Use taskkill on Windows to kill all descendant processes on exit

[Lyncredible]

This should fix issues like #3736 and #3763 where bash or zsh is
manually started inside cmd.exe. It also works for other long
running processes like SSH sessions inside cmd.exe or wsl.exe.

[mf]

Looks good!

[Stanzilla]

Would this not cause a problem if you did this intentionally? Maybe some people want to start a long running process and close the terminal?

[Lyncredible]

That is a good question, though I think this is the right behavior. child_process.kill() kills all descendant processes on Linux and Mac, but it does not work as advertised on Windows. This is the workaround suggested by the Node team, and will make the behavior consistent across all platforms.

In the *nix world, background jobs are shutdown when a shell is exited. If a user wants to keep a job running even after the terminal is closed, they should use something like the disown or nohup command to dissociate the job with the current terminal.

The Windows equivalent seems to be start, though that will create a new terminal window.

[ivanwonder]

I think it's the problem of node-pty, see the pr #3781, it has been merged, you can update your code and try whether the problem has resolved or not. @Lyncredible

[Lyncredible]

@ivanwonder That did the trick. I will close this PR. Thank you!

@Stanzilla If you look at the node-pty PR(microsoft/node-pty#262) that fixed the issue, they are also trying to kill the entire process tree 😃

[Stanzilla]

Ah, great we figured it out, thanks guys!