Fix wide_bar width computation with a multiline message

[glehmann]

Before this PR, the whole width of the message was used to compute the bar width, making the bar very small or invisible.
In practice, only the first line of the message should have an impact on the bar width.

[djc]

Nice catch!

Is it always the first line, or is it the line in which the bar appears?

[djc]

I think spelling it like this would be easier to understand:

&match cur.split_once('\n') {
     Some((first, _)) => first,
     None => &cur,
}.replace('\x00', "")

[glehmann]

Is it always the first line, or is it the line in which the bar appears?

I suppose it can be anywhere, indeed.

So maybe rather split the text in lines, find the line with \x00 and measure its width?

[djc]

I think we should be able to hoist the measure_text_width() call out of the match? I also don't think it makes sense to take a & of the scrutinee.

[glehmann]

I think the & just after the match can be removed. I though clippy would have complained about that…

measure_text_width(s: &str) forces us to pass a reference.

line.replace() returns a String so we would have to cur.clone() in the other match arm if we want to put the measure_text_width() out of the match.
I suppose we could use a variable outside the match to hold the output of line.replace(), but that would be less compact code and would not be more efficient.

        let line0;
        let left = (width as usize).saturating_sub(measure_text_width(
            match cur.lines().find(|line| line.contains('\x00')) {
                Some(line) => {
                    line0 = line.replace('\x00', "");
                    &line0
                }
                None => &cur,
            },
        ));

[glehmann]

thanks!