Unclear which part of long lines is being pointed to

[ysthakur]

With long lines that are wrapped, it's unclear which part of the line is being pointed to.

Here's a screenshot, as an example:

And as text:

Error: gen_completions::deser::kdl::duplicate_flag (link)

  × Error encountered while deserializing
  ╰─▶ Error encountered while reading command information
   ╭─[test.kdl:2:1]
 2 │     flags {
 3 │         "-h" "--very long string in between to make it span multiple lines aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" "-h" {
   ·         ──┬─                                                                                                                                                                   ──┬─
   ·           │                                                                                                                                                                      ╰── duplicate flag
   ·           ╰── already given here
 4 │             desc "foo bar baz"
   ╰────

As you can see, when my terminal wraps that long line, it can be hard to tell where exactly the span is pointing. Is there a way to underline or highlight the text covered by those spans? I checked out GraphicalTheme, but that doesn't seem to have a way to configure this. I guess I could write my own ReportHandler based off of miette's, but that would take effort.

If such a feature doesn't exist in miette but the maintainers are fine with adding it, I could try implementing it. Apologies if someone's asked about this already, but I couldn't find any issues.

[olivia-fl]

#20 is possibly related. My understanding of the idea with #20 is that we could trim snippets horizontally similar to the way we're currently trimming them vertically (by only rendering a few context lines around the span).

In your example, I'm imagining that might look something like this:

Error: gen_completions::deser::kdl::duplicate_flag (link)

  × Error encountered while deserializing
  ╰─▶ Error encountered while reading command information
   ╭─[test.kdl:2:1]
 2 │     flags {
 3 │         "-h" "--very long string ··· aaaaaa" "-h" {
   ·         ──┬─                                 ──┬─
   ·           │                                    ╰── duplicate flag
   ·           ╰── already given here
 4 │             desc "foo bar baz"
   ╰────

I think having an option in GraphicalTheme to highlight spans by swapping the fg/bg colors or with ansi underlines would be useful, even if the issues with long lines are solved another way. There was a great blog post I saw a while ago that recommended fg/bg swap as the default way to format compiler errors because it has a better shot at handling things like bidi text or misprediction of character display widths. I don't fully agree that it should be the default, but think it would be a good to support as an option. Unfortunately, I couldn't find the original post :(