Inconsistent Roslyn version in .NET SDK 10.0.100 depending on source

[addabis]

Describe the bug

.NET 10.0.100 SDK contains inconsistently targeted Roslyn (under <sdkroot>/Roslyn/bincore) on Ubuntu 22.04 x64, depending on how you install the SDK.

This matters because of analyzers and their references.

Is assuming that within one version of the SDK, the compiler will have same target correct?

To Reproduce

Aptitude: sudo apt install dotnet-sdk-10.0 - this contains Roslyn that targets net10.0
Web: wget https://builds.dotnet.microsoft.com/dotnet/Sdk/10.0.100/dotnet-sdk-10.0.100-linux-x64.tar.gz - this contains Roslyn that targets net9.0

Web downloads seem to be consistent across OSs.

Further details

Look at the target framework (or referenced assemblies) of <sdkroot>/Roslyn/bincore/Microsoft.CodeAnalysis.CSharp.dll.

[jjonescz]

I think this is by design, Roslyn has different target frameworks in source build (which is what goes into apt afaik) and other builds. Those target frameworks are defined in https://github.com/dotnet/roslyn/blob/main/eng/targets/TargetFrameworks.props.

cc @jaredpar

This matters because of analyzers and their references.

Can you elaborate on this? If your analyzers depend on the lower of those versions, they will work. In other contexts, even older system assemblies might be loaded (for example, in Visual Studio, I think your analyzers won't work if they don't target net8.0 or lower). In general, it is recommended for analyzers to target netstandard2.0 if you want them loadable in .NET Framework hosts too (VS 2022, for example).

[jaredpar]

Is assuming that within one version of the SDK, the compiler will have same target correct?

No. This is not a goal of the compiler at the moment. The only guarantee is that all the TF used by the compiler will be compatible with the runtime corresponding with the .NET SDK.

Note: in the future it's likely that we will switch to a model where the TF match the TF of the .NET SDK. There were reasons this was extremely hard before. Now that we're in unified build though, it's a much more achievable goal.

.NET 10.0.100 SDK contains inconsistently targeted Roslyn (under /Roslyn/bincore) on Ubuntu 22.04 x64, depending on how you install the SDK.

What TF are you seeing?

[addabis]

If this is by design, I don't have anything else to add, and you can close this.

@jaredpar As I write further down, the .NET 10.0.100 SDK tarball on Microsoft's download page targets net9.0, and the build available in apt has net10.0.

[jaredpar]

Ah okay. You're referring to inconsistencies between the TFM in different distributions of the .NET 10 SDK, not that DLLs within a given SDK having different TFMs. That is also expected. The individual Linux distributions maintain their own build of the .NET SDK and they make some tweaks like that which aren't intended to impact the execution of the .NET SDK.

Overall though this should normalize out in .NET 11 timeframe. Our expectation is that at that point we will be shipping binaries that are TFM aligned with the .NET SDK.