upgrade: prepare code (and output) for the idea of upgrading share
This would work for a subset of action only. Our first target is dirstate-v2.
Differential Revision: https://phab.mercurial-scm.org/D12196
#!/usr/bin/env python3
#
# This is literally `cat` but in python, one char at a time.
#
# see sigpipe-remote.py for details.
from __future__ import print_function
import io
import os
import sys
if isinstance(sys.stdout.buffer, io.BufferedWriter):
print('SIGPIPE-WORKER: script need unbuffered output', file=sys.stderr)
sys.exit(255)
while True:
c = os.read(sys.stdin.fileno(), 1)
os.write(sys.stdout.fileno(), c)