Libraries and runtime updates in .NET 9 Preview 4

[richlander]

Here's a summary of what's new in .NET Libraries in this preview release:

• New Tensor type
• Tokenizer library enhancements
• OpenTelemetry: Make activity linking more flexible
• PDB support for System.Reflection.Emit.PersistedAssemblyBuilder

Here's a summary of what's new in the .NET Runtime in this preview release:

• UnsafeAccessorAttribute supports generic parameters
• Feature switches with trimming support

Release notes:

• Libraries release notes
• Runtime release notes

.NET 9 Preview 4:

• Discussion
• Release notes
• What's new in .NET 9

[KalleOlaviNiemitalo]

"Tokenizer library enhancements" seems to refer to https://github.com/dotnet/machinelearning/tree/v4.0.0-preview1/src/Microsoft.ML.Tokenizers. Please consider linking from the release notes to https://dot.net/ml and https://learn.microsoft.com/dotnet/api/microsoft.ml.tokenizers.tokenizer?view=ml-dotnet-preview, to clarify what this is about; but the API changes after version 0.21.1 of the Microsoft.ML.Tokenizers package are not documented there yet.

[luisquintanilla]

cc: @tarekgh

[tarekgh]

I have created the PR dotnet/core#9327. Please let me know if you have any more comments. Thanks!

[KeterSCP]

https://github.com/dotnet/core/blob/main/release-notes/9.0/preview/preview4/libraries.md has invalid link to New Tensor<T> type. The link is #new-tensor-type, but it should be #new-tensort-type (notice the additional t)

[richlander]

Thanks for reporting.

dotnet/core#9330

[richlander]

FYI: The community is free to make PRs on release notes.

[ReneeGA2020]

It looks like dotnet workload install wasi-experimental always fail on Downloading Aspire.Hosting.Sdk.Msi.x64. I cannot install this workload in preview 4.

[richlander]

@lewing

[ReneeGA2020]

It worked now.

[Edited]
ok, not.

I reinstalled preview 4,and tried it again, it failed again.
Error NU3004, this package is unsigned: Aspire.Hosting.Sdk.Msi.x64.9.0.0-preview.2.24163.9

[richlander]

@baronfel

[ReneeGA2020]

Ok, I figured it out. In an earlier day, I added dotnet 9 package source into the global package manager.

https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet9/nuget/v3/index.json

It looks like this package source is no longer needed for preview 4, and was causing conflicts.

I'm now able to download and install dotnet 9 workloads correctly after deleted this package source.

[PaskalSunari]

I have installed preview 4 created the project with target framework net 9.0..But the build error is thrown while building the project.. does anybody has the solution for this error..

Severity Code Description Project File Line Suppression State
Error (active) NETSDK1045 The current .NET SDK does not support targeting .NET 9.0. Either target .NET 8.0 or lower, or use a version of the .NET SDK that supports .NET 9.0. Download the .NET SDK from https://aka.ms/dotnet/download MyFirstDotNet9WebApp C:\Program Files\dotnet\sdk\8.0.300\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.TargetFrameworkInference.targets 166

[huoyaoyuan]

To use a preview version of .NET SDK in Visual Studio, you should do either of following:

• Enable "Use previews of the .NET SDK" in Visual Studio Options->Environment->Preview Features
• Use a global.json that specifies the preview SDK version.