WPF tmpproj is excluding Microsoft.Net.Compilers.Toolset package

[davkean]

Version Used:
Version 16.8.0 Preview 2.0 [30404.163.master]

Steps to Reproduce:
Build.zip

From a VS developer prompt from the above version:

1. git clone http://github.com/dotnet/project-system
2. cd project-system
3. git checkout 90acd3b85ed4fa5eaef154f71d480800332a9946
4. build.cmd

Expected Behavior:
No errors

Actual Behavior:

Errors because we're picking up csc from the VS directory instead of the package we're using:

G:\project-system\src\Microsoft.VisualStudio.ProjectSystem.Managed.VS\ProjectSystem\VS\Waiting\VisualStudioWaitIndicator.cs(101,24): error CS8619: Nullability of reference types in value of type '
(WaitIndicatorResult Canceled, T?)' doesn't match target type '(WaitIndicatorResult, T)'. [G:\project-system\src\Microsoft.VisualStudio.ProjectSystem.Managed.VS\Microsoft.VisualStudio.ProjectSyste
m.Managed.VS_jrfzhkfp_wpftmp.csproj]
G:\project-system\src\Microsoft.VisualStudio.ProjectSystem.Managed.VS\ProjectSystem\VS\Waiting\VisualStudioWaitIndicator.cs(108,24): error CS8619: Nullability of reference types in value of type '
(WaitIndicatorResult Canceled, T?)' doesn't match target type '(WaitIndicatorResult, T)'. [G:\project-system\src\Microsoft.VisualStudio.ProjectSystem.Managed.VS\Microsoft.VisualStudio.ProjectSyste
m.Managed.VS_jrfzhkfp_wpftmp.csproj]

Related part of the build log:

[davkean]

This is one from the same log which makes this line: http://sourceroslyn.io/#Microsoft.Build.Tasks.CodeAnalysis/ManagedCompiler.cs,499

[davkean]

Looking through the log, this has something to do with the autogenerated XAML project - it seems to be the only one picking up the wrong Csc:

[jaredpar]

The problem here isn't with Microsoft.Net.Compilers.Toolset picking the wrong csc, it's that the project simply isn't using Microsoft.Net.Compilers.Toolset. The easiest way to see what is going on here is to select "View" on the project that contains the errors. This is the generated .wpftmp.csproj file. That generated file has no <PackageReference> entries in it. The trimmed down file looks essentially like this:

<!-- Licensed to the .NET Foundation under one or more agreements. The .NET Foundation licenses this file to you under the MIT license. See the LICENSE.md file in the project root for more information. -->
<Project Sdk="Microsoft.NET.Sdk">
  <Import Project="..\..\build\import\VisualStudio.props" />
  <PropertyGroup>
    <RootNamespace>Microsoft.VisualStudio</RootNamespace>
    <!-- VSIX -->
    <GeneratePkgDefFile>true</GeneratePkgDefFile>
    <CreateVsixContainer>false</CreateVsixContainer>
    <!-- Nuget -->
    <IsPackable>true</IsPackable>
    <Description>Microsoft VisualStudio ProjectSystem for Managed Languages Project hosts that interact with VisualStudio interfaces.</Description>
    <Summary>Microsoft VisualStudio Managed Project System VS Components</Summary>
    <PackageTags>Roslyn Managed Project System VisualStudio</PackageTags>
    <NoWarn>$(NoWarn);NU5125</NoWarn>
  </PropertyGroup>
  <ItemGroup>
    <ProjectReference Include="..\Microsoft.VisualStudio.ProjectSystem.Managed\Microsoft.VisualStudio.ProjectSystem.Managed.csproj" />
  </ItemGroup>
  <ItemGroup>
    <InternalsVisibleTo Include="Microsoft.VisualStudio.ProjectSystem.Managed.VS.UnitTests" />
    <InternalsVisibleTo Include="DynamicProxyGenAssembly2" Key="$(MoqPublicKey)" />
  </ItemGroup>
  <ItemGroup>
    <Compile Update="ProjectSystem\VS\LanguageServices\CSharp\CSharpCodeDomProvider.cs">
      <SubType>Component</SubType>
    </Compile>
    <!-- Lots more Compile entries -->
  </ItemGroup>
  <!-- trimmed out a few ItemGroup for resources -->
  <ItemGroup>
    <ReferencePath Include="C:\Users\dmon\.nuget\packages\envdte\8.0.1\lib\net10\EnvDTE.dll" />
    <ReferencePath Include="C:\Users\dmon\.nuget\packages\envdte80\8.0.1\lib\net10\EnvDTE80.dll" />
    <ReferencePath Include="C:\Users\dmon\.nuget\packages\envdte90\9.0.1\lib\net10\EnvDTE90.dll" />
    <ReferencePath Include="C:\Users\dmon\.nuget\packages\messagepack.annotations\2.1.90\lib\netstandard2.0\MessagePack.Annotations.dll" />
    <!-- trimmed out a couple hundred more ReferencePath entries -->
  </ItemGroup>
  <ItemGroup>
    <Compile Include="G:\project-system\artifacts\Debug\obj\Microsoft.VisualStudio.ProjectSystem.Managed.VS\ProjectSystem\VS\PropertyPages\DebugPageControl.g.cs" />
    <Compile Include="G:\project-system\artifacts\Debug\obj\Microsoft.VisualStudio.ProjectSystem.Managed.VS\ProjectSystem\VS\PropertyPages\GetProfileNameDialog.g.cs" />
    <Compile Include="G:\project-system\artifacts\Debug\obj\Microsoft.VisualStudio.ProjectSystem.Managed.VS\ProjectSystem\VS\UI\DontShowAgainMessageBox.g.cs" />
    <Compile Include="G:\project-system\artifacts\Debug\obj\Microsoft.VisualStudio.ProjectSystem.Managed.VS\GeneratedInternalTypeHelper.g.cs" />
  </ItemGroup>
</Project>

I'm a little confused why it doesn't propagate from the referenced csproj file. But given that it doesn't look like restore ever ran on this project file at all that could be the reason.

Either case though this doesn't appear to be a problem in Microsoft.Net.Compilers.Toolset. The package just doesn't seem to be involved here due to the structure of this generated tmpproj.

At the same time that does feel very wrong. The customer has added a <PackageReference> to their project and the build assets are not being included in the tmpproj that WPF generates. That can definitely lead to unexpected behavior like this.

Moving to WPF team so they can comment on the reasoning here.

[tmat]

Dup of #810. Workaround is available in Arcade SDK:
https://github.com/dotnet/arcade/blob/cbfa29d4e859622ada3d226f90f103f659665d31/src/Microsoft.DotNet.Arcade.Sdk/tools/Workarounds.props#L14