# rebase.py - rebasing feature for mercurial

#

# Copyright 2008 Stefano Tortarolo <stefano.tortarolo at gmail dot com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

'''command to move sets of revisions to a different ancestor

This extension lets you rebase changesets in an existing Mercurial

repository.

For more information:

https://mercurial-scm.org/wiki/RebaseExtension

'''

from mercurial import hg, util, repair, merge, cmdutil, commands, bookmarks

from mercurial import extensions, patch, scmutil, phases, obsolete, error

from mercurial import copies, repoview, revset

from mercurial.commands import templateopts

from mercurial.node import nullrev, nullid, hex, short

from mercurial.lock import release

from mercurial.i18n import _

import os, errno

# The following constants are used throughout the rebase module. The ordering of

# their values must be maintained.

# Indicates that a revision needs to be rebased

revtodo = -1

nullmerge = -2

revignored = -3

# successor in rebase destination

revprecursor = -4

# plain prune (no successor)

revpruned = -5

revskipped = (revignored, revprecursor, revpruned)

cmdtable = {}

command = cmdutil.command(cmdtable)

# Note for extension authors: ONLY specify testedwith = 'internal' 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 = 'internal'

def _nothingtorebase():

    return 1

def _savegraft(ctx, extra):

    s = ctx.extra().get('source', None)

    if s is not None:

        extra['source'] = s

    s = ctx.extra().get('intermediate-source', None)

    if s is not None:

        extra['intermediate-source'] = s

def _savebranch(ctx, extra):

    extra['branch'] = ctx.branch()

def _makeextrafn(copiers):

    """make an extrafn out of the given copy-functions.

    A copy function takes a context and an extra dict, and mutates the

    extra dict as needed based on the given context.

    """

    def extrafn(ctx, extra):

        for c in copiers:

            c(ctx, extra)

    return extrafn

def _destrebase(repo):

    # Destination defaults to the latest revision in the

    # current branch

    branch = repo[None].branch()

    return repo[branch].rev()

revsetpredicate = revset.extpredicate()

@revsetpredicate('_destrebase')

def _revsetdestrebase(repo, subset, x):

    # ``_rebasedefaultdest()``

    # default destination for rebase.

    # # XXX: Currently private because I expect the signature to change.

    # # XXX: - taking rev as arguments,

    # # XXX: - bailing out in case of ambiguity vs returning all data.

    # # XXX: - probably merging with the merge destination.

    # i18n: "_rebasedefaultdest" is a keyword

    revset.getargs(x, 0, 0, _("_rebasedefaultdest takes no arguments"))

    return subset & revset.baseset([_destrebase(repo)])

@command('rebase',

    [('s', 'source', '',

     _('rebase the specified changeset and descendants'), _('REV')),

    ('b', 'base', '',

     _('rebase everything from branching point of specified changeset'),

     _('REV')),

    ('r', 'rev', [],

     _('rebase these revisions'),

     _('REV')),

    ('d', 'dest', '',

     _('rebase onto the specified changeset'), _('REV')),

    ('', 'collapse', False, _('collapse the rebased changesets')),

    ('m', 'message', '',

     _('use text as collapse commit message'), _('TEXT')),

    ('e', 'edit', False, _('invoke editor on commit messages')),

    ('l', 'logfile', '',

     _('read collapse commit message from file'), _('FILE')),

    ('k', 'keep', False, _('keep original changesets')),

    ('', 'keepbranches', False, _('keep original branch names')),

    ('D', 'detach', False, _('(DEPRECATED)')),

    ('i', 'interactive', False, _('(DEPRECATED)')),

    ('t', 'tool', '', _('specify merge tool')),

    ('c', 'continue', False, _('continue an interrupted rebase')),

    ('a', 'abort', False, _('abort an interrupted rebase'))] +

     templateopts,

    _('[-s REV | -b REV] [-d REV] [OPTION]'))

def rebase(ui, repo, **opts):

    """move changeset (and descendants) to a different branch

    Rebase uses repeated merging to graft changesets from one part of

    history (the source) onto another (the destination). This can be

    useful for linearizing *local* changes relative to a master

    development tree.

    Published commits cannot be rebased (see :hg:`help phases`).

    To copy commits, see :hg:`help graft`.

    If you don't specify a destination changeset (``-d/--dest``),

    rebase uses the current branch tip as the destination. (The

    destination changeset is not modified by rebasing, but new

    changesets are added as its descendants.)

