From 0fb47684c8c9f40b580c1279949ae4daac0d409c Mon Sep 17 00:00:00 2001
From: Ryan Nowak <nowakra@gmail.com>
Date: Thu, 7 Jun 2018 11:56:09 -0700
Subject: [PATCH] Fix #974

The root cause here was that we weren't setting the language version in
MSBuild, which is only for the command line version.

(cherry picked from commit 319e31f71a150e9b0d91e724f0e358390caec4c2)
---
 .../targets/RazorCompilation.targets                |  2 ++
 .../Tests/ComponentRenderingTest.cs                 | 13 ++++++++++++-
 test/testapps/BasicTestApp/DataDashComponent.cshtml |  5 +++++
 3 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 test/testapps/BasicTestApp/DataDashComponent.cshtml

diff --git a/src/Microsoft.AspNetCore.Blazor.Build/targets/RazorCompilation.targets b/src/Microsoft.AspNetCore.Blazor.Build/targets/RazorCompilation.targets
index 2d6896c5eb..fa40d6c86f 100644
--- a/src/Microsoft.AspNetCore.Blazor.Build/targets/RazorCompilation.targets
+++ b/src/Microsoft.AspNetCore.Blazor.Build/targets/RazorCompilation.targets
@@ -14,6 +14,8 @@
     <!-- Deactivates the Razor SDK's build-time compilation. We do our own -->
     <RazorCompileOnBuild>false</RazorCompileOnBuild>
 
+    <RazorLangVersion>Experimental</RazorLangVersion>
+
     <!-- 
       This version is used to build our RazorConfiguration, and is hardcoded into the tools in VS. If you change
       This to a value that doesn't match VS, then the Blazor Razor experience won't work for those documents.
diff --git a/test/Microsoft.AspNetCore.Blazor.E2ETest/Tests/ComponentRenderingTest.cs b/test/Microsoft.AspNetCore.Blazor.E2ETest/Tests/ComponentRenderingTest.cs
index 5b716e29fa..ef77b7cfee 100644
--- a/test/Microsoft.AspNetCore.Blazor.E2ETest/Tests/ComponentRenderingTest.cs
+++ b/test/Microsoft.AspNetCore.Blazor.E2ETest/Tests/ComponentRenderingTest.cs
@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// 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;
@@ -40,6 +40,17 @@ namespace Microsoft.AspNetCore.Blazor.E2ETest.Tests
             Assert.Equal("Hello from TextOnlyComponent", appElement.Text);
         }
 
+        // This verifies that we've correctly configured the Razor language version via MSBuild.
+        // See #974
+        [Fact]
+        public void CanRenderComponentWithDataDash()
+        {
+            var appElement = MountTestComponent<DataDashComponent>();
+            var element = appElement.FindElement(By.Id("cool_beans"));
+            Assert.Equal("17", element.GetAttribute("data-tab"));
+            Assert.Equal("17", element.Text);
+        }
+
         [Fact]
         public void CanRenderComponentWithAttributes()
         {
diff --git a/test/testapps/BasicTestApp/DataDashComponent.cshtml b/test/testapps/BasicTestApp/DataDashComponent.cshtml
new file mode 100644
index 0000000000..ae00ab1bc9
--- /dev/null
+++ b/test/testapps/BasicTestApp/DataDashComponent.cshtml
@@ -0,0 +1,5 @@
+<div id="cool_beans" data-tab="@TabId">@TabId</div>
+
+@functions {
+    string TabId = "17";
+}