[Python] How do I manage a python subprocess with an infinite loop

I want to read input from a subprocess in python, interact with it, see the results of that interaction, and then kill the process. I have the following parent and child processes.

child.py

from random import randint

x = 1
while x < 9:
x = randint(0, 10)
print("weeeee got", x)


name = input("what's your name?\n")
print("hello", name)

x = 0
while True:
x += 1
print("bad", x)


parent.py

import curio
from curio import subprocess


async def main():
p = subprocess.Popen(
["./out"],
stdout=subprocess.PIPE,
stdin=subprocess.PIPE,
)

async for line in p.stdout:
line = line.decode("ascii")
print(p.pid, "got:", line, end="")
if "what" in line and "name" in line:
out, _ = await p.communicate(input=b"yaboi\n")
print(p.pid, "got:", out.decode("ascii"), end="")
# stuff to properly kill the process ...
return


if __name__ == "__main__:
curio.run(main)


If I run this, the parent hangs on:

out, _ = await p.communicate(input=b"yaboi\n")


Removing the following section from the child fixes the issue:

x = 1
while x < 9:
x = randint(0, 10)
print("weeeee got", x)


Why doesn't it work with the infinite loop? How do I fix this?

Edit 1: putting flush=True in the print statement does not fix the issue.

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