Update default Razor search paths to include ~/[PagesRoot]/Shared

Fixes #6604

src/Microsoft.AspNetCore.Mvc.Razor/RazorViewEngineOptions.cs

@@ -113,6 +113,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
         ///  /Pages/Account/{0}.cshtml
         ///  /Pages/{0}.cshtml
         ///  /Views/Shared/{0}.cshtml
+        ///  /Pages/Shared/{0}.cshtml
         /// </para>
         /// </remarks>
         public IList<string> PageViewLocationFormats { get; } = new List<string>();

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

@@ -1,6 +1,7 @@
 // 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;
 using System.Diagnostics;
 using Microsoft.AspNetCore.Mvc.Razor;
 using Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure;
@@ -10,29 +11,45 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
 {
     public class RazorPagesRazorViewEngineOptionsSetup : IConfigureOptions<RazorViewEngineOptions>
     {
-        private readonly IOptions<RazorPagesOptions> _pagesOptions;
+        private readonly RazorPagesOptions _pagesOptions;
 
         public RazorPagesRazorViewEngineOptionsSetup(IOptions<RazorPagesOptions> pagesOptions)
         {
-            _pagesOptions = pagesOptions;
+            _pagesOptions = pagesOptions?.Value ?? throw new ArgumentNullException(nameof(pagesOptions));
         }
 
         public void Configure(RazorViewEngineOptions options)
         {
-            Debug.Assert(_pagesOptions.Value.RootDirectory.Length > 0);
+            if (options == null)
+            {
+                throw new ArgumentNullException(nameof(options));
+            }
 
-            if (_pagesOptions.Value.RootDirectory == "/")
+            var rootDirectory = _pagesOptions.RootDirectory;
-            {
+            Debug.Assert(!string.IsNullOrEmpty(rootDirectory));
-                options.PageViewLocationFormats.Add("/{1}/{0}" + RazorViewEngine.ViewExtension);
+            var defaultPageSearchPath = CombinePath(rootDirectory, "{1}/{0}");
-            }
+            options.PageViewLocationFormats.Add(defaultPageSearchPath);
-            else
+
-            {
+            // /Pages/Shared/{0}.cshtml
-                options.PageViewLocationFormats.Add(_pagesOptions.Value.RootDirectory + "/{1}/{0}" + RazorViewEngine.ViewExtension);
+            var pagesSharedDirectory = CombinePath(rootDirectory, "Shared/{0}");
-            }
+            options.PageViewLocationFormats.Add(pagesSharedDirectory);
 
             options.PageViewLocationFormats.Add("/Views/Shared/{0}" + RazorViewEngine.ViewExtension);
 
+            options.ViewLocationFormats.Add(pagesSharedDirectory);
+            options.AreaViewLocationFormats.Add(pagesSharedDirectory);
+
             options.ViewLocationExpanders.Add(new PageViewLocationExpander());
         }
+
+        private static string CombinePath(string path1, string path2)
+        {
+            if (path1.EndsWith("/", StringComparison.Ordinal))
+            {
+                return path1 + path2 + RazorViewEngine.ViewExtension;
+            }
+
+            return path1 + "/" + path2 + RazorViewEngine.ViewExtension;
+        }
     }
 }

test/Microsoft.AspNetCore.Mvc.FunctionalTests/RazorPagesWithBasePathTest.cs

@@ -274,5 +274,18 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             // Assert
             Assert.Equal(expected, response.Trim());
         }
+
+        [Fact]
+        public async Task Pages_ReturnsFromPagesSharedDirectory()
+        {
+            // Arrange
+            var expected = "Hello from Pages/Shared";
+
+            // Act
+            var response = await Client.GetStringAsync("/SearchInPages");
+
+            // Assert
+            Assert.Equal(expected, response.Trim());
+        }
     }
 }

test/Microsoft.AspNetCore.Mvc.FunctionalTests/ViewEngineTests.cs

@@ -513,5 +513,18 @@ Partial";
             // Assert
             Assert.Equal(expected, responseContent.Trim());
         }
+
+        [Fact]
+        public async Task ViewEngine_DiscoversViewsFromPagesSharedDirectory()
+        {
+            // Arrange
+            var expected = "Hello from Pages/Shared";
+
+            // Act
+            var responseContent = await Client.GetStringAsync("/ViewEngine/SearchInPages");
+
+            // Assert
+            Assert.Equal(expected, responseContent.Trim());
+        }
     }
 }

test/Microsoft.AspNetCore.Mvc.Razor.Test/RazorViewEngineTest.cs

@@ -1990,6 +1990,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             var options = new RazorViewEngineOptions();
             optionsSetup.Configure(options);
             options.PageViewLocationFormats.Add("/Views/Shared/{0}.cshtml");
+            options.PageViewLocationFormats.Add("/Pages/Shared/{0}.cshtml");
 
