debugger; and breakpoints don't work with node --inspect

[snapwich]

Currently breakpoints can be set for use with node debug using the keyword debugger;, but any breakpoints set with debugger; when using node --inspect are ignored. This only applies to the test code; breakpoints set with debugger; within Jest or other node_module libraries are honored.

I set up a test repository to demonstrate the difference: https://github.com/snapwich/jest-inspect. Both methods can be tested by pulling the repo and running the following:

npm install

// works
node debug --debug-brk ./node_modules/.bin/jest -i

// doesn't honor "debugger;"
node --inspect --debug-brk ./node_modules/.bin/jest -i

Also, after the initial run-through with node --inspect, breakpoints can be applied to the code in the Sources tab. Any breakpoints placed in test code (such as __tests__/jest.js in jest-inspect repo above) will be ignored, but breakpoints placed in any other files (Jest or other node_modules code) will work correctly when the suite is rerun.

node --inspect is only available in node v6.3.0+ and I'm running on OSX using node v6.4.0 and npm v3.10.3

/cc @kentcdodds

[maximderbin]

run into the same problem today

[maximderbin]

Also in your example if I run npm run debug

  6
  7     // break won't be triggered
> 8     debugger;
  9
 10     expect(test).toBe(true);
test
ReferenceError: test is not defined

Am I doing something wrong or it doesn't have access to context?

[snapwich]

@maximderbin not sure why you're getting that ReferenceError, test should be defined just a few lines above there: https://github.com/snapwich/jest-inspect/blob/master/__tests__/jest.js#L5

edit - just tested, you need to type repl before typing test so the code runs in the proper context.

[maximderbin]

related issue facebook/create-react-app#594

[cpojer]

This is interesting. Is it possible that node's --debug flag doesn't work when using the vm module to create a context?

[aleclarson]

Any news on this?

[aleclarson]

Was this ever working before?

I don't think vm.runInContext supports the debugger protocol.

This article mentions port forwarding to support debugging VM code. Not sure if that's relevant.

Beyond that, maybe it's possible to use websockets within the VM (to support the debugger protocol)?

What do you think, @cpojer?

[gbiryukov]

maybe it is possible to run tests without vm context in debug mode?

[damonbauer]

This issue is the biggest reason why I can't switch to Jest. Any updates or ideas on how to make progress?