# Copyright (C) 2005, 2006, 2007 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

import os
from StringIO import StringIO

from bzrlib import (
    conflicts,
    errors,
    knit,
    memorytree,
    merge as _mod_merge,
    option,
    progress,
    tests,
    transform,
    versionedfile,
    )
from bzrlib.branch import Branch
from bzrlib.conflicts import ConflictList, TextConflict
from bzrlib.errors import UnrelatedBranches, NoCommits, BzrCommandError
from bzrlib.merge import transform_tree, merge_inner, _PlanMerge
from bzrlib.osutils import pathjoin, file_kind
from bzrlib.tests import TestCaseWithTransport, TestCaseWithMemoryTransport
from bzrlib.workingtree import WorkingTree
from bzrlib.transform import TreeTransform

class TestMerge(TestCaseWithTransport):
    """Test appending more than one revision"""

    def test_pending(self):
        wt = self.make_branch_and_tree('.')
        rev_a = wt.commit("lala!")
        self.assertEqual([rev_a], wt.get_parent_ids())
        self.assertRaises(errors.PointlessMerge, wt.merge_from_branch,
                          wt.branch)
        self.assertEqual([rev_a], wt.get_parent_ids())
        return wt

    def test_undo(self):
        wt = self.make_branch_and_tree('.')
        wt.commit("lala!")
        wt.commit("haha!")
        wt.commit("blabla!")
        wt.merge_from_branch(wt.branch, wt.branch.get_rev_id(2),
                             wt.branch.get_rev_id(1))

    def test_nocommits(self):
        wt = self.test_pending()
        wt2 = self.make_branch_and_tree('branch2')
        self.assertRaises(NoCommits, wt.merge_from_branch, wt2.branch)
        return wt, wt2

    def test_unrelated(self):
        wt, wt2 = self.test_nocommits()
        wt2.commit("blah")
        self.assertRaises(UnrelatedBranches, wt.merge_from_branch, wt2.branch)
        return wt2

    def test_merge_one_file(self):
        """Do a partial merge of a tree which should not affect tree parents."""
        wt1 = self.make_branch_and_tree('branch1')
        tip = wt1.commit('empty commit')
        wt2 = self.make_branch_and_tree('branch2')
        wt2.pull(wt1.branch)
        file('branch1/foo', 'wb').write('foo')
        file('branch1/bar', 'wb').write('bar')
        wt1.add('foo')
        wt1.add('bar')
        wt1.commit('add foobar')
        os.chdir('branch2')
        self.run_bzr('merge ../branch1/baz', retcode=3)
        self.run_bzr('merge ../branch1/foo')
        self.failUnlessExists('foo')
        self.failIfExists('bar')
        wt2 = WorkingTree.open('.') # opens branch2
        self.assertEqual([tip], wt2.get_parent_ids())

    def test_pending_with_null(self):
        """When base is forced to revno 0, parent_ids are set"""
        wt2 = self.test_unrelated()
        wt1 = WorkingTree.open('.')
        br1 = wt1.branch
        br1.fetch(wt2.branch)
        # merge all of branch 2 into branch 1 even though they
        # are not related.
        wt1.merge_from_branch(wt2.branch, wt2.last_revision(), 'null:')
        self.assertEqual([br1.last_revision(), wt2.branch.last_revision()],
            wt1.get_parent_ids())
        return (wt1, wt2.branch)

    def test_two_roots(self):
        """Merge base is sane when two unrelated branches are merged"""
        wt1, br2 = self.test_pending_with_null()
        wt1.commit("blah")
        wt1.lock_read()
        try:
            last = wt1.branch.last_revision()
            last2 = br2.last_revision()
            graph = wt1.branch.repository.get_graph()
            self.assertEqual(last2, graph.find_unique_lca(last, last2))
        finally:
            wt1.unlock()

    def test_create_rename(self):
        """Rename an inventory entry while creating the file"""
        tree =self.make_branch_and_tree('.')
        file('name1', 'wb').write('Hello')
        tree.add('name1')
        tree.commit(message="hello")
        tree.rename_one('name1', 'name2')
        os.unlink('name2')
        transform_tree(tree, tree.branch.basis_tree())

    def test_layered_rename(self):
        """Rename both child and parent at same time"""
        tree =self.make_branch_and_tree('.')
        os.mkdir('dirname1')
        tree.add('dirname1')
        filename = pathjoin('dirname1', 'name1')
        file(filename, 'wb').write('Hello')
        tree.add(filename)
        tree.commit(message="hello")
        filename2 = pathjoin('dirname1', 'name2')
        tree.rename_one(filename, filename2)
        tree.rename_one('dirname1', 'dirname2')
        transform_tree(tree, tree.branch.basis_tree())

    def test_ignore_zero_merge_inner(self):
        # Test that merge_inner's ignore zero parameter is effective
        tree_a =self.make_branch_and_tree('a')
        tree_a.commit(message="hello")
        dir_b = tree_a.bzrdir.sprout('b')
        tree_b = dir_b.open_workingtree()
        tree_b.lock_write()
        self.addCleanup(tree_b.unlock)
        tree_a.commit(message="hello again")
        log = StringIO()
        merge_inner(tree_b.branch, tree_a, tree_b.basis_tree(),
                    this_tree=tree_b, ignore_zero=True)
        log = self._get_log(keep_log_file=True)
        self.failUnless('All changes applied successfully.\n' not in log)
        tree_b.revert()
        merge_inner(tree_b.branch, tree_a, tree_b.basis_tree(),
                    this_tree=tree_b, ignore_zero=False)
        log = self._get_log(keep_log_file=True)
        self.failUnless('All changes applied successfully.\n' in log)

    def test_merge_inner_conflicts(self):
        tree_a = self.make_branch_and_tree('a')
        tree_a.set_conflicts(ConflictList([TextConflict('patha')]))
        merge_inner(tree_a.branch, tree_a, tree_a, this_tree=tree_a)
        self.assertEqual(1, len(tree_a.conflicts()))

    def test_rmdir_conflict(self):
        tree_a = self.make_branch_and_tree('a')
        self.build_tree(['a/b/'])
        tree_a.add('b', 'b-id')
        tree_a.commit('added b')
        # basis_tree() is only guaranteed to be valid as long as it is actually
        # the basis tree. This mutates the tree after grabbing basis, so go to
        # the repository.
        base_tree = tree_a.branch.repository.revision_tree(tree_a.last_revision())
        tree_z = tree_a.bzrdir.sprout('z').open_workingtree()
        self.build_tree(['a/b/c'])
        tree_a.add('b/c')
        tree_a.commit('added c')
        os.rmdir('z/b')
        tree_z.commit('removed b')
        merge_inner(tree_z.branch, tree_a, base_tree, this_tree=tree_z)
        self.assertEqual([
            conflicts.MissingParent('Created directory', 'b', 'b-id'),
            conflicts.UnversionedParent('Versioned directory', 'b', 'b-id')],
            tree_z.conflicts())
        merge_inner(tree_a.branch, tree_z.basis_tree(), base_tree,
                    this_tree=tree_a)
        self.assertEqual([
            conflicts.DeletingParent('Not deleting', 'b', 'b-id'),
            conflicts.UnversionedParent('Versioned directory', 'b', 'b-id')],
            tree_a.conflicts())

    def test_nested_merge(self):
        tree = self.make_branch_and_tree('tree',
            format='dirstate-with-subtree')
        sub_tree = self.make_branch_and_tree('tree/sub-tree',
            format='dirstate-with-subtree')
        sub_tree.set_root_id('sub-tree-root')
        self.build_tree_contents([('tree/sub-tree/file', 'text1')])
        sub_tree.add('file')
        sub_tree.commit('foo')
        tree.add_reference(sub_tree)
        tree.commit('set text to 1')
        tree2 = tree.bzrdir.sprout('tree2').open_workingtree()
        # modify the file in the subtree
        self.build_tree_contents([('tree2/sub-tree/file', 'text2')])
        # and merge the changes from the diverged subtree into the containing
        # tree
        tree2.commit('changed file text')
        tree.merge_from_branch(tree2.branch)
        self.assertFileEqual('text2', 'tree/sub-tree/file')

    def test_merge_with_missing(self):
        tree_a = self.make_branch_and_tree('tree_a')
        self.build_tree_contents([('tree_a/file', 'content_1')])
        tree_a.add('file')
        tree_a.commit('commit base')
        # basis_tree() is only guaranteed to be valid as long as it is actually
        # the basis tree. This test commits to the tree after grabbing basis,
        # so we go to the repository.
        base_tree = tree_a.branch.repository.revision_tree(tree_a.last_revision())
        tree_b = tree_a.bzrdir.sprout('tree_b').open_workingtree()
        self.build_tree_contents([('tree_a/file', 'content_2')])
        tree_a.commit('commit other')
        other_tree = tree_a.basis_tree()
        # 'file' is now missing but isn't altered in any commit in b so no
        # change should be applied.
        os.unlink('tree_b/file')
        merge_inner(tree_b.branch, other_tree, base_tree, this_tree=tree_b)

