Updated Razor Pages areas for compatibility switches

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

@@ -51,9 +51,8 @@ namespace Microsoft.AspNetCore.Mvc
         /// <remarks>
         /// ASP.NET Core MVC 2.1 introduces compatibility switches for the following:
         /// <list type="bullet">
-        ///     <item>
+        ///     <item><description><see cref="MvcOptions.SuppressBindingUndefinedValueToEnumType"/></description></item>
-        ///         <description><see cref="MvcOptions.SuppressBindingUndefinedValueToEnumType"/></description>    
+        ///     <item><description><c>RazorPagesOptions.AllowAreas</c></description></item>
-        ///     </item>
         /// </list>
         /// </remarks>
         Version_2_1,

src/Microsoft.AspNetCore.Mvc.RazorPages/DependencyInjection/MvcRazorPagesMvcCoreBuilderExtensions.cs

@@ -81,6 +81,8 @@ namespace Microsoft.Extensions.DependencyInjection
             // Options
             services.TryAddEnumerable(
                 ServiceDescriptor.Transient<IConfigureOptions<RazorViewEngineOptions>, RazorPagesRazorViewEngineOptionsSetup>());
+            services.TryAddEnumerable(
+                ServiceDescriptor.Transient<IPostConfigureOptions<RazorPagesOptions>, RazorPagesOptionsConfigureCompatibilityOptions>());
 
             // Action description and invocation
             services.TryAddEnumerable(

src/Microsoft.AspNetCore.Mvc.RazorPages/Internal/CompiledPageRouteModelProvider.cs

@@ -77,7 +77,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
                     {
                         model = GetPageRouteModel(rootDirectory, viewDescriptor);
                     }
-                    else if (_pagesOptions.EnableAreas && viewDescriptor.RelativePath.StartsWith(areaRootDirectory, StringComparison.OrdinalIgnoreCase))
+                    else if (_pagesOptions.AllowAreas && viewDescriptor.RelativePath.StartsWith(areaRootDirectory, StringComparison.OrdinalIgnoreCase))
                     {
                         model = GetAreaPageRouteModel(areaRootDirectory, viewDescriptor);
                     }

src/Microsoft.AspNetCore.Mvc.RazorPages/Internal/PageActionDescriptorChangeProvider.cs

@@ -56,7 +56,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
             var additionalImportFilePaths = templateEngine.GetImportItems(importFileAtPagesRoot)
                 .Select(item => item.FilePath);
 
-            if (razorPagesOptions.Value.EnableAreas)
+            if (razorPagesOptions.Value.AllowAreas)
             {
                 var areaRootDirectory = razorPagesOptions.Value.AreaRootDirectory;
                 Debug.Assert(!string.IsNullOrEmpty(areaRootDirectory));

src/Microsoft.AspNetCore.Mvc.RazorPages/Internal/RazorProjectPageRouteModelProvider.cs

@@ -39,7 +39,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
         {
             AddPageModels(context);
 
-            if (_pagesOptions.EnableAreas)
+            if (_pagesOptions.AllowAreas)
             {
                 AddAreaPageModels(context);
             }

src/Microsoft.AspNetCore.Mvc.RazorPages/RazorPagesOptions.cs

@@ -2,18 +2,34 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections;
+using System.Collections.Generic;
 using Microsoft.AspNetCore.Mvc.ApplicationModels;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
 
 namespace Microsoft.AspNetCore.Mvc.RazorPages
 {
     /// <summary>
     /// Provides configuration for RazorPages.
     /// </summary>
-    public class RazorPagesOptions
+    public class RazorPagesOptions : IEnumerable<ICompatibilitySwitch>
     {
+        private readonly CompatibilitySwitch<bool> _allowAreas;
+        private readonly ICompatibilitySwitch[] _switches;
+
         private string _root = "/Pages";
         private string _areasRoot = "/Areas";
 
