view hgext/fetch.py @ 22028:3d0572ab3b4a

merge: add an internal:merge3 tool

This variant gives access to a feature already present in ``internal:merge``:
displaying merge base content.

In the basic merge (calling ``hg merge``) case, including more context to the
merge markers is an interesting addition.

But this extra information is the only viable option in case conflict from
grafting (, rebase, etc…).

When grafting ``source`` on ``destination``, the parent of ``source`` is
used as the ``base``. When all three changesets add content in the same
location, the marker for ``source`` will contains both ``base`` and ``source``
content. Without the content of base exposed, there is no way for the user
to discriminate content coming from ``base`` and content commit from ``source``.

Practical example (all addition are in the same place):

* ``destination`` adds ``Dest-Content``
* ``base``        adds ``Base-Content``
* ``source``      adds ``Src-Content``

Grafting ``source`` on ``destination`` will produce the following conflict:

  <<<<<<< destination
  Dest-Content
  =======
  Base-Content
  Src-Content
  >>>>>>> source

This that case there is no way to distinct ``base`` from ``source``. As a result
content from ``base`` are likely to slip in the resolution result.

However, adding the base make the situation very clear:

  <<<<<<< destination
  Dest-Content
  ||||||| base
  Base-Content
  ======= base
  Base-Content
  Src-Content
  >>>>>>> source

Once the base is added, the addition from the grafted changeset is made clear.
User can compare the content from ``base`` and ``source`` to make an enlightened
decision during merge resolution.

# 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 mercurial.i18n import _
from mercurial.node import nullid, short
from mercurial import commands, cmdutil, hg, util, error
from mercurial.lock import release

cmdtable = {}
command = cmdutil.command(cmdtable)
testedwith = 'internal'

@command('fetch',
    [('r', 'rev', [],
     _('a specific revision you would like to pull'), _('REV')),
    ('e', 'edit', None, _('invoke editor on commit messages')),
    ('', 'force-editor', None, _('edit commit message (DEPRECATED)')),
    ('', 'switch-parent', None, _('switch parents when merging')),
    ] + commands.commitopts + commands.commitopts2 + commands.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 util.Abort(_('working dir not at branch tip '
                           '(use "hg update" to check out branch tip)'))

    if p2 != nullid:
        raise util.Abort(_('outstanding uncommitted merge'))

    wlock = lock = None
    try:
        wlock = repo.wlock()
        lock = repo.lock()
        mod, add, rem, del_ = repo.status()[:4]

        if mod or add or rem:
            raise util.Abort(_('outstanding uncommitted changes'))
        if del_:
            raise util.Abort(_('working directory is missing some files'))
        bheads = repo.branchheads(branch)
        bheads = [head for head in bheads if len(repo[head].children()) == 0]
        if len(bheads) > 1:
            raise util.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 util.Abort(err)

        # Are there any changes at all?
        modheads = repo.pull(other, heads=revs)
        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)