child_process: handling fork( path, undefined / null, obj )

[shobhitchittora]

Closes: #20749

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

NOTE: Run test using - python ./tools/test.py parallel/test-child-process-fork-options.js

Affected subsystem(s)

child_process / fork

[BridgeAR]

Please add a test for this.

[shobhitchittora]

@jasnell @BridgeAR with this fix we can make the options work when args is undefined or null, but it still fails when args is an empty object {}. Should we also incorporate this by throwing if an object is passed as the second argument? -

fork('test.js', {} , {env: {foo: 'bar'}});

[shobhitchittora]

@jasnell A CITGM run is required.

[shobhitchittora]

Ping @jasnell.

[lundibundi]

LGTM

[lundibundi]

CI: https://ci.nodejs.org/job/node-test-pull-request/16840/

[lundibundi]

Related failure:
https://ci.nodejs.org/job/node-test-commit-linuxone/nodes=rhel72-s390x/4549/testReport/junit/(root)/test/parallel_test_child_process_fork_options/
(I suspect that the process exited faster than you've got the message)

[shobhitchittora]

@lundibundi Need some help fixing the failure that you've mentioned. Cannot reproduce in my local.

[BridgeAR]

@shobhitchittora fork is an async operation that does not keep the event loop alive. Therefore the test exits before the spawned file is done and in that case the test will not receive the message and the test fails.

[BridgeAR]

Ping @shobhitchittora

[shobhitchittora]

@BridgeAR I've removed exit(0) from the forked process fixture. I haven't found any existing fixture to use here.

Also I've no clue about how to make the test wait for the fork's response.

[lundibundi]

@shobhitchittora I think using .on('exit', common.mustCall()) might help.

[shobhitchittora]

@lundibundi Are you sure? I don't see a point of using onexit. Can you please explain? Also any other ideas? This seems weird to me.

[lundibundi]

Theoretically, it should make current node process wait until fork finishes as we are listening on its close event. Also, this seems to be the way it's done with other fork tests. Anyway I think it's worth a try, this is a simple change anyway.

[lundibundi]

CI: https://ci.nodejs.org/job/node-test-pull-request/17602/

[shobhitchittora]

Any idea why the status code returned by child is 127 or 1 in the CI? This seems that there was some error while executing the forked process.

Also I tried running the child js file in local and got the below error -

TypeError: process.send is not a function
    at Object.<anonymous> (/Users/schittora/Desktop/node/test/fixtures/child-process-spawn-node.js:10:9)
    at Module._compile (module.js:635:30)
    at Object.Module._extensions..js (module.js:646:10)
    at Module.load (module.js:554:32)
    at tryModuleLoad (module.js:497:12)
    at Function.Module._load (module.js:489:3)
    at Function.Module.runMain (module.js:676:10)
    at startup (bootstrap_node.js:187:16)
    at bootstrap_node.js:608:3

[lundibundi]

Sorry, forgot about this one.
Resume CI: https://ci.nodejs.org/job/node-test-pull-request/18238/.

[shobhitchittora]

@lundibundi Everything looks green 💚 . Thanks!! 👍

[Trott]

Landed in 0d9d32a