+        public RazorPagesOptions()
+        {
+            _allowAreas = new CompatibilitySwitch<bool>(nameof(AllowAreas));
+
+            _switches = new ICompatibilitySwitch[]
+            {
+                _allowAreas,
+            };
+        }
+
         /// <summary>
         /// Gets a collection of <see cref="IPageConvention"/> instances that are applied during
         /// route and page model construction.
@@ -45,20 +61,43 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
         /// <summary>
         /// Gets or sets a value that determines if areas are enabled for Razor Pages.
-        /// Defaults to <c>true</c>.
+        /// Defaults to <c>false</c>.
+        /// </summary>
+        /// <remarks>
         /// <para>
         /// When enabled, any Razor Page under the directory structure <c>/{AreaRootDirectory}/AreaName/{RootDirectory}/</c>
         /// will be associated with an area with the name <c>AreaName</c>.
         /// <seealso cref="AreaRootDirectory"/>
         /// <seealso cref="RootDirectory"/>
         /// </para>
-        /// </summary>
+        /// <para>
-        public bool EnableAreas { get; set; }
+        /// 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 AllowAreas
+        {
+            get => _allowAreas.Value;
+            set => _allowAreas.Value = value;
+        }
 
         /// <summary>
         /// Application relative path used as the root of discovery for Razor Page files associated with areas.
         /// Defaults to the <c>/Areas</c> directory under application root.
-        /// <seealso cref="EnableAreas" />
+        /// <seealso cref="AllowAreas" />
         /// </summary>
         public string AreaRootDirectory
         {
@@ -78,5 +117,12 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
                 _areasRoot = value;
             }
         }
+
+        IEnumerator<ICompatibilitySwitch> IEnumerable<ICompatibilitySwitch>.GetEnumerator()
+        {
+            return ((IEnumerable<ICompatibilitySwitch>)_switches).GetEnumerator();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator() => _switches.GetEnumerator();
     }
 }

src/Microsoft.AspNetCore.Mvc.RazorPages/RazorPagesOptionsConfigureCompatibilityOptions.cs

@@ -0,0 +1,35 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+
+namespace Microsoft.AspNetCore.Mvc.RazorPages
+{
+    internal class RazorPagesOptionsConfigureCompatibilityOptions : ConfigureCompatibilityOptions<RazorPagesOptions>
+    {
+        public RazorPagesOptionsConfigureCompatibilityOptions(
+            ILoggerFactory loggerFactory,
+            IOptions<MvcCompatibilityOptions> compatibilityOptions) 
+            : base(loggerFactory, compatibilityOptions)
+        {
+        }
+
+        protected override IReadOnlyDictionary<string, object> DefaultValues
+        {
+            get
+            {
+                var values = new Dictionary<string, object>();
+
+                if (Version >= CompatibilityVersion.Version_2_1)
+                {
+                    values[nameof(RazorPagesOptions.AllowAreas)] = true;
+                }
+
+                return values;
+            }
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.RazorPages.Test/Internal/CompiledPageRouteModelProviderTest.cs

@@ -73,7 +73,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
             };
             var options = new RazorPagesOptions
             {
-                EnableAreas = true,
+                AllowAreas = true,
                 AreaRootDirectory = "/Features",
                 RootDirectory = "/Files",
             };
@@ -151,7 +151,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
                 GetDescriptor("/Pages/About.cshtml"),
                 GetDescriptor("/Areas/Accounts/Pages/Home.cshtml"),
             };
-            var options = new RazorPagesOptions { EnableAreas = false };
+            var options = new RazorPagesOptions { AllowAreas = false };
             var provider = new TestCompiledPageRouteModelProvider(descriptors, options);
             var context = new PageRouteModelProviderContext();
 

test/Microsoft.AspNetCore.Mvc.RazorPages.Test/Internal/PageActionDescriptorChangeProviderTest.cs

@@ -74,7 +74,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
             var templateEngine = new RazorTemplateEngine(
                 RazorEngine.Create(),
                 new FileProviderRazorProject(accessor));
-            var options = Options.Create(new RazorPagesOptions { EnableAreas = true });
+            var options = Options.Create(new RazorPagesOptions { AllowAreas = true });
             var changeProvider = new PageActionDescriptorChangeProvider(templateEngine, accessor, options);
 
