Update the Enum Invalid Value setting for compat

Updated the naming to follow guidelines, and set the default for 2.0
apps to false. Note that I inverted the naming, which means that I had
to invert the logic in a few places.

src/Microsoft.AspNetCore.Mvc.Core/CompatibilityVersion.cs

@@ -48,6 +48,14 @@ namespace Microsoft.AspNetCore.Mvc
         /// Sets the default value of settings on <see cref="MvcOptions"/> to match the behavior of 
         /// ASP.NET Core MVC 2.1.
         /// </summary>
+        /// <remarks>
+        /// ASP.NET Core MVC 2.1 introduces compatibility switches for the following:
+        /// <list type="bullet">
+        ///     <item>
+        ///         <description><see cref="MvcOptions.SuppressBindingUndefinedValueToEnumType"/></description>    
+        ///     </item>
+        /// </list>
+        /// </remarks>
         Version_2_1,
 
         /// <summary>

src/Microsoft.AspNetCore.Mvc.Core/Infrastructure/MvcOptionsConfigureCompatibilityOptions.cs

@@ -25,6 +25,7 @@ namespace Microsoft.AspNetCore.Mvc.Infrastructure
 
                 if (Version >= CompatibilityVersion.Version_2_1)
                 {
+                    values[nameof(MvcOptions.SuppressBindingUndefinedValueToEnumType)] = true;
                     values[nameof(MvcOptions.InputFormatterExceptionModelStatePolicy)] = InputFormatterExceptionModelStatePolicy.MalformedInputExceptions;
                 }
 

src/Microsoft.AspNetCore.Mvc.Core/ModelBinding/Binders/EnumTypeModelBinder.cs

@@ -11,9 +11,9 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding.Binders
     /// </summary>
     public class EnumTypeModelBinder : SimpleTypeModelBinder
     {
-        private readonly bool _allowBindingUndefinedValueToEnumType;
+        private readonly bool _suppressBindingUndefinedValueToEnumType;
 
-        public EnumTypeModelBinder(bool allowBindingUndefinedValueToEnumType, Type modelType)
+        public EnumTypeModelBinder(bool supressBindingUndefinedValueToEnumType, Type modelType)
             : base(modelType)
         {
             if (modelType == null)
@@ -21,7 +21,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding.Binders
                 throw new ArgumentNullException(nameof(modelType));
             }
 
-            _allowBindingUndefinedValueToEnumType = allowBindingUndefinedValueToEnumType;
+            _suppressBindingUndefinedValueToEnumType = supressBindingUndefinedValueToEnumType;
         }
 
         protected override void CheckModel(
@@ -29,7 +29,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding.Binders
             ValueProviderResult valueProviderResult,
             object model)
         {
-            if (model == null || _allowBindingUndefinedValueToEnumType)
+            if (model == null || !_suppressBindingUndefinedValueToEnumType)
             {
                 base.CheckModel(bindingContext, valueProviderResult, model);
             }

src/Microsoft.AspNetCore.Mvc.Core/ModelBinding/Binders/EnumTypeModelBinderProvider.cs

@@ -28,7 +28,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding.Binders
             if (context.Metadata.IsEnum)
             {
                 return new EnumTypeModelBinder(
-                    _options.AllowBindingUndefinedValueToEnumType,
+                    _options.SuppressBindingUndefinedValueToEnumType,
                     context.Metadata.UnderlyingOrModelType);
             }
 

src/Microsoft.AspNetCore.Mvc.Core/MvcOptions.cs

@@ -22,8 +22,8 @@ namespace Microsoft.AspNetCore.Mvc
         private int _maxModelStateErrors = ModelStateDictionary.DefaultMaxAllowedErrors;
 
         // See CompatibilitySwitch.cs for guide on how to implement these.
-        private readonly CompatibilitySwitch<bool> _allowBindingUndefinedValueToEnumType;
         private readonly CompatibilitySwitch<InputFormatterExceptionModelStatePolicy> _inputFormatterExceptionModelStatePolicy;
+        private readonly CompatibilitySwitch<bool> _suppressBindingUndefinedValueToEnumType;
         private readonly CompatibilitySwitch<bool> _suppressJsonDeserializationExceptionMessagesInModelState;
         private readonly ICompatibilitySwitch[] _switches;
 
@@ -41,13 +41,13 @@ namespace Microsoft.AspNetCore.Mvc
             ModelValidatorProviders = new List<IModelValidatorProvider>();
             ValueProviderFactories = new List<IValueProviderFactory>();
 
