view hgext/fetch.py @ 33619:609606d21765

rebase: use one dirstateguard for when using rebase.singletransaction

This was previously landed as 2519994d25ca but backed out in b63351f6a2 because
it broke hooks mid-rebase and caused conflict resolution data loss in the event
of unexpected exceptions. This new version adds the behavior back but behind a
config flag, since the performance improvement is notable in large repositories.

The old commit message was:

Recently we switched rebases to run the entire rebase inside a single
transaction, which dramatically improved the speed of rebases in repos with
large working copies. Let's also move the dirstate into a single dirstateguard
to get the same benefits. This let's us avoid serializing the dirstate after
each commit.

In a large repo, rebasing 27 commits is sped up by about 20%.

I believe the test changes are because us touching the dirstate gave the
transaction something to actually rollback.
(grafted from 9e3dc3a1638b9754b58a0cb26aaa75d868058109)
(grafted from 7d38b41d2266d9a02a15c64229fae0da5738dcec)

Differential Revision: https://phab.mercurial-scm.org/D135

# fetch.py - pull and merge remote changes
#
# Copyright 2006 Vadim Gelfer <[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.

'''pull, update and merge in one command (DEPRECATED)'''

from __future__ import absolute_import

from mercurial.i18n import _
from mercurial.node import (
    short,
)
from mercurial import (
    cmdutil,
    error,
    exchange,
    hg,
    lock,
    registrar,
    util,
)

release = lock.release
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'

@command('fetch',
    [('r', 'rev', [],
     _('a specific revision you would like to pull'), _('REV')),
    ('', 'edit', None, _('invoke editor on commit messages')),
    ('', 'force-editor', None, _('edit commit message (DEPRECATED)')),
    ('', 'switch-parent', None, _('switch parents when merging')),
    ] + cmdutil.commitopts + cmdutil.commitopts2 + cmdutil.remoteopts,
    _('hg fetch [SOURCE]'))
def fetch(ui, repo, source='default', **opts):
    '''pull changes from a remote repository, merge new changes if needed.

    This finds all changes from the repository at the specified path
    or URL and adds them to the local repository.

    If the pulled changes add a new branch head, the head is
    automatically merged, and the result of the merge is committed.
    Otherwise, the working directory is updated to include the new
    changes.

    When a merge is needed, the working directory is first updated to
    the newly pulled changes. Local changes are then merged into the
    pulled changes. To switch the merge order, use --switch-parent.

    See :hg:`help dates` for a list of formats valid for -d/--date.

    Returns 0 on success.
    '''

    date = opts.get('date')
    if date:
        opts['date'] = util.parsedate(date)

    parent, _p2 = repo.dirstate.parents()
    branch = repo.dirstate.branch()
    try:
        branchnode = repo.branchtip(branch)
    except error.RepoLookupError:
        branchnode = None
    if parent != branchnode:
        raise error.Abort(_('working directory not at branch tip'),
                         hint=_("use 'hg update' to check out branch tip"))

    wlock = lock = None
    try:
        wlock = repo.wlock()
        lock = repo.lock()

        cmdutil.bailifchanged(repo)

        bheads = repo.branchheads(branch)
        bheads = [head for head in bheads if len(repo[head].children()) == 0]
        if len(bheads) > 1:
            raise error.Abort(_('multiple heads in this branch '
                               '(use "hg heads ." and "hg merge" to merge)'))

        other = hg.peer(repo, opts, ui.expandpath(source))
        ui.status(_('pulling from %s\n') %
                  util.hidepassword(ui.expandpath(source)))
        revs = None
        if opts['rev']:
            try:
                revs = [other.lookup(rev) for rev in opts['rev']]
            except error.CapabilityError:
                err = _("other repository doesn't support revision lookup, "
                        "so a rev cannot be specified.")
                raise error.Abort(err)

        # Are there any changes at all?
        modheads = exchange.pull(repo, other, heads=revs).cgresult
        if modheads == 0:
            return 0

        # Is this a simple fast-forward along the current branch?
        newheads = repo.branchheads(branch)
        newchildren = repo.changelog.nodesbetween([parent], newheads)[2]
        if len(newheads) == 1 and len(newchildren):
            if newchildren[0] != parent:
                return hg.update(repo, newchildren[0])
            else:
                return 0

        # Are there more than one additional branch heads?
        newchildren = [n for n in newchildren if n != parent]
        newparent = parent
        if newchildren:
            newparent = newchildren[0]
            hg.clean(repo, newparent)
        newheads = [n for n in newheads if n != newparent]
        if len(newheads) > 1:
            ui.status(_('not merging with %d other new branch heads '
                        '(use "hg heads ." and "hg merge" to merge them)\n') %
                      (len(newheads) - 1))
            return 1

        if not newheads:
            return 0

        # Otherwise, let's merge.
        err = False
        if newheads:
            # By default, we consider the repository we're pulling
            # *from* as authoritative, so we merge our changes into
            # theirs.
            if opts['switch_parent']:
                firstparent, secondparent = newparent, newheads[0]
            else:
                firstparent, secondparent = newheads[0], newparent
                ui.status(_('updating to %d:%s\n') %
                          (repo.changelog.rev(firstparent),
                           short(firstparent)))
            hg.clean(repo, firstparent)
            ui.status(_('merging with %d:%s\n') %
                      (repo.changelog.rev(secondparent), short(secondparent)))
            err = hg.merge(repo, secondparent, remind=False)

        if not err:
            # we don't translate commit messages
            message = (cmdutil.logmessage(ui, opts) or
                       ('Automated merge with %s' %
                        util.removeauth(other.url())))
            editopt = opts.get('edit') or opts.get('force_editor')
            editor = cmdutil.getcommiteditor(edit=editopt, editform='fetch')
            n = repo.commit(message, opts['user'], opts['date'], editor=editor)
            ui.status(_('new changeset %d:%s merges remote changes '
                        'with local\n') % (repo.changelog.rev(n),
                                           short(n)))

        return err

    finally:
        release(lock, wlock)