ref: Add special case for extracting name of rewritten async function in Dart lang

[kamilogorek]

Unfortunately dart_web is setting the platform to javascript for this variant of the SDK, so we cannot use it to make any distinction between the incoming events.

It appears that there is no way to make a distinction between regular JS code and the scenario we're solving here :(
The only way that I found is indeed actually using scope.startsWith('$async$') - https://github.com/dart-lang/sdk/blob/main/pkg/compiler/lib/src/js_backend/namer.dart#L1845-L1866

@marandaneto could you please provide us with the most barebone repo case for this? Basically, a single async function that throws?
I don't want to commit 62k lines of fixtures for such a simple test case.

Fixes getsentry/symbolic#791

[marandaneto]

@kamilogorek thank you.
Will do it on Monday unless @blaugold beats me :D

[marandaneto]

@kamilogorek thank you. Will do it on Monday unless @blaugold beats me :D

https://manoeltest.sentry.io/issues/4303672281/?project=4505499492941824&query=is%3Aunresolved&statsPeriod=24h&stream_index=0
Download source maps: https://manoeltest.sentry.io/settings/projects/flutter/source-maps/artifact-bundles/751f0a63-3c32-5bbc-b78b-51b6208a6b23/
The file is still massive, but I'm afraid I can't generate any shorter unless you clean it up for all nonrelated properties of the file.
Repo https://github.com/marandaneto/fluttersampleweb/tree/main

This is a bare-bones flutter web app, I tried a simpler dart web app, but release builds don't generate source maps, or they are deleted automatically afterward.

[blaugold]

I've compiled the program below with dart compile js bin/main.dart -O4:

void main() async {
  await Future(() {});
  throw StateError('');
}

This yields out.js and out.map.js.

Hope that helps. :) It should be a lot smaller than event the most basic Flutter app.

[marandaneto]

Oh yeah, good call, I was using webdev build, totally forgot about calling dart compile by hand, thanks @blaugold

[kamilogorek]

Lovely, thanks! Verified it works with the new fixtures.

[loewenheim]

Awesome, thanks for doing this.