dotnet/command-line-api

Mutually exclusive options

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#381 opened on Jan 20, 2019

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 (16 comments) (14 reactions) (0 assignees)C# (3,665 stars) (421 forks)auto 404
Area-Parser and Binderenhancementhelp wanted

Description

It would be great to be able to handle mutually exclusive options.

Example

For example, if I had a command that either took an --all option or a --tenant <tenant-id> option, but never both.

public static Command Rebuild(IContainer container)
{
    var rebuild = new Command("rebuild", "Rebuilds a search index for one (--tenant <tenant-id>) or all (--all) tenants.")
    {
        Handler = CommandHandler.Create<bool, Guid>((all, tenant) =>
            container.Resolve<SearchRebuildTask>().ExecuteAsync(all, tenant))
    };

    rebuild.AddOption(new Option(new[] {"--all", "-a"},
        "Indicates if all tenants should be rebuilt.",
        new Argument<bool>(false) {Arity = ArgumentArity.ZeroOrOne}));

    rebuild.AddOption(new Option(new[] {"--tenant", "-t"},
        "Specifies the specific tenant that should be rebuilt.",
        new Argument<Guid> {Arity = ArgumentArity.ZeroOrOne}));

    return rebuild;
}

Contributor guide

Tech stack
csharp
Domain
cli
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Familiarity with .NET command line parsingUnderstanding of option validation patterns
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45
Research direction
Investigate how options are currently validated in System.CommandLine, starting with the Option class and the binding logic in the parser. Review the issue comments for any proposed designs or rejected approaches. The goal is to design a mechanism to define mutually exclusive option groups, likely by adding a property or validation rule that checks for conflicts at parse time. A good starting point is examining the existing validation in the Command and Option classes.