    def test_merge_kind_change(self):
        tree_a = self.make_branch_and_tree('tree_a')
        self.build_tree_contents([('tree_a/file', 'content_1')])
        tree_a.add('file', 'file-id')
        tree_a.commit('added file')
        tree_b = tree_a.bzrdir.sprout('tree_b').open_workingtree()
        os.unlink('tree_a/file')
        self.build_tree(['tree_a/file/'])
        tree_a.commit('changed file to directory')
        tree_b.merge_from_branch(tree_a.branch)
        self.assertEqual('directory', file_kind('tree_b/file'))
        tree_b.revert()
        self.assertEqual('file', file_kind('tree_b/file'))
        self.build_tree_contents([('tree_b/file', 'content_2')])
        tree_b.commit('content change')
        tree_b.merge_from_branch(tree_a.branch)
        self.assertEqual(tree_b.conflicts(),
                         [conflicts.ContentsConflict('file',
                          file_id='file-id')])

    def test_merge_type_registry(self):
        merge_type_option = option.Option.OPTIONS['merge-type']
        self.assertFalse('merge4' in [x[0] for x in
                        merge_type_option.iter_switches()])
        registry = _mod_merge.get_merge_type_registry()
        registry.register_lazy('merge4', 'bzrlib.merge', 'Merge4Merger',
                               'time-travelling merge')
        self.assertTrue('merge4' in [x[0] for x in
                        merge_type_option.iter_switches()])
        registry.remove('merge4')
        self.assertFalse('merge4' in [x[0] for x in
                        merge_type_option.iter_switches()])

    def test_merge_other_moves_we_deleted(self):
        tree_a = self.make_branch_and_tree('A')
        tree_a.lock_write()
        self.addCleanup(tree_a.unlock)
        self.build_tree(['A/a'])
        tree_a.add('a')
        tree_a.commit('1', rev_id='rev-1')
        tree_a.flush()
        tree_a.rename_one('a', 'b')
        tree_a.commit('2')
        bzrdir_b = tree_a.bzrdir.sprout('B', revision_id='rev-1')
        tree_b = bzrdir_b.open_workingtree()
        tree_b.lock_write()
        self.addCleanup(tree_b.unlock)
        os.unlink('B/a')
        tree_b.commit('3')
        try:
            tree_b.merge_from_branch(tree_a.branch)
        except AttributeError:
            self.fail('tried to join a path when name was None')

    def test_merge_uncommitted_otherbasis_ancestor_of_thisbasis(self):
        tree_a = self.make_branch_and_tree('a')
        self.build_tree(['a/file_1', 'a/file_2'])
        tree_a.add(['file_1'])
        tree_a.commit('commit 1')
        tree_a.add(['file_2'])
        tree_a.commit('commit 2')
        tree_b = tree_a.bzrdir.sprout('b').open_workingtree()
        tree_b.rename_one('file_1', 'renamed')
        merger = _mod_merge.Merger.from_uncommitted(tree_a, tree_b,
                                                    progress.DummyProgress())
        merger.merge_type = _mod_merge.Merge3Merger
        merger.do_merge()
        self.assertEqual(tree_a.get_parent_ids(), [tree_b.last_revision()])

    def test_merge_uncommitted_otherbasis_ancestor_of_thisbasis_weave(self):
        tree_a = self.make_branch_and_tree('a')
        self.build_tree(['a/file_1', 'a/file_2'])
        tree_a.add(['file_1'])
        tree_a.commit('commit 1')
        tree_a.add(['file_2'])
        tree_a.commit('commit 2')
        tree_b = tree_a.bzrdir.sprout('b').open_workingtree()
        tree_b.rename_one('file_1', 'renamed')
        merger = _mod_merge.Merger.from_uncommitted(tree_a, tree_b,
                                                    progress.DummyProgress())
        merger.merge_type = _mod_merge.WeaveMerger
        merger.do_merge()
        self.assertEqual(tree_a.get_parent_ids(), [tree_b.last_revision()])

    def test_Merger_defaults_to_DummyProgress(self):
        branch = self.make_branch('branch')
        merger = _mod_merge.Merger(branch, pb=None)
        self.assertIsInstance(merger._pb, progress.DummyProgress)

    def prepare_cherrypick(self):
        """Prepare a pair of trees for cherrypicking tests.

        Both trees have a file, 'file'.
        rev1 sets content to 'a'.
        rev2b adds 'b'.
        rev3b adds 'c'.
        A full merge of rev2b and rev3b into this_tree would add both 'b' and
        'c'.  A successful cherrypick of rev2b-rev3b into this_tree will add
        'c', but not 'b'.
        """
        this_tree = self.make_branch_and_tree('this')
        self.build_tree_contents([('this/file', "a\n")])
        this_tree.add('file')
        this_tree.commit('rev1')
        other_tree = this_tree.bzrdir.sprout('other').open_workingtree()
        self.build_tree_contents([('other/file', "a\nb\n")])
        other_tree.commit('rev2b', rev_id='rev2b')
        self.build_tree_contents([('other/file', "c\na\nb\n")])
        other_tree.commit('rev3b', rev_id='rev3b')
        this_tree.lock_write()
        self.addCleanup(this_tree.unlock)
        return this_tree, other_tree

    def test_weave_cherrypick(self):
        this_tree, other_tree = self.prepare_cherrypick()
        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            this_tree, 'rev3b', 'rev2b', other_tree.branch)
        merger.merge_type = _mod_merge.WeaveMerger
        merger.do_merge()
        self.assertFileEqual('c\na\n', 'this/file')

    def test_weave_cannot_reverse_cherrypick(self):
        this_tree, other_tree = self.prepare_cherrypick()
        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            this_tree, 'rev2b', 'rev3b', other_tree.branch)
        merger.merge_type = _mod_merge.WeaveMerger
        self.assertRaises(errors.CannotReverseCherrypick, merger.do_merge)

    def test_merge3_can_reverse_cherrypick(self):
        this_tree, other_tree = self.prepare_cherrypick()
        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            this_tree, 'rev2b', 'rev3b', other_tree.branch)
        merger.merge_type = _mod_merge.Merge3Merger
        merger.do_merge()

    def test_merge3_will_detect_cherrypick(self):
        this_tree = self.make_branch_and_tree('this')
        self.build_tree_contents([('this/file', "a\n")])
        this_tree.add('file')
        this_tree.commit('rev1')
        other_tree = this_tree.bzrdir.sprout('other').open_workingtree()
        self.build_tree_contents([('other/file', "a\nb\n")])
        other_tree.commit('rev2b', rev_id='rev2b')
        self.build_tree_contents([('other/file', "a\nb\nc\n")])
        other_tree.commit('rev3b', rev_id='rev3b')
        this_tree.lock_write()
        self.addCleanup(this_tree.unlock)

        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            this_tree, 'rev3b', 'rev2b', other_tree.branch)
        merger.merge_type = _mod_merge.Merge3Merger
        merger.do_merge()
        self.assertFileEqual('a\n'
                             '<<<<<<< TREE\n'
                             '=======\n'
                             'c\n'
                             '>>>>>>> MERGE-SOURCE\n',
                             'this/file')

    def test_make_merger(self):
        this_tree = self.make_branch_and_tree('this')
        this_tree.commit('rev1', rev_id='rev1')
        other_tree = this_tree.bzrdir.sprout('other').open_workingtree()
        this_tree.commit('rev2', rev_id='rev2a')
        other_tree.commit('rev2', rev_id='rev2b')
        this_tree.lock_write()
        self.addCleanup(this_tree.unlock)
        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress,
            this_tree, 'rev2b', other_branch=other_tree.branch)
        merger.merge_type = _mod_merge.Merge3Merger
        tree_merger = merger.make_merger()
        self.assertIs(_mod_merge.Merge3Merger, tree_merger.__class__)
        self.assertEqual('rev2b', tree_merger.other_tree.get_revision_id())
        self.assertEqual('rev1', tree_merger.base_tree.get_revision_id())

    def test_make_preview_transform(self):
        this_tree = self.make_branch_and_tree('this')
        self.build_tree_contents([('this/file', '1\n')])
        this_tree.add('file', 'file-id')
        this_tree.commit('rev1', rev_id='rev1')
        other_tree = this_tree.bzrdir.sprout('other').open_workingtree()
        self.build_tree_contents([('this/file', '1\n2a\n')])
        this_tree.commit('rev2', rev_id='rev2a')
        self.build_tree_contents([('other/file', '2b\n1\n')])
        other_tree.commit('rev2', rev_id='rev2b')
        this_tree.lock_write()
        self.addCleanup(this_tree.unlock)
        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            this_tree, 'rev2b', other_branch=other_tree.branch)
        merger.merge_type = _mod_merge.Merge3Merger
        tree_merger = merger.make_merger()
        tt = tree_merger.make_preview_transform()
        self.addCleanup(tt.finalize)
        preview_tree = tt.get_preview_tree()
        tree_file = this_tree.get_file('file-id')
        try:
            self.assertEqual('1\n2a\n', tree_file.read())
        finally:
            tree_file.close()
        preview_file = preview_tree.get_file('file-id')
        try:
            self.assertEqual('2b\n1\n2a\n', preview_file.read())
        finally:
            preview_file.close()

