PAGER=batcat turns into a fork nightmare

[rsamuelklatchko]

I decided to make batcat my PAGER and when I tried setting:

PAGER=batcat

it didn't work. After some troubleshooting I realized that batcat was forking/execing itself and was able to fix it by also adding:

BAT_PAGER=less

while this solved the problem it was not obvious. One suggestion is when reading PAGER, if the value is the binary name (or ends with /{binary_name}) the value is ignored and the default is used instead.

[Enselic]

Thanks for reporting!

There is code to prevent that from happening, but it does not take into account that the binary can be called something other than bat.

See

bat/src/pager.rs

Lines 105 to 106 in 9287cf6

	// If PAGER=bat, silently use 'less' instead to prevent
	// recursion.

I would be happy to review PRs that solves this

[rsamuelklatchko]

My thought would be to modify PagerKind::from_bin to support other names. I have a couple of ideas:

1. Just add "batcat" (I'm on Debian which is what the binary is named) and possibly any other common alternate names if you know of any.
2. Find the name the binary is being run as using env::args.

For #2, I'm thinking to reuse

bat/src/pager.rs

Lines 43 to 46 in 9287cf6

	match Path::new(bin)
	.file_stem()
	.map(|s| s.to_string_lossy())
	.as_deref()

to get the name from env::args[0].

[Enselic]

My first choice would be 2., but the code to get the program name is something more like std::env::args().nth(0)

Or even better is std::env::args_os().nth(0) but that might require a bigger change

[rsamuelklatchko]

I have a code fix but having not used GitHub I'm not sure if exactly how to send it to you. What I'm suggesting is this:

impl PagerKind {
    fn from_bin(bin: &str) -> PagerKind {
        use std::path::Path;

        let file_stem = Path::new(bin).file_stem();

        match file_stem.map(|s| s.to_string_lossy()).as_deref() {
            Some("bat") => PagerKind::Bat,
            Some("less") => PagerKind::Less,
            Some("more") => PagerKind::More,
            Some("most") => PagerKind::Most,
            _ => {
                if env::args_os()
                    .nth(0)
                    .map(|arg0| Path::new(&arg0).file_stem() == file_stem)
                    .unwrap_or(false)
                {
                    PagerKind::Bat
                } else {
                    PagerKind::Unknown
                }
            }
        }
    }
}