Treat ValidationContext as required in validation resolver APIs

src/Http/Http.Abstractions/src/PublicAPI.Unshipped.txt

@@ -24,7 +24,7 @@ Microsoft.AspNetCore.Http.Validation.ValidateContext.CurrentDepth.set -> void
 Microsoft.AspNetCore.Http.Validation.ValidateContext.CurrentValidationPath.get -> string!
 Microsoft.AspNetCore.Http.Validation.ValidateContext.CurrentValidationPath.set -> void
 Microsoft.AspNetCore.Http.Validation.ValidateContext.ValidateContext() -> void
-Microsoft.AspNetCore.Http.Validation.ValidateContext.ValidationContext.get -> System.ComponentModel.DataAnnotations.ValidationContext?
+Microsoft.AspNetCore.Http.Validation.ValidateContext.ValidationContext.get -> System.ComponentModel.DataAnnotations.ValidationContext!
 Microsoft.AspNetCore.Http.Validation.ValidateContext.ValidationContext.set -> void
 Microsoft.AspNetCore.Http.Validation.ValidateContext.ValidationErrors.get -> System.Collections.Generic.Dictionary<string!, string![]!>?
 Microsoft.AspNetCore.Http.Validation.ValidateContext.ValidationErrors.set -> void

src/Http/Http.Abstractions/src/Validation/ValidatableParameterInfo.cs

@@ -3,7 +3,6 @@
 
 using System.Collections;
 using System.ComponentModel.DataAnnotations;
-using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 
 namespace Microsoft.AspNetCore.Http.Validation;
@@ -60,8 +59,6 @@ protected ValidatableParameterInfo(
     /// </remarks>
     public virtual async Task ValidateAsync(object? value, ValidateContext context, CancellationToken cancellationToken)
     {
-        Debug.Assert(context.ValidationContext is not null);
-
         // Skip validation if value is null and parameter is optional
         if (value == null && ParameterType.IsNullable())
         {

src/Http/Http.Abstractions/src/Validation/ValidatablePropertyInfo.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.ComponentModel.DataAnnotations;
-using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 
 namespace Microsoft.AspNetCore.Http.Validation;
@@ -61,8 +60,6 @@ protected ValidatablePropertyInfo(
     /// <inheritdoc />
     public virtual async Task ValidateAsync(object? value, ValidateContext context, CancellationToken cancellationToken)
     {
-        Debug.Assert(context.ValidationContext is not null);
-
         var property = DeclaringType.GetProperty(Name) ?? throw new InvalidOperationException($"Property '{Name}' not found on type '{DeclaringType.Name}'.");
         var propertyValue = property.GetValue(value);
         var validationAttributes = GetValidationAttributes();

src/Http/Http.Abstractions/src/Validation/ValidatableTypeInfo.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.ComponentModel.DataAnnotations;
-using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 
@@ -45,7 +44,6 @@ protected ValidatableTypeInfo(
     /// <inheritdoc />
     public virtual async Task ValidateAsync(object? value, ValidateContext context, CancellationToken cancellationToken)
     {
-        Debug.Assert(context.ValidationContext is not null);
         if (value == null)
         {
             return;

src/Http/Http.Abstractions/src/Validation/ValidateContext.cs

@@ -16,7 +16,24 @@ public sealed class ValidateContext
     /// Gets or sets the validation context used for validating objects that implement <see cref="IValidatableObject"/> or have <see cref="ValidationAttribute"/>.
     /// This context provides access to service provider and other validation metadata.
     /// </summary>
-    public ValidationContext? ValidationContext { get; set; }
+    /// <remarks>
+    /// This property should be set by the consumer of the <see cref="IValidatableInfo"/>
+    /// interface to provide the necessary context for validation. The object should be initialized
+    /// with the current object being validated, the display name, and the service provider to support
+    /// the complete set of validation scenarios.
+    /// </remarks>
+    /// <example>
+    /// <code>
+    /// var validationContext = new ValidationContext(objectToValidate, serviceProvider, items);
+    /// var validationOptions = serviceProvider.GetService&lt;IOptions&lt;ValidationOptions&gt;&gt;()?.Value;
+    /// var validateContext = new ValidateContext
+    /// {
+    ///     ValidationContext = validationContext,
+    ///     ValidationOptions = validationOptions
+    /// };
+    /// </code>
+    /// </example>
+    public required ValidationContext ValidationContext { get; set; }
 
