Underscore derive options converted to hyphen?

[ristillu]

Please complete the following tasks

• I have searched the discussions
• I have searched the open and rejected issues

Rust Version

rustc 1.59.0 (9d1b2106e 2022-02-23)

Clap Version

{ version = "3.1.6", features = ["derive"] }

Minimal reproducible code

extern crate clap;

use clap::{ArgEnum, Parser};

#[derive(Debug, Parser)]
struct Args {
    #[clap(
        short,
        long,
        multiple_occurrences(true),
        multiple_values(true),
        required = true,
        arg_enum
    )]
    filters: Vec<Filter>,
}

#[derive(ArgEnum, Clone, Debug)]
#[allow(non_camel_case_types)]
enum Filter {
    filter1,
    filter1_option1,
    filter1_option2,
    filter2,
    filter2_option1,
    filter2_option2,
}

fn main() {
    let args = Args::parse();
    println!("args: {:?}", args);
}

Steps to reproduce the bug with the above code

cargo build && target/debug/prog -f filter1_option1

Actual Behaviour

error: "filter1_option1" isn't a valid value for '--filters <FILTERS>...'
	[possible values: filter1, filter1-option1, filter1-option2, filter2, filter2-option1, filter2-option2]

	Did you mean "filter1-option1"?

USAGE:
    prog --filters <FILTERS>...

For more information try --help

Expected Behaviour

args: Args { filters: [filter1_option1] }

Additional Context

I get the Expected Behaviour when I flip things and invoke the program with a hyphen, like target/debug/prog -f filter1-option1. My domain users will be familiar with the underscore format so that's what I want to constrain them to and that's what matches options that my enum will match in other aspects of my full fledged program where I noticed this behaviour.