    def test_do_merge(self):
        this_tree = self.make_branch_and_tree('this')
        self.build_tree_contents([('this/file', '1\n')])
        this_tree.add('file', 'file-id')
        this_tree.commit('rev1', rev_id='rev1')
        other_tree = this_tree.bzrdir.sprout('other').open_workingtree()
        self.build_tree_contents([('this/file', '1\n2a\n')])
        this_tree.commit('rev2', rev_id='rev2a')
        self.build_tree_contents([('other/file', '2b\n1\n')])
        other_tree.commit('rev2', rev_id='rev2b')
        this_tree.lock_write()
        self.addCleanup(this_tree.unlock)
        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            this_tree, 'rev2b', other_branch=other_tree.branch)
        merger.merge_type = _mod_merge.Merge3Merger
        tree_merger = merger.make_merger()
        tt = tree_merger.do_merge()
        tree_file = this_tree.get_file('file-id')
        try:
            self.assertEqual('2b\n1\n2a\n', tree_file.read())
        finally:
            tree_file.close()

    def test_merge_add_into_deleted_root(self):
        # Yes, people actually do this.  And report bugs if it breaks.
        source = self.make_branch_and_tree('source', format='rich-root-pack')
        self.build_tree(['source/foo/'])
        source.add('foo', 'foo-id')
        source.commit('Add foo')
        target = source.bzrdir.sprout('target').open_workingtree()
        subtree = target.extract('foo-id')
        subtree.commit('Delete root')
        self.build_tree(['source/bar'])
        source.add('bar', 'bar-id')
        source.commit('Add bar')
        subtree.merge_from_branch(source.branch)

    def test_merge_joined_branch(self):
        source = self.make_branch_and_tree('source', format='rich-root-pack')
        self.build_tree(['source/foo'])
        source.add('foo')
        source.commit('Add foo')
        target = self.make_branch_and_tree('target', format='rich-root-pack')
        self.build_tree(['target/bla'])
        target.add('bla')
        target.commit('Add bla')
        nested = source.bzrdir.sprout('target/subtree').open_workingtree()
        target.subsume(nested)
        target.commit('Join nested')
        self.build_tree(['source/bar'])
        source.add('bar')
        source.commit('Add bar')
        target.merge_from_branch(source.branch)
        target.commit('Merge source')


class TestPlanMerge(TestCaseWithMemoryTransport):

    def setUp(self):
        TestCaseWithMemoryTransport.setUp(self)
        mapper = versionedfile.PrefixMapper()
        factory = knit.make_file_factory(True, mapper)
        self.vf = factory(self.get_transport())
        self.plan_merge_vf = versionedfile._PlanMergeVersionedFile('root')
        self.plan_merge_vf.fallback_versionedfiles.append(self.vf)

    def add_version(self, key, parents, text):
        self.vf.add_lines(key, parents, [c+'\n' for c in text])

    def add_rev(self, prefix, revision_id, parents, text):
        self.add_version((prefix, revision_id), [(prefix, p) for p in parents],
                         text)

    def add_uncommitted_version(self, key, parents, text):
        self.plan_merge_vf.add_lines(key, parents,
                                     [c+'\n' for c in text])

    def setup_plan_merge(self):
        self.add_rev('root', 'A', [], 'abc')
        self.add_rev('root', 'B', ['A'], 'acehg')
        self.add_rev('root', 'C', ['A'], 'fabg')
        return _PlanMerge('B', 'C', self.plan_merge_vf, ('root',))

    def setup_plan_merge_uncommitted(self):
        self.add_version(('root', 'A'), [], 'abc')
        self.add_uncommitted_version(('root', 'B:'), [('root', 'A')], 'acehg')
        self.add_uncommitted_version(('root', 'C:'), [('root', 'A')], 'fabg')
        return _PlanMerge('B:', 'C:', self.plan_merge_vf, ('root',))

    def test_unique_lines(self):
        plan = self.setup_plan_merge()
        self.assertEqual(plan._unique_lines(
            plan._get_matching_blocks('B', 'C')),
            ([1, 2, 3], [0, 2]))

    def test_plan_merge(self):
        self.setup_plan_merge()
        plan = self.plan_merge_vf.plan_merge('B', 'C')
        self.assertEqual([
                          ('new-b', 'f\n'),
                          ('unchanged', 'a\n'),
                          ('killed-a', 'b\n'),
                          ('killed-b', 'c\n'),
                          ('new-a', 'e\n'),
                          ('new-a', 'h\n'),
                          ('new-a', 'g\n'),
                          ('new-b', 'g\n')],
                         list(plan))

    def test_plan_merge_cherrypick(self):
        self.add_rev('root', 'A', [], 'abc')
        self.add_rev('root', 'B', ['A'], 'abcde')
        self.add_rev('root', 'C', ['A'], 'abcefg')
        self.add_rev('root', 'D', ['A', 'B', 'C'], 'abcdegh')
        my_plan = _PlanMerge('B', 'D', self.plan_merge_vf, ('root',))
        # We shortcut when one text supersedes the other in the per-file graph.
        # We don't actually need to compare the texts at this point.
        self.assertEqual([
                          ('new-b', 'a\n'),
                          ('new-b', 'b\n'),
                          ('new-b', 'c\n'),
                          ('new-b', 'd\n'),
                          ('new-b', 'e\n'),
                          ('new-b', 'g\n'),
                          ('new-b', 'h\n')],
                          list(my_plan.plan_merge()))

    def test_plan_merge_no_common_ancestor(self):
        self.add_rev('root', 'A', [], 'abc')
        self.add_rev('root', 'B', [], 'xyz')
        my_plan = _PlanMerge('A', 'B', self.plan_merge_vf, ('root',))
        self.assertEqual([
                          ('new-a', 'a\n'),
                          ('new-a', 'b\n'),
                          ('new-a', 'c\n'),
                          ('new-b', 'x\n'),
                          ('new-b', 'y\n'),
                          ('new-b', 'z\n')],
                          list(my_plan.plan_merge()))

    def test_plan_merge_tail_ancestors(self):
        # The graph looks like this:
        #       A       # Common to all ancestors
        #      / \
        #     B   C     # Ancestors of E, only common to one side
        #     |\ /|
        #     D E F     # D, F are unique to G, H respectively
        #     |/ \|     # E is the LCA for G & H, and the unique LCA for
        #     G   H     # I, J
        #     |\ /|
        #     | X |
        #     |/ \|
        #     I   J     # criss-cross merge of G, H
        #
        # In this situation, a simple pruning of ancestors of E will leave D &
        # F "dangling", which looks like they introduce lines different from
        # the ones in E, but in actuality C&B introduced the lines, and they
        # are already present in E

        # Introduce the base text
        self.add_rev('root', 'A', [], 'abc')
        # Introduces a new line B
        self.add_rev('root', 'B', ['A'], 'aBbc')
        # Introduces a new line C
        self.add_rev('root', 'C', ['A'], 'abCc')
        # Introduce new line D
        self.add_rev('root', 'D', ['B'], 'DaBbc')
        # Merges B and C by just incorporating both
        self.add_rev('root', 'E', ['B', 'C'], 'aBbCc')
        # Introduce new line F
        self.add_rev('root', 'F', ['C'], 'abCcF')
        # Merge D & E by just combining the texts
        self.add_rev('root', 'G', ['D', 'E'], 'DaBbCc')
        # Merge F & E by just combining the texts
        self.add_rev('root', 'H', ['F', 'E'], 'aBbCcF')
        # Merge G & H by just combining texts
        self.add_rev('root', 'I', ['G', 'H'], 'DaBbCcF')
        # Merge G & H but supersede an old line in B
        self.add_rev('root', 'J', ['H', 'G'], 'DaJbCcF')
        plan = self.plan_merge_vf.plan_merge('I', 'J')
        self.assertEqual([
                          ('unchanged', 'D\n'),
                          ('unchanged', 'a\n'),
                          ('killed-b', 'B\n'),
                          ('new-b', 'J\n'),
                          ('unchanged', 'b\n'),
                          ('unchanged', 'C\n'),
                          ('unchanged', 'c\n'),
                          ('unchanged', 'F\n')],
                         list(plan))

    def test_plan_merge_tail_triple_ancestors(self):
        # The graph looks like this:
        #       A       # Common to all ancestors
        #      / \
        #     B   C     # Ancestors of E, only common to one side
        #     |\ /|
        #     D E F     # D, F are unique to G, H respectively
        #     |/|\|     # E is the LCA for G & H, and the unique LCA for
        #     G Q H     # I, J
        #     |\ /|     # Q is just an extra node which is merged into both
        #     | X |     # I and J
        #     |/ \|
        #     I   J     # criss-cross merge of G, H
        #
        # This is the same as the test_plan_merge_tail_ancestors, except we add
        # a third LCA that doesn't add new lines, but will trigger our more
        # involved ancestry logic