-            _allowBindingUndefinedValueToEnumType = new CompatibilitySwitch<bool>(nameof(AllowBindingUndefinedValueToEnumType));
             _inputFormatterExceptionModelStatePolicy = new CompatibilitySwitch<InputFormatterExceptionModelStatePolicy>(nameof(InputFormatterExceptionModelStatePolicy), InputFormatterExceptionModelStatePolicy.AllExceptions);
+            _suppressBindingUndefinedValueToEnumType = new CompatibilitySwitch<bool>(nameof(SuppressBindingUndefinedValueToEnumType));
             _suppressJsonDeserializationExceptionMessagesInModelState = new CompatibilitySwitch<bool>(nameof(SuppressJsonDeserializationExceptionMessagesInModelState));
             _switches = new ICompatibilitySwitch[]
             {
-                _allowBindingUndefinedValueToEnumType,
                 _inputFormatterExceptionModelStatePolicy,
+                _suppressBindingUndefinedValueToEnumType,
                 _suppressJsonDeserializationExceptionMessagesInModelState,
             };
         }
@@ -92,6 +92,35 @@ namespace Microsoft.AspNetCore.Mvc
         /// </summary>
         public FormatterCollection<IInputFormatter> InputFormatters { get; }
 
+        /// <summary>
+        /// Gets or sets an value indicating whether the model binding system will bind undefined values to 
+        /// enum types. The default value of the property is <c>false</c>. 
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// This property is associated with a compatibility switch and can provide a different behavior depending on 
+        /// the configured compatibility version for the application. See <see cref="CompatibilityVersion"/> for 
+        /// guidance and examples of setting the application's compatibility version.
+        /// </para>
+        /// <para>
+        /// Configuring the desired of the value compatibility switch by calling this property's setter will take precedence
+        /// over the value implied by the application's <see cref="CompatibilityVersion"/>.
+        /// </para>
+        /// <para>
+        /// If the application's compatibility version is set to <see cref="CompatibilityVersion.Version_2_0"/> then
+        /// this setting will have value <c>false</c> if not explicitly configured.
+        /// </para>
+        /// <para>
+        /// If the application's compatibility version is set to <see cref="CompatibilityVersion.Version_2_1"/> or
+        /// higher then this setting will have value <c>true</c> if not explicitly configured.
+        /// </para>
+        /// </remarks>
+        public bool SuppressBindingUndefinedValueToEnumType
+        {
+            get => _suppressBindingUndefinedValueToEnumType.Value;
+            set => _suppressBindingUndefinedValueToEnumType.Value = value;
+        }
+
         /// <summary>
         /// Gets or sets the flag to buffer the request body in input formatters. Default is <c>false</c>.
         /// </summary>
@@ -181,15 +210,6 @@ namespace Microsoft.AspNetCore.Mvc
         /// </summary>
         public bool RequireHttpsPermanent { get; set; }
 
-        /// <summary>
-        /// Gets or sets an indication whether the model binding system will bind undefined values to enumeration types.
-        /// <see langword="false"/> by default.
-        /// </summary>
-        public bool AllowBindingUndefinedValueToEnumType
-        {
-            get => _allowBindingUndefinedValueToEnumType.Value;
-            set => _allowBindingUndefinedValueToEnumType.Value = value;
-        }
 
         /// <summary>
         /// Gets or sets the option to determine if model binding should convert all exceptions (including ones not related to bad input)

test/Microsoft.AspNetCore.Mvc.Core.Test/ModelBinding/Binders/EnumTypeModelBinderProviderTest.cs

@@ -15,7 +15,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
         public void ReturnsBinder_ForEnumType(Type modelType)
         {
             // Arrange
-            var provider = new EnumTypeModelBinderProvider(new MvcOptions { AllowBindingUndefinedValueToEnumType = true });
+            var provider = new EnumTypeModelBinderProvider(new MvcOptions());
             var context = new TestModelBinderProviderContext(modelType);
 
             // Act
@@ -31,7 +31,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
         public void ReturnsBinder_ForFlagsEnumType(Type modelType)
         {
             // Arrange
-            var provider = new EnumTypeModelBinderProvider(new MvcOptions { AllowBindingUndefinedValueToEnumType = true });
+            var provider = new EnumTypeModelBinderProvider(new MvcOptions());
             var context = new TestModelBinderProviderContext(modelType);
 
             // Act
@@ -48,7 +48,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
         public void DoesNotReturnBinder_ForNonEnumTypes(Type modelType)
         {
             // Arrange
-            var provider = new EnumTypeModelBinderProvider(new MvcOptions { AllowBindingUndefinedValueToEnumType = false });
+            var provider = new EnumTypeModelBinderProvider(new MvcOptions());
             var context = new TestModelBinderProviderContext(modelType);
 
