Polling/awaiting HUP on Popen.stdin

It turns out the answer was as trivially simple as: Use EPOLLERR instead of EPOLLHUP.

I have serious doubts that this the right solution*, but it certainly seems to work:

import select, subprocess, time

E = select.epoll()

p = subprocess.Popen(["sh", "-c", "sleep 3"], stdin=subprocess.PIPE)

#time.sleep(5) #Uncomment this line to convince yourself there is no race-condition here
E.register(p.stdin, select.EPOLLERR)

print("Polling...")
evs = E.poll()
print("Caught events!")

assert (p.stdin.fileno(), select.EPOLLERR) in evs

E.close()

*If this isn’t the right solution, then I would, even now, very much like to discover what the right solution is.

(Here’s the completed version of the script from the original question, if anyone cares.)