automation: shore up rebooting behavior
There was a race condition in the old code. Use
instance.stop()/instance.start() to eliminate it.
As part of debugging this, I also found another race condition
related to PowerShell permissions after the reboot. Unfortunately,
I'm not sure the best way to work around it. I've added a comment
for now.
Differential Revision: https://phab.mercurial-scm.org/D6288
#!/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)