1280258 - Add saner error reporting APIs

Status: NEW

(Core :: JavaScript Engine, defect, P3)

Description

[Jan de Mooij [:jandem]]

We have many lines like:

  JS_ReportErrorNumber(cx, GetErrorMessage, nullptr, JSMSG_BAD_ARRAY_LENGTH);

A lot of boilerplate, but it doesn't tell us the exception type (RangeError in this case). It'd be really nice to replace this with just:

  JS::ThrowRangeError(cx, JSMSG_BAD_ARRAY_LENGTH);

I think we can remove the error message callbacks somehow if we make JSMSG_BAD_ARRAY_LENGTH expand to something (pointer or struct) that stores the error number, error message, etc.

Comment 1

[Jeff Walden [:Waldo]]

This is arguably a dup of bug 1063241, but having a clean bug for what's likely to be a bunch of fresh work (existing patchwork having bitrotted) probably isn't a bad idea.  Much a fan of having JS::ThrowRangeError and similar, for sure, then.

Comment 2

[Jan de Mooij [:jandem]]

Looking at this I noticed there's a problem with the js::GetErrorMessage call in xpc::ErrorReport::Init - because the embedding can supply its own *.msg files, multiple messages (say one in js.msg and one in jsshell.msg) can have the same error number.

Not sure yet what to do about that.

Comment 3

[Jan de Mooij [:jandem]]

(In reply to Jan de Mooij [:jandem] from comment #2)
> Not sure yet what to do about that.

If we use the template class approach in bug 1063241, we can store the identifier we use for devtools/MDN in it - that way we can kill the error number completely.