        self.add_rev('root', 'A', [], 'abc')
        self.add_rev('root', 'B', ['A'], 'aBbc')
        self.add_rev('root', 'C', ['A'], 'abCc')
        self.add_rev('root', 'D', ['B'], 'DaBbc')
        self.add_rev('root', 'E', ['B', 'C'], 'aBbCc')
        self.add_rev('root', 'F', ['C'], 'abCcF')
        self.add_rev('root', 'G', ['D', 'E'], 'DaBbCc')
        self.add_rev('root', 'H', ['F', 'E'], 'aBbCcF')
        self.add_rev('root', 'Q', ['E'], 'aBbCc')
        self.add_rev('root', 'I', ['G', 'Q', 'H'], 'DaBbCcF')
        # Merge G & H but supersede an old line in B
        self.add_rev('root', 'J', ['H', 'Q', 'G'], 'DaJbCcF')
        plan = self.plan_merge_vf.plan_merge('I', 'J')
        self.assertEqual([
                          ('unchanged', 'D\n'),
                          ('unchanged', 'a\n'),
                          ('killed-b', 'B\n'),
                          ('new-b', 'J\n'),
                          ('unchanged', 'b\n'),
                          ('unchanged', 'C\n'),
                          ('unchanged', 'c\n'),
                          ('unchanged', 'F\n')],
                         list(plan))

    def test_plan_merge_2_tail_triple_ancestors(self):
        # The graph looks like this:
        #     A   B     # 2 tails going back to NULL
        #     |\ /|
        #     D E F     # D, is unique to G, F to H
        #     |/|\|     # E is the LCA for G & H, and the unique LCA for
        #     G Q H     # I, J
        #     |\ /|     # Q is just an extra node which is merged into both
        #     | X |     # I and J
        #     |/ \|
        #     I   J     # criss-cross merge of G, H (and Q)
        #

        # This is meant to test after hitting a 3-way LCA, and multiple tail
        # ancestors (only have NULL_REVISION in common)

        self.add_rev('root', 'A', [], 'abc')
        self.add_rev('root', 'B', [], 'def')
        self.add_rev('root', 'D', ['A'], 'Dabc')
        self.add_rev('root', 'E', ['A', 'B'], 'abcdef')
        self.add_rev('root', 'F', ['B'], 'defF')
        self.add_rev('root', 'G', ['D', 'E'], 'Dabcdef')
        self.add_rev('root', 'H', ['F', 'E'], 'abcdefF')
        self.add_rev('root', 'Q', ['E'], 'abcdef')
        self.add_rev('root', 'I', ['G', 'Q', 'H'], 'DabcdefF')
        # Merge G & H but supersede an old line in B
        self.add_rev('root', 'J', ['H', 'Q', 'G'], 'DabcdJfF')
        plan = self.plan_merge_vf.plan_merge('I', 'J')
        self.assertEqual([
                          ('unchanged', 'D\n'),
                          ('unchanged', 'a\n'),
                          ('unchanged', 'b\n'),
                          ('unchanged', 'c\n'),
                          ('unchanged', 'd\n'),
                          ('killed-b', 'e\n'),
                          ('new-b', 'J\n'),
                          ('unchanged', 'f\n'),
                          ('unchanged', 'F\n')],
                         list(plan))

    def test_plan_merge_uncommitted_files(self):
        self.setup_plan_merge_uncommitted()
        plan = self.plan_merge_vf.plan_merge('B:', 'C:')
        self.assertEqual([
                          ('new-b', 'f\n'),
                          ('unchanged', 'a\n'),
                          ('killed-a', 'b\n'),
                          ('killed-b', 'c\n'),
                          ('new-a', 'e\n'),
                          ('new-a', 'h\n'),
                          ('new-a', 'g\n'),
                          ('new-b', 'g\n')],
                         list(plan))

    def test_plan_merge_insert_order(self):
        """Weave merges are sensitive to the order of insertion.

        Specifically for overlapping regions, it effects which region gets put
        'first'. And when a user resolves an overlapping merge, if they use the
        same ordering, then the lines match the parents, if they don't only
        *some* of the lines match.
        """
        self.add_rev('root', 'A', [], 'abcdef')
        self.add_rev('root', 'B', ['A'], 'abwxcdef')
        self.add_rev('root', 'C', ['A'], 'abyzcdef')
        # Merge, and resolve the conflict by adding *both* sets of lines
        # If we get the ordering wrong, these will look like new lines in D,
        # rather than carried over from B, C
        self.add_rev('root', 'D', ['B', 'C'],
                         'abwxyzcdef')
        # Supersede the lines in B and delete the lines in C, which will
        # conflict if they are treated as being in D
        self.add_rev('root', 'E', ['C', 'B'],
                         'abnocdef')
        # Same thing for the lines in C
        self.add_rev('root', 'F', ['C'], 'abpqcdef')
        plan = self.plan_merge_vf.plan_merge('D', 'E')
        self.assertEqual([
                          ('unchanged', 'a\n'),
                          ('unchanged', 'b\n'),
                          ('killed-b', 'w\n'),
                          ('killed-b', 'x\n'),
                          ('killed-b', 'y\n'),
                          ('killed-b', 'z\n'),
                          ('new-b', 'n\n'),
                          ('new-b', 'o\n'),
                          ('unchanged', 'c\n'),
                          ('unchanged', 'd\n'),
                          ('unchanged', 'e\n'),
                          ('unchanged', 'f\n')],
                         list(plan))
        plan = self.plan_merge_vf.plan_merge('E', 'D')
        # Going in the opposite direction shows the effect of the opposite plan
        self.assertEqual([
                          ('unchanged', 'a\n'),
                          ('unchanged', 'b\n'),
                          ('new-b', 'w\n'),
                          ('new-b', 'x\n'),
                          ('killed-a', 'y\n'),
                          ('killed-a', 'z\n'),
                          ('killed-both', 'w\n'),
                          ('killed-both', 'x\n'),
                          ('new-a', 'n\n'),
                          ('new-a', 'o\n'),
                          ('unchanged', 'c\n'),
                          ('unchanged', 'd\n'),
                          ('unchanged', 'e\n'),
                          ('unchanged', 'f\n')],
                         list(plan))

    def test_plan_merge_criss_cross(self):
        # This is specificly trying to trigger problems when using limited
        # ancestry and weaves. The ancestry graph looks like:
        #       XX      unused ancestor, should not show up in the weave
        #       |
        #       A       Unique LCA
        #       |\
        #       B \     Introduces a line 'foo'
        #      / \ \
        #     C   D E   C & D both have 'foo', E has different changes
        #     |\ /| |
        #     | X | |
        #     |/ \|/
        #     F   G      All of C, D, E are merged into F and G, so they are
        #                all common ancestors.
        #
        # The specific issue with weaves:
        #   B introduced a text ('foo') that is present in both C and D.
        #   If we do not include B (because it isn't an ancestor of E), then
        #   the A=>C and A=>D look like both sides independently introduce the
        #   text ('foo'). If F does not modify the text, it would still appear
        #   to have deleted on of the versions from C or D. If G then modifies
        #   'foo', it should appear as superseding the value in F (since it
        #   came from B), rather than conflict because of the resolution during
        #   C & D.
        self.add_rev('root', 'XX', [], 'qrs')
        self.add_rev('root', 'A', ['XX'], 'abcdef')
        self.add_rev('root', 'B', ['A'], 'axcdef')
        self.add_rev('root', 'C', ['B'], 'axcdefg')
        self.add_rev('root', 'D', ['B'], 'haxcdef')
        self.add_rev('root', 'E', ['A'], 'abcdyf')
        # Simple combining of all texts
        self.add_rev('root', 'F', ['C', 'D', 'E'], 'haxcdyfg')
        # combine and supersede 'x'
        self.add_rev('root', 'G', ['C', 'D', 'E'], 'hazcdyfg')
        plan = self.plan_merge_vf.plan_merge('F', 'G')
        self.assertEqual([
                          ('unchanged', 'h\n'),
                          ('unchanged', 'a\n'),
                          ('killed-base', 'b\n'),
                          ('killed-b', 'x\n'),
                          ('new-b', 'z\n'),
                          ('unchanged', 'c\n'),
                          ('unchanged', 'd\n'),
                          ('killed-base', 'e\n'),
                          ('unchanged', 'y\n'),
                          ('unchanged', 'f\n'),
                          ('unchanged', 'g\n')],
                         list(plan))

    def assertRemoveExternalReferences(self, filtered_parent_map,
                                       child_map, tails, parent_map):
        """Assert results for _PlanMerge._remove_external_references."""
        (act_filtered_parent_map, act_child_map,
         act_tails) = _PlanMerge._remove_external_references(parent_map)

