revsetbenchmark: add some simpler revset for heads and roots
This revset might leverage compiled code in the future so lets start to track
them.
#!/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='')