Add help option to list --help output

[sfoslund]

From manual testers: On Windows

Run "dotnet-core-uninstall list": it does not have the option "-h|--help", but using "dotnet-core-uninstall list --help" can work well.

[NikiforovAll]

I've investigated this issue. It looks like there is nothing wrong with the source code but rather System.CommandLine.Experimental being outdated.

using System;
using System.CommandLine;
using System.CommandLine.Builder;
using System.CommandLine.Invocation;

class Program
{
    static void Main()
    {
        var root = new RootCommand("test-description");
        root.Handler = CommandHandler.Create(() => { });
        var UninstallCommandParser = new CommandLineBuilder(root)
                    .UseDefaults()
                    .UseVersionOption() // this is redundant
                    .Build();

        UninstallCommandParser.Invoke(Environment.GetCommandLineArgs());
    }
}

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <AssemblyName>dotnet-core-uninstall</AssemblyName>
    <OutputType>Exe</OutputType>
    <RuntimeIdentifiers>win-x86;osx-x64</RuntimeIdentifiers>
    <SignAssembly>true</SignAssembly>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>

  <PropertyGroup>
    <LangVersion>preview</LangVersion>
    <RootNamespace>Microsoft.DotNet.Tools.Uninstall</RootNamespace>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="System.CommandLine.Experimental" Version="0.3.0-alpha.*" />
    <PackageReference Include="System.CommandLine.Rendering" Version="0.3.0-alpha.19573.2" />
  </ItemGroup>
</Project>

root ➜ /demo $ .dotnet/dotnet run -- -h
dotnet-core-uninstall:
  test-description

Usage:
  dotnet-core-uninstall [options]

Options:
  --version    Display version information

---

E.g.

  <ItemGroup>
    <PackageReference Include="System.CommandLine.Experimental" Version="2.0.0-beta1.*" />
    <PackageReference Include="System.CommandLine.Rendering" Version="0.3.0-alpha.19573.2" />
  </ItemGroup>

[sfoslund]

@NikiforovAll thanks for looking into this! If you want to make a PR to update I would be happy to review, otherwise I'll fix this in our next release.

[NikiforovAll]

I would be glad to contribute!

[NikiforovAll]

I plan to upgrade the System.CommandLine package:

-   <PackageReference Include="System.CommandLine.Experimental" Version="0.3.0-alpha.19573.2" />
+   <PackageReference Include="System.CommandLine" Version="2.0.0-beta1.20574.7" />

It will lead to the next changes:

.\dotnet-core-uninstall.exe whatif -h
dry-run:
  Display .NET Core SDKs and Runtimes that will be removed.

Usage:
  dotnet-core-uninstall dry-run [options] [<VERSION>...]

Arguments:
  <VERSION>    The specified version to uninstall. You may list several versions. Response files are
               supported.

Options:
  --all                          Remove all .NET Core SDKs or Runtimes. (*)
  --all-below <VERSION>          Remove .NET Core SDKs or Runtimes below the specified version. The
                                 specified version will remain. (*)
  --all-but <VERSIONS>           Remove .NET Core SDKs or Runtimes, except those specified. (*)
  --all-but-latest               Remove .NET Core SDKs or Runtimes, except the one highest version. (*)
  --all-lower-patches            Remove .NET Core SDKs or Runtimes superseded by higher patches.
                                 Protects global.json. (*)
  --all-previews                 Remove .NET Core SDKs or Runtimes marked as previews. (*)
  --all-previews-but-latest      Remove .NET Core SDKs or Runtimes marked as previews, except the one
                                 highest preview. (*)
  --aspnet-runtime               Remove ASP.NET Core Runtimes only.
  --force                        Force removal of versions that might be used by Visual Studio.
  --hosting-bundle               Remove .NET Core Runtime & Hosting Bundles only.
  --major-minor <MAJOR_MINOR>    Remove .NET Core SDKs or Runtimes that match the specified
                                 `major.minor` version.
  --runtime                      Remove .NET Core Runtimes only.
  --sdk                          Remove .NET Core SDKs only.
  -v, --verbosity <LEVEL>        Set the verbosity level. Allowed values are q[uiet], m[inimal],
                                 n[ormal], d[etailed], and diag[nostic].
  --x64                          Can be used with --sdk, --runtime and --aspnet-runtime to remove x64.
  --x86                          Can be used with --sdk, --runtime and --aspnet-runtime to remove x86.
+  -?, -h, --help                 Show help and usage information

(*) By default, SDKs and Runtimes that have a high probability of being used by Visual Studio are not removed. To remove these, specify them individually or use --force. If removing SDKs or Runtimes causes issues with your installation of Visual Studio, run "Repair". SDKs and Runtimes are available for download at aka.ms/dotnet-core-download.

Regarding the --version option. It is expected behavior for subcommand to hide it. Please see https://github.com/dotnet/command-line-api/blob/main/src/System.CommandLine.Tests/VersionOptionTests.cs#L110 for more details.

[NikiforovAll]

I'm sorry for inconvenience, but I won't have spare time for that in nearest future.

[sfoslund]

I'm sorry for inconvenience, but I won't have spare time for that in nearest future.

No problem, I can take over the PR, thanks for your help!