    Here are the ways to select changesets:

      1. Explicitly select them using ``--rev``.

      2. Use ``--source`` to select a root changeset and include all of its

         descendants.

      3. Use ``--base`` to select a changeset; rebase will find ancestors

         and their descendants which are not also ancestors of the destination.

      4. If you do not specify any of ``--rev``, ``source``, or ``--base``,

         rebase will use ``--base .`` as above.

    Rebase will destroy original changesets unless you use ``--keep``.

    It will also move your bookmarks (even if you do).

    Some changesets may be dropped if they do not contribute changes

    (e.g. merges from the destination branch).

    Unlike ``merge``, rebase will do nothing if you are at the branch tip of

    a named branch with two heads. You will need to explicitly specify source

    and/or destination.

    If you need to use a tool to automate merge/conflict decisions, you

    can specify one with ``--tool``, see :hg:`help merge-tools`.

    As a caveat: the tool will not be used to mediate when a file was

    deleted, there is no hook presently available for this.

    If a rebase is interrupted to manually resolve a conflict, it can be

    continued with --continue/-c or aborted with --abort/-a.

    .. container:: verbose

      Examples:

      - move "local changes" (current commit back to branching point)

        to the current branch tip after a pull::

          hg rebase

      - move a single changeset to the stable branch::

          hg rebase -r 5f493448 -d stable

      - splice a commit and all its descendants onto another part of history::

          hg rebase --source c0c3 --dest 4cf9

      - rebase everything on a branch marked by a bookmark onto the

        default branch::

          hg rebase --base myfeature --dest default

      - collapse a sequence of changes into a single commit::

          hg rebase --collapse -r 1520:1525 -d .

      - move a named branch while preserving its name::

          hg rebase -r "branch(featureX)" -d 1.3 --keepbranches

    Returns 0 on success, 1 if nothing to rebase or there are

    unresolved conflicts.

    """

    originalwd = target = None

    activebookmark = None

    external = nullrev

    # Mapping between the old revision id and either what is the new rebased

    # revision or what needs to be done with the old revision. The state dict

    # will be what contains most of the rebase progress state.

    state = {}

    skipped = set()

    targetancestors = set()

    lock = wlock = None

    try:

        wlock = repo.wlock()

        lock = repo.lock()

        # Validate input and define rebasing points

        destf = opts.get('dest', None)

        srcf = opts.get('source', None)

        basef = opts.get('base', None)

        revf = opts.get('rev', [])

        contf = opts.get('continue')

        abortf = opts.get('abort')

        collapsef = opts.get('collapse', False)

        collapsemsg = cmdutil.logmessage(ui, opts)

        date = opts.get('date', None)

        e = opts.get('extrafn') # internal, used by e.g. hgsubversion

        extrafns = [_savegraft]

        if e:

            extrafns = [e]

        keepf = opts.get('keep', False)

        keepbranchesf = opts.get('keepbranches', False)

        # keepopen is not meant for use on the command line, but by

        # other extensions

        keepopen = opts.get('keepopen', False)

        if opts.get('interactive'):

            try:

                if extensions.find('histedit'):

                    enablehistedit = ''

            except KeyError:

                enablehistedit = " --config extensions.histedit="

            help = "hg%s help -e histedit" % enablehistedit

            msg = _("interactive history editing is supported by the "

                    "'histedit' extension (see \"%s\")") % help

            raise error.Abort(msg)

        if collapsemsg and not collapsef:

            raise error.Abort(

                _('message can only be specified with collapse'))

        if contf or abortf:

            if contf and abortf:

                raise error.Abort(_('cannot use both abort and continue'))

            if collapsef:

                raise error.Abort(

                    _('cannot use collapse with continue or abort'))

            if srcf or basef or destf:

                raise error.Abort(

                    _('abort and continue do not allow specifying revisions'))

            if abortf and opts.get('tool', False):

                ui.warn(_('tool option will be ignored\n'))

            try:

                (originalwd, target, state, skipped, collapsef, keepf,

                 keepbranchesf, external, activebookmark) = restorestatus(repo)

            except error.RepoLookupError:

                if abortf:

                    clearstatus(repo)

                    repo.ui.warn(_('rebase aborted (no revision is removed,'

