System.CommandLine 2.0.1 ships outdated reference assemblies (beta API surface instead of stable API)

[mstruys]

Description

While using System.CommandLine 2.0.1 on .NET 10, I noticed that the package exposes an API surface that does not match the documentation or the expected stable 2.0.1 API.

Even though the runtime assembly reports version 2.0.1.0, the compiler sees API signatures that match 2.0.0‑beta4, for example:

• Option<T>.Required exists, but IsRequired does not
• RootCommand.Options.Add(...) exists, but AddOption(...) does not
• RootCommand does not contain InvokeAsync
• SetHandler exists, but other 2.0.1 APIs are missing

This results in a hybrid API surface:
runtime = 2.0.1, reference assemblies = beta API.

Expected behavior

The 2.0.1 NuGet package should ship reference assemblies that match the documented 2.0.1 API, including:

• IsRequired
• AddOption
• InvokeAsync on RootCommand
• Updated command/handler patterns

Actual behavior

The compiler exposes the older beta API surface, while the runtime loads the 2.0.1 assembly. This causes documented samples to fail to compile and forces developers to fall back to beta-era APIs.

Reproduction steps

1. Create a new .NET 10 console project

2. Add:

   <PackageReference Include="System.CommandLine" Version="2.0.1" />
   

3. Attempt to use documented APIs such as IsRequired or AddOption.

4. Observe that the compiler reports these members do not exist.

5. Print the runtime assembly version:

   csharp Console.WriteLine(typeof(System.CommandLine.Command).Assembly.GetName().Version);
   

   Output:

   2.0.1.0

Environment

• .NET 10
• System.CommandLine 2.0.1
• Windows 11
• Reproducible in a clean project with no other dependencies

Impact

This mismatch makes it difficult to rely on the stable release, since:

• Documentation does not match the shipped API
• Code samples fail to compile
• Developers must fall back to beta-era APIs
• The package appears stable but behaves like a preview

Request

Please update the 2.0.1 package (or release a 2.0.2) with correct reference assemblies that match the intended stable API surface.

[KalleOlaviNiemitalo]

The Command.Add(Option) method is documented at https://learn.microsoft.com/en-us/dotnet/api/system.commandline.command.add?view=net-10.0-pp#system-commandline-command-add(system-commandline-option).

The Option.Required property is documented at https://learn.microsoft.com/en-us/dotnet/api/system.commandline.option.required?view=net-10.0-pp.

Where do you see documentation of AddOption and IsRequired?