             // Act

test/Microsoft.AspNetCore.Mvc.Core.Test/ModelBinding/Binders/EnumTypeModelBinderTest.cs

@@ -5,7 +5,6 @@ using System;
 using System.ComponentModel;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Mvc.ModelBinding.Binders;
-using Microsoft.Extensions.Options;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Mvc.ModelBinding
@@ -18,13 +17,13 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
         [InlineData(false, typeof(IntEnum?))]
         [InlineData(false, typeof(FlagsEnum?))]
         public async Task BindModel_SetsModel_ForEmptyValue_AndNullableEnumTypes(
-            bool allowBindingUndefinedValueToEnumType,
+            bool suppressBindingUndefinedValueToEnumType,
             Type modelType)
         {
             // Arrange
             var binderInfo = GetBinderAndContext(
                 modelType,
-                allowBindingUndefinedValueToEnumType,
+                suppressBindingUndefinedValueToEnumType,
                 valueProviderValue: "");
             var bindingContext = binderInfo.Item1;
             var binder = binderInfo.Item2;
@@ -43,14 +42,14 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
         [InlineData(false, typeof(IntEnum))]
         [InlineData(false, typeof(FlagsEnum))]
         public async Task BindModel_AddsErrorToModelState_ForEmptyValue_AndNonNullableEnumTypes(
-            bool allowBindingUndefinedValueToEnumType,
+            bool suprressBindingUndefinedValueToEnumType,
             Type modelType)
         {
             // Arrange
             var message = "The value '' is invalid.";
             var binderInfo = GetBinderAndContext(
                 modelType,
-                allowBindingUndefinedValueToEnumType,
+                suprressBindingUndefinedValueToEnumType,
                 valueProviderValue: "");
             var bindingContext = binderInfo.Item1;
             var binder = binderInfo.Item2;
@@ -72,14 +71,14 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
         [InlineData(false, "Value1")]
         [InlineData(false, "1")]
         public async Task BindModel_BindsEnumModels_ForValuesInArray(
-            bool allowBindingUndefinedValueToEnumType,
+            bool suppressBindingUndefinedValueToEnumType,
             string enumValue)
         {
             // Arrange
             var modelType = typeof(IntEnum);
             var binderInfo = GetBinderAndContext(
                 modelType,
-                allowBindingUndefinedValueToEnumType,
+                suppressBindingUndefinedValueToEnumType,
                 valueProviderValue: new object[] { enumValue });
             var bindingContext = binderInfo.Item1;
             var binder = binderInfo.Item2;
@@ -102,7 +101,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
         [InlineData("8, 1", false)]
         [InlineData("Value2, Value8", false)]
         [InlineData("value8,value4,value2,value1", false)]
-        public async Task BindModel_BindsTo_NonNullableFlagsEnumType(string flagsEnumValue, bool allowBindingUndefinedValueToEnumType)
+        public async Task BindModel_BindsTo_NonNullableFlagsEnumType(string flagsEnumValue, bool suppressBindingUndefinedValueToEnumType)
         {
             // Arrange
             var modelType = typeof(FlagsEnum);
@@ -110,7 +109,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
             var expected = enumConverter.ConvertFrom(flagsEnumValue).ToString();
             var binderInfo = GetBinderAndContext(
                 modelType,
-                allowBindingUndefinedValueToEnumType,
+                suppressBindingUndefinedValueToEnumType,
                 valueProviderValue: new object[] { flagsEnumValue });
             var bindingContext = binderInfo.Item1;
             var binder = binderInfo.Item2;
@@ -133,7 +132,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
         [InlineData("8, 1", false)]
         [InlineData("Value2, Value8", false)]
         [InlineData("value8,value4,value2,value1", false)]
-        public async Task BindModel_BindsTo_NullableFlagsEnumType(string flagsEnumValue, bool allowBindingUndefinedValueToEnumType)
+        public async Task BindModel_BindsTo_NullableFlagsEnumType(string flagsEnumValue, bool suppressBindingUndefinedValueToEnumType)
         {
             // Arrange
             var modelType = typeof(FlagsEnum?);
@@ -141,7 +140,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
             var expected = enumConverter.ConvertFrom(flagsEnumValue).ToString();
             var binderInfo = GetBinderAndContext(
                 modelType,
-                allowBindingUndefinedValueToEnumType,
+                suppressBindingUndefinedValueToEnumType,
                 valueProviderValue: new object[] { flagsEnumValue });
             var bindingContext = binderInfo.Item1;
             var binder = binderInfo.Item2;
@@ -168,7 +167,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
             var message = $"The value '{suppliedValue}' is not valid.";
             var binderInfo = GetBinderAndContext(
                 modelType,
-                allowBindingUndefinedValueToEnumType: true,
+                suppressBindingUndefinedValueToEnumType: false,
                 valueProviderValue: new object[] { suppliedValue });
             var bindingContext = binderInfo.Item1;
             var binder = binderInfo.Item2;
@@ -209,7 +208,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
             var message = $"The value '{suppliedValue}' is invalid.";
             var binderInfo = GetBinderAndContext(
                 modelType,
-                allowBindingUndefinedValueToEnumType: false,
+                suppressBindingUndefinedValueToEnumType: true,
                 valueProviderValue: new object[] { suppliedValue });
             var bindingContext = binderInfo.Item1;
             var binder = binderInfo.Item2;
@@ -251,7 +250,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
             var binderProviderContext = new TestModelBinderProviderContext(modelType);
             var binderInfo = GetBinderAndContext(
                 modelType,
-                allowBindingUndefinedValueToEnumType: true,
+                suppressBindingUndefinedValueToEnumType: false,
                 valueProviderValue: new object[] { suppliedValue });
             var bindingContext = binderInfo.Item1;
             var binder = binderInfo.Item2;
@@ -267,7 +266,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
 
