[Question] UnrecognizedCommandParsingException Help Txt

[JunFWu]

source code
McMaster.Extensions.CommandLineUtils CommandLineProcessor

   private bool ProcessUnexpectedArg(string argTypeName, string? argValue = null)
   {
       switch (_currentCommand.UnrecognizedArgumentHandling)
       {
           case UnrecognizedArgumentHandling.Throw:
               _currentCommand.ShowHint();
               var value = argValue ?? _enumerator.Current?.Raw;

               var suggestions = Enumerable.Empty<string>();

               if (_currentCommand.MakeSuggestionsInErrorMessage && !string.IsNullOrEmpty(value))
               {
                   suggestions = SuggestionCreator.GetTopSuggestions(_currentCommand, value);
               }

               throw new UnrecognizedCommandParsingException(_currentCommand, suggestions,
                   $"Unrecognized {argTypeName} '{value}'");

           case UnrecognizedArgumentHandling.CollectAndContinue:
               var arg = _enumerator.Current;
               if (arg != null)
               {
                   _currentCommand._remainingArguments.Add(arg.Raw);
               }
               return true;

           case UnrecognizedArgumentHandling.StopParsingAndCollect:
               // All remaining arguments are stored for further use
               AddRemainingArgumentValues();
               return false;
           default:
               throw new NotImplementedException();
       }
   }

when throw UnrecognizedCommandParsingException,this write Specify {flag} for a list of available options and commands.

come from _currentCommand.ShowHint();

What can I do to avoid the_currentCommand.ShowHint(); output while still throwing the 'UnrecognizedCommandParsingException' error

[natemcmaster]

@claude any suggestions?

[claude]

Claude finished @natemcmaster's task in 59s —— View job

---

Suggestions for suppressing ShowHint() output

• Review relevant source code
• Identify possible solutions
• Provide suggestions

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Good news — there's already a clean workaround. ShowHint() is a virtual method on CommandLineApplication (CommandLineApplication.cs:1002), so you can override it to suppress the output:

public class MyApp : CommandLineApplication
{
    public override void ShowHint()
    {
        // intentionally empty — suppress hint on unrecognized args
    }
}

Then use MyApp instead of CommandLineApplication when building your CLI.

If using the attribute API, you can pass your custom subclass as the context:

var app = new MyApp();
app.Conventions.UseDefaultConventions();
app.Execute(args);

---

Alternative approaches:

1. Catch and re-handle the exception — Use UnrecognizedArgumentHandling.Throw, catch UnrecognizedCommandParsingException in your own code, and print only what you want. The ShowHint() output goes to app.Out, so if you redirect Out to a StringWriter you could discard that output while still getting the exception.

2. Use CollectAndContinue — Set UnrecognizedArgumentHandling = UnrecognizedArgumentHandling.CollectAndContinue, then check RemainingArguments after parsing and throw your own error if any unrecognized args were collected.

The virtual override is the most straightforward option. If there's interest in a more first-class API (e.g., a ShowHintOnParsingError boolean property), that could be added as a feature, but the override approach works well today.