     /// <summary>
     /// Gets or sets the prefix used to identify the current object being validated in a complex object graph.

src/Http/Http.Abstractions/test/Validation/ValidatableTypeInfoTests.cs

@@ -41,17 +41,16 @@ [new RequiredAttribute()])
             { typeof(Address), addressType }
         });
 
-        var context = new ValidateContext
-        {
-            ValidationOptions = validationOptions,
-        };
-
         var personWithMissingRequiredFields = new Person
         {
             Age = 150, // Invalid age
             Address = new Address() // Missing required City and Street
         };
-        context.ValidationContext = new ValidationContext(personWithMissingRequiredFields);
+        var context = new ValidateContext
+        {
+            ValidationOptions = validationOptions,
+            ValidationContext = new ValidationContext(personWithMissingRequiredFields)
+        };
 
         // Act
         await personType.ValidateAsync(personWithMissingRequiredFields, context, default);
@@ -96,21 +95,20 @@ [new RequiredAttribute()]),
                     [])
             ]);
 
-        var context = new ValidateContext
-        {
-            ValidationOptions = new TestValidationOptions(new Dictionary<Type, ValidatableTypeInfo>
-            {
-                { typeof(Employee), employeeType }
-            })
-        };
-
         var employee = new Employee
         {
             Name = "John Doe",
             Department = "IT",
             Salary = -5000 // Negative salary will trigger IValidatableObject validation
         };
-        context.ValidationContext = new ValidationContext(employee);
+        var context = new ValidateContext
+        {
+            ValidationOptions = new TestValidationOptions(new Dictionary<Type, ValidatableTypeInfo>
+            {
+                { typeof(Employee), employeeType }
+            }),
+            ValidationContext = new ValidationContext(employee)
+        };
 
         // Act
         await employeeType.ValidateAsync(employee, context, default);
@@ -142,22 +140,21 @@ [new RequiredAttribute()])
                     [new RangeAttribute(2, 5)])
             ]);
 
+        var car = new Car
+        {
+            // Missing Make and Model (required in base type)
+            Doors = 7 // Invalid number of doors
+        };
         var context = new ValidateContext
         {
             ValidationOptions = new TestValidationOptions(new Dictionary<Type, ValidatableTypeInfo>
             {
                 { typeof(Vehicle), baseType },
                 { typeof(Car), derivedType }
-            })
+            }),
+            ValidationContext = new ValidationContext(car)
         };
 
-        var car = new Car
-        {
-            // Missing Make and Model (required in base type)
-            Doors = 7 // Invalid number of doors
-        };
-        context.ValidationContext = new ValidationContext(car);
-
         // Act
         await derivedType.ValidateAsync(car, context, default);
 
@@ -203,15 +200,6 @@ [new RequiredAttribute()]),
                     [])
             ]);
 
-        var context = new ValidateContext
-        {
-            ValidationOptions = new TestValidationOptions(new Dictionary<Type, ValidatableTypeInfo>
-            {
-                { typeof(OrderItem), itemType },
-                { typeof(Order), orderType }
-            })
-        };
-
         var order = new Order
         {
             OrderNumber = "ORD-12345",
@@ -222,7 +210,15 @@ [new RequiredAttribute()]),
                 new OrderItem { ProductName = "Another Product", Quantity = 200 /* Invalid quantity */ }
             ]
         };
-        context.ValidationContext = new ValidationContext(order);
+        var context = new ValidateContext
+        {
+            ValidationOptions = new TestValidationOptions(new Dictionary<Type, ValidatableTypeInfo>
+            {
+                { typeof(OrderItem), itemType },
+                { typeof(Order), orderType }
+            }),
+            ValidationContext = new ValidationContext(order)
+        };
 