        # The parent map *should* preserve ordering, but the ordering of
        # children is not strictly defined
        # child_map = dict((k, sorted(children))
        #                  for k, children in child_map.iteritems())
        # act_child_map = dict(k, sorted(children)
        #                      for k, children in act_child_map.iteritems())
        self.assertEqual(filtered_parent_map, act_filtered_parent_map)
        self.assertEqual(child_map, act_child_map)
        self.assertEqual(sorted(tails), sorted(act_tails))

    def test__remove_external_references(self):
        # First, nothing to remove
        self.assertRemoveExternalReferences({3: [2], 2: [1], 1: []},
            {1: [2], 2: [3], 3: []}, [1], {3: [2], 2: [1], 1: []})
        # The reverse direction
        self.assertRemoveExternalReferences({1: [2], 2: [3], 3: []},
            {3: [2], 2: [1], 1: []}, [3], {1: [2], 2: [3], 3: []})
        # Extra references
        self.assertRemoveExternalReferences({3: [2], 2: [1], 1: []},
            {1: [2], 2: [3], 3: []}, [1], {3: [2, 4], 2: [1, 5], 1: [6]})
        # Multiple tails
        self.assertRemoveExternalReferences(
            {4: [2, 3], 3: [], 2: [1], 1: []},
            {1: [2], 2: [4], 3: [4], 4: []},
            [1, 3],
            {4: [2, 3], 3: [5], 2: [1], 1: [6]})
        # Multiple children
        self.assertRemoveExternalReferences(
            {1: [3], 2: [3, 4], 3: [], 4: []},
            {1: [], 2: [], 3: [1, 2], 4: [2]},
            [3, 4],
            {1: [3], 2: [3, 4], 3: [5], 4: []})

    def assertPruneTails(self, pruned_map, tails, parent_map):
        child_map = {}
        for key, parent_keys in parent_map.iteritems():
            child_map.setdefault(key, [])
            for pkey in parent_keys:
                child_map.setdefault(pkey, []).append(key)
        _PlanMerge._prune_tails(parent_map, child_map, tails)
        self.assertEqual(pruned_map, parent_map)

    def test__prune_tails(self):
        # Nothing requested to prune
        self.assertPruneTails({1: [], 2: [], 3: []}, [],
                              {1: [], 2: [], 3: []})
        # Prune a single entry
        self.assertPruneTails({1: [], 3: []}, [2],
                              {1: [], 2: [], 3: []})
        # Prune a chain
        self.assertPruneTails({1: []}, [3],
                              {1: [], 2: [3], 3: []})
        # Prune a chain with a diamond
        self.assertPruneTails({1: []}, [5],
                              {1: [], 2: [3, 4], 3: [5], 4: [5], 5: []})
        # Prune a partial chain
        self.assertPruneTails({1: [6], 6:[]}, [5],
                              {1: [2, 6], 2: [3, 4], 3: [5], 4: [5], 5: [],
                               6: []})
        # Prune a chain with multiple tips, that pulls out intermediates
        self.assertPruneTails({1:[3], 3:[]}, [4, 5],
                              {1: [2, 3], 2: [4, 5], 3: [], 4:[], 5:[]})
        self.assertPruneTails({1:[3], 3:[]}, [5, 4],
                              {1: [2, 3], 2: [4, 5], 3: [], 4:[], 5:[]})

    def test_subtract_plans(self):
        old_plan = [
        ('unchanged', 'a\n'),
        ('new-a', 'b\n'),
        ('killed-a', 'c\n'),
        ('new-b', 'd\n'),
        ('new-b', 'e\n'),
        ('killed-b', 'f\n'),
        ('killed-b', 'g\n'),
        ]
        new_plan = [
        ('unchanged', 'a\n'),
        ('new-a', 'b\n'),
        ('killed-a', 'c\n'),
        ('new-b', 'd\n'),
        ('new-b', 'h\n'),
        ('killed-b', 'f\n'),
        ('killed-b', 'i\n'),
        ]
        subtracted_plan = [
        ('unchanged', 'a\n'),
        ('new-a', 'b\n'),
        ('killed-a', 'c\n'),
        ('new-b', 'h\n'),
        ('unchanged', 'f\n'),
        ('killed-b', 'i\n'),
        ]
        self.assertEqual(subtracted_plan,
            list(_PlanMerge._subtract_plans(old_plan, new_plan)))

    def setup_merge_with_base(self):
        self.add_rev('root', 'COMMON', [], 'abc')
        self.add_rev('root', 'THIS', ['COMMON'], 'abcd')
        self.add_rev('root', 'BASE', ['COMMON'], 'eabc')
        self.add_rev('root', 'OTHER', ['BASE'], 'eafb')

    def test_plan_merge_with_base(self):
        self.setup_merge_with_base()
        plan = self.plan_merge_vf.plan_merge('THIS', 'OTHER', 'BASE')
        self.assertEqual([('unchanged', 'a\n'),
                          ('new-b', 'f\n'),
                          ('unchanged', 'b\n'),
                          ('killed-b', 'c\n'),
                          ('new-a', 'd\n')
                         ], list(plan))

    def test_plan_lca_merge(self):
        self.setup_plan_merge()
        plan = self.plan_merge_vf.plan_lca_merge('B', 'C')
        self.assertEqual([
                          ('new-b', 'f\n'),
                          ('unchanged', 'a\n'),
                          ('killed-b', 'c\n'),
                          ('new-a', 'e\n'),
                          ('new-a', 'h\n'),
                          ('killed-a', 'b\n'),
                          ('unchanged', 'g\n')],
                         list(plan))

    def test_plan_lca_merge_uncommitted_files(self):
        self.setup_plan_merge_uncommitted()
        plan = self.plan_merge_vf.plan_lca_merge('B:', 'C:')
        self.assertEqual([
                          ('new-b', 'f\n'),
                          ('unchanged', 'a\n'),
                          ('killed-b', 'c\n'),
                          ('new-a', 'e\n'),
                          ('new-a', 'h\n'),
                          ('killed-a', 'b\n'),
                          ('unchanged', 'g\n')],
                         list(plan))

    def test_plan_lca_merge_with_base(self):
        self.setup_merge_with_base()
        plan = self.plan_merge_vf.plan_lca_merge('THIS', 'OTHER', 'BASE')
        self.assertEqual([('unchanged', 'a\n'),
                          ('new-b', 'f\n'),
                          ('unchanged', 'b\n'),
                          ('killed-b', 'c\n'),
                          ('new-a', 'd\n')
                         ], list(plan))

    def test_plan_lca_merge_with_criss_cross(self):
        self.add_version(('root', 'ROOT'), [], 'abc')
        # each side makes a change
        self.add_version(('root', 'REV1'), [('root', 'ROOT')], 'abcd')
        self.add_version(('root', 'REV2'), [('root', 'ROOT')], 'abce')
        # both sides merge, discarding others' changes
        self.add_version(('root', 'LCA1'),
            [('root', 'REV1'), ('root', 'REV2')], 'abcd')
        self.add_version(('root', 'LCA2'),
            [('root', 'REV1'), ('root', 'REV2')], 'fabce')
        plan = self.plan_merge_vf.plan_lca_merge('LCA1', 'LCA2')
        self.assertEqual([('new-b', 'f\n'),
                          ('unchanged', 'a\n'),
                          ('unchanged', 'b\n'),
                          ('unchanged', 'c\n'),
                          ('conflicted-a', 'd\n'),
                          ('conflicted-b', 'e\n'),
                         ], list(plan))

    def test_plan_lca_merge_with_null(self):
        self.add_version(('root', 'A'), [], 'ab')
        self.add_version(('root', 'B'), [], 'bc')
        plan = self.plan_merge_vf.plan_lca_merge('A', 'B')
        self.assertEqual([('new-a', 'a\n'),
                          ('unchanged', 'b\n'),
                          ('new-b', 'c\n'),
                         ], list(plan))

    def test_plan_merge_with_delete_and_change(self):
        self.add_rev('root', 'C', [], 'a')
        self.add_rev('root', 'A', ['C'], 'b')
        self.add_rev('root', 'B', ['C'], '')
        plan = self.plan_merge_vf.plan_merge('A', 'B')
        self.assertEqual([('killed-both', 'a\n'),
                          ('new-a', 'b\n'),
                         ], list(plan))

    def test_plan_merge_with_move_and_change(self):
        self.add_rev('root', 'C', [], 'abcd')
        self.add_rev('root', 'A', ['C'], 'acbd')
        self.add_rev('root', 'B', ['C'], 'aBcd')
        plan = self.plan_merge_vf.plan_merge('A', 'B')
        self.assertEqual([('unchanged', 'a\n'),
                          ('new-a', 'c\n'),
                          ('killed-b', 'b\n'),
                          ('new-b', 'B\n'),
                          ('killed-a', 'c\n'),
                          ('unchanged', 'd\n'),
                         ], list(plan))


