Cancellation on Windows: Pass /T to taskkill

[amitsaha]

/T will make taskkill kill all the child processes as well. This should improve the cancellation behavior. (#794)

Please let me know if I should file a separate issue.

[lox]

This seems sensible. I'll do some testing on Windows.

[lox]

Some interesting context and alternative approaches in golang/dep#862.

[amitsaha]

thanks for the merge @lox

[amitsaha]

Some interesting context and alternative approaches in golang/dep#862.

Very useful reference. Any objections to incorporating TerminateTree() for the cancellation as implemented here?

[lox]

@amitsaha I didn't see any huge upside in TerminateTree() over shelling out to taskkill, did you?

[amitsaha]

@lox It looks like TerminateTree would kill the entire tree i.e. including processes spawned by child processes of the parent process? (whereas, it seems taskkill /T would kill only the immediate child processes)? (I haven't verified the taskkill /T behavior, so could be wrong)

[lox]

Ah right, in that case I'd absolutely support TerminateTree() being used, I assumed the /T would have the same behaviour.

[amitsaha]

I will have to look into this more, but it seems taskkill /T does also terminate child processes spawned by child processes.

[amitsaha]

indeed, that's the case, so, we don't need TerminateTree. Some demo code: https://github.com/amitsaha/golang-powershell-task-kill-demo