phases: avoid N² behavior in `advanceboundary`
We allowed duplicated entries in the deque, which each entry could potentially
insert all its ancestors. So advancing boundary for the full repository would
mean each revision would walk all its ancestors, resulting in O(N²) iteration.
For repository of any decent size, N² is quickly insane.
We introduce a simple set to avoid this and get back to reasonable performance.
#!/usr/bin/env python3
# Filters traceback lines from stdin.
import io
import sys
if sys.version_info[0] >= 3:
# Prevent \r from being inserted on Windows.
sys.stdout = io.TextIOWrapper(
sys.stdout.buffer,
sys.stdout.encoding,
sys.stdout.errors,
newline="\n",
line_buffering=sys.stdout.line_buffering,
)
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 not line.replace('^', '').replace('~', '').strip():
# PEP 657: Fine-grained error locations in tracebacks
# ~~~~~~^^^^^^^^^
continue
elif state == 'file':
# Ignore lines after " File "
state = 'tb'
continue
print(line, end='')