tests/readlink.py

chg: deduplicate error handling of ui.system()

This moves 'onerr' handling from low-level util.system() to higher level,
which seems better API separation.

#!/usr/bin/env python

from __future__ import absolute_import, print_function

import errno
import os
import sys

for f in sys.argv[1:]:
    try:
        print(f, '->', os.readlink(f))
    except OSError as err:
        if err.errno != errno.EINVAL:
            raise
        print(f, '->', f, 'not a symlink')

sys.exit(0)