             if (expanders != null)
             {

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

@@ -0,0 +1,142 @@
+// 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 Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Mvc.Razor;
+using Microsoft.AspNetCore.Mvc.Razor.Internal;
+using Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure;
+using Moq;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.RazorPages.Internal
+{
+    public class RazorPagesRazorViewEngineOptionsSetupTest
+    {
+        [Fact]
+        public void Configure_AddsPageViewLocationFormats_WhenPagesRootIsAppRoot()
+        {
+            // Arrange
+            var expected = new[]
+            {
+                "/{1}/{0}.cshtml",
+                "/Shared/{0}.cshtml",
+                "/Views/Shared/{0}.cshtml",
+            };
+
+            var razorPagesOptions = new RazorPagesOptions
+            {
+                RootDirectory = "/"
+            };
+            var viewEngineOptions = GetViewEngineOptions();
+            var setup = new RazorPagesRazorViewEngineOptionsSetup(
+                new TestOptionsManager<RazorPagesOptions>(razorPagesOptions));
+
+            // Act
+            setup.Configure(viewEngineOptions);
+
+            // Assert
+            Assert.Equal(expected, viewEngineOptions.PageViewLocationFormats);
+        }
+
+        [Fact]
+        public void Configure_AddsPageViewLocationFormats_WithDefaultPagesRoot()
+        {
+            // Arrange
+            var expected = new[]
+            {
+                "/Pages/{1}/{0}.cshtml",
+                "/Pages/Shared/{0}.cshtml",
+                "/Views/Shared/{0}.cshtml",
+            };
+
+            var razorPagesOptions = new RazorPagesOptions();
+            var viewEngineOptions = GetViewEngineOptions();
+            var setup = new RazorPagesRazorViewEngineOptionsSetup(
+                new TestOptionsManager<RazorPagesOptions>(razorPagesOptions));
+
+            // Act
+            setup.Configure(viewEngineOptions);
+
+            // Assert
+            Assert.Equal(expected, viewEngineOptions.PageViewLocationFormats);
+        }
+
+        [Fact]
+        public void Configure_AddsSharedPagesDirectoryToViewLocationFormats()
+        {
+            // Arrange
+            var expected = new[]
+            {
+                "/Views/{1}/{0}.cshtml",
+                "/Views/Shared/{0}.cshtml",
+                "/PagesRoot/Shared/{0}.cshtml",
+            };
+
+            var razorPagesOptions = new RazorPagesOptions
+            {
+                RootDirectory = "/PagesRoot",
+            };
+            var viewEngineOptions = GetViewEngineOptions();
+            var setup = new RazorPagesRazorViewEngineOptionsSetup(
+                new TestOptionsManager<RazorPagesOptions>(razorPagesOptions));
+
+            // Act
+            setup.Configure(viewEngineOptions);
+
+            // Assert
+            Assert.Equal(expected, viewEngineOptions.ViewLocationFormats);
+        }
+
+        [Fact]
+        public void Configure_AddsSharedPagesDirectoryToAreaViewLocationFormats()
+        {
+            // Arrange
+            var expected = new[]
+            {
+                "/Areas/{2}/Views/{1}/{0}.cshtml",
+                "/Areas/{2}/Views/Shared/{0}.cshtml",
+                "/Views/Shared/{0}.cshtml",
+                "/PagesRoot/Shared/{0}.cshtml",
+            };
+
+            var razorPagesOptions = new RazorPagesOptions
+            {
+                RootDirectory = "/PagesRoot",
+            };
+            var viewEngineOptions = GetViewEngineOptions();
+            var setup = new RazorPagesRazorViewEngineOptionsSetup(
+                new TestOptionsManager<RazorPagesOptions>(razorPagesOptions));
+
+            // Act
+            setup.Configure(viewEngineOptions);
+
+            // Assert
+            Assert.Equal(expected, viewEngineOptions.AreaViewLocationFormats);
+        }
+
+        [Fact]
+        public void Configure_RegistersPageViewLocationExpander()
+        {
+            // Arrange
+            var viewEngineOptions = GetViewEngineOptions();
+            var setup = new RazorPagesRazorViewEngineOptionsSetup(new TestOptionsManager<RazorPagesOptions>());
+
+            // Act
+            setup.Configure(viewEngineOptions);
+
+            // Assert
+            Assert.Collection(
+                viewEngineOptions.ViewLocationExpanders,
+                expander => Assert.IsType<PageViewLocationExpander>(expander));
+        }
+
+        private static RazorViewEngineOptions GetViewEngineOptions()
+        {
+            var defaultSetup = new RazorViewEngineOptionsSetup(Mock.Of<IHostingEnvironment>());
+            var options = new RazorViewEngineOptions();
+            defaultSetup.Configure(options);
+
+            return options;
+        }
+    }
+}

test/WebSites/RazorPagesWebSite/Pages/FileFromShared

@@ -0,0 +1 @@
+@Html.Partial("_FileInShared)

test/WebSites/RazorPagesWebSite/Pages/SearchInPages.cshtml

@@ -0,0 +1,2 @@
+@page
+@Html.Partial("_FileInShared")

test/WebSites/RazorPagesWebSite/Pages/Shared/_FileInShared.cshtml

@@ -0,0 +1 @@
+Hello from Pages/Shared

test/WebSites/RazorPagesWebSite/Views/Shared/_FileInShared.cshtml

@@ -0,0 +1 @@
+@{ throw new Exception("This file should not be processed"); }

test/WebSites/RazorWebSite/Controllers/ViewEngineController.cs

@@ -77,5 +77,7 @@ namespace RazorWebSite.Controllers
         {
             return View();
         }
+
+        public IActionResult SearchInPages() => View();
     }
 }

test/WebSites/RazorWebSite/Pages/Shared/_Layout.cshtml

@@ -0,0 +1 @@
+@{ throw new Exception("This file should not be processed"); }

test/WebSites/RazorWebSite/Pages/Shared/_SharedFromPages.cshtml

@@ -0,0 +1 @@
+Hello from Pages/Shared

test/WebSites/RazorWebSite/Views/ViewEngine/SearchInPages.cshtml

@@ -0,0 +1 @@
+@Html.Partial("_SharedFromPages")