setup-dotnet in version 1.7.0 no longer works correctly for channel versions, such as 3.1 or 3.1.x

Description

setup-dotnet in version 1.7.0 no longer works correctly for channel versions, such as 3.1 or 3.1.x (which is interpreted the same).

Details

This is a regression. Version 1.6.0 is working fine. Example log output can be found here

Run actions/setup-dotnet@v1
  with:
    dotnet-version: 3.1
  env:
    CONFIGURATION: Release
    DOTNET_CLI_TELEMETRY_OPTOUT: 1
    DOTNET_NOLOGO: 1
    DOTNET_SDK_VERSION: 3.1
    NET_CORE_VERSION: netcoreapp3.1
    NET_FRAMEWORK_VERSION: net48
    NODE_JS_VERSION: 12
    STEAM_TOKEN_DUMPER_NAME: ArchiSteamFarm.OfficialPlugins.SteamTokenDumper
    STEAM_TOKEN_DUMPER_TOKEN: ***
/Users/runner/work/_actions/actions/setup-dotnet/v1/externals/install-dotnet.sh --version 3.1
dotnet-install: Downloading link: https://dotnetcli.azureedge.net/dotnet/Sdk/3.1/dotnet-sdk-3.1-osx-x64.tar.gz
curl: (22) The requested URL returned error: 404 Not Found
dotnet-install: Cannot download: https://dotnetcli.azureedge.net/dotnet/Sdk/3.1/dotnet-sdk-3.1-osx-x64.tar.gz
dotnet-install: Downloading legacy link: https://dotnetcli.azureedge.net/dotnet/Sdk/3.1/dotnet-dev-osx-x64.3.1.tar.gz
curl: (22) The requested URL returned error: 404 Not Found
dotnet-install: Cannot download: https://dotnetcli.azureedge.net/dotnet/Sdk/3.1/dotnet-dev-osx-x64.3.1.tar.gz
dotnet_install: Error: Could not find/download: `.NET Core SDK` with version = 3.1
dotnet_install: Error: Refer to: https://aka.ms/dotnet-os-lifecycle for information on .NET Core support
##[error]The process '/Users/runner/work/_actions/actions/setup-dotnet/v1/externals/install-dotnet.sh' failed with exit code 1

Example yaml file can be found here. Replacing @v1 (which points to 1.7.0 as of today) with @v1.6.0 fixes the issue, as can be verified here.

Let me know if you need more info. Judging from how easily it regressed in my setup, I believe there shouldn’t be too much trouble localizing the culprit. Thank you in advance for your interest.

[veilofsecurity]

Confirming all of our deployments are also broken now, commits this morning worked but latest ones failing.

[iris-hpaterson]

We’ve experienced this issue breaking the ${{ env.DOTNET_ROOT }} environment environment variable in Github Actions. The variable is either set empty or not set at all.

Actions provided by Microsoft Azure to deploy webapps depend on DOTNET_ROOT being set.

This also breaks version requests in the style dotnet-version: 3.1.x, which have to be hard pegged to a version.

We’ve hotfixed by rolling back to v1.6.0.