contrib/python3-ratchet.py

phases: large rewrite on retract boundary

The new code is still pure Python, so we still have room to going significantly
faster. However its complexity of the complex part is `O(|[min_new_draft, tip]|)` instead of
`O(|[min_draft, tip]|` which should help tremendously one repository with old
draft (like mercurial-devel or mozilla-try).

This is especially useful as the most common "retract boundary" operation
happens when we commit/rewrite new drafts or when we push new draft to a
non-publishing server. In this case, the smallest new_revs is very close to the
tip and there is very few work to do.

A few smaller optimisation could be done for these cases and will be introduced in
later changesets.

We still have iterate over large sets of roots, but this is already a great
improvement for a very small amount of work. We gather information on the
affected changeset as we go as we can put it to use in the next changesets.
This extra data collection might slowdown the `register_new` case a bit, however
for register_new, it should not really matters. The set of new nodes is either
small, so the impact is negligible, or the set of new nodes is large, and the
amount of work to do to had them will dominate the overhead the collecting
information in `changed_revs`.

As this new code compute the changes on the fly, it unlock other interesting
improvement to be done in later changeset.

# 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
"""

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:])