Emit validation info for types that have IValidatableObject interface and no validation attributes

src/Shared/RoslynUtils/WellKnownTypeData.cs

@@ -124,6 +124,7 @@ public enum WellKnownType
         System_ComponentModel_DataAnnotations_ValidationAttribute,
         System_ComponentModel_DataAnnotations_RequiredAttribute,
         System_ComponentModel_DataAnnotations_CustomValidationAttribute,
+        System_ComponentModel_DataAnnotations_IValidatableObject,
         Microsoft_Extensions_Validation_SkipValidationAttribute,
         System_Type,
     }
@@ -247,6 +248,7 @@ public enum WellKnownType
         "System.ComponentModel.DataAnnotations.ValidationAttribute",
         "System.ComponentModel.DataAnnotations.RequiredAttribute",
         "System.ComponentModel.DataAnnotations.CustomValidationAttribute",
+        "System.ComponentModel.DataAnnotations.IValidatableObject",
         "Microsoft.Extensions.Validation.SkipValidationAttribute",
         "System.Type",
     ];

src/Validation/gen/Parsers/ValidationsGenerator.TypesParser.cs

@@ -82,7 +82,7 @@ internal bool TryExtractValidatableType(ITypeSymbol incomingTypeSymbol, WellKnow
 
         visitedTypes.Add(typeSymbol);
 
-        var hasValidationAttributes = HasValidationAttributes(typeSymbol, wellKnownTypes);
+        var hasTypeLevelValidation = HasValidationAttributes(typeSymbol, wellKnownTypes) || HasIValidatableObjectInterface(typeSymbol, wellKnownTypes);
 
         // Extract validatable types discovered in base types of this type and add them to the top-level list.
         var current = typeSymbol.BaseType;
@@ -109,7 +109,7 @@ internal bool TryExtractValidatableType(ITypeSymbol incomingTypeSymbol, WellKnow
         }
 
         // No validatable members or derived types found, so we don't need to add this type.
-        if (members.IsDefaultOrEmpty && !hasValidationAttributes && !hasValidatableBaseType && !hasValidatableDerivedTypes)
+        if (members.IsDefaultOrEmpty && !hasTypeLevelValidation && !hasValidatableBaseType && !hasValidatableDerivedTypes)
         {
             return false;
         }
@@ -301,4 +301,19 @@ internal static bool HasValidationAttributes(ISymbol symbol, WellKnownTypes well
 
         return false;
     }
+
+    internal static bool HasIValidatableObjectInterface(ITypeSymbol typeSymbol, WellKnownTypes wellKnownTypes)
+    {
+        var validatableObjectSymbol = wellKnownTypes.Get(WellKnownTypeData.WellKnownType.System_ComponentModel_DataAnnotations_IValidatableObject);
+
+        foreach (var inter in typeSymbol.AllInterfaces)
+        {
+            if (SymbolEqualityComparer.Default.Equals(inter, validatableObjectSymbol))
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
 }

src/Validation/test/Microsoft.Extensions.Validation.GeneratorTests/ValidationsGenerator.IValidatableObject.cs

@@ -164,4 +164,101 @@ async Task ValidateForTopLevelInvoked()
             }
         });
     }
+
+    [Fact]
+    public async Task CanValidateIValidatableObject_WithoutPropertyValidations()
+    {
+        var source = """
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Validation;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.DependencyInjection;
+
+WebApplicationBuilder builder = WebApplication.CreateBuilder(args);
+
+builder.Services.AddValidation();
+
+WebApplication app = builder. Build();
+
+app.MapPost("/base", (BaseClass model) => Results.Ok(model));
+app.MapPost("/derived", (DerivedClass model) => Results.Ok(model));
+
+app.Run();
+
+public class BaseClass : IValidatableObject
+{
+    public string? Value { get; set; }
+
+    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
+    {
+        if (string.IsNullOrEmpty(Value))
+        {
+            yield return new ValidationResult("Value cannot be null or empty.", [nameof(Value)]);
+        }
+    }
+}
+
+public class DerivedClass : BaseClass
+{
+}
+""";
+
+        await Verify(source, out var compilation);
+
+        await VerifyEndpoint(compilation, "/base", async (endpoint, serviceProvider) =>
+        {
+            await ValidateMethodCalled();
+
+            async Task ValidateMethodCalled()
+            {
+                var httpContext = CreateHttpContextWithPayload("""
+                {
+                    "Value": ""
+                }
+                """, serviceProvider);
+
+                await endpoint.RequestDelegate(httpContext);
+
+                var problemDetails = await AssertBadRequest(httpContext);
+                Assert.Collection(problemDetails.Errors,
+                    error =>
+                    {
+                        Assert.Equal("Value", error.Key);
+                        Assert.Collection(error.Value,
+                            msg => Assert.Equal("Value cannot be null or empty.", msg));
+                    });
+            }
+        });
+
+        await VerifyEndpoint(compilation, "/derived", async (endpoint, serviceProvider) =>
+        {
+            await ValidateMethodCalled();
+
+            async Task ValidateMethodCalled()
+            {
+                var httpContext = CreateHttpContextWithPayload("""
+                {
+                    "Value": ""
+                }
+                """, serviceProvider);
+
+                await endpoint.RequestDelegate(httpContext);
+
+                var problemDetails = await AssertBadRequest(httpContext);
+                Assert.Collection(problemDetails.Errors,
+                    error =>
+                    {
+                        Assert.Equal("Value", error.Key);
+                        Assert.Collection(error.Value,
+                            msg => Assert.Equal("Value cannot be null or empty.", msg));
+                    });
+            }
+        });
+    }
+
 }

