Allow specifying 'latest' as dotnet-version

[CamJN]

Description:
A workflow with the following would install the latest major version of dotnet.

    - name: Setup .NET
      uses: actions/setup-dotnet@v4
      with:
        dotnet-version: latest

Justification:
It would be nice to be able to just stick latest in the dotnet-version field and not have to update the tag when a new major version comes out. This is available in the node and ruby setup actions and is quite nice.

Are you willing to submit a PR?
Unlikely.

[aparnajyothi-y]

Hello @CamJN,
Thank you for creating this issue, we will investigate it and come back to you as soon as we have some feedback.

[kevinoid]

I'd also appreciate this feature. For reference, it is currently possible to install the latest LTS version with:

    - name: Setup .NET
      uses: actions/setup-dotnet@v4
      with:
        dotnet-version: x

Unfortunately, this always installs a version from the LTS channel due to

setup-dotnet/src/installer.ts

Lines 77 to 78 in 3e891b0

	// If "dotnet-version" is specified as *, x or X resolve latest version of .NET explicitly from LTS channel. The version argument will default to "latest" by install-dotnet script.
	this.resolvedArgument.value = 'LTS';

[vRune4]

I'm utterly confused.

AFAICT the docs state that the latest SDK should be able to build projects that target older versions.

So why would I ever want to lock down the SDK version? Isn't the 80% use case that you'd want to build using the latest project and not have to mess around with strange global.json files?

I have a reusable workflow shared by several projects. These projects will gradually move towards whatever is the latest .net version. They currently do not have a global.json file. I see dependabot can be used to update global.json. (again: why would I want this? Just use the latest SDK already!)

[guardrex]

It's been a year, would someone prioritize this for work? Having to update the version every .NET SDK major release is a pain, and this Action is now being used by an official Microsoft samples repo (dotnet/blazor-samples).

[ericsampson]

useless comment, but good to see @guardrex still fighting to make things better after all these years 👍

[Frulfump]

Is latest here referring to (public) preview, latest stable or latest nightly (called daily for the quality with this action) build? I'd like all three of those options to be available. I think it makes most sense if "latest" by default means latest stable and then use a channel option to control if you get the others. EDIT: Also seems like there's an additional option supported in the install script called -Quality | ----quality
https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-install-script#options

docs for --quality

Downloads the latest build of the specified quality in the channel. The possible values are: daily, preview, and GA.

The different quality values signal different stages of the release process of the SDK or Runtime installed.

daily: The latest builds of the SDK or Runtime. They're built every day and aren't tested. They aren't recommended for production use but can often be used to test specific features or fixes immediately after they are merged into the product. These builds are from the dotnet/installer repo, and so if you're looking for fixes from dotnet/sdk you must wait for code to flow and be merged from SDK to Installer before it appears in a daily build.
preview: The monthly public releases of the next version of .NET, intended for public use. Not recommended for production use. Intended to allow users to experiment and test the new major version before release.
GA: The final stable releases of the .NET SDK and Runtime. Intended for public use as well as production support.

The --quality option works only in combination with --channel, but is not applicable for the STS and LTS channels and will be ignored if one of those channels is used.

For an SDK installation, use a channel value that is in A.B or A.B.Cxx format. For a runtime installation, use channel in A.B format.

Don't use both version and quality parameters. When quality is specified, the script determines the proper version on its own.

Available since the 5.0 release.

Sadly there isn't much attention paid to either issues or community PRs for this repo so I think it's better to either fork this repo or just use the install scripts from Microsoft directly. https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-install-script I wonder why they don't let GitHub Copilot try to fix the currently 34 open issues and review the currently 22 open PRs, we could be done within a week.