Suprised by error from is_not on empty result

[barskern]

I was suprised when using is_not that it errored when the resulting slice is empty, despite the fact that it finds the terminating character. I would think that it should only 'care' about finding the terminating character (similarly to take_till), and that it shouldn't enforce anything regarding the output. I assumed the following test case would hold. Is this the intended behaviour?

Prerequisites

Here are a few things you should provide to help me understand the issue:

• Rust version : rustc 1.78.0 (9b00956e5 2024-04-29)
• nom version : 7.1.3
• nom compilation features used: default

Test case

#[test]
fn nom_bytes_is_not_assumption() {
    use nom::Parser;

    let input = "\n";
    let mut p = nom::bytes::complete::is_not::<_, _, nom::error::VerboseError<&str>>("\r\n\t");
    let (rem, v) = p.parse(input).unwrap();

    assert_eq!("", v);
    assert_eq!(input, rem);
}

[docwilco]

is_not wants at least one character to match. It's basically is_not1 and not is_not0.

Now I would suggest making two parsers, is_not0 and is_not1. To make this distinction clear, and make it consistent with all the other foo0 and foo1 functions.