tests/check-perf-code.py

rhg: desambiguate status without decompressing filelog if possible

When status is unsure based on `stat()` and the dirstate if a file is clean
or modified, we need to compare it against the filelog.

This comparison can skip looking at contents if the lengths differ.
This changeset optimize this further to deduce what we can about the length
if the filelog without decompressing it or resolving deltas.

Differential Revision: https://phab.mercurial-scm.org/D11965

#!/usr/bin/env python3
#
# check-perf-code - (historical) portability checker for contrib/perf.py

from __future__ import absolute_import

import os
import sys

# write static check patterns here
perfpypats = [
    [
        (
            r'(branchmap|repoview|repoviewutil)\.subsettable',
            "use getbranchmapsubsettable() for early Mercurial",
        ),
        (
            r'\.(vfs|svfs|opener|sopener)',
            "use getvfs()/getsvfs() for early Mercurial",
        ),
        (
            r'ui\.configint',
            "use getint() instead of ui.configint() for early Mercurial",
        ),
    ],
    # warnings
    [],
]


def modulewhitelist(names):
    replacement = [
        ('.py', ''),
        ('.c', ''),  # trim suffix
        ('mercurial%s' % '/', ''),  # trim "mercurial/" path
    ]
    ignored = {'__init__'}
    modules = {}

    # convert from file name to module name, and count # of appearances
    for name in names:
        name = name.strip()
        for old, new in replacement:
            name = name.replace(old, new)
        if name not in ignored:
            modules[name] = modules.get(name, 0) + 1

    # list up module names, which appear multiple times
    whitelist = []
    for name, count in modules.items():
        if count > 1:
            whitelist.append(name)

    return whitelist


if __name__ == "__main__":
    # in this case, it is assumed that result of "hg files" at
    # multiple revisions is given via stdin
    whitelist = modulewhitelist(sys.stdin)
    assert whitelist, "module whitelist is empty"

    # build up module whitelist check from file names given at runtime
    perfpypats[0].append(
        # this matching pattern assumes importing modules from
        # "mercurial" package in the current style below, for simplicity
        #
        #    from mercurial import (
        #        foo,
        #        bar,
        #        baz
        #    )
        (
            (
                r'from mercurial import [(][a-z0-9, \n#]*\n(?! *%s,|^[ #]*\n|[)])'
                % ',| *'.join(whitelist)
            ),
            "import newer module separately in try clause for early Mercurial",
        )
    )

    # import contrib/check-code.py as checkcode
    assert 'RUNTESTDIR' in os.environ, "use check-perf-code.py in *.t script"
    contribpath = os.path.join(os.environ['RUNTESTDIR'], '..', 'contrib')
    sys.path.insert(0, contribpath)
    checkcode = __import__('check-code')

    # register perf.py specific entry with "checks" in check-code.py
    checkcode.checks.append(
        ('perf.py', r'contrib/perf.py$', '', checkcode.pyfilters, perfpypats)
    )

    sys.exit(checkcode.main())