Order-preserving error reporting

[yannham]

Currently, the order in which labels are displayed depends on the respective position of the annotated snippets in the source.
For example, if I do:

let mut files = Files::new();
let id = files.add("<test>", "line 1\nline 2");
let writer = StandardStream::stderr(ColorChoice::Always);
let config = codespan_reporting::term::Config::default();
codespan_reporting::term::emit(&mut writer.lock(), &config, &files, &diag).unwrap();

let diag = Diagnostic::error()
    .with_message("Test bad order")
    .with_labels(vec![Label::primary(id, 7..12).with_message("first msg"),
        Label::primary(id, 0..6).with_message("second msg")]);

codespan_reporting::term::emit(&mut writer.lock(), &config, &files, &diag).unwrap();

I get

error: Test bad order
  ┌─ <test>:1:1
  │
1 │ line 1
  │ ^^^^^^ second msg
2 │ line 2
  │ ^^^^^^ first msg

The second message is reported first. This makes sense for compile-time errors, but in my case I use codespan for an interpreted language and I want to report runtime errors where there is an associated temporal order of the labels, such as printing a callstack for example (a list of successive calls to some functions). In this case I don't want the labels to be re-ordered based on the position of their snippet in the original source file, and I would like the end result to be:

error: Test bad order
  ┌─ <test>:1:1
  │
2 │ line 2
  │ ^^^^^^ first msg
1 │ line 1
  │ ^^^^^^ second msg

Is there a simple way to do that using codespan ?

[Johann150]

Thanks for your issue, but this was basically already discussed in #231.
This means there is no simple way to do this in the current version of codespan. Maybe by using multiple diagnostics? But other than that I think codespan is not quite intended for what you want to do.

Maybe this should be added to the documentation.