class TestMergeImplementation(object):

    def do_merge(self, target_tree, source_tree, **kwargs):
        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            target_tree, source_tree.last_revision(),
            other_branch=source_tree.branch)
        merger.merge_type=self.merge_type
        for name, value in kwargs.items():
            setattr(merger, name, value)
        merger.do_merge()

    def test_merge_specific_file(self):
        this_tree = self.make_branch_and_tree('this')
        this_tree.lock_write()
        self.addCleanup(this_tree.unlock)
        self.build_tree_contents([
            ('this/file1', 'a\nb\n'),
            ('this/file2', 'a\nb\n')
        ])
        this_tree.add(['file1', 'file2'])
        this_tree.commit('Added files')
        other_tree = this_tree.bzrdir.sprout('other').open_workingtree()
        self.build_tree_contents([
            ('other/file1', 'a\nb\nc\n'),
            ('other/file2', 'a\nb\nc\n')
        ])
        other_tree.commit('modified both')
        self.build_tree_contents([
            ('this/file1', 'd\na\nb\n'),
            ('this/file2', 'd\na\nb\n')
        ])
        this_tree.commit('modified both')
        self.do_merge(this_tree, other_tree, interesting_files=['file1'])
        self.assertFileEqual('d\na\nb\nc\n', 'this/file1')
        self.assertFileEqual('d\na\nb\n', 'this/file2')

    def test_merge_move_and_change(self):
        this_tree = self.make_branch_and_tree('this')
        this_tree.lock_write()
        self.addCleanup(this_tree.unlock)
        self.build_tree_contents([
            ('this/file1', 'line 1\nline 2\nline 3\nline 4\n'),
        ])
        this_tree.add('file1',)
        this_tree.commit('Added file')
        other_tree = this_tree.bzrdir.sprout('other').open_workingtree()
        self.build_tree_contents([
            ('other/file1', 'line 1\nline 2 to 2.1\nline 3\nline 4\n'),
        ])
        other_tree.commit('Changed 2 to 2.1')
        self.build_tree_contents([
            ('this/file1', 'line 1\nline 3\nline 2\nline 4\n'),
        ])
        this_tree.commit('Swapped 2 & 3')
        self.do_merge(this_tree, other_tree)
        self.assertFileEqual('line 1\n'
            '<<<<<<< TREE\n'
            'line 3\n'
            'line 2\n'
            '=======\n'
            'line 2 to 2.1\n'
            'line 3\n'
            '>>>>>>> MERGE-SOURCE\n'
            'line 4\n', 'this/file1')

    def test_modify_conflicts_with_delete(self):
        # If one side deletes a line, and the other modifies that line, then
        # the modification should be considered a conflict
        builder = self.make_branch_builder('test')
        builder.start_series()
        builder.build_snapshot('BASE-id', None,
            [('add', ('', None, 'directory', None)),
             ('add', ('foo', 'foo-id', 'file', 'a\nb\nc\nd\ne\n')),
            ])
        # Delete 'b\n'
        builder.build_snapshot('OTHER-id', ['BASE-id'],
            [('modify', ('foo-id', 'a\nc\nd\ne\n'))])
        # Modify 'b\n', add 'X\n'
        builder.build_snapshot('THIS-id', ['BASE-id'],
            [('modify', ('foo-id', 'a\nb2\nc\nd\nX\ne\n'))])
        builder.finish_series()
        branch = builder.get_branch()
        this_tree = branch.bzrdir.create_workingtree()
        this_tree.lock_write()
        self.addCleanup(this_tree.unlock)
        other_tree = this_tree.bzrdir.sprout('other', 'OTHER-id').open_workingtree()
        self.do_merge(this_tree, other_tree)
        if self.merge_type is _mod_merge.LCAMerger:
            self.expectFailure("lca merge doesn't track deleted lines",
                self.assertFileEqual,
                    'a\n'
                    '<<<<<<< TREE\n'
                    'b2\n'
                    '=======\n'
                    '>>>>>>> MERGE-SOURCE\n'
                    'c\n'
                    'd\n'
                    'X\n'
                    'e\n', 'test/foo')
        else:
            self.assertFileEqual(
                'a\n'
                '<<<<<<< TREE\n'
                'b2\n'
                '=======\n'
                '>>>>>>> MERGE-SOURCE\n'
                'c\n'
                'd\n'
                'X\n'
                'e\n', 'test/foo')

    def get_limbodir_deletiondir(self, wt):
        transform = TreeTransform(wt)
        limbodir = transform._limbodir
        deletiondir = transform._deletiondir
        transform.finalize()
        return (limbodir, deletiondir)
    
    def test_merge_with_existing_limbo(self):
        wt = self.make_branch_and_tree('this')
        (limbodir, deletiondir) =  self.get_limbodir_deletiondir(wt)
        os.mkdir(limbodir)
        self.assertRaises(errors.ExistingLimbo, self.do_merge, wt, wt)
        self.assertRaises(errors.LockError, wt.unlock)

    def test_merge_with_pending_deletion(self):
        wt = self.make_branch_and_tree('this')
        (limbodir, deletiondir) =  self.get_limbodir_deletiondir(wt)
        os.mkdir(deletiondir)
        self.assertRaises(errors.ExistingPendingDeletion, self.do_merge, wt, wt)
        self.assertRaises(errors.LockError, wt.unlock)


class TestMerge3Merge(TestCaseWithTransport, TestMergeImplementation):

    merge_type = _mod_merge.Merge3Merger


class TestWeaveMerge(TestCaseWithTransport, TestMergeImplementation):

    merge_type = _mod_merge.WeaveMerger


class TestLCAMerge(TestCaseWithTransport, TestMergeImplementation):

    merge_type = _mod_merge.LCAMerger

    def test_merge_move_and_change(self):
        self.expectFailure("lca merge doesn't conflict for move and change",
            super(TestLCAMerge, self).test_merge_move_and_change)


class LoggingMerger(object):
    # These seem to be the required attributes
    requires_base = False
    supports_reprocess = False
    supports_show_base = False
    supports_cherrypick = False
    # We intentionally do not define supports_lca_trees

    def __init__(self, *args, **kwargs):
        self.args = args
        self.kwargs = kwargs


class TestMergerBase(TestCaseWithMemoryTransport):
    """Common functionality for Merger tests that don't write to disk."""

    def get_builder(self):
        builder = self.make_branch_builder('path')
        builder.start_series()
        self.addCleanup(builder.finish_series)
        return builder

    def setup_simple_graph(self):
        """Create a simple 3-node graph.

        :return: A BranchBuilder
        """
        #
        #  A
        #  |\
        #  B C
        #
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', ('', None, 'directory', None))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'], [])
        return builder

    def setup_criss_cross_graph(self):
        """Create a 5-node graph with a criss-cross.

        :return: A BranchBuilder
        """
        # A
        # |\
        # B C
        # |X|
        # D E
        builder = self.setup_simple_graph()
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        return builder

    def make_Merger(self, builder, other_revision_id,
                    interesting_files=None, interesting_ids=None):
        """Make a Merger object from a branch builder"""
        mem_tree = memorytree.MemoryTree.create_on_branch(builder.get_branch())
        mem_tree.lock_write()
        self.addCleanup(mem_tree.unlock)
        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            mem_tree, other_revision_id)
        merger.set_interesting_files(interesting_files)
        # It seems there is no matching function for set_interesting_ids
        merger.interesting_ids = interesting_ids
        merger.merge_type = _mod_merge.Merge3Merger
        return merger


class TestMergerInMemory(TestMergerBase):

    def test_cache_trees_with_revision_ids_None(self):
        merger = self.make_Merger(self.setup_simple_graph(), 'C-id')
        original_cache = dict(merger._cached_trees)
        merger.cache_trees_with_revision_ids([None])
        self.assertEqual(original_cache, merger._cached_trees)

    def test_cache_trees_with_revision_ids_no_revision_id(self):
        merger = self.make_Merger(self.setup_simple_graph(), 'C-id')
        original_cache = dict(merger._cached_trees)
        tree = self.make_branch_and_memory_tree('tree')
        merger.cache_trees_with_revision_ids([tree])
        self.assertEqual(original_cache, merger._cached_trees)

    def test_cache_trees_with_revision_ids_having_revision_id(self):
        merger = self.make_Merger(self.setup_simple_graph(), 'C-id')
        original_cache = dict(merger._cached_trees)
        tree = merger.this_branch.repository.revision_tree('B-id')
        original_cache['B-id'] = tree
        merger.cache_trees_with_revision_ids([tree])
        self.assertEqual(original_cache, merger._cached_trees)

    def test_find_base(self):
        merger = self.make_Merger(self.setup_simple_graph(), 'C-id')
        self.assertEqual('A-id', merger.base_rev_id)
        self.assertFalse(merger._is_criss_cross)
        self.assertIs(None, merger._lca_trees)

