Feature request: Support major.minor in global.json for aspnetcore

[mconnew]

• This issue is blocking
• This issue is causing unreasonable pain

There is currently no mechanism such as darc/maestro to automatically keep up to date the version of aspnetcore that is referenced in a global.json. The dotnet/wcf repo has a global.json file that looks similar to the following:

{
  "tools": {
    "dotnet": "10.0.100",
    "runtimes": {
      "aspnetcore": [
        "8.0.22",
        "10.0.1"
      ]
    }
  },
  "sdk": {
    "version": "10.0.100"
  },
  "msbuild-sdks": {
    "Microsoft.DotNet.Arcade.Sdk": "11.0.0-beta.25615.1",
    "Microsoft.DotNet.Helix.Sdk": "11.0.0-beta.25615.1"
  }
}

It's a manual process to keep updating the aspnetcore version as new releases come out, and as a result often gets missed, sometimes for long durations of time. It would be sufficient for WCF's needs to simply support specifying major.minor for the versions and automatically using the latest version that's available.

[akoeplinger]

This will need some changes in

arcade/src/Microsoft.DotNet.Arcade.Sdk/src/InstallDotNetCore.cs

Lines 78 to 128 in 47a8a69

	if (runtimeItems.Count > 0)
	{
	System.Linq.ILookup<string, ProjectProperty> properties = null;
	// Only load Versions.props if there's a need to look for a version identifier (ie, there's a value listed that's not a parsable version).
	if (runtimeItems.SelectMany(r => r.Value).Select(r => r.Key).FirstOrDefault(f => !SemanticVersion.TryParse(f, out SemanticVersion version)) != null)
	{
	if (!File.Exists(VersionsPropsPath))
	{
	Log.LogError($"Unable to find translation file {VersionsPropsPath}");
	return !Log.HasLoggedErrors;
	}
	else
	{
	var proj = Project.FromFile(VersionsPropsPath, new Build.Definition.ProjectOptions() { ProjectCollection = new ProjectCollection() });
	properties = proj.AllEvaluatedProperties.ToLookup(p => p.Name, StringComparer.OrdinalIgnoreCase);
	}
	}
	foreach (var runtimeItem in runtimeItems)
	{
	foreach (var item in runtimeItem.Value)
	{
	string architecture = GetArchitecture(item.Value);
	if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && string.Equals("x86", architecture, StringComparison.OrdinalIgnoreCase))
	{
	Log.LogMessage(MessageImportance.Low, "Skipping installing x86 runtimes because this is a non-Windows platform and .NET Core x86 is not currently supported on any non-Windows platform.");
	continue;
	}
	SemanticVersion version = null;
	// Try to parse version
	if (!SemanticVersion.TryParse(item.Key, out version))
	{
	var propertyName = item.Key.Trim(s_keyTrimChars);
	// Unable to parse version, try to find the corresponding identifier from the MSBuild loaded MSBuild properties
	ProjectProperty property = properties[propertyName].FirstOrDefault();
	if (property == null)
	{
	Log.LogError($"Unable to find '{item.Key}' in properties defined in '{VersionsPropsPath}'");
	}
	else if (!SemanticVersion.TryParse(property.EvaluatedValue, out version))
	{
	Log.LogError($"Unable to parse '{item.Key}' from properties defined in '{VersionsPropsPath}'");
	}
	}
	if (version != null)
	{
	string arguments = $"-runtime \"{runtimeItem.Key}\" -version \"{version.ToNormalizedString()}\"";

We need to detect a two-part version like "8.0" or "10.0" and then pass that to the -channel parameter of the dotnet-install script instead of -version: https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-install-script#options

-Channel|--channel <CHANNEL>

Specifies the source channel for the installation. The possible values are:

STS: The most recent Standard Term Support release.
LTS: The most recent Long Term Support release.
Two-part version in A.B format, representing a specific release (for example, 3.1 or 8.0).
Three-part version in A.B.Cxx format, representing a specific SDK release (for example, 8.0.1xx or 8.0.2xx). Available since the 5.0 release.
The version parameter overrides the channel parameter when any version other than latest is used.