Description

When a worker thread tries to listen for data on stdin, it gets killed.
Not even finally blocks get called.

Environment

• Version: v12.0.0
• Platform: Darwin Joshs-MacBook-Air.local 18.6.0 Darwin Kernel Version 18.6.0: Thu Apr 25 23:16:27 PDT 2019; root:xnu-4903.261.4~2/RELEASE_X86_64 x86_64
• Subsystem: Probably worker_thread

Example

A worker is started, it prints "processing" 10 times:

const { Worker, isMainThread } = require('worker_threads')
if(isMainThread) {
  new Worker(__filename).on('exit', (exitStatus) => console.log({ exitStatus }))
} else {
  // process.stdin.on('data', console.log) // <-- this line is commented out
  for(i=0; i < 10; ++i) console.log(`processing(${i})`)
}
// => processing(0)
// => processing(1)
// => processing(2)
// => processing(3)
// => processing(4)
// => processing(5)
// => processing(6)
// => processing(7)
// => processing(8)
// => processing(9)
// => { exitStatus: 0 }

Now we uncomment the line that listens for data, it gets killed after 2 or 3 iterations (on my machine, guessing quicker on faster machines):

const { Worker, isMainThread } = require('worker_threads')
if(isMainThread) {
  new Worker(__filename).on('exit', (exitStatus) => console.log({ exitStatus }))
} else {
  process.stdin.on('data', console.log) // <-- now this line runs
  for(i=0; i < 10; ++i) console.log(`processing(${i})`)
}
// => processing(0)
// => processing(1)
// => processing(2)
// => { exitStatus: 0 }

Expected Behaviour

• I expected the second example to behave the same as the first example. Which is to say that I expect my worker would be able to process my stdin.
• However, if this behaviour is intentional, then I'd expect
  • The behaviour to be documented here
  • To respect finally blocks (omitted from my example to keep it short/focused)
  • To exit with a nonzero status (docs say "If the worker was terminated, the exitCode parameter will be 1")