    def test_find_base_criss_cross(self):
        builder = self.setup_criss_cross_graph()
        merger = self.make_Merger(builder, 'E-id')
        self.assertEqual('A-id', merger.base_rev_id)
        self.assertTrue(merger._is_criss_cross)
        self.assertEqual(['B-id', 'C-id'], [t.get_revision_id()
                                            for t in merger._lca_trees])
        # If we swap the order, we should get a different lca order
        builder.build_snapshot('F-id', ['E-id'], [])
        merger = self.make_Merger(builder, 'D-id')
        self.assertEqual(['C-id', 'B-id'], [t.get_revision_id()
                                            for t in merger._lca_trees])

    def test_find_base_triple_criss_cross(self):
        #       A-.
        #      / \ \
        #     B   C F # F is merged into both branches
        #     |\ /| |
        #     | X | |\
        #     |/ \| | :
        #   : D   E |
        #    \|   |/
        #     G   H
        builder = self.setup_criss_cross_graph()
        builder.build_snapshot('F-id', ['A-id'], [])
        builder.build_snapshot('H-id', ['E-id', 'F-id'], [])
        builder.build_snapshot('G-id', ['D-id', 'F-id'], [])
        merger = self.make_Merger(builder, 'H-id')
        self.assertEqual(['B-id', 'C-id', 'F-id'],
                         [t.get_revision_id() for t in merger._lca_trees])

    def test_no_criss_cross_passed_to_merge_type(self):
        class LCATreesMerger(LoggingMerger):
            supports_lca_trees = True

        merger = self.make_Merger(self.setup_simple_graph(), 'C-id')
        merger.merge_type = LCATreesMerger
        merge_obj = merger.make_merger()
        self.assertIsInstance(merge_obj, LCATreesMerger)
        self.assertFalse('lca_trees' in merge_obj.kwargs)

    def test_criss_cross_passed_to_merge_type(self):
        merger = self.make_Merger(self.setup_criss_cross_graph(), 'E-id')
        merger.merge_type = _mod_merge.Merge3Merger
        merge_obj = merger.make_merger()
        self.assertEqual(['B-id', 'C-id'], [t.get_revision_id()
                                            for t in merger._lca_trees])

    def test_criss_cross_not_supported_merge_type(self):
        merger = self.make_Merger(self.setup_criss_cross_graph(), 'E-id')
        # We explicitly do not define supports_lca_trees
        merger.merge_type = LoggingMerger
        merge_obj = merger.make_merger()
        self.assertIsInstance(merge_obj, LoggingMerger)
        self.assertFalse('lca_trees' in merge_obj.kwargs)

    def test_criss_cross_unsupported_merge_type(self):
        class UnsupportedLCATreesMerger(LoggingMerger):
            supports_lca_trees = False

        merger = self.make_Merger(self.setup_criss_cross_graph(), 'E-id')
        merger.merge_type = UnsupportedLCATreesMerger
        merge_obj = merger.make_merger()
        self.assertIsInstance(merge_obj, UnsupportedLCATreesMerger)
        self.assertFalse('lca_trees' in merge_obj.kwargs)


class TestMergerEntriesLCA(TestMergerBase):

    def make_merge_obj(self, builder, other_revision_id,
                       interesting_files=None, interesting_ids=None):
        merger = self.make_Merger(builder, other_revision_id,
            interesting_files=interesting_files,
            interesting_ids=interesting_ids)
        return merger.make_merger()

    def test_simple(self):
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('C-id', ['A-id'],
            [('modify', ('a-id', 'a\nb\nC\nc\n'))])
        builder.build_snapshot('B-id', ['A-id'],
            [('modify', ('a-id', 'a\nB\nb\nc\n'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('modify', ('a-id', 'a\nB\nb\nC\nc\nE\n'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'],
            [('modify', ('a-id', 'a\nB\nb\nC\nc\n'))])
        merge_obj = self.make_merge_obj(builder, 'E-id')

        self.assertEqual(['B-id', 'C-id'], [t.get_revision_id()
                                            for t in merge_obj._lca_trees])
        self.assertEqual('A-id', merge_obj.base_tree.get_revision_id())
        entries = list(merge_obj._entries_lca())

        # (file_id, changed, parents, names, executable)
        # BASE, lca1, lca2, OTHER, THIS
        root_id = 'a-root-id'
        self.assertEqual([('a-id', True,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'a', [u'a', u'a']), u'a', u'a'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_not_in_base(self):
        # LCAs all have the same last-modified revision for the file, as do
        # the tips, but the base has something different
        #       A    base, doesn't have the file
        #       |\
        #       B C  B introduces 'foo', C introduces 'bar'
        #       |X|
        #       D E  D and E now both have 'foo' and 'bar'
        #       |X|
        #       F G  the files are now in F, G, D and E, but not in A
        #            G modifies 'bar'

        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None))])
        builder.build_snapshot('B-id', ['A-id'],
            [('add', (u'foo', 'foo-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('C-id', ['A-id'],
            [('add', (u'bar', 'bar-id', 'file', 'd\ne\nf\n'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'],
            [('add', (u'bar', 'bar-id', 'file', 'd\ne\nf\n'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('add', (u'foo', 'foo-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('G-id', ['E-id', 'D-id'],
            [('modify', (u'bar-id', 'd\ne\nf\nG\n'))])
        builder.build_snapshot('F-id', ['D-id', 'E-id'], [])
        merge_obj = self.make_merge_obj(builder, 'G-id')

        self.assertEqual(['D-id', 'E-id'], [t.get_revision_id()
                                            for t in merge_obj._lca_trees])
        self.assertEqual('A-id', merge_obj.base_tree.get_revision_id())
        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('bar-id', True,
                           ((None, [root_id, root_id]), root_id, root_id),
                           ((None, [u'bar', u'bar']), u'bar', u'bar'),
                           ((None, [False, False]), False, False)),
                         ], entries)

    def test_not_in_this(self):
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('B-id', ['A-id'],
            [('modify', ('a-id', 'a\nB\nb\nc\n'))])
        builder.build_snapshot('C-id', ['A-id'],
            [('modify', ('a-id', 'a\nb\nC\nc\n'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('modify', ('a-id', 'a\nB\nb\nC\nc\nE\n'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'],
            [('unversion', 'a-id')])
        merge_obj = self.make_merge_obj(builder, 'E-id')

        self.assertEqual(['B-id', 'C-id'], [t.get_revision_id()
                                            for t in merge_obj._lca_trees])
        self.assertEqual('A-id', merge_obj.base_tree.get_revision_id())

        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('a-id', True,
                           ((root_id, [root_id, root_id]), root_id, None),
                           ((u'a', [u'a', u'a']), u'a', None),
                           ((False, [False, False]), False, None)),
                         ], entries)

    def test_file_not_in_one_lca(self):
        #   A   # just root
        #   |\
        #   B C # B no file, C introduces a file
        #   |X|
        #   D E # D and E both have the file, unchanged from C
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None))])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('C-id', ['A-id'],
            [('add', (u'a', 'a-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], []) # Inherited from C
        builder.build_snapshot('D-id', ['B-id', 'C-id'], # Merged from C
            [('add', (u'a', 'a-id', 'file', 'a\nb\nc\n'))])
        merge_obj = self.make_merge_obj(builder, 'E-id')

        self.assertEqual(['B-id', 'C-id'], [t.get_revision_id()
                                            for t in merge_obj._lca_trees])
        self.assertEqual('A-id', merge_obj.base_tree.get_revision_id())

        entries = list(merge_obj._entries_lca())
        self.assertEqual([], entries)

    def test_not_in_other(self):
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('unversion', 'a-id')])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        merge_obj = self.make_merge_obj(builder, 'E-id')

        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('a-id', True,
                           ((root_id, [root_id, root_id]), None, root_id),
                           ((u'a', [u'a', u'a']), None, u'a'),
                           ((False, [False, False]), None, False)),
                         ], entries)

    def test_not_in_other_or_lca(self):
        #       A    base, introduces 'foo'
        #       |\
        #       B C  B nothing, C deletes foo
        #       |X|
        #       D E  D restores foo (same as B), E leaves it deleted
        # Analysis:
        #   A => B, no changes
        #   A => C, delete foo (C should supersede B)
        #   C => D, restore foo
        #   C => E, no changes
        # D would then win 'cleanly' and no record would be given
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'content\n'))])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('C-id', ['A-id'],
            [('unversion', 'foo-id')])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        merge_obj = self.make_merge_obj(builder, 'E-id')

        entries = list(merge_obj._entries_lca())
        self.assertEqual([], entries)

    def test_not_in_other_mod_in_lca1_not_in_lca2(self):
        #       A    base, introduces 'foo'
        #       |\
        #       B C  B changes 'foo', C deletes foo
        #       |X|
        #       D E  D restores foo (same as B), E leaves it deleted (as C)
        # Analysis:
        #   A => B, modified foo
        #   A => C, delete foo, C does not supersede B
        #   B => D, no changes
        #   C => D, resolve in favor of B
        #   B => E, resolve in favor of E
        #   C => E, no changes
        # In this case, we have a conflict of how the changes were resolved. E
        # picked C and D picked B, so we should issue a conflict
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'content\n'))])
        builder.build_snapshot('B-id', ['A-id'], [
            ('modify', ('foo-id', 'new-content\n'))])
        builder.build_snapshot('C-id', ['A-id'],
            [('unversion', 'foo-id')])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        merge_obj = self.make_merge_obj(builder, 'E-id')

