Blocks in threads should be killed if the command finishes first

[ripienaar]

Given the following:

>> systemu("sleep 1") {|i| sleep 10;Process.kill 9, i}
=> [#<Process::Status: pid=4793,exited(0)>, "", ""]
>> (irb):1:in `kill': No such process (Errno::ESRCH)
        from (irb):1:in `irb_binding'

I think if the command being run finishes before the thread for its block that thread should be killed else absolutely some weird stuff lke here can happen - and you have no guarantee that something else havnt since started on that pid

[ahoward]

you could say the same about this code

pid = fork{ sleep }

parent = !!pid
child = !parent

if parent
  sleep(rand * 100)
  Process.kill(-9, pid)  # you actually have no idea here, if the pid has been recycled!
end

you need to do way more work to know, in the general case, if a pid is your child such as maintaining unix domain sockets to communicate between the parent/child (a lifeline) or using the Process based call to tell.

knowing that a particular pid is

• yours
• alive
• not recycled

is a general problem that's way outside the scope of a library