hgext/closehead.py

wireprotov2: implement command for retrieving raw store files

Implementing shallow clone of the changelog is hard. We want the 4.8
release to have a fast implementation of partial clone in wireprotov2. In
order to achieve fast, we can't use deltas for transferring changelog and
manifestlog data.

Per discussions at the 4.8 sprint, this commit implements a somwwhat hacky
and likely-to-be-changed-drastically-or-dropped command in wireprotov2 that
facilitates access to raw store files, namely the changelog and manifestlog.
Using this command, clients can perform a "stream clone" of sorts for just
the changelog and manifestlog. This will allow clients to fetch the changelog
and manifest revlogs, stream them to disk (which should be fast), then follow
up filesdata requests for files revision data for a particular changeset.

Differential Revision: https://phab.mercurial-scm.org/D5134

# closehead.py - Close arbitrary heads without checking them out first
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''close arbitrary heads without checking them out first'''

from __future__ import absolute_import

from mercurial.i18n import _
from mercurial import (
    bookmarks,
    cmdutil,
    context,
    error,
    pycompat,
    registrar,
    scmutil,
)

cmdtable = {}
command = registrar.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'

commitopts = cmdutil.commitopts
commitopts2 = cmdutil.commitopts2
commitopts3 = [('r', 'rev', [],
               _('revision to check'), _('REV'))]

@command('close-head|close-heads', commitopts + commitopts2 + commitopts3,
    _('[OPTION]... [REV]...'),
    helpcategory=command.CATEGORY_CHANGE_MANAGEMENT,
    inferrepo=True)
def close_branch(ui, repo, *revs, **opts):
    """close the given head revisions

    This is equivalent to checking out each revision in a clean tree and running
    ``hg commit --close-branch``, except that it doesn't change the working
    directory.

    The commit message must be specified with -l or -m.
    """
    def docommit(rev):
        cctx = context.memctx(repo, parents=[rev, None], text=message,
                              files=[], filectxfn=None, user=opts.get('user'),
                              date=opts.get('date'), extra=extra)
        tr = repo.transaction('commit')
        ret = repo.commitctx(cctx, True)
        bookmarks.update(repo, [rev, None], ret)
        cctx.markcommitted(ret)
        tr.close()

    opts = pycompat.byteskwargs(opts)

    revs += tuple(opts.get('rev', []))
    revs = scmutil.revrange(repo, revs)

    if not revs:
        raise error.Abort(_('no revisions specified'))

    heads = []
    for branch in repo.branchmap():
        heads.extend(repo.branchheads(branch))
    heads = set(repo[h].rev() for h in heads)
    for rev in revs:
        if rev not in heads:
            raise error.Abort(_('revision is not an open head: %d') % rev)

    message = cmdutil.logmessage(ui, opts)
    if not message:
        raise error.Abort(_("no commit message specified with -l or -m"))
    extra = { 'close': '1' }

    with repo.wlock(), repo.lock():
        for rev in revs:
            r = repo[rev]
            branch = r.branch()
            extra['branch'] = branch
            docommit(r)
    return 0