# 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:

http://mercurial.selenic.com/wiki/RebaseExtension

'''

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

from mercurial import extensions, patch, scmutil, phases

from mercurial.commands import templateopts

from mercurial.node import nullrev

from mercurial.lock import release

from mercurial.i18n import _

import os, errno

nullmerge = -2

cmdtable = {}

command = cmdutil.command(cmdtable)

@command('rebase',

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

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

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

     _('rebase from the base of the specified changeset '

       '(up to greatest common ancestor of base and dest)'),

     _('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')),

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

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

    ('D', 'detach', False, _('force detaching of source from its original '

                            'branch')),

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

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

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

     templateopts,

    _('hg rebase [-s REV | -b REV] [-d REV] [options]\n'

      'hg rebase {-a|-c}'))

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.

    You should not rebase changesets that have already been shared

    with others. Doing so will force everybody else to perform the

    same rebase or they will end up with duplicated changesets after

    pulling in your rebased changesets.

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

    rebase uses the tipmost head of the current named branch as the

    destination. (The destination changeset is not modified by

    rebasing, but new changesets are added as its descendants.)

    You can specify which changesets to rebase in two ways: as a

    "source" changeset or as a "base" changeset. Both are shorthand

    for a topologically related set of changesets (the "source

    branch"). If you specify source (``-s/--source``), rebase will

    rebase that changeset and all of its descendants onto dest. If you

    specify base (``-b/--base``), rebase will select ancestors of base

    back to but not including the common ancestor with dest. Thus,

    ``-b`` is less precise but more convenient than ``-s``: you can

    specify any changeset in the source branch, and rebase will select

    the whole branch. If you specify neither ``-s`` nor ``-b``, rebase

    uses the parent of the working directory as the base.

    By default, rebase recreates the changesets in the source branch

    as descendants of dest and then destroys the originals. Use

    ``--keep`` to preserve the original source changesets. Some

    changesets in the source branch (e.g. merges from the destination

    branch) may be dropped if they no longer contribute any change.

    One result of the rules for selecting the destination changeset

    and source branch is that, unlike ``merge``, rebase will do

    nothing if you are at the latest (tipmost) head of a named branch

    with two heads. You need to explicitly specify source and/or

    destination (or ``update`` to the other head, if it's the head of

    the intended source branch).

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

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

    Returns 0 on success, 1 if nothing to rebase.

    """

    originalwd = target = None

    external = nullrev

    state = {}

    skipped = set()

    targetancestors = set()

    editor = None

    if opts.get('edit'):

        editor = cmdutil.commitforceeditor

    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)

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

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

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

        detachf = opts.get('detach', False)

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

        # other extensions

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

        if collapsemsg and not collapsef:

            raise util.Abort(

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

        if contf or abortf:

            if contf and abortf:

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

            if collapsef:

                raise util.Abort(

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

            if detachf:

                raise util.Abort(_('cannot use detach with continue or abort'))

            if srcf or basef or destf:

                raise util.Abort(

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

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

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

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

                                keepbranchesf, external) = restorestatus(repo)

            if abortf:

                return abort(repo, originalwd, target, state)

        else:

            if srcf and basef:

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

                                   'source and a base'))

            if revf and basef:

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

                                   'revision and a base'))

            if revf and srcf:

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

                                   'revision and a source'))

            if detachf:

                if not (srcf or revf):

                    raise util.Abort(

                        _('detach requires a revision to be specified'))

                if basef:

                    raise util.Abort(_('cannot specify a base with detach'))

            cmdutil.bailifchanged(repo)

            if not destf:

                # Destination defaults to the latest revision in the

                # current branch

                branch = repo[None].branch()

                dest = repo[branch]

            else:

                dest = repo[destf]

            if revf:

                rebaseset = repo.revs('%lr', revf)

            elif srcf:

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

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

            else:

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

                rebaseset = repo.revs(

                    '(children(ancestor(%ld, %d)) and ::(%ld))::',

                    base, dest, base)

            if rebaseset:

                root = min(rebaseset)

            else:

                root = None

            if not rebaseset:

                repo.ui.debug('base is ancestor of destination')

                result = None

            elif not keepf and list(repo.revs('first(children(%ld) - %ld)',

                                              rebaseset, rebaseset)):

                raise util.Abort(

                    _("can't remove original changesets with"

                      " unrebased descendants"),

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

            elif not keepf and not repo[root].mutable():

                raise util.Abort(_("can't rebase immutable changeset %s")

                                 % repo[root],

                                 hint=_('see hg help phases for details'))

            else:

                result = buildstate(repo, dest, rebaseset, detachf)

            if not result:

                # Empty state built, nothing to rebase

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

                return 1

            else:

                originalwd, target, state = result

                if collapsef:

                    targetancestors = set(repo.changelog.ancestors(target))

                    targetancestors.add(target)

                    external = checkexternal(repo, state, targetancestors)

        if keepbranchesf:

            assert not extrafn, 'cannot use both keepbranches and extrafn'

            def extrafn(ctx, extra):