src/Validation/test/Microsoft.Extensions.Validation.GeneratorTests/snapshots/ValidationsGeneratorTests.CanValidateIValidatableObject_WithoutPropertyValidations#ValidatableInfoResolver.g.verified.cs

@@ -0,0 +1,190 @@
+//HintName: ValidatableInfoResolver.g.cs
+#nullable enable annotations
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+#nullable enable
+#pragma warning disable ASP0029
+
+namespace System.Runtime.CompilerServices
+{
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.Extensions.Validation.ValidationsGenerator, Version=42.42.42.42, Culture=neutral, PublicKeyToken=adb9793829ddae60", "42.42.42.42")]
+    [AttributeUsage(AttributeTargets.Method, AllowMultiple = true)]
+    file sealed class InterceptsLocationAttribute : System.Attribute
+    {
+        public InterceptsLocationAttribute(int version, string data)
+        {
+        }
+    }
+}
+
+namespace Microsoft.Extensions.Validation.Generated
+{
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.Extensions.Validation.ValidationsGenerator, Version=42.42.42.42, Culture=neutral, PublicKeyToken=adb9793829ddae60", "42.42.42.42")]
+    file sealed class GeneratedValidatablePropertyInfo : global::Microsoft.Extensions.Validation.ValidatablePropertyInfo
+    {
+        public GeneratedValidatablePropertyInfo(
+            [param: global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembers(global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicProperties | global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)]
+            global::System.Type containingType,
+            global::System.Type propertyType,
+            string name,
+            string displayName) : base(containingType, propertyType, name, displayName)
+        {
+            ContainingType = containingType;
+            Name = name;
+        }
+
+        [global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembers(global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicProperties | global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)]
+        internal global::System.Type ContainingType { get; }
+        internal string Name { get; }
+
+        protected override global::System.ComponentModel.DataAnnotations.ValidationAttribute[] GetValidationAttributes()
+            => ValidationAttributeCache.GetPropertyValidationAttributes(ContainingType, Name);
+    }
+
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.Extensions.Validation.ValidationsGenerator, Version=42.42.42.42, Culture=neutral, PublicKeyToken=adb9793829ddae60", "42.42.42.42")]
+    file sealed class GeneratedValidatableTypeInfo : global::Microsoft.Extensions.Validation.ValidatableTypeInfo
+    {
+        public GeneratedValidatableTypeInfo(
+            [param: global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembers(global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.Interfaces)]
+            global::System.Type type,
+            ValidatablePropertyInfo[] members) : base(type, members)
+        {
+            Type = type;
+        }
+
+        [global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembers(global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.Interfaces)]
+        internal global::System.Type Type { get; }
+
+        protected override global::System.ComponentModel.DataAnnotations.ValidationAttribute[] GetValidationAttributes()
+            => ValidationAttributeCache.GetTypeValidationAttributes(Type);
+    }
+
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.Extensions.Validation.ValidationsGenerator, Version=42.42.42.42, Culture=neutral, PublicKeyToken=adb9793829ddae60", "42.42.42.42")]
+    file class GeneratedValidatableInfoResolver : global::Microsoft.Extensions.Validation.IValidatableInfoResolver
+    {
+        public bool TryGetValidatableTypeInfo(global::System.Type type, [global::System.Diagnostics.CodeAnalysis.NotNullWhen(true)] out global::Microsoft.Extensions.Validation.IValidatableInfo? validatableInfo)
+        {
+            validatableInfo = null;
+            if (type == typeof(global::BaseClass))
+            {
+                validatableInfo = new GeneratedValidatableTypeInfo(
+                    type: typeof(global::BaseClass),
+                    members: []
+                );
+                return true;
+            }
+            if (type == typeof(global::DerivedClass))
+            {
+                validatableInfo = new GeneratedValidatableTypeInfo(
+                    type: typeof(global::DerivedClass),
+                    members: []
+                );
+                return true;
+            }
+
+            return false;
+        }
+
+        // No-ops, rely on runtime code for ParameterInfo-based resolution
+        public bool TryGetValidatableParameterInfo(global::System.Reflection.ParameterInfo parameterInfo, [global::System.Diagnostics.CodeAnalysis.NotNullWhen(true)] out global::Microsoft.Extensions.Validation.IValidatableInfo? validatableInfo)
+        {
+            validatableInfo = null;
+            return false;
+        }
+    }
+
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.Extensions.Validation.ValidationsGenerator, Version=42.42.42.42, Culture=neutral, PublicKeyToken=adb9793829ddae60", "42.42.42.42")]
+    file static class GeneratedServiceCollectionExtensions
+    {
+        [InterceptsLocation]
