Fix for #2414 - Remove [DefaultValue] support from ModelBinding

This part of the change removes default value support from ModelBinding.

Updated some unit tests to verify that it does nothing in that case.
Deleted a functional test as it was pure duplication of another
(supported) case where the property has a pre-initialized value.

src/Microsoft.AspNet.Mvc.Core/ModelBinding/MutableObjectModelBinder.cs

@@ -324,21 +324,6 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             };
         }
 
-        private static bool TryGetPropertyDefaultValue(PropertyInfo propertyInfo, out object value)
-        {
-            var attribute = propertyInfo.GetCustomAttribute<DefaultValueAttribute>();
-            if (attribute == null)
-            {
-                value = null;
-                return false;
-            }
-            else
-            {
-                value = attribute.Value;
-                return true;
-            }
-        }
-
         internal static PropertyValidationInfo GetPropertyValidationInfo(ModelBindingContext bindingContext)
         {
             var validationInfo = new PropertyValidationInfo();
@@ -473,16 +458,11 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
                 return;
             }
 
-            object value;
+            object value = null;
-            var hasDefaultValue = false;
             if (dtoResult.IsModelSet)
             {
                 value = dtoResult.Model;
             }
-            else
-            {
-                hasDefaultValue = TryGetPropertyDefaultValue(property, out value);
-            }
 
             // 'Required' validators need to run first so that we can provide useful error messages if
             // the property setters throw, e.g. if we're setting entity keys to null.
@@ -504,7 +484,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
                 }
             }
 
-            if (!dtoResult.IsModelSet && !hasDefaultValue)
+            if (!dtoResult.IsModelSet)
             {
                 // If we don't have a value, don't set it on the model and trounce a pre-initialized
                 // value.

test/Microsoft.AspNet.Mvc.Core.Test/ModelBinding/MutableObjectModelBinderTest.cs

@@ -1057,8 +1057,8 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             var dto = new ComplexModelDto(containerMetadata, containerMetadata.Properties);
             var testableBinder = new TestableMutableObjectModelBinder();
 
-            // ValueTypeRequiredWithDefaultValue value comes from [DefaultValue] when !isModelSet.
+            // The [DefaultValue] on ValueTypeRequiredWithDefaultValue is ignored by model binding.
-            var expectedValue = isModelSet ? 0 : 42;
+            var expectedValue = 0;
 
             // Make ValueTypeRequired invalid.
             var propertyMetadata = dto.PropertyMetadata.Single(p => p.PropertyName == nameof(Person.ValueTypeRequired));
@@ -1160,7 +1160,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             // Model gets provided values.
             Assert.Equal(41, model.ValueTypeRequired);
             Assert.Equal(57, model.ValueTypeRequiredWithDefaultValue);
-            Assert.Equal(123.456m, model.PropertyWithDefaultValue);     // from [DefaultValue]
+            Assert.Equal(0m, model.PropertyWithDefaultValue);     // [DefaultValue] has no effect
         }
 
         [Fact]
@@ -1205,7 +1205,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
         }
 
         [Fact]
-        public void SetProperty_PropertyHasDefaultValue_SetsDefaultValue()
+        public void SetProperty_PropertyHasDefaultValue_DefaultValueAttributeDoesNothing()
         {
             // Arrange
             var model = new Person();
@@ -1238,7 +1238,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
 
             // Assert
             var person = Assert.IsType<Person>(bindingContext.Model);
-            Assert.Equal(123.456m, person.PropertyWithDefaultValue);
+            Assert.Equal(0m, person.PropertyWithDefaultValue);
             Assert.True(bindingContext.ModelState.IsValid);
         }
 
@@ -1276,7 +1276,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
         }
 
         [Fact]
-        public void SetProperty_PropertyIsPreinitialized_WithDefaultValue_NoValue_CallsSetter()
+        public void SetProperty_PropertyIsPreinitialized_DefaultValueAttributeDoesNothing()
         {
             // Arrange
             var model = new Person();
@@ -1304,7 +1304,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
 
             // Assert
             var person = Assert.IsType<Person>(bindingContext.Model);
-            Assert.Equal("default", person.PropertyWithInitializedValueAndDefault);
+            Assert.Equal("preinitialized", person.PropertyWithInitializedValueAndDefault);
             Assert.True(bindingContext.ModelState.IsValid);
         }
 

test/Microsoft.AspNet.Mvc.FunctionalTests/ModelBindingFromHeaderTest.cs

@@ -325,39 +325,6 @@ namespace Microsoft.AspNet.Mvc.FunctionalTests
             Assert.Equal("Title", error);
         }
 
-        // This model uses [DefaultValueAttribute(...)] for 'Title', and the model binder won't 
-        // trounce it.
-        //
-        // There's a validation error because we validate the value in the request (not present).
-        [Fact]
-        public async Task FromHeader_BindHeader_ToModel_NoValues_DefaultValueAttribute_ValidationError()
-        {
-            // Arrange
-            var server = TestHelper.CreateServer(_app, SiteName, _configureServices);
-            var client = server.CreateClient();
-
-            var request = new HttpRequestMessage(
-                HttpMethod.Get,
-                "http://localhost/Blog/BindToModelWithDefaultValue?author=Marvin");
-
-            // Intentionally not setting a title or tags
-
-            // Act
-            var response = await client.SendAsync(request);
-
-            // Assert
-            Assert.Equal(HttpStatusCode.OK, response.StatusCode);
-
-            var body = await response.Content.ReadAsStringAsync();
-            var result = JsonConvert.DeserializeObject<Result>(body);
-
-            Assert.Equal("How to Make Soup", result.HeaderValue);
-            Assert.Equal<string>(new[] { "Cooking" }, result.HeaderValues);
-
-            var error = Assert.Single(result.ModelStateErrors);
-            Assert.Equal("Title", error);
-        }
-
         private class Result
         {
             public string HeaderValue { get; set; }

test/WebSites/ModelBindingWebSite/Controllers/FromHeader_BlogController.cs

@@ -87,18 +87,6 @@ namespace ModelBindingWebSite.Controllers
             };
         }
 
-        [HttpGet("BindToModelWithDefaultValue")]
-        public object BindToModelWithDefaultValue(BlogPostWithDefaultValue blogPost)
-        {
-            return new Result()
-            {
-                HeaderValue = blogPost.Title,
-                HeaderValues = blogPost.Tags,
-                ModelStateErrors = ModelState.Where(kvp => kvp.Value.Errors.Count > 0).Select(kvp => kvp.Key).ToArray(),
-            };
-        }
-
-
         private class Result
         {
             public string HeaderValue { get; set; }
@@ -144,19 +132,5 @@ namespace ModelBindingWebSite.Controllers
 
             public string Author { get; set; }
         }
-
-        public class BlogPostWithDefaultValue
-        {
-            [Required]
-            [FromHeader]
-            [DefaultValue("How to Make Soup")]
-            public string Title { get; set; }
-
-            [FromHeader]
-            [DefaultValue(new string[] { "Cooking" })]
-            public string[] Tags { get; set; }
-
-            public string Author { get; set; }
-        }
     }
 }