tests/testlib/sigpipe-worker.py

rust-changelog: start parsing changeset data

This patch makes `ChangelogRevisionData` do some coarse, line-level
splitting of the changeset data into manifest node, user, timestamp,
files list, and description. There are no (in-tree) users of these
functions yet, but I've added tests to prevent regressions. We'll
surely add callers at some point.

Differential Revision: https://phab.mercurial-scm.org/D12439

#!/usr/bin/env python3
#
# This is literally `cat` but in python, one char at a time.
#
# see sigpipe-remote.py for details.

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)