Getting wrong dotnet version

[JCash]

Description:
Our CI has started to fail because we get the new dotnet-10-rc version and not the 9.x version we specify.

Here's how we request the version:

{ name: 'Setup dotnet', uses: actions/setup-dotnet@v4, with: {dotnet-version: '9.x'}},

And here is the actual script that runs:

Run actions/setup-dotnet@v4
  with:
    dotnet-version: 9.x
    cache: false
    ...
/Users/runner/work/_actions/actions/setup-dotnet/v4/externals/install-dotnet.sh --skip-non-versioned-files --runtime dotnet --channel LTS
dotnet-install: Attempting to download using aka.ms link https://builds.dotnet.microsoft.com/dotnet/Runtime/10.0.0-rc.2.25502.107/dotnet-runtime-10.0.0-rc.2.25502.107-osx-arm64.tar.gz
...
/Users/runner/work/_actions/actions/setup-dotnet/v4/externals/install-dotnet.sh --skip-non-versioned-files --channel 9.0
dotnet-install: Attempting to download using aka.ms link https://builds.dotnet.microsoft.com/dotnet/Sdk/9.0.306/dotnet-sdk-9.0.306-osx-arm64.tar.gz

It seems related to #642

When I run dotnet, I clearly expect 9.x, not 10.x?
How am I supposed to get the correct version?

Task version:
Specify the task version

Platform:

• Ubuntu
• macOS
• Windows

Runner type:

• Hosted
• Self-hosted

Repro steps:
Add the action in your workflow:

{ name: 'Setup dotnet', uses: actions/setup-dotnet@v4, with: {dotnet-version: '9.x'}},

Expected behavior:
I expect the version to stay on 9.x.

Actual behavior:
I get dotnet 10 release candidate.

[priyagupta108]

Hello @JCash 👋,
Thank you for your report. We'll investigate the issue and get back to you with the details!

[priya-kinthali]

Hello @JCash👋,
Thank you for providing detailed reproduction steps.
Starting with setup-dotnet@v4, the installation process is designed to work as follows:

• Minimal Installation: The action first installs the latest .NET runtime, ensuring that the newest stable dotnet executable is always available.
• SDK Installation: It then installs the specific .NET SDK version you have requested (in this case, 9.x).

This approach addresses issue#387. In previous versions (setup-dotnet@v3), the .NET executable was overwritten on every action run, which could lead to failures if the executable was still in use. In setup-dotnet@v4, this has been resolved by installing the LTS version of the .NET executable, which is then used for all subsequent installations (see #433).

The appearance of the 10.0 RC (release candidate) in your logs is likely due to Microsoft temporarily pointing the LTS channel to the .NET 10.0 RC prior to the official LTS release. For further details and official updates, please refer to the Official .NET Downloads page and this thread for additional community context.

Could you please re-run your workflow and confirm whether the .NET 8 runtime is being installed alongside 9.x? Your feedback will help clarify if the workflow is now functioning as intended.

Thank you!