Debugging Web Apps: Stacktrace/Mapping seems broken

[nilsdoehring]

When debugging a web app that is producing cast errors at runtime, a user would expect that:

• Debugger gets triggered, displaying the error message and Dart stack/code
• Console prints meaningful info, or at least the same contents as Chrome dev tools console

What happens instead?

• Debugger doesn't get triggered
• Console prints only a subset of Chrome dev tools console (Screenshot 1)
• User has to look at Chrome's console output and make best guesses where the error lies in Dart code (Screenshot 2)

What steps will reproduce the problem?

1. Checkout this branch (it is missing a typecast when parsing json)
2. Activate Dart, pub get
3. Debug example/swords_man/index.html

Screenshot 1

Screenshot 2 (Chrome console)

IDEA EAP 2018.2
Dart SDK 2.0.0-dev.60.0
build_runner: ^0.8.9
build_test: ^0.10.2
build_web_compilers: ^0.4.0+3
OSX, Chrome

Also reported in Jetbrains YouTrack as WEB-33172

[eredo]

Not sure if that's applicable to this log output, but there was a comment in a similar angular issue about turning on custom formatters for in Chrome Dev Tools: angulardart/angular#1367 (comment)

[jakemac53]

@nilsdoehring can you confirm if enabling the custom formatter fixes this issue for you?

[afpatmin]

Enabling it does not fix it for me unfortunately. When I ran it in Firefox, it output a warning in the console;

Source map error: request failed with status 404
Resource URL: http://localhost:8080/packages/$sdk/dev_compiler/amd/dart_sdk.js
Source Map URL: dart_sdk.js.map[Learn More]

[afpatmin]

Update; removing <base href="/"> in index.html made it reference dart files directly again on my end

[nilsdoehring]

Enabling custom formatters indeed makes Chrome console reference the dart files (see pic below). No changes on the IDEA side, though (i.e. console output exactly the same as in OP).

[matanlurey]

@natebosch Do you want to track IDE issues here or elsewhere?

[natebosch]

@jwren - where is the best place to track IntelliJ issues like this one?

[jwren]

In YouTrack, when @nilsdoehring opened the issue he included a link to https://youtrack.jetbrains.com/issue/WEB-33172

[natebosch]

Sounds good, we'll track there. We can reopen this issue if we need any changes on the build side.

[jwren]

SGTM. Are we sure then that the source maps are all correct from the DDC side?

[natebosch]

Are we sure then that the source maps are all correct from the DDC side?

I think we're confident with them. We have some tests for source maps and things seem to be working in the browser once the config is set up.