annotate contrib/python3-ratchet.py @ 45095:8e04607023e5

procutil: ensure that procutil.std{out,err}.write() writes all bytes

Python 3 offers different kind of streams and it’s not guaranteed for all of
them that calling write() writes all bytes.

When Python is started in unbuffered mode, sys.std{out,err}.buffer are
instances of io.FileIO, whose write() can write less bytes for
platform-specific reasons (e.g. Linux has a 0x7ffff000 bytes maximum and could
write less if interrupted by a signal; when writing to Windows consoles, it’s
limited to 32767 bytes to avoid the "not enough space" error). This can lead to
silent loss of data, both when using sys.std{out,err}.buffer (which may in fact
not be a buffered stream) and when using the text streams sys.std{out,err}
(I’ve created a CPython bug report for that:
https://bugs.python.org/issue41221).

Python may fix the problem at some point. For now, we implement our own wrapper
for procutil.std{out,err} that calls the raw stream’s write() method until all
bytes have been written. We don’t use sys.std{out,err} for larger writes, so I
think it’s not worth the effort to patch them.

# Copyright 2012 Facebook
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""Find tests that newly pass under Python 3.

The approach is simple: we maintain a whitelist of Python 3 passing
tests in the repository, and periodically run all the /other/ tests
and look for new passes. Any newly passing tests get automatically
added to the whitelist.

You probably want to run it like this:

  $ cd tests
  $ python3 ../contrib/python3-ratchet.py \
  >   --working-tests=../contrib/python3-whitelist
"""
from __future__ import print_function
from __future__ import absolute_import

import argparse
import json
import os
import subprocess
import sys

_hgenv = dict(os.environ)
_hgenv.update(
    {'HGPLAIN': '1',}
)

_HG_FIRST_CHANGE = '9117c6561b0bd7792fa13b50d28239d51b78e51f'


def _runhg(*args):
    return subprocess.check_output(args, env=_hgenv)


def _is_hg_repo(path):
    return (
        _runhg('hg', 'log', '-R', path, '-r0', '--template={node}').strip()
        == _HG_FIRST_CHANGE
    )


def _py3default():
    if sys.version_info[0] >= 3:
        return sys.executable
    return 'python3'


def main(argv=()):
    p = argparse.ArgumentParser()
    p.add_argument(
        '--working-tests', help='List of tests that already work in Python 3.'
    )
    p.add_argument(
        '--commit-to-repo',
        help='If set, commit newly fixed tests to the given repo',
    )
    p.add_argument(
        '-j',
        default=os.sysconf('SC_NPROCESSORS_ONLN'),
        type=int,
        help='Number of parallel tests to run.',
    )
    p.add_argument(
        '--python3',
        default=_py3default(),
        help='python3 interpreter to use for test run',
    )
    p.add_argument(
        '--commit-user',
        default='[e-mail]',
        help='Username to specify when committing to a repo.',
    )
    opts = p.parse_args(argv)
    if opts.commit_to_repo:
        if not _is_hg_repo(opts.commit_to_repo):
            print('abort: specified repository is not the hg repository')
            sys.exit(1)
    if not opts.working_tests or not os.path.isfile(opts.working_tests):
        print(
            'abort: --working-tests must exist and be a file (got %r)'
            % opts.working_tests
        )
        sys.exit(1)
    elif opts.commit_to_repo:
        root = _runhg('hg', 'root').strip()
        if not opts.working_tests.startswith(root):
            print(
                'abort: if --commit-to-repo is given, '
                '--working-tests must be from that repo'
            )
            sys.exit(1)
    try:
        subprocess.check_call(
            [
                opts.python3,
                '-c',
                'import sys ; '
                'assert ((3, 5) <= sys.version_info < (3, 6) '
                'or sys.version_info >= (3, 6, 2))',
            ]
        )
    except subprocess.CalledProcessError:
        print(
            'warning: Python 3.6.0 and 3.6.1 have '
            'a bug which breaks Mercurial'
        )
        print('(see https://bugs.python.org/issue29714 for details)')
        sys.exit(1)

    rt = subprocess.Popen(
        [
            opts.python3,
            'run-tests.py',
            '-j',
            str(opts.j),
            '--blacklist',
            opts.working_tests,
            '--json',
        ]
    )
    rt.wait()
    with open('report.json') as f:
        data = f.read()
    report = json.loads(data.split('=', 1)[1])
    newpass = set()
    for test, result in report.items():
        if result['result'] != 'success':
            continue
        # A new passing test! Huzzah!
        newpass.add(test)
    if newpass:
        # We already validated the repo, so we can just dive right in
        # and commit.
        if opts.commit_to_repo:
            print(len(newpass), 'new passing tests on Python 3!')
            with open(opts.working_tests) as f:
                oldpass = {l for l in f.read().splitlines() if l}
            with open(opts.working_tests, 'w') as f:
                for p in sorted(oldpass | newpass):
                    f.write('%s\n' % p)
            _runhg(
                'hg',
                'commit',
                '-R',
                opts.commit_to_repo,
                '--user',
                opts.commit_user,
                '--message',
                'python3: expand list of passing tests',
            )
        else:
            print('Newly passing tests:', '\n'.join(sorted(newpass)))
            sys.exit(2)


if __name__ == '__main__':
    main(sys.argv[1:])