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  • Committer: Martin Pool
  • Date: 2009-03-03 01:45:32 UTC
  • mto: (4070.4.5 gnu-changelog)
  • mto: This revision was merged to the branch mainline in revision 4081.
  • Revision ID: mbp@sourcefrog.net-20090303014532-d223fxy97cb1og8f
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bzrlib/switch.py
 
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# Copyright (C) 2006, 2007 Canonical Ltd.
 
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#
 
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# This program is free software; you can redistribute it and/or modify
 
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# it under the terms of the GNU General Public License as published by
 
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# the Free Software Foundation; either version 2 of the License, or
 
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# (at your option) any later version.
 
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#
 
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# This program is distributed in the hope that it will be useful,
 
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
 
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 
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# GNU General Public License for more details.
 
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#
 
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# You should have received a copy of the GNU General Public License
 
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# along with this program; if not, write to the Free Software
 
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
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# Original author: David Allouche
 
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from bzrlib import errors, merge, revision
 
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from bzrlib.branch import Branch, BranchFormat, BranchReferenceFormat
 
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from bzrlib.bzrdir import BzrDir
 
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from bzrlib.trace import note
 
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def switch(control_dir, to_branch, force=False):
 
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    """Switch the branch associated with a checkout.
 
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    :param control_dir: BzrDir of the checkout to change
 
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    :param to_branch: branch that the checkout is to reference
 
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    :param force: skip the check for local commits in a heavy checkout
 
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    """
 
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    _check_pending_merges(control_dir, force)
 
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    try:
 
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        source_repository = control_dir.open_branch().repository
 
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    except errors.NotBranchError:
 
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        source_repository = to_branch.repository
 
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    _set_branch_location(control_dir, to_branch, force)
 
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    tree = control_dir.open_workingtree()
 
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    _update(tree, source_repository)
 
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def _check_pending_merges(control, force=False):
 
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    """Check that there are no outstanding pending merges before switching.
 
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    :param control: BzrDir of the branch to check
 
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    """
 
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    try:
 
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        tree = control.open_workingtree()
 
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    except errors.NotBranchError, ex:
 
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        # Lightweight checkout and branch is no longer there
 
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        if force:
 
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            return
 
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        else:
 
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            raise ex
 
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    # XXX: Should the tree be locked for get_parent_ids?
 
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    existing_pending_merges = tree.get_parent_ids()[1:]
 
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    if len(existing_pending_merges) > 0:
 
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        raise errors.BzrCommandError('Pending merges must be '
 
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            'committed or reverted before using switch.')
 
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def _set_branch_location(control, to_branch, force=False):
 
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    """Set location value of a branch reference.
 
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    :param control: BzrDir of the checkout to change
 
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    :param to_branch: branch that the checkout is to reference
 
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    :param force: skip the check for local commits in a heavy checkout
 
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    """
 
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    branch_format = control.find_branch_format()
 
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    if branch_format.get_reference(control) is not None:
 
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        # Lightweight checkout: update the branch reference
 
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        branch_format.set_reference(control, to_branch)
 
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    else:
 
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        b = control.open_branch()
 
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        bound_branch = b.get_bound_location()
 
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        if bound_branch is not None:
 
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            # Heavyweight checkout: check all local commits
 
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            # have been pushed to the current bound branch then
 
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            # synchronise the local branch with the new remote branch
 
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            # and bind to it
 
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            possible_transports = []
 
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            if not force and _any_local_commits(b, possible_transports):
 
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                raise errors.BzrCommandError(
 
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                    'Cannot switch as local commits found in the checkout. '
 
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                    'Commit these to the bound branch or use --force to '
 
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                    'throw them away.')
 
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            b.set_bound_location(None)
 
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            b.pull(to_branch, overwrite=True,
 
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                possible_transports=possible_transports)
 
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            b.set_bound_location(to_branch.base)
 
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        else:
 
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            raise errors.BzrCommandError('Cannot switch a branch, '
 
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                'only a checkout.')
 
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def _any_local_commits(this_branch, possible_transports):
 
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    """Does this branch have any commits not in the master branch?"""
 
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    last_rev = revision.ensure_null(this_branch.last_revision())
 
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    if last_rev != revision.NULL_REVISION:
 
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        other_branch = this_branch.get_master_branch(possible_transports)
 
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        this_branch.lock_read()
 
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        other_branch.lock_read()
 
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        try:
 
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            other_last_rev = other_branch.last_revision()
 
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            graph = this_branch.repository.get_graph(
 
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                other_branch.repository)
 
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            if not graph.is_ancestor(last_rev, other_last_rev):
 
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                return True
 
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        finally:
 
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            other_branch.unlock()
 
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            this_branch.unlock()
 
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    return False
 
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def _update(tree, source_repository):
 
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    """Update a working tree to the latest revision of its branch.
 
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    :param tree: the working tree
 
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    :param source_repository: repository holding the revisions
 
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    """
 
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    tree.lock_tree_write()
 
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    try:
 
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        to_branch = tree.branch
 
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        if tree.last_revision() == to_branch.last_revision():
 
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            note("Tree is up to date at revision %d.", to_branch.revno())
 
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            return
 
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        base_tree = source_repository.revision_tree(tree.last_revision())
 
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        merge.Merge3Merger(tree, tree, base_tree, to_branch.basis_tree())
 
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        tree.set_last_revision(to_branch.last_revision())
 
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        note('Updated to revision %d.' % to_branch.revno())
 
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    finally:
 
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        tree.unlock()