Support specifying paths starting with ~/ for layout and partial views

Fixes #821

Author: pranavkm

src/Microsoft.AspNet.Mvc.Razor/VirtualPathRazorPageFactory.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using Microsoft.AspNet.Mvc.Core;
 using Microsoft.Framework.DependencyInjection;
 
 namespace Microsoft.AspNet.Mvc.Razor
@@ -32,6 +31,12 @@ public VirtualPathRazorPageFactory(IRazorCompilationService compilationService,
         /// <inheritdoc />
         public IRazorPage CreateInstance([NotNull] string relativePath, bool enableInstrumentation)
         {
+            if (relativePath.StartsWith("~/", StringComparison.Ordinal))
+            {
+                // For tilde slash paths, drop the leading ~ to make it work with the underlying IFileSystem.
+                relativePath = relativePath.Substring(1);
+            }
+
             var fileInfo = _fileInfoCache.GetFileInfo(relativePath);
 
             if (fileInfo != null)

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

@@ -69,11 +69,14 @@ public async Task RazorView_ExecutesPageAndLayout(string actionName, string expe
         [Fact]
         public async Task RazorView_ExecutesPartialPagesWithCorrectContext()
         {
-            var expected =
-@"<partial>98052
-
-</partial>
-test-value";
+            var expected = string.Join(Environment.NewLine,
+                                       "<partial>98052",
+                                       "",
+                                       "</partial>",
+                                       "<partial2>98052",
+                                       "",
+                                       "</partial2>",
+                                       "test-value");
             var server = TestServer.Create(_provider, _app);
             var client = server.CreateClient();
 

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

@@ -1,4 +1,4 @@
 @{ 
-    Layout = "/Views/Shared/_Layout.cshtml";
+    Layout = "~/Views/Shared/_Layout.cshtml";
 }
 ViewWithFullPath-content

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

@@ -2,4 +2,6 @@
 @model Person
 <partial>@await Html.PartialAsync("_Partial", Model.Address)
 </partial>
+<partial2>@await Html.PartialAsync("~/Views/Shared/_Partial.cshtml", Model.Address)
+</partial2>
 @ViewBag.TestKey