         // Act
         await orderType.ValidateAsync(order, context, default);
@@ -260,20 +256,19 @@ public async Task Validate_HandlesNullValues_Appropriately()
                     [])
             ]);
 
+        var person = new Person
+        {
+            Name = null,
+            Address = null
+        };
         var context = new ValidateContext
         {
             ValidationOptions = new TestValidationOptions(new Dictionary<Type, ValidatableTypeInfo>
             {
                 { typeof(Person), personType }
-            })
-        };
-
-        var person = new Person
-        {
-            Name = null,
-            Address = null
+            }),
+            ValidationContext = new ValidationContext(person)
         };
-        context.ValidationContext = new ValidationContext(person);
 
         // Act
         await personType.ValidateAsync(person, context, default);
@@ -305,12 +300,6 @@ [new RequiredAttribute()]),
         });
         validationOptions.MaxDepth = 3; // Set a small max depth to trigger the limit
 
-        var context = new ValidateContext
-        {
-            ValidationOptions = validationOptions,
-            ValidationErrors = []
-        };
-
         // Create a deep tree with circular references
         var rootNode = new TreeNode { Name = "Root" };
         var level1 = new TreeNode { Name = "Level1", Parent = rootNode };
@@ -328,7 +317,12 @@ [new RequiredAttribute()]),
         // Add a circular reference
         level5.Children.Add(rootNode);
 
-        context.ValidationContext = new ValidationContext(rootNode);
+        var context = new ValidateContext
+        {
+            ValidationOptions = validationOptions,
+            ValidationErrors = [],
+            ValidationContext = new ValidationContext(rootNode)
+        };
 
         // Act + Assert
         var exception = await Assert.ThrowsAsync<InvalidOperationException>(
@@ -349,17 +343,16 @@ public async Task Validate_HandlesCustomValidationAttributes()
                 CreatePropertyInfo(typeof(Product), typeof(string), "SKU", "SKU", [new RequiredAttribute(), new CustomSkuValidationAttribute()]),
             ]);
 
+        var product = new Product { SKU = "INVALID-SKU" };
         var context = new ValidateContext
         {
             ValidationOptions = new TestValidationOptions(new Dictionary<Type, ValidatableTypeInfo>
             {
                 { typeof(Product), productType }
-            })
+            }),
+            ValidationContext = new ValidationContext(product)
         };
 
-        var product = new Product { SKU = "INVALID-SKU" };
-        context.ValidationContext = new ValidationContext(product);
-
         // Act
         await productType.ValidateAsync(product, context, default);
 
@@ -385,17 +378,16 @@ public async Task Validate_HandlesMultipleErrorsOnSameProperty()
                     ])
             ]);
 
+        var user = new User { Password = "abc" };  // Too short and not complex enough
         var context = new ValidateContext
         {
             ValidationOptions = new TestValidationOptions(new Dictionary<Type, ValidatableTypeInfo>
             {
                 { typeof(User), userType }
-            })
+            }),
+            ValidationContext = new ValidationContext(user)
         };
 
-        var user = new User { Password = "abc" };  // Too short and not complex enough
-        context.ValidationContext = new ValidationContext(user);
-
         // Act
         await userType.ValidateAsync(user, context, default);
 
@@ -429,23 +421,22 @@ public async Task Validate_HandlesMultiLevelInheritance()
                 CreatePropertyInfo(typeof(DerivedEntity), typeof(string), "Name", "Name", [new RequiredAttribute()])
             ]);
 
+        var entity = new DerivedEntity
+        {
+            Name = "",  // Invalid: required
+            CreatedAt = DateTime.Now.AddDays(1) // Invalid: future date
+        };
         var context = new ValidateContext
         {
             ValidationOptions = new TestValidationOptions(new Dictionary<Type, ValidatableTypeInfo>
             {
                 { typeof(BaseEntity), baseType },
                 { typeof(IntermediateEntity), intermediateType },
                 { typeof(DerivedEntity), derivedType }
-            })
+            }),
+            ValidationContext = new ValidationContext(entity)
         };
 
