clap_app macro incorrectly parses long argument with hyphen

[ghost]

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• Searched the closed issues

Code

use clap::clap_app;

fn main() {
    clap_app!(app =>
        (@arg proxy: -p --proxy [PROXY] "Use the specified proxy.")
        (@arg no_proxy: --no-proxy "Don't use a proxy.")
    );
}

Steps to reproduce the issue

Run cargo run.

Version

• Rust: rustc 1.48.0 (7eac88abb 2020-11-16)
• Clap: 2.33.3

Actual Behavior Summary

It panics with Argument short must be unique -p is already in use'.

Expected Behavior Summary

It should run without panicking.

Additional context

Replacing --no-proxy with --no_proxy fixes the issue. It parses it as --no and -p.

Debug output

No output.

[ghost]

This only happens with the clap_app macro, using App::arg works.

[ghost]

I found a workaround: By using stringify, the program works.
p.s. The rule in the macro causing the problem is on line 748 of src/macros.rs.

[ghost]

(@arg no_proxy --(stringify!(no-proxy)) /*...*/)

[pksunkara]

Can you please try it with master? You don't need stringify.

clap/src/macros.rs

Lines 385 to 401 in 3520a30

	(@arg ($arg:expr) $modes:tt --($long:expr) $($tail:tt)*) => {
	$crate::clap_app!{ @arg ($arg.long($long)) $modes $($tail)* }
	};
	(@arg ($arg:expr) $modes:tt --$long:literal $($tail:tt)*) => {
	$crate::clap_app!{ @arg ($arg.long(stringify!($long).trim_matches('"'))) $modes $($tail)* }
	};
	(@arg ($arg:expr) $modes:tt --$long:ident $($tail:tt)*) => {
	$crate::clap_app!{ @arg ($arg.long(stringify!($long))) $modes $($tail)* }
	};
	(@arg ($arg:expr) $modes:tt -($short:expr) $($tail:tt)*) => {
	$crate::clap_app!{ @arg ($arg.short($short)) $modes $($tail)* }
	};
	(@arg ($arg:expr) $modes:tt -$short:literal $($tail:tt)*) => {
	$crate::clap_app!{ @arg ($arg.short($short.to_string().chars().next().expect(r#""" is not allowed here"#))) $modes $($tail)* }
	};
	(@arg ($arg:expr) $modes:tt -$short:ident $($tail:tt)*) => {
	$crate::clap_app!{ @arg ($arg.short(stringify!($short).chars().next().unwrap())) $modes $($tail)* }

[ghost]

Using master, it works when I do (@arg no_proxy --"no-proxy" /*...*/).

[pksunkara]

Yup, that is the intention. There's no other workaround.