Argument descriptions not aligned when mixing positional arguments with others under a help heading

[pemistahl]

Please complete the following tasks

• [X] I have searched the discussions
• [X] I have searched the open and rejected issues

Rust Version

rustc 1.61.0 (fe5b13d68 2022-05-18)

Clap Version

3.2.2

Minimal reproducible code

use clap::Parser;
use std::path::PathBuf;

#[derive(Parser)]
struct Cli {
    /// One or more test cases separated by blank space.
    #[clap(value_name = "INPUT", value_parser, help_heading = "INPUT")]
    input: Vec<String>,

    /// Reads test cases on separate lines from a file.
    #[clap(
        name = "file",
        value_name = "FILE",
        short,
        long,
        value_parser,
        help_heading = "INPUT"
    )]
    file_path: Option<PathBuf>
}

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

Steps to reproduce the bug with the above code

1. Compile the binary.
2. Print the help using binary -h.

Actual Behaviour

The help messages are not properly aligned.

INPUT:
    -f, --file <FILE>    Reads test cases on separate lines from a file
    <INPUT>...       One or more test cases separated by blank space

Expected Behaviour

The help messages should be properly aligned.

INPUT:
    -f, --file <FILE>    Reads test cases on separate lines from a file
    <INPUT>...           One or more test cases separated by blank space

Additional Context

I understand that proper alignment is not always possible or appropriate. Grouped arguments, however, should always be aligned correctly, in my opinion. The problem here is probably that help messages of flags are aligned differently than help messages of arguments receiving arbitrary input.

Debug Output

No response

[epage]

Thanks for reporting this!

Currently, our help output is making the assumption that positionals and named arguments are in separate sections. Supporting them in the same section will take a little bit of finagling to ensure all of the padding situations work out correctly especially to not over-pad in positional-only cases.

If we can reduce leading padding in long-flag only cases, that'd be a bonus to fixing this.