Cannot benchmark netcoreapp3.0

[timcassell]

I got this error when trying to run a benchmark on CoreRuntime.Core30. Should BDN try to fix this and keep supporting older build targets, or just drop support?

// Build Error: Standard output:

 Standard error:
 MSBuild version 17.7.0-preview-23281-03+4ce2ff1f8 for .NET
C:\Users\Tim\.nuget\packages\system.runtime.compilerservices.unsafe\6.0.0\buildTransitive\netcoreapp2.0\System.Runtime.CompilerServices.Unsafe.targets(4,5): error : System.Runtime.CompilerServices.Unsafe doesn't support netcoreapp3.0. Consider updating your TargetFramework to netcoreapp3.1 or later. [C:\Users\Tim\Documents\git\ProtoPromiseBenchmarks\AsynchronousBenchmarks\bin\Release\net472\c449f68f-17cc-4372-a6f3-e6f7e2ae26c3\BenchmarkDotNet.Autogenerated.csproj]
Build FAILED.
C:\Users\Tim\.nuget\packages\system.runtime.compilerservices.unsafe\6.0.0\buildTransitive\netcoreapp2.0\System.Runtime.CompilerServices.Unsafe.targets(4,5): error : System.Runtime.CompilerServices.Unsafe doesn't support netcoreapp3.0. Consider updating your TargetFramework to netcoreapp3.1 or later. [C:\Users\Tim\Documents\git\ProtoPromiseBenchmarks\AsynchronousBenchmarks\bin\Release\net472\c449f68f-17cc-4372-a6f3-e6f7e2ae26c3\BenchmarkDotNet.Autogenerated.csproj]
    0 Warning(s)
    1 Error(s)
Time Elapsed 00:00:00.64

[adamsitnik]

Hi @timcassell !

This error comes from the SDK, as far as I know there is nothing we can do about it on our side.

Moreover, it seems to be related to netcoreapp2.0 version of the Unsafe package?

netcoreapp2.0\System.Runtime.CompilerServices.Unsafe

Which is not supported anymore, so I don't expect anyone to fix it on the SDK side.

[timcassell]

@adamsitnik If we really can't do anything about it, then core versions older than 3.1 should be removed. Otherwise, to make it work again, I think adding a netcoreapp2.0 BDN build target that uses older nuget package versions should do the trick.

cc @AndreyAkinshin

[Edit] Also the latest preview version of the Unsafe package dropped 3.1 support, so even 3.1 and 5.0 may stop working if it's updated.

[AndreyAkinshin]

@timcassell I think we can safely drop support of all .NET Core versions below 3.1 ("End of support" for 3.0 happened more than two years ago). Would you like to send a PR with proper fixes?

[timcassell]

@AndreyAkinshin Should we drop support for any core version below 6.0? Or only below 3.1?

[AndreyAkinshin]

Only below 3.1. Typically, we try to support all the old runtimes while it doesn't require additional maintenance efforts.

[adamsitnik]

If we really can't do anything about it, then core versions older than 3.1 should be removed.

But people can still use 3.1 SDK and it should work just fine.

My point is that if a newer SDK does not allow the users to build apps targeting older TFMs we can't do anything about it. But we should also not change the code, as people might still use older SDKs and everything should work fine.

[timcassell]

Using an older SDK doesn't make it work. It's a problem with the nuget package. I tried with sdk 3.0.103 and got the same error.

[adamsitnik]

@ViktorHofer does it mean that using newer version of packages like System.Runtime.CompilerServices.Unsafe that still target netstandard2.0 will actually not work for old tfm like netcoreapp3.1 etc?

[ViktorHofer]

Yes that behavior was introduced with .NET 6 packages: dotnet/announcements#190

• For .NET 7 packages the supported TFMs are net6.0 and net7.0
• For .NET 8 packages the supported TFMs are net6.0, net7.0 and net8.0
• Similarly for .NET 9 packages, the supported TFMs will be net8.0 and net9.0

Note that the .NET 6 packages emitted an error when being consumed on an unsupported TFM. We then later changed that to a warning.

[timcassell]

How does that explain the issue? Netcoreapp3.0 implements netstandard2.0, which the net6 packages still support, so why does it not just consume the netstandard2.0 dlls rather than error?

[ViktorHofer]

In the linked announcement it states that a .NET 6 package supports netcoreapp3.1, net5.0 and net6.0 but not netcoreapp3.0. Overall, netcoreapp3.0, netcoreapp3.1 and net5.0 are all out-of-support and shouldn't be used anymore.

[timcassell]

It also says that it supports netstandard2.0.