Debug Output

[        clap::build::command] 	App::_do_parse
[        clap::build::command] 	App::_build
[        clap::build::command] 	App::_propagate:prog
[        clap::build::command] 	App::_check_help_and_version: prog
[        clap::build::command] 	App::_check_help_and_version: Removing generated version
[        clap::build::command] 	App::_propagate_global_args:prog
[        clap::build::command] 	App::_derive_display_order:prog
[  clap::build::debug_asserts] 	Command::_debug_asserts
[  clap::build::debug_asserts] 	Arg::_debug_asserts:help
[  clap::build::debug_asserts] 	Arg::_debug_asserts:filters
[  clap::build::debug_asserts] 	Command::_verify_positionals
[         clap::parse::parser] 	Parser::get_matches_with
[         clap::parse::parser] 	Parser::get_matches_with: Begin parsing 'RawOsStr("-f")' ([45, 102])
[         clap::parse::parser] 	Parser::get_matches_with: Positional counter...1
[         clap::parse::parser] 	Parser::get_matches_with: Low index multiples...false
[         clap::parse::parser] 	Parser::possible_subcommand: arg=RawOsStr("-f")
[         clap::parse::parser] 	Parser::get_matches_with: sc=None
[         clap::parse::parser] 	Parser::parse_short_arg: short_arg=RawOsStr("f")
[         clap::parse::parser] 	Parser::parse_short_arg:iter:f
[         clap::parse::parser] 	Parser::parse_short_arg:iter:f: cur_idx:=1
[         clap::parse::parser] 	Parser::parse_short_arg:iter:f: Found valid opt or flag
[         clap::parse::parser] 	Parser::parse_short_arg:iter:f: val=RawOsStr("") (bytes), val=[] (ascii), short_arg=RawOsStr("f")
[         clap::parse::parser] 	Parser::parse_opt; opt=filters, val=None
[         clap::parse::parser] 	Parser::parse_opt; opt.settings=ArgFlags(REQUIRED | MULTIPLE_OCC | TAKES_VAL | MULTIPLE_VALS | MULTIPLE)
[         clap::parse::parser] 	Parser::parse_opt; Checking for val...
[         clap::parse::parser] 	Parser::parse_opt: More arg vals required...
[         clap::parse::parser] 	Parser::remove_overrides: id=filters
[    clap::parse::arg_matcher] 	ArgMatcher::inc_occurrence_of_arg: id=filters
[        clap::build::command] 	App::groups_for_arg: id=filters
[        clap::build::command] 	App::groups_for_arg: id=filters
[         clap::parse::parser] 	Parser::get_matches_with: After parse_short_arg Opt(filters)
[         clap::parse::parser] 	Parser::get_matches_with: Begin parsing 'RawOsStr("filter1_option1")' ([102, 105, 108, 116, 101, 114, 49, 95, 111, 112, 116, 105, 111, 110, 49])
[         clap::parse::parser] 	Parser::get_matches_with: Positional counter...1
[         clap::parse::parser] 	Parser::get_matches_with: Low index multiples...false
[         clap::parse::parser] 	Parser::add_val_to_arg; arg=filters, val=RawOsStr("filter1_option1")
[         clap::parse::parser] 	Parser::add_val_to_arg; trailing_values=false, DontDelimTrailingVals=false
[         clap::parse::parser] 	Parser::add_single_val_to_arg: adding val..."filter1_option1"
[         clap::parse::parser] 	Parser::add_single_val_to_arg: cur_idx:=2
[        clap::build::command] 	App::groups_for_arg: id=filters
[    clap::parse::arg_matcher] 	ArgMatcher::needs_more_vals: o=filters
[      clap::parse::validator] 	Validator::validate
[         clap::parse::parser] 	Parser::add_defaults
[         clap::parse::parser] 	Parser::add_defaults:iter:filters:
[         clap::parse::parser] 	Parser::add_value: doesn't have conditional defaults
[         clap::parse::parser] 	Parser::add_value:iter:filters: doesn't have default vals
[         clap::parse::parser] 	Parser::add_value:iter:filters: doesn't have default missing vals
[      clap::parse::validator] 	Validator::validate: needs_val_of=filters
[      clap::parse::validator] 	Validator::validate_conflicts
[      clap::parse::validator] 	Validator::validate_exclusive
[      clap::parse::validator] 	Validator::validate_exclusive:iter:filters
[      clap::parse::validator] 	Validator::validate_conflicts::iter: id=filters
[      clap::parse::validator] 	Conflicts::gather_conflicts
[      clap::parse::validator] 	Validator::validate_required: required=ChildGraph([Child { id: filters, children: [] }])
[      clap::parse::validator] 	Validator::gather_requires
[      clap::parse::validator] 	Validator::gather_requires:iter:filters
[      clap::parse::validator] 	Validator::validate_required_unless
[      clap::parse::validator] 	Validator::validate_matched_args
[      clap::parse::validator] 	Validator::validate_matched_args:iter:filters: vals=Flatten {
    inner: FlattenCompat {
        iter: Fuse {
            iter: Some(
                Iter(
                    [
                        [
                            "filter1_option1",
                        ],
                    ],
                ),
            ),
        },
        frontiter: None,
        backiter: None,
    },
}
[      clap::parse::validator] 	Validator::validate_arg_num_vals
[      clap::parse::validator] 	Validator::validate_arg_values: arg="filters"
[      clap::parse::validator] 	Validator::validate_arg_values: possible_vals=[PossibleValue { name: "filter1", help: None, aliases: [], hide: false }, PossibleValue { name: "filter1-option1", help: None, aliases: [], hide: false }, PossibleValue { name: "filter1-option2", help: None, aliases: [], hide: false }, PossibleValue { name: "filter2", help: None, aliases: [], hide: false }, PossibleValue { name: "filter2-option1", help: None, aliases: [], hide: false }, PossibleValue { name: "filter2-option2", help: None, aliases: [], hide: false }]
[         clap::output::usage] 	Usage::create_usage_with_title
[         clap::output::usage] 	Usage::create_usage_no_title
[         clap::output::usage] 	Usage::create_help_usage; incl_reqs=true
[         clap::output::usage] 	Usage::get_required_usage_from: incls=[], matcher=false, incl_last=false
[         clap::output::usage] 	Usage::get_required_usage_from: unrolled_reqs={filters}
[         clap::output::usage] 	Usage::get_required_usage_from:iter:filters
[         clap::output::usage] 	Usage::get_required_usage_from: ret_val=["--filters <FILTERS>..."]
[         clap::output::usage] 	Usage::needs_options_tag
[         clap::output::usage] 	Usage::needs_options_tag:iter: f=help
[         clap::output::usage] 	Usage::needs_options_tag:iter Option is built-in
[         clap::output::usage] 	Usage::needs_options_tag:iter: f=filters
[         clap::output::usage] 	Usage::needs_options_tag:iter Option is required
[         clap::output::usage] 	Usage::needs_options_tag: [OPTIONS] not required
[         clap::output::usage] 	Usage::create_help_usage: usage=prog --filters <FILTERS>...
[        clap::build::command] 	App::color: Color setting...
[        clap::build::command] 	Auto
error: "filter1_option1" isn't a valid value for '--filters <FILTERS>...'
	[possible values: filter1, filter1-option1, filter1-option2, filter2, filter2-option1, filter2-option2]

	Did you mean "filter1-option1"?

USAGE:
    prog --filters <FILTERS>...

For more information try --help

[epage]

By default, clap switches the case to follow common conventions. To customize this, see rename_all and name attributes in the reference.

[ristillu]

Thanks @epage. That solves my question. Apologies for not finding the answer myself - I searched for keywords "hyphen" and "underscore" when I needed to search for things like "snake-case" and "kebab-case".