Allow hiding tab-completion values from help

[CurtisLusmore]

I have an argument for one of my commands which represents a path/ID to a resource. I want to be able to provide tab-completion to allow easily cycling between existing paths/IDs, but I don't want these values to be enumerated if I run --help for my command.

I'm thinking this could be an option on the CompletionItem object, like a boolean property called Hidden. You could then do something this like.

var myarg = new Option<string>("--id", "The id of the item to get");
myarg.AddCompletions(ctx => GetIdSuggestions(ctx));

private IEnumerable<CompletionItem> GetIdSuggestions(CompletionContext ctx)
    => GetExistingIds(prefix: ctx.WordToComplete).Select(id => new CompletionItem(id) { Hidden = true });

and then when you attempt to run the command from the terminal

app command --id <TAB>

it will cycle through existing IDs returned by my method, but when I run

app command --help

It will still only print out

Options:
 --id <id>   The id of the item to get

rather than

Options:
 --id <id1|id2|id3|id4|...>   The id of the item to get

[KalleOlaviNiemitalo]

You can hide the completions of the option argument from help by setting the ArgumentHelpName property. Help will still enumerate the completions though, just not display them. dotnet/sdk#27374 (comment), #2038

[CurtisLusmore]

Thanks! For the benefit of those who stumble upon this issue trying to do the same thing, the solution is to do the following

var myarg = new Argument<string>("arg", "An argument with completions") { HelpName = "arg" };
myarg.AddCompletions(/*...*/);
var myopt = new Option<string>("--opt", "An option with completions") { ArgumentHelpName = "opt" };
myopt.AddCompletions(/*...*/);

which will produce the following output when you run --help

Arguments:
  <arg>  An argument with completions

Options:
  --opt <opt>  An option with completions