Version 17.14.0 fails to run on Net 6

[sm-cdecker]

We have a few packages we haven't upgraded yet and our pipeline failed to build and test this morning due to the major upgrade from 17.13.0 to 17.14.0.
I know Net 6 is end of life and no longer supported, but I didn't expect a major version to break compatibility.

Microsoft.VisualStudio.TestPlatform.ObjectModel.TestPlatformException: Could not find testhost
   at Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Hosting.DotnetTestHostManager.GetTestHostProcessStartInfo(IEnumerable`1 sources, IDictionary`2 environmentVariables, TestRunnerConnectionInfo connectionInfo) in /_/src/Microsoft.TestPlatform.TestHostProvider/Hosting/DotnetTestHostManager.cs:line 410
   at Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.ProxyOperationManager.SetupChannel(IEnumerable`1 sources, String runSettings) in /_/src/Microsoft.TestPlatform.CrossPlatEngine/Client/ProxyOperationManager.cs:line 223
   at Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.ProxyDiscoveryManager.InitializeDiscovery(DiscoveryCriteria discoveryCriteria, ITestDiscoveryEventsHandler2 eventHandler, Boolean skipDefaultAdapters) in /_/src/Microsoft.TestPlatform.CrossPlatEngine/Client/ProxyDiscoveryManager.cs:line 149

[nohwnd]

VSTest is not following semantic versioning, it is following VisualStudio versioning (sadly). NET6 tfm is end-of-life for a while, you should be able to stick with microsoft.net.test.sdk 17.13.0 for a (long) while.

Can you tell me more about the crash and what exactly you updated? Which packages or which product?

[Varorbc]

I have the same issue, too. I am using .NET 6.0 and the following packages

    <PackageReference Include="coverlet.collector" Version="6.0.4" />
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.0" />
    <PackageReference Include="xunit" Version="2.9.3" />
    <PackageReference Include="xunit.runner.visualstudio" Version="3.0.2" />

[Varorbc]

I have a little doubt that Microsoft.NET.Test.Sdk clearly requires net8.0, why can it be installed by net6.0?

[nohwnd]

I think this is unfortunate "feature" of the package, it also did nothing for years for .net framework 4 (until code coverage was added to it as dependency), but it was still able to restore with it, because it is a common combo of multi tfms, so you probably don't want to condition it.

I am assuming there is no warning because of the buildMulitTargeting, will try.

[Varorbc]

Although it is a multi tfms, it is targeted at net462 and net8.0. However, net6.0 is lower than net8.0. I still don't understand why it can be installed normally

[ForNeVeR]

Folks I think I know what the problem is!

All the havoc is likely caused by the fact that nuget thinks in can use net462-compatible version in .NET 6 (and .NET 7) projects.

It formally should work, but in runtime it apparently doesn't.

It breaks test runs in VS and in dotnet test, I see this across my other repositories targeting .NET 7 and .NET 6 (probably earlier versions as well).

Yes, I should probably update these projects, but obviously Microsoft.NET.Test.Sdk is not designed to work in this way.

I believe that the easiest way to fix it would be to (temporarily?) restore compat with net6 in 17.14.1, and then think how to work around it in the future builds.

[ForNeVeR]

I assume the same problem will happen to those poor souls using netcoreapp3.1 and net5.0 as well, because 17.13.0 was compatible with all these as well. This was a big bump in the compatibility level indeed.

[Varorbc]

All the havoc is likely caused by the fact that nuget thinks in can use net462-compatible version in .NET 6 (and .NET 7) projects.

@ForNeVeR I published a package for net462 and net8.0 myself, and found that it cannot be installed by net6.0. I don't know what magic is in the Microsoft.NET.Test.Sdk package.

[nohwnd]

We had non-specific buildMultitargeting which makes it show no warning. When I changed that it started giving warning about restoring via net462, because of $(AssetTargetFallback) https://learn.microsoft.com/en-us/nuget/consume-packages/package-references-in-project-files#assettargetfallback

So the package will happily restore with .net framework, but will show warning.

In the PR above I am adding a specific warning that allows you to suppress it if you want to do that, it should warn on all unsupported frameworks.

[nohwnd]

I published a package for net462 and net8.0 myself, and found that it cannot be installed by net6.0. I don't know what magic is in the Microsoft.NET.Test.Sdk package.

Can you show that nuget? I don't think we do any magic regarding that.

[Varorbc]

@nohwnd I just renamed Microsoft.NET.Test.Sdk and uploaded it to the private source, and then it couldn't be installed normally. I think this is the expected behavior

[nohwnd]

What is the warnings you are seeing? I would expect the target files to complain about not being named correctly if you rename the package.

[Varorbc]

Warnings from the net framework cannot be referenced