[6.0 preview 1] MSB4062 error when referencing Microsoft.AspNetCore.Mvc.Testing

[martincostello]

Describe the bug

If an assembly references Microsoft.AspNetCore.Mvc.Testing version 6.0.0-preview.1.21103.6, it fails to compile with an error similar to the following (build log):

C:\Users\runneradmin\.nuget\packages\microsoft.aspnetcore.mvc.testing\6.0.0-preview.1.21103.6\build\net6.0\Microsoft.AspNetCore.Mvc.Testing.targets(38,5): error MSB4062: The "GenerateMvcTestManifestTask" task could not be loaded from the assembly C:\Users\runneradmin\.nuget\packages\microsoft.aspnetcore.mvc.testing\6.0.0-preview.1.21103.6\build\net6.0\..\tasks\Microsoft.AspNetCore.Mvc.Testing.dll. Could not load file or assembly 'C:\Users\runneradmin\.nuget\packages\microsoft.aspnetcore.mvc.testing\6.0.0-preview.1.21103.6\build\tasks\Microsoft.AspNetCore.Mvc.Testing.dll'. The system cannot find the path specified. Confirm that the <UsingTask> declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask. [D:\a\adventofcode\adventofcode\tests\AdventOfCode.Tests\AdventOfCode.Tests.csproj]

This appears to have been introduced by #28575 which added this to the targets file:

aspnetcore/src/Mvc/Mvc.Testing/src/Microsoft.AspNetCore.Mvc.Testing.targets

Lines 3 to 6 in 7244d55

	<PropertyGroup>
	<_MvcTestingTasksAssembly Condition="$(_MvcTestingTasksAssembly) == ''">$(MSBuildThisFileDirectory)..\tasks\Microsoft.AspNetCore.Mvc.Testing.dll</_MvcTestingTasksAssembly>
	</PropertyGroup>
	<UsingTask TaskName="GenerateMvcTestManifestTask" AssemblyFile="$(_MvcTestingTasksAssembly)"/>

To Reproduce

Clone martincostello/adventofcode@d00ce63 and run build.ps1.

Exceptions (if any)

N/A

Further technical details

C:\Coding> dotnet --info
.NET SDK (reflecting any global.json):
 Version:   6.0.100-preview.1.21103.13
 Commit:    b8a03527b2

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19041
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\6.0.100-preview.1.21103.13\

Host (useful for support):
  Version: 6.0.0-preview.1.21102.12
  Commit:  9b2776d481

.NET SDKs installed:
  2.1.813 [C:\Program Files\dotnet\sdk]
  3.1.104 [C:\Program Files\dotnet\sdk]
  3.1.201 [C:\Program Files\dotnet\sdk]
  3.1.302 [C:\Program Files\dotnet\sdk]
  3.1.303 [C:\Program Files\dotnet\sdk]
  3.1.403 [C:\Program Files\dotnet\sdk]
  3.1.406 [C:\Program Files\dotnet\sdk]
  5.0.100-preview.8.20417.9 [C:\Program Files\dotnet\sdk]
  5.0.103 [C:\Program Files\dotnet\sdk]
  5.0.200-preview.20601.7 [C:\Program Files\dotnet\sdk]
  6.0.100-preview.1.21103.13 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.0-preview.8.20414.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.0-preview.1.21103.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.0-preview.8.20407.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0-preview.1.21102.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.0-preview.8.20411.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.0-preview.1.21103.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs:
  https://aka.ms/dotnet-download

[javiercn]

@martincostello thanks for reporting this issue.

@captainsafia is this part of what we did in Mvc.Testing that you completed over christmas? Can you take a quick peak?

If you have cycles to fix it in preview2 that would be great

[captainsafia]

Yep -- I think I've tracked down the issue here. PR incoming.