/brz/remove-bazaar

# Copyright (C) 2006 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""Remove the last revision from the history of the current branch."""

# TODO: make the guts of this methods on tree, branch.

import os

from bzrlib import (

    errors,

    revision as _mod_revision,

    )

from bzrlib.branch import Branch

from bzrlib.errors import BoundBranchOutOfDate

def uncommit(branch, dry_run=False, verbose=False, revno=None, tree=None,

             local=False):

    """Remove the last revision from the supplied branch.

    :param dry_run: Don't actually change anything

    :param verbose: Print each step as you do it

    :param revno: Remove back to this revision

    :param local: If this branch is bound, only remove the revisions from the

        local branch. If this branch is not bound, it is an error to pass

        local=True.

    """

    unlockable = []

    try:

        if tree is not None:

            tree.lock_write()

            unlockable.append(tree)

        branch.lock_write()

        unlockable.append(branch)

        pending_merges = []

        if tree is not None:

            pending_merges = tree.get_parent_ids()[1:]

        if local:

            master = None

            if branch.get_bound_location() is None:

                raise errors.LocalRequiresBoundBranch()

        else:

            master = branch.get_master_branch()

            if master is not None:

                master.lock_write()

                unlockable.append(master)

        old_revno, old_tip = branch.last_revision_info()

        if master is not None and old_tip != master.last_revision():

            raise BoundBranchOutOfDate(branch, master)

        if revno is None:

            revno = old_revno

        new_revno = revno - 1

        revid_iterator = branch.repository.iter_reverse_revision_history(

                            old_tip)

        cur_revno = old_revno

        new_revision_id = old_tip

        graph = branch.repository.get_graph()

        for rev_id in revid_iterator:

            if cur_revno == new_revno:

                new_revision_id = rev_id

                break

            if verbose:

                print 'Removing revno %d: %s' % (cur_revno, rev_id)

            cur_revno -= 1

            parents = graph.get_parent_map([rev_id]).get(rev_id, None)

            if not parents:

                continue

            # When we finish popping off the pending merges, we want

            # them to stay in the order that they used to be.

            # but we pop from the end, so reverse the order, and

            # then get the order right at the end

            pending_merges.extend(reversed(parents[1:]))

        else:

            # We ran off the end of revisions, which means we should be trying

            # to get to NULL_REVISION

            new_revision_id = _mod_revision.NULL_REVISION

        if not dry_run:

            if master is not None:

                master.set_last_revision_info(new_revno, new_revision_id)

            branch.set_last_revision_info(new_revno, new_revision_id)

            if master is None:

                hook_local = None

                hook_master = branch

            else:

                hook_local = branch

                hook_master = master

            for hook in Branch.hooks['post_uncommit']:

                hook_new_tip = new_revision_id

                if hook_new_tip == _mod_revision.NULL_REVISION:

                    hook_new_tip = None

                hook(hook_local, hook_master, old_revno, old_tip, new_revno,

                     hook_new_tip)

            if tree is not None:

                if not _mod_revision.is_null(new_revision_id):

                    parents = [new_revision_id]

                else:

                    parents = []

                parents.extend(reversed(pending_merges))

                tree.set_parent_ids(parents)

    finally:

        for item in reversed(unlockable):

            item.unlock()