                                   ' only broken state is cleared)\n'))

                    return 0

                else:

                    msg = _('cannot continue inconsistent rebase')

                    hint = _('use "hg rebase --abort" to clear broken state')

                    raise error.Abort(msg, hint=hint)

            if abortf:

                return abort(repo, originalwd, target, state,

                             activebookmark=activebookmark)

        else:

            if srcf and basef:

                raise error.Abort(_('cannot specify both a '

                                   'source and a base'))

            if revf and basef:

                raise error.Abort(_('cannot specify both a '

                                   'revision and a base'))

            if revf and srcf:

                raise error.Abort(_('cannot specify both a '

                                   'revision and a source'))

            cmdutil.checkunfinished(repo)

            cmdutil.bailifchanged(repo)

            if destf:

                dest = scmutil.revsingle(repo, destf)

            else:

                dest = repo[_destrebase(repo)]

                destf = str(dest)

            if revf:

                rebaseset = scmutil.revrange(repo, revf)

                if not rebaseset:

                    ui.status(_('empty "rev" revision set - '

                                'nothing to rebase\n'))

                    return _nothingtorebase()

            elif srcf:

                src = scmutil.revrange(repo, [srcf])

                if not src:

                    ui.status(_('empty "source" revision set - '

                                'nothing to rebase\n'))

                    return _nothingtorebase()

                rebaseset = repo.revs('(%ld)::', src)

                assert rebaseset

            else:

                base = scmutil.revrange(repo, [basef or '.'])

                if not base:

                    ui.status(_('empty "base" revision set - '

                                "can't compute rebase set\n"))

                    return _nothingtorebase()

                commonanc = repo.revs('ancestor(%ld, %d)', base, dest).first()

                if commonanc is not None:

                    rebaseset = repo.revs('(%d::(%ld) - %d)::',

                                          commonanc, base, commonanc)

                else:

                    rebaseset = []

                if not rebaseset:

                    # transform to list because smartsets are not comparable to

                    # lists. This should be improved to honor laziness of

                    # smartset.

                    if list(base) == [dest.rev()]:

                        if basef:

                            ui.status(_('nothing to rebase - %s is both "base"'

                                        ' and destination\n') % dest)

                        else:

                            ui.status(_('nothing to rebase - working directory '

                                        'parent is also destination\n'))

                    elif not repo.revs('%ld - ::%d', base, dest):

                        if basef:

                            ui.status(_('nothing to rebase - "base" %s is '

                                        'already an ancestor of destination '

                                        '%s\n') %

                                      ('+'.join(str(repo[r]) for r in base),

                                       dest))

                        else:

                            ui.status(_('nothing to rebase - working '

                                        'directory parent is already an '

                                        'ancestor of destination %s\n') % dest)

                    else: # can it happen?

                        ui.status(_('nothing to rebase from %s to %s\n') %

                                  ('+'.join(str(repo[r]) for r in base), dest))

                    return _nothingtorebase()

            allowunstable = obsolete.isenabled(repo, obsolete.allowunstableopt)

            if (not (keepf or allowunstable)

                  and repo.revs('first(children(%ld) - %ld)',

                                rebaseset, rebaseset)):

                raise error.Abort(

                    _("can't remove original changesets with"

                      " unrebased descendants"),

                    hint=_('use --keep to keep original changesets'))

            obsoletenotrebased = {}

            if ui.configbool('experimental', 'rebaseskipobsolete'):

                rebasesetrevs = set(rebaseset)

                rebaseobsrevs = _filterobsoleterevs(repo, rebasesetrevs)

                obsoletenotrebased = _computeobsoletenotrebased(repo,

                                                                rebaseobsrevs,

                                                                dest)

                rebaseobsskipped = set(obsoletenotrebased)

                # Obsolete node with successors not in dest leads to divergence

                divergenceok = ui.configbool('rebase',

                                             'allowdivergence')

                divergencebasecandidates = rebaseobsrevs - rebaseobsskipped

                if divergencebasecandidates and not divergenceok:

                    msg = _("this rebase will cause divergence")

                    h = _("to force the rebase please set "

                          "rebase.allowdivergence=True")

                    raise error.Abort(msg, hint=h)

                # - plain prune (no successor) changesets are rebased

                # - split changesets are not rebased if at least one of the

                # changeset resulting from the split is an ancestor of dest

                rebaseset = rebasesetrevs - rebaseobsskipped

                if rebasesetrevs and not rebaseset:

                    msg = _('all requested changesets have equivalents '

                            'or were marked as obsolete')

                    hint = _('to force the rebase, set the config '