contrib/python3-ratchet.py

help: add internals.extensions topic

I think it's better to include the API overview in core as we now have the
internals section in our help system.

Retrieved from the wiki, and formatted as reST. Several wiki links are
removed since they are invalid in the help. The sections about example
extension are removed at all as they seemed too verbose.

https://www.mercurial-scm.org/wiki/WritingExtensions

# 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(r'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:])