Adding help alias modifies help command argument rendering?

[SUPERCILEX]

Adding #[clap(mut_arg("help", |arg| arg.short_alias('?')))] changes the way the help command is rendered. See this diff: SUPERCILEX/ftzz@6daf6aa. Seems like a bug that adding the alias makes the help command show up inside itself. Or not (as long as its consistent I don't mind).

[epage]

Could you follow the bug report template? Being able to have small reproduction cases, debug traces before/after, etc are a big help to triaging this.

[SUPERCILEX]

#!/usr/bin/env -S rust-script --debug

//! ```cargo
//! [dependencies]
//! clap = { version = "3.2.16", features = ["derive"] }
//! ```

use clap::{Parser, Subcommand};

#[derive(Parser)]
#[clap(mut_arg("help", |arg| arg.short_alias('?')))]
struct Cli {
  #[clap(subcommand)]
  command: Commands,
}

#[derive(Subcommand)]
enum Commands { Foo }

fn main() {
    let mut _command = Cli::parse();
}

Run:

$ ./foo.rs help help
foo_bcd390fa607fcb4d15f74b68-help 
Print this message or the help of the given subcommand(s)

USAGE:
    foo_bcd390fa607fcb4d15f74b68 help [SUBCOMMAND]...

ARGS:
    <SUBCOMMAND>...    The subcommand whose help message to display

OPTIONS:
    -h, --help    Print help information

[SUPERCILEX]

Note that $ ./foo.rs help -h doesn't work so those options shouldn't show up.

[epage]

FYI there are still parts of the template missing, like debug output.

My first guess is that this is because we do this

            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

but when we _build_self, we overwrite settings with global settings. We need to also set the global setting to disable it.

[epage]

Correction, the challenge is with

        {
            let generated_help_pos = self
                .args
                .args()
                .position(|x| x.id == Id::help_hash() && x.provider == ArgProvider::Generated);

            if let Some(index) = generated_help_pos {
                debug!("Command::_check_help_and_version: Removing generated help");
                self.args.remove(index);
            }

So if a user modifies it, it becomes GeneratedMutated.
The comments suggest that that is meant to deal with another problem,.