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

            if collapsef:

                branches = set()

                for rev in state:

                    branches.add(repo[rev].branch())

                    if len(branches) > 1:

                        raise util.Abort(_('cannot collapse multiple named '

                            'branches'))

        # Rebase

        if not targetancestors:

            targetancestors = set(repo.changelog.ancestors(target))

            targetancestors.add(target)

        # Keep track of the current bookmarks in order to reset them later

        currentbookmarks = repo._bookmarks.copy()

        sortedstate = sorted(state)

        total = len(sortedstate)

        pos = 0

        for rev in sortedstate:

            pos += 1

            if state[rev] == -1:

                ui.progress(_("rebasing"), pos, ("%d:%s" % (rev, repo[rev])),

                            _('changesets'), total)

                storestatus(repo, originalwd, target, state, collapsef, keepf,

                                                    keepbranchesf, external)

                p1, p2 = defineparents(repo, rev, target, state,

                                                        targetancestors)

                if len(repo.parents()) == 2:

                    repo.ui.debug('resuming interrupted rebase\n')

                else:

                    try:

                        ui.setconfig('ui', 'forcemerge', opts.get('tool', ''))

                        stats = rebasenode(repo, rev, p1, state)

                        if stats and stats[3] > 0:

                            raise util.Abort(_('unresolved conflicts (see hg '

                                        'resolve, then hg rebase --continue)'))

                    finally:

                        ui.setconfig('ui', 'forcemerge', '')

                cmdutil.duplicatecopies(repo, rev, target)

                if not collapsef:

                    newrev = concludenode(repo, rev, p1, p2, extrafn=extrafn,

                                          editor=editor)

                else:

                    # Skip commit if we are collapsing

                    newrev = None

                # Update the state

                if newrev is not None:

                    state[rev] = repo[newrev].rev()

                else:

                    if not collapsef:

                        ui.note(_('no changes, revision %d skipped\n') % rev)

                        ui.debug('next revision set to %s\n' % p1)

                        skipped.add(rev)

                    state[rev] = p1

        ui.progress(_('rebasing'), None)

        ui.note(_('rebase merging completed\n'))

        if collapsef and not keepopen:

            p1, p2 = defineparents(repo, min(state), target,

                                                        state, targetancestors)

            if collapsemsg:

                commitmsg = collapsemsg

            else:

                commitmsg = 'Collapsed revision'

                for rebased in state:

                    if rebased not in skipped and state[rebased] != nullmerge:

                        commitmsg += '\n* %s' % repo[rebased].description()

                commitmsg = ui.edit(commitmsg, repo.ui.username())

            newrev = concludenode(repo, rev, p1, external, commitmsg=commitmsg,

                                  extrafn=extrafn, editor=editor)

        if 'qtip' in repo.tags():

            updatemq(repo, state, skipped, **opts)

        if currentbookmarks:

            # Nodeids are needed to reset bookmarks

            nstate = {}

            for k, v in state.iteritems():

                if v != nullmerge:

                    nstate[repo[k].node()] = repo[v].node()

        if not keepf:

            # Remove no more useful revisions

            rebased = [rev for rev in state if state[rev] != nullmerge]

            if rebased:

                if set(repo.changelog.descendants(min(rebased))) - set(state):

                    ui.warn(_("warning: new changesets detected "

                              "on source branch, not stripping\n"))

                else:

                    # backup the old csets by default

                    repair.strip(ui, repo, repo[min(rebased)].node(), "all")

        if currentbookmarks:

            updatebookmarks(repo, nstate, currentbookmarks, **opts)

        clearstatus(repo)

        ui.note(_("rebase completed\n"))

        if os.path.exists(repo.sjoin('undo')):

            util.unlinkpath(repo.sjoin('undo'))

        if skipped:

            ui.note(_("%d revisions have been skipped\n") % len(skipped))

    finally:

        release(lock, wlock)

def checkexternal(repo, state, targetancestors):

    """Check whether one or more external revisions need to be taken in

    consideration. In the latter case, abort.

    """

    external = nullrev

    source = min(state)

    for rev in state:

        if rev == source:

            continue

        # Check externals and fail if there are more than one

        for p in repo[rev].parents():

            if (p.rev() not in state

                        and p.rev() not in targetancestors):

                if external != nullrev:

                    raise util.Abort(_('unable to collapse, there is more '

                            'than one external parent'))

                external = p.rev()

    return external

def concludenode(repo, rev, p1, p2, commitmsg=None, editor=None, extrafn=None):

    'Commit the changes and store useful information in extra'

    try:

        ctx = repo[rev]

        if commitmsg is None:

            commitmsg = ctx.description()

        extra = {'rebase_source': ctx.hex()}

        if extrafn:

            extrafn(ctx, extra)

        # Commit might fail if unresolved files exist