        return info is not null;
+    }
+
+    // Parameter discovery is handled elsewhere
+    public bool TryGetValidatableParameterInfo(ParameterInfo parameterInfo, [NotNullWhen(true)] out IValidatableInfo? info)
+    {
+        info = null;
+        return false;
+    }
+
+    private static IValidatableInfo? BuildValidatableTypeInfo([DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicProperties | DynamicallyAccessedMemberTypes.Interfaces)] Type type, HashSet<Type> visitedTypes)
+    {
+        // Prevent cycles - if we've already seen this type, return null
+        if (!visitedTypes.Add(type))
+        {
+            return null;
+        }
+
+        try
+        {
+            // Bail out early if this isn't a validatable class
+            if (!IsValidatableClass(type))
+            {
+                return null;
+            }
+
+            // Get public instance properties
+            var properties = type.GetProperties(BindingFlags.Public | BindingFlags.Instance)
+                .Where(p => p.CanRead)
+                .ToArray();
+
+            var validatableProperties = new List<RuntimeValidatablePropertyInfo>();
+
+            foreach (var property in properties)
+            {
+                var propertyInfo = BuildValidatablePropertyInfo(property, visitedTypes);
+                if (propertyInfo is not null)
+                {
+                    validatableProperties.Add(propertyInfo);
+                }
+            }
+
+            // Only create type info if there are validatable properties
+            if (validatableProperties.Count > 0)
+            {
+                return new RuntimeValidatableTypeInfo(type, validatableProperties);
+            }
+
+            return null;
+        }
+        finally
+        {
+            visitedTypes.Remove(type);
+        }
+    }
+
+    private static RuntimeValidatablePropertyInfo? BuildValidatablePropertyInfo(PropertyInfo property, HashSet<Type> visitedTypes)
+    {
+        var validationAttributes = property
+            .GetCustomAttributes<ValidationAttribute>()
+            .ToArray();
+
+        // Check if the property type itself is validatable (recursive check)
+        var hasValidatableType = false;
+        if (IsValidatableClass(property.PropertyType))
+        {
+            var nestedTypeInfo = BuildValidatableTypeInfo(property.PropertyType, visitedTypes);
+            hasValidatableType = nestedTypeInfo is not null;
+        }
+
+        // Only create property info if it has validation attributes or a validatable type
+        if (validationAttributes.Length > 0 || hasValidatableType)
+        {
+            var displayName = GetDisplayName(property);
+            return new RuntimeValidatablePropertyInfo(
+                property.DeclaringType!,
+                property.PropertyType,
+                property.Name,
+                displayName,
+                validationAttributes);
+        }
+
+        return null;
+    }
+
+    private static string GetDisplayName(PropertyInfo property)
+    {
+        var displayAttribute = property.GetCustomAttribute<DisplayAttribute>();
+        if (displayAttribute is not null)
+        {
+            return displayAttribute.Name ?? property.Name;
+        }
+
+        return property.Name;
+    }
+
+    private static bool IsValidatableClass(Type type)
+    {
+        // Skip primitives, enums, common built-in types, and types that are specially
+        // handled by RDF/RDG that don't need validation if they don't have attributes
+        if (type.IsPrimitive ||
+            type.IsEnum ||
+            type == typeof(string) ||
+            type == typeof(decimal) ||
+            type == typeof(DateTime) ||
+            type == typeof(DateTimeOffset) ||
+            type == typeof(TimeOnly) ||
+            type == typeof(DateOnly) ||
+            type == typeof(TimeSpan) ||
+            type == typeof(Guid) ||
+            type == typeof(IFormFile) ||
+            type == typeof(IFormFileCollection) ||
+            type == typeof(IFormCollection) ||
+            type == typeof(HttpContext) ||
+            type == typeof(HttpRequest) ||
+            type == typeof(HttpResponse) ||
+            type == typeof(ClaimsPrincipal) ||
+            type == typeof(CancellationToken) ||
+            type == typeof(Stream) ||
+            type == typeof(PipeReader))
+        {
+            return false;
+        }
+
+        // Check if the underlying type in a nullable is valid
+        if (Nullable.GetUnderlyingType(type) is { } nullableType)
+        {
+            return IsValidatableClass(nullableType);
+        }
+
+        return type.IsClass || type.IsValueType;
+    }
+
+    internal sealed class RuntimeValidatableTypeInfo(
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.Interfaces)] Type type,
+        IReadOnlyList<RuntimeValidatablePropertyInfo> members) :
+            ValidatableTypeInfo(type, members.Cast<ValidatablePropertyInfo>().ToArray())
+    {
+    }
+
+    internal sealed class RuntimeValidatablePropertyInfo(
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicProperties)] Type declaringType,
+        Type propertyType,
+        string name,
+        string displayName,
+        ValidationAttribute[] validationAttributes) :
+            ValidatablePropertyInfo(declaringType, propertyType, name, displayName)
+    {
+        private readonly ValidationAttribute[] _validationAttributes = validationAttributes;
+
+        protected override ValidationAttribute[] GetValidationAttributes() => _validationAttributes;
+    }
+}

src/Http/Http.Abstractions/src/Validation/ValidationServiceCollectionExtensions.cs

@@ -27,6 +27,10 @@ public static IServiceCollection AddValidation(this IServiceCollection services,
             // Support ParameterInfo resolution at runtime
 #pragma warning disable ASP0029 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
             options.Resolvers.Add(new RuntimeValidatableParameterInfoResolver());
+            // Support Type resolution at runtime
+#pragma warning disable IL2026 // Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code
+            options.Resolvers.Add(new RuntimeValidatableTypeInfoResolver());
+#pragma warning restore IL2026 // Members annotated with 'RequiresUnreferencedCodeAttribute' require dynamic access otherwise can break functionality when trimming application code
 #pragma warning restore ASP0029 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
         });
         return services;