rust-dirstate: use EntryState enum instead of literals
This improves code readability quite a bit, while also adding a layer of
safety because we're checking the state byte against the enum.
Differential Revision: https://phab.mercurial-scm.org/D6629
#!/usr/bin/env python
# Filters traceback lines from stdin.
from __future__ import absolute_import, print_function
import sys
state = 'none'
for line in sys.stdin:
if state == 'none':
if line.startswith('Traceback '):
state = 'tb'
elif state == 'tb':
if line.startswith(' File '):
state = 'file'
continue
elif not line.startswith(' '):
state = 'none'
elif state == 'file':
# Ignore lines after " File "
state = 'tb'
continue
print(line, end='')