view tests/filtertraceback.py @ 45999:c4c7a6b61146

match: skip walking up the directory hierarchy if the number of pats are small

Previously, we would receive a path like abc/def/ghi and "walk up" the directory
hierarchy, checking abc/def, abc, and `b''` to see if they were in the set of
prefixes that this matcher covered. We did this indiscriminately - we generated
all of these paths even if the set of prefixes the matcher covered was
completely empty, which is the case for a lot of repos at my company (the narrow
matcher we use is usually non-recursive).

This brings the time for a rebase in one of my repos from 12.20s to 10.87s. In
this particular repo, this is entirely due to the `len(prefix_set) == 0` check,
as I do not have any recursive patterns in the narrowspec.

Differential Revision: https://phab.mercurial-scm.org/D9488

#!/usr/bin/env python3

# Filters traceback lines from stdin.

from __future__ import absolute_import, print_function

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 state == 'file':
        # Ignore lines after "  File "
        state = 'tb'
        continue

    print(line, end='')