+        public static global::Microsoft.Extensions.DependencyInjection.IServiceCollection AddValidation(this global::Microsoft.Extensions.DependencyInjection.IServiceCollection services, global::System.Action<global::Microsoft.Extensions.Validation.ValidationOptions>? configureOptions = null)
+        {
+            // Use non-extension method to avoid infinite recursion.
+            return global::Microsoft.Extensions.DependencyInjection.ValidationServiceCollectionExtensions.AddValidation(services, options =>
+            {
+                options.Resolvers.Insert(0, new GeneratedValidatableInfoResolver());
+                if (configureOptions is not null)
+                {
+                    configureOptions(options);
+                }
+            });
+        }
+    }
+
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.Extensions.Validation.ValidationsGenerator, Version=42.42.42.42, Culture=neutral, PublicKeyToken=adb9793829ddae60", "42.42.42.42")]
+    file static class ValidationAttributeCache
+    {
+        private sealed record CacheKey(
+            [param: global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembers(global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicProperties | global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)]
+            [property: global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembers(global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicProperties | global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)]
+            global::System.Type ContainingType,
+            string PropertyName);
+        private static readonly global::System.Collections.Concurrent.ConcurrentDictionary<CacheKey, global::System.ComponentModel.DataAnnotations.ValidationAttribute[]> _propertyCache = new();
+        private static readonly global::System.Lazy<global::System.Collections.Concurrent.ConcurrentDictionary<global::System.Type, global::System.ComponentModel.DataAnnotations.ValidationAttribute[]>> _lazyTypeCache = new (() => new ());
+        private static global::System.Collections.Concurrent.ConcurrentDictionary<global::System.Type, global::System.ComponentModel.DataAnnotations.ValidationAttribute[]> TypeCache => _lazyTypeCache.Value;
+
+        public static global::System.ComponentModel.DataAnnotations.ValidationAttribute[] GetPropertyValidationAttributes(
+            [global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembers(global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicProperties | global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.PublicConstructors)]
+            global::System.Type containingType,
+            string propertyName)
+        {
+            var key = new CacheKey(containingType, propertyName);
+            return _propertyCache.GetOrAdd(key, static k =>
+            {
+                var results = new global::System.Collections.Generic.List<global::System.ComponentModel.DataAnnotations.ValidationAttribute>();
+
+                // Get attributes from the property
+                var property = k.ContainingType.GetProperty(k.PropertyName);
+                if (property != null)
+                {
+                    var propertyAttributes = global::System.Reflection.CustomAttributeExtensions
+                        .GetCustomAttributes<global::System.ComponentModel.DataAnnotations.ValidationAttribute>(property, inherit: true);
+
+                    results.AddRange(propertyAttributes);
+                }
+
+                // Check constructors for parameters that match the property name
+                // to handle record scenarios
+                foreach (var constructor in k.ContainingType.GetConstructors())
+                {
+                    // Look for parameter with matching name (case insensitive)
+                    var parameter = global::System.Linq.Enumerable.FirstOrDefault(
+                        constructor.GetParameters(),
+                        p => string.Equals(p.Name, k.PropertyName, global::System.StringComparison.OrdinalIgnoreCase));
+
+                    if (parameter != null)
+                    {
+                        var paramAttributes = global::System.Reflection.CustomAttributeExtensions
+                            .GetCustomAttributes<global::System.ComponentModel.DataAnnotations.ValidationAttribute>(parameter, inherit: true);
+
+                        results.AddRange(paramAttributes);
+
+                        break;
+                    }
+                }
+
+                return results.ToArray();
+            });
+        }
+
+
+        public static global::System.ComponentModel.DataAnnotations.ValidationAttribute[] GetTypeValidationAttributes(
+            [global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembers(global::System.Diagnostics.CodeAnalysis.DynamicallyAccessedMemberTypes.Interfaces)]
+            global::System.Type type
+        )
+        {
+            return TypeCache.GetOrAdd(type, static t =>
+            {
+                var typeAttributes = global::System.Reflection.CustomAttributeExtensions
+                        .GetCustomAttributes<global::System.ComponentModel.DataAnnotations.ValidationAttribute>(t, inherit: true);
+                return global::System.Linq.Enumerable.ToArray(typeAttributes);
+            });
+        }
+    }
+}