hgext/infinitepush/bundleparts.py

continue: added logic for hg continue

This is part of GSoC19 project `Implement abort and
continue commands`. This patch is part of the continue plan.

This adds the basic logic for hg continue. This command
aborts an multistep operation like graft, histedit, rebase,
transplant and unshelve if they are in an unfinished state.

The first part of the logic is determining the unfinished
operation from the state detection API under statemod.
This API is extended to support hg continue by adding a method
to register the abort logic as a function (here continuefunc).

Once the unfinished operation is determined the registered
logic is used to resume the command in case it is interrupted.
The benefit of this kind of framework is that any new extension
developed can support hg continue by registering the command
and logic under statedetection API.

hg continue currently supports --dry-run/-n flag only.
It is used to dry run hg abort

Differential Revision: https://phab.mercurial-scm.org/D6645

# Copyright 2017 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

from mercurial.i18n import _

from mercurial import (
    bundle2,
    changegroup,
    error,
    extensions,
    revsetlang,
    util,
)

from . import common

isremotebooksenabled = common.isremotebooksenabled

scratchbranchparttype = 'b2x:infinitepush'

def getscratchbranchparts(repo, peer, outgoing, ui, bookmark):
    if not outgoing.missing:
        raise error.Abort(_('no commits to push'))

    if scratchbranchparttype not in bundle2.bundle2caps(peer):
        raise error.Abort(_('no server support for %r') % scratchbranchparttype)

    _validaterevset(repo, revsetlang.formatspec('%ln', outgoing.missing),
                    bookmark)

    supportedversions = changegroup.supportedoutgoingversions(repo)
    # Explicitly avoid using '01' changegroup version in infinitepush to
    # support general delta
    supportedversions.discard('01')
    cgversion = min(supportedversions)
    _handlelfs(repo, outgoing.missing)
    cg = changegroup.makestream(repo, outgoing, cgversion, 'push')

    params = {}
    params['cgversion'] = cgversion
    if bookmark:
        params['bookmark'] = bookmark
        # 'prevbooknode' is necessary for pushkey reply part
        params['bookprevnode'] = ''
        bookmarks = repo._bookmarks
        if bookmark in bookmarks:
            params['bookprevnode'] = bookmarks.changectx(bookmark).hex()

    # Do not send pushback bundle2 part with bookmarks if remotenames extension
    # is enabled. It will be handled manually in `_push()`
    if not isremotebooksenabled(ui):
        params['pushbackbookmarks'] = '1'

    parts = []

    # .upper() marks this as a mandatory part: server will abort if there's no
    #  handler
    parts.append(bundle2.bundlepart(
        scratchbranchparttype.upper(),
        advisoryparams=params.iteritems(),
        data=cg))

    return parts

def _validaterevset(repo, revset, bookmark):
    """Abort if the revs to be pushed aren't valid for a scratch branch."""
    if not repo.revs(revset):
        raise error.Abort(_('nothing to push'))
    if bookmark:
        # Allow bundle with many heads only if no bookmark is specified
        heads = repo.revs('heads(%r)', revset)
        if len(heads) > 1:
            raise error.Abort(
                _('cannot push more than one head to a scratch branch'))

def _handlelfs(repo, missing):
    '''Special case if lfs is enabled

    If lfs is enabled then we need to call prepush hook
    to make sure large files are uploaded to lfs
    '''
    try:
        lfsmod = extensions.find('lfs')
        lfsmod.wrapper.uploadblobsfromrevs(repo, missing)
    except KeyError:
        # Ignore if lfs extension is not enabled
        return

class copiedpart(object):
    """a copy of unbundlepart content that can be consumed later"""

    def __init__(self, part):
        # copy "public properties"
        self.type = part.type
        self.id = part.id
        self.mandatory = part.mandatory
        self.mandatoryparams = part.mandatoryparams
        self.advisoryparams = part.advisoryparams
        self.params = part.params
        self.mandatorykeys = part.mandatorykeys
        # copy the buffer
        self._io = util.stringio(part.read())

    def consume(self):
        return

    def read(self, size=None):
        if size is None:
            return self._io.read()
        else:
            return self._io.read(size)