contrib/benchmarks/__init__.py

pycompat: use os.fsencode() to re-encode sys.argv

Historically, the previous code made sense, as Py_EncodeLocale() and
fs.fsencode() could possibly use different encodings. However, this is not the
case anymore for Python 3.2, which uses the locale encoding as the filesystem
encoding (this is not true for later Python versions, but see below). See
https://vstinner.github.io/painful-history-python-filesystem-encoding.html for
a source and more background information.

Using os.fsencode() is safer, as the documentation for sys.argv says that it can
be used to get the original bytes. When doing further changes, the Python
developers will take care that this continues to work.

One concrete case where os.fsencode() is more correct is when enabling Python's
UTF-8 mode. Py_DecodeLocale() will use UTF-8 in this case. Our previous code
would have encoded it using the locale encoding (which might be different),
whereas os.fsencode() will encode it with UTF-8.

Since we don’t claim to support the UTF-8 mode, this is not really a bug and the
patch can go to the default branch. It might be a good idea to not commit this
to the stable branch, as it could in theory introduce regressions.

# __init__.py - asv benchmark suite
#
# Copyright 2016 Logilab SA <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

# "historical portability" policy of contrib/benchmarks:
#
# We have to make this code work correctly with current mercurial stable branch
# and if possible with reasonable cost with early Mercurial versions.

'''ASV (https://asv.readthedocs.io) benchmark suite

Benchmark are parameterized against reference repositories found in the
directory pointed by the REPOS_DIR environment variable.

Invocation example:

    $ export REPOS_DIR=~/hgperf/repos
    # run suite on given revision
    $ asv --config contrib/asv.conf.json run REV
    # run suite on new changesets found in stable and default branch
    $ asv --config contrib/asv.conf.json run NEW
    # display a comparative result table of benchmark results between two given
    # revisions
    $ asv --config contrib/asv.conf.json compare REV1 REV2
    # compute regression detection and generate ASV static website
    $ asv --config contrib/asv.conf.json publish
    # serve the static website
    $ asv --config contrib/asv.conf.json preview
'''

from __future__ import absolute_import

import functools
import os
import re

from mercurial import (
    extensions,
    hg,
    ui as uimod,
    util,
)

basedir = os.path.abspath(
    os.path.join(os.path.dirname(__file__), os.path.pardir, os.path.pardir)
)
reposdir = os.environ['REPOS_DIR']
reposnames = [
    name
    for name in os.listdir(reposdir)
    if os.path.isdir(os.path.join(reposdir, name, ".hg"))
]
if not reposnames:
    raise ValueError("No repositories found in $REPO_DIR")
outputre = re.compile(
    (
        r'! wall (\d+.\d+) comb \d+.\d+ user \d+.\d+ sys '
        r'\d+.\d+ \(best of \d+\)'
    )
)


def runperfcommand(reponame, command, *args, **kwargs):
    os.environ["HGRCPATH"] = os.environ.get("ASVHGRCPATH", "")
    # for "historical portability"
    # ui.load() has been available since d83ca85
    if util.safehasattr(uimod.ui, "load"):
        ui = uimod.ui.load()
    else:
        ui = uimod.ui()
    repo = hg.repository(ui, os.path.join(reposdir, reponame))
    perfext = extensions.load(
        ui, 'perfext', os.path.join(basedir, 'contrib', 'perf.py')
    )
    cmd = getattr(perfext, command)
    ui.pushbuffer()
    cmd(ui, repo, *args, **kwargs)
    output = ui.popbuffer()
    match = outputre.search(output)
    if not match:
        raise ValueError("Invalid output {}".format(output))
    return float(match.group(1))


def perfbench(repos=reposnames, name=None, params=None):
    """decorator to declare ASV benchmark based on contrib/perf.py extension

    An ASV benchmark is a python function with the given attributes:

    __name__: should start with track_, time_ or mem_ to be collected by ASV
    params and param_name: parameter matrix to display multiple graphs on the
    same page.
    pretty_name: If defined it's displayed in web-ui instead of __name__
    (useful for revsets)
    the module name is prepended to the benchmark name and displayed as
    "category" in webui.

    Benchmarks are automatically parameterized with repositories found in the
    REPOS_DIR environment variable.

    `params` is the param matrix in the form of a list of tuple
    (param_name, [value0, value1])

    For example [(x, [a, b]), (y, [c, d])] declare benchmarks for
    (a, c), (a, d), (b, c) and (b, d).
    """
    params = list(params or [])
    params.insert(0, ("repo", repos))

    def decorator(func):
        @functools.wraps(func)
        def wrapped(repo, *args):
            def perf(command, *a, **kw):
                return runperfcommand(repo, command, *a, **kw)

            return func(perf, *args)

        wrapped.params = [p[1] for p in params]
        wrapped.param_names = [p[0] for p in params]
        wrapped.pretty_name = name
        return wrapped

    return decorator