         private static (DefaultModelBindingContext, IModelBinder) GetBinderAndContext(
             Type modelType,
-            bool allowBindingUndefinedValueToEnumType,
+            bool suppressBindingUndefinedValueToEnumType,
             object valueProviderValue)
         {
             var binderProviderContext = new TestModelBinderProviderContext(modelType);
@@ -284,7 +283,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding
             };
             var binderProvider = new EnumTypeModelBinderProvider(new MvcOptions
             {
-                AllowBindingUndefinedValueToEnumType = allowBindingUndefinedValueToEnumType
+                SuppressBindingUndefinedValueToEnumType = suppressBindingUndefinedValueToEnumType
             });
             var binder = binderProvider.GetBinder(binderProviderContext);
             return (bindingContext, binder);

test/Microsoft.AspNetCore.Mvc.Test/IntegrationTest/CompatibilitySwitchIntegrationTest.cs

@@ -30,7 +30,7 @@ namespace Microsoft.AspNetCore.Mvc.IntegrationTest
             var mvcOptions = services.GetRequiredService<IOptions<MvcOptions>>().Value;
 
             // Assert
-            Assert.False(mvcOptions.AllowBindingUndefinedValueToEnumType);
+            Assert.False(mvcOptions.SuppressBindingUndefinedValueToEnumType);
             Assert.Equal(InputFormatterExceptionModelStatePolicy.AllExceptions, mvcOptions.InputFormatterExceptionModelStatePolicy);
             Assert.False(mvcOptions.SuppressJsonDeserializationExceptionMessagesInModelState); // This name needs to be inverted in #7157
         }
@@ -49,7 +49,7 @@ namespace Microsoft.AspNetCore.Mvc.IntegrationTest
             var mvcOptions = services.GetRequiredService<IOptions<MvcOptions>>().Value;
 
             // Assert
-            Assert.True(mvcOptions.AllowBindingUndefinedValueToEnumType);
+            Assert.True(mvcOptions.SuppressBindingUndefinedValueToEnumType);
             Assert.Equal(InputFormatterExceptionModelStatePolicy.MalformedInputExceptions, mvcOptions.InputFormatterExceptionModelStatePolicy);
             Assert.True(mvcOptions.SuppressJsonDeserializationExceptionMessagesInModelState); // This name needs to be inverted in #7157
         }
@@ -68,7 +68,7 @@ namespace Microsoft.AspNetCore.Mvc.IntegrationTest
             var mvcOptions = services.GetRequiredService<IOptions<MvcOptions>>().Value;
 
             // Assert
-            Assert.True(mvcOptions.AllowBindingUndefinedValueToEnumType);
+            Assert.True(mvcOptions.SuppressBindingUndefinedValueToEnumType);
             Assert.Equal(InputFormatterExceptionModelStatePolicy.MalformedInputExceptions, mvcOptions.InputFormatterExceptionModelStatePolicy);
             Assert.True(mvcOptions.SuppressJsonDeserializationExceptionMessagesInModelState); // This name needs to be inverted in #7157
         }