-        var entity = new DerivedEntity
-        {
-            Name = "",  // Invalid: required
-            CreatedAt = DateTime.Now.AddDays(1) // Invalid: future date
-        };
-        context.ValidationContext = new ValidationContext(entity);
-
         // Act
         await derivedType.ValidateAsync(entity, context, default);
 
@@ -475,17 +466,16 @@ public async Task Validate_RequiredOnPropertyShortCircuitsOtherValidations()
                     [new RequiredAttribute(), new PasswordComplexityAttribute()])
             ]);
 
+        var user = new User { Password = null }; // Invalid: required
         var context = new ValidateContext
         {
             ValidationOptions = new TestValidationOptions(new Dictionary<Type, ValidatableTypeInfo>
             {
                 { typeof(User), userType }
-            })
+            }),
+            ValidationContext = new ValidationContext(user) // Invalid: required
         };
 
-        var user = new User { Password = null };  // Invalid: required
-        context.ValidationContext = new ValidationContext(user);
-
         // Act
         await userType.ValidateAsync(user, context, default);
 
@@ -503,18 +493,17 @@ public async Task Validate_IValidatableObject_WithZeroAndMultipleMemberNames_Beh
         var globalType = new TestValidatableTypeInfo(
             typeof(GlobalErrorObject),
             []); // no properties – nothing sets MemberName
+        var globalErrorInstance = new GlobalErrorObject { Data = -1 };
 
         var context = new ValidateContext
         {
             ValidationOptions = new TestValidationOptions(new Dictionary<Type, ValidatableTypeInfo>
             {
                 { typeof(GlobalErrorObject), globalType }
-            })
+            }),
+            ValidationContext = new ValidationContext(globalErrorInstance)
         };
 
-        var globalErrorInstance = new GlobalErrorObject { Data = -1 };
-        context.ValidationContext = new ValidationContext(globalErrorInstance);
-
         await globalType.ValidateAsync(globalErrorInstance, context, default);
 
         Assert.NotNull(context.ValidationErrors);

src/Http/Routing/src/ValidationEndpointFilterFactory.cs

@@ -43,7 +43,7 @@ public static EndpointFilterDelegate Create(EndpointFilterFactoryContext context
 
         return async (context) =>
         {
-            var validatableContext = new ValidateContext { ValidationOptions = options };
+            ValidateContext? validateContext = null;
 
             for (var i = 0; i < context.Arguments.Count; i++)
             {
@@ -57,15 +57,28 @@ public static EndpointFilterDelegate Create(EndpointFilterFactoryContext context
                 }
 
                 var validationContext = new ValidationContext(argument, displayName, context.HttpContext.RequestServices, items: null);
-                validatableContext.ValidationContext = validationContext;
-                await validatableParameter.ValidateAsync(argument, validatableContext, context.HttpContext.RequestAborted);
+
+                if (validateContext == null)
+                {
+                    validateContext = new ValidateContext
+                    {
+                        ValidationOptions = options,
+                        ValidationContext = validationContext
+                    };
+                }
+                else
+                {
+                    validateContext.ValidationContext = validationContext;
+                }
+
+                await validatableParameter.ValidateAsync(argument, validateContext, context.HttpContext.RequestAborted);
             }
 
-            if (validatableContext.ValidationErrors is { Count: > 0 })
+            if (validateContext is { ValidationErrors.Count: > 0 })
             {
                 context.HttpContext.Response.StatusCode = StatusCodes.Status400BadRequest;
                 context.HttpContext.Response.ContentType = "application/problem+json";
-                return await ValueTask.FromResult(new HttpValidationProblemDetails(validatableContext.ValidationErrors));
+                return await ValueTask.FromResult(new HttpValidationProblemDetails(validateContext.ValidationErrors));
             }
 
             return await next(context);