             // Act
@@ -100,7 +100,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
                 new FileProviderRazorProject(accessor));
             var options = Options.Create(new RazorPagesOptions
             {
-                EnableAreas = true,
+                AllowAreas = true,
                 AreaRootDirectory = rootDirectory,
             });
             var changeProvider = new PageActionDescriptorChangeProvider(templateEngine, accessor, options);
@@ -150,7 +150,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
             var options = Options.Create(new RazorPagesOptions());
             options.Value.RootDirectory = "/dir1/dir2";
             options.Value.AreaRootDirectory = "/dir3/dir4";
-            options.Value.EnableAreas = true;
+            options.Value.AllowAreas = true;
 
             var changeProvider = new PageActionDescriptorChangeProvider(templateEngine, accessor, options);
 
@@ -175,7 +175,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
                 RazorEngine.Create(),
                 new FileProviderRazorProject(accessor));
             templateEngine.Options.ImportsFileName = "_ViewImports.cshtml";
-            var options = Options.Create(new RazorPagesOptions { EnableAreas = false });
+            var options = Options.Create(new RazorPagesOptions { AllowAreas = false });
 
             var changeProvider = new PageActionDescriptorChangeProvider(templateEngine, accessor, options);
 

test/Microsoft.AspNetCore.Mvc.RazorPages.Test/Internal/RazorProjectPageRouteModelProviderTest.cs

@@ -69,7 +69,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
 
             var project = new TestRazorProject(fileProvider);
 
-            var optionsManager = Options.Create(new RazorPagesOptions { EnableAreas = true });
+            var optionsManager = Options.Create(new RazorPagesOptions { AllowAreas = true });
             var provider = new RazorProjectPageRouteModelProvider(project, optionsManager, NullLoggerFactory.Instance);
             var context = new PageRouteModelProviderContext();
 
@@ -153,7 +153,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
 
             var project = new TestRazorProject(fileProvider);
 
-            var optionsManager = Options.Create(new RazorPagesOptions { EnableAreas = false });
+            var optionsManager = Options.Create(new RazorPagesOptions { AllowAreas = false });
             var provider = new RazorProjectPageRouteModelProvider(project, optionsManager, NullLoggerFactory.Instance);
             var context = new PageRouteModelProviderContext();
 

test/Microsoft.AspNetCore.Mvc.Test/MvcServiceCollectionExtensionsTest.cs

@@ -23,6 +23,7 @@ using Microsoft.AspNetCore.Mvc.Razor;
 using Microsoft.AspNetCore.Mvc.Razor.Compilation;
 using Microsoft.AspNetCore.Mvc.Razor.Internal;
 using Microsoft.AspNetCore.Mvc.Razor.TagHelpers;
+using Microsoft.AspNetCore.Mvc.RazorPages;
 using Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure;
 using Microsoft.AspNetCore.Mvc.RazorPages.Internal;
 using Microsoft.AspNetCore.Mvc.TagHelpers;
@@ -371,6 +372,20 @@ namespace Microsoft.AspNetCore.Mvc
                             typeof(RazorPagesRazorViewEngineOptionsSetup),
                         }
                     },
+                    {
+                        typeof(IPostConfigureOptions<MvcOptions>),
+                        new[]
+                        {
+                            typeof(MvcOptions).Assembly.GetType("Microsoft.AspNetCore.Mvc.Infrastructure.MvcOptionsConfigureCompatibilityOptions", throwOnError: true),
+                        }
+                    },
+                    {
+                        typeof(IPostConfigureOptions<RazorPagesOptions>),
+                        new[]
+                        {
+                            typeof(RazorPagesOptions).Assembly.GetType("Microsoft.AspNetCore.Mvc.RazorPages.RazorPagesOptionsConfigureCompatibilityOptions", throwOnError: true),
+                        }
+                    },
                     {
                         typeof(IActionConstraintProvider),
                         new Type[]

test/WebSites/RazorPagesWebSite/StartupWithBasePath.cs

@@ -17,7 +17,7 @@ namespace RazorPagesWebSite
                 .AddCookieTempDataProvider()
                 .AddRazorPagesOptions(options =>
                 {
-                    options.EnableAreas = true;
+                    options.AllowAreas = true;
                     options.Conventions.AuthorizePage("/Conventions/Auth");
                     options.Conventions.AuthorizeFolder("/Conventions/AuthFolder");
                 });