        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('foo-id', True,
                           ((root_id, [root_id, None]), None, root_id),
                           ((u'foo', [u'foo', None]), None, 'foo'),
                           ((False, [False, None]), None, False)),
                         ], entries)

    def test_only_in_one_lca(self):
        #   A   add only root
        #   |\
        #   B C B nothing, C add file
        #   |X|
        #   D E D still has nothing, E removes file
        # Analysis:
        #   B => D, no change
        #   C => D, removed the file
        #   B => E, no change
        #   C => E, removed the file
        # Thus D & E have identical changes, and this is a no-op
        # Alternatively:
        #   A => B, no change
        #   A => C, add file, thus C supersedes B
        #   w/ C=BASE, D=THIS, E=OTHER we have 'happy convergence'
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None))])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('C-id', ['A-id'],
            [('add', (u'a', 'a-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('unversion', 'a-id')])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        merge_obj = self.make_merge_obj(builder, 'E-id')

        entries = list(merge_obj._entries_lca())
        self.assertEqual([], entries)

    def test_only_in_other(self):
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None))])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('add', (u'a', 'a-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        merge_obj = self.make_merge_obj(builder, 'E-id')

        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('a-id', True,
                           ((None, [None, None]), root_id, None),
                           ((None, [None, None]), u'a', None),
                           ((None, [None, None]), False, None)),
                         ], entries)

    def test_one_lca_supersedes(self):
        # One LCA supersedes the other LCAs last modified value, but the
        # value is not the same as BASE.
        #       A    base, introduces 'foo', last mod A
        #       |\
        #       B C  B modifies 'foo' (mod B), C does nothing (mod A)
        #       |X|
        #       D E  D does nothing (mod B), E updates 'foo' (mod E)
        #       |X|
        #       F G  F updates 'foo' (mod F). G does nothing (mod E)
        #
        #   At this point, G should not be considered to modify 'foo', even
        #   though its LCAs disagree. This is because the modification in E
        #   completely supersedes the value in D.
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'A content\n'))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'],
            [('modify', ('foo-id', 'B content\n'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('modify', ('foo-id', 'E content\n'))])
        builder.build_snapshot('G-id', ['E-id', 'D-id'], [])
        builder.build_snapshot('F-id', ['D-id', 'E-id'],
            [('modify', ('foo-id', 'F content\n'))])
        merge_obj = self.make_merge_obj(builder, 'G-id')

        self.assertEqual([], list(merge_obj._entries_lca()))

    def test_one_lca_supersedes_path(self):
        # Double-criss-cross merge, the ultimate base value is different from
        # the intermediate.
        #   A    value 'foo'
        #   |\
        #   B C  B value 'bar', C = 'foo'
        #   |X|
        #   D E  D = 'bar', E supersedes to 'bing'
        #   |X|
        #   F G  F = 'bing', G supersedes to 'barry'
        #
        # In this case, we technically should not care about the value 'bar' for
        # D, because it was clearly superseded by E's 'bing'. The
        # per-file/attribute graph would actually look like:
        #   A
        #   |
        #   B
        #   |
        #   E
        #   |
        #   G
        #
        # Because the other side of the merge never modifies the value, it just
        # takes the value from the merge.
        #
        # ATM this fails because we will prune 'foo' from the LCAs, but we
        # won't prune 'bar'. This is getting far off into edge-case land, so we
        # aren't supporting it yet.
        #
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'A content\n'))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'],
            [('rename', ('foo', 'bar'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('rename', ('foo', 'bing'))]) # override to bing
        builder.build_snapshot('G-id', ['E-id', 'D-id'],
            [('rename', ('bing', 'barry'))]) # override to barry
        builder.build_snapshot('F-id', ['D-id', 'E-id'],
            [('rename', ('bar', 'bing'))]) # Merge in E's change
        merge_obj = self.make_merge_obj(builder, 'G-id')

        self.expectFailure("We don't do an actual heads() check on lca values,"
            " or use the per-attribute graph",
            self.assertEqual, [], list(merge_obj._entries_lca()))

    def test_one_lca_accidentally_pruned(self):
        # Another incorrect resolution from the same basic flaw:
        #   A    value 'foo'
        #   |\
        #   B C  B value 'bar', C = 'foo'
        #   |X|
        #   D E  D = 'bar', E reverts to 'foo'
        #   |X|
        #   F G  F = 'bing', G switches to 'bar'
        #
        # 'bar' will not be seen as an interesting change, because 'foo' will
        # be pruned from the LCAs, even though it was newly introduced by E
        # (superseding B).
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'A content\n'))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'],
            [('rename', ('foo', 'bar'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        builder.build_snapshot('G-id', ['E-id', 'D-id'],
            [('rename', ('foo', 'bar'))])
        builder.build_snapshot('F-id', ['D-id', 'E-id'],
            [('rename', ('bar', 'bing'))]) # should end up conflicting
        merge_obj = self.make_merge_obj(builder, 'G-id')

        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.expectFailure("We prune values from BASE even when relevant.",
            self.assertEqual,
                [('foo-id', False,
                  ((root_id, [root_id, root_id]), root_id, root_id),
                  ((u'foo', [u'bar', u'foo']), u'bar', u'bing'),
                  ((False, [False, False]), False, False)),
                ], entries)

    def test_both_sides_revert(self):
        # Both sides of a criss-cross revert the text to the lca
        #       A    base, introduces 'foo'
        #       |\
        #       B C  B modifies 'foo', C modifies 'foo'
        #       |X|
        #       D E  D reverts to B, E reverts to C
        # This should conflict
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'A content\n'))])
        builder.build_snapshot('B-id', ['A-id'],
            [('modify', ('foo-id', 'B content\n'))])
        builder.build_snapshot('C-id', ['A-id'],
            [('modify', ('foo-id', 'C content\n'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        merge_obj = self.make_merge_obj(builder, 'E-id')

        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('foo-id', True,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'foo', [u'foo', u'foo']), u'foo', u'foo'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_different_lca_resolve_one_side_updates_content(self):
        # Both sides converge, but then one side updates the text.
        #       A    base, introduces 'foo'
        #       |\
        #       B C  B modifies 'foo', C modifies 'foo'
        #       |X|
        #       D E  D reverts to B, E reverts to C
        #       |
        #       F    F updates to a new value
        # We need to emit an entry for 'foo', because D & E differed on the
        # merge resolution
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'A content\n'))])
        builder.build_snapshot('B-id', ['A-id'],
            [('modify', ('foo-id', 'B content\n'))])
        builder.build_snapshot('C-id', ['A-id'],
            [('modify', ('foo-id', 'C content\n'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        builder.build_snapshot('F-id', ['D-id'],
            [('modify', ('foo-id', 'F content\n'))])
        merge_obj = self.make_merge_obj(builder, 'E-id')

        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('foo-id', True,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'foo', [u'foo', u'foo']), u'foo', u'foo'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_same_lca_resolution_one_side_updates_content(self):
        # Both sides converge, but then one side updates the text.
        #       A    base, introduces 'foo'
        #       |\
        #       B C  B modifies 'foo', C modifies 'foo'
        #       |X|
        #       D E  D and E use C's value
        #       |
        #       F    F updates to a new value
        # I think it is a bug that this conflicts, but we don't have a way to
        # detect otherwise. And because of:
        #   test_different_lca_resolve_one_side_updates_content
        # We need to conflict.

        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'A content\n'))])
        builder.build_snapshot('B-id', ['A-id'],
            [('modify', ('foo-id', 'B content\n'))])
        builder.build_snapshot('C-id', ['A-id'],
            [('modify', ('foo-id', 'C content\n'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        builder.build_snapshot('D-id', ['B-id', 'C-id'],
            [('modify', ('foo-id', 'C content\n'))]) # Same as E
        builder.build_snapshot('F-id', ['D-id'],
            [('modify', ('foo-id', 'F content\n'))])
        merge_obj = self.make_merge_obj(builder, 'E-id')

        entries = list(merge_obj._entries_lca())
        self.expectFailure("We don't detect that LCA resolution was the"
                           " same on both sides",
            self.assertEqual, [], entries)

    def test_only_path_changed(self):
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'content\n'))])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('rename', (u'a', u'b'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        merge_obj = self.make_merge_obj(builder, 'E-id')
        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        # The content was not changed, only the path
        self.assertEqual([('a-id', False,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'a', [u'a', u'a']), u'b', u'a'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_kind_changed(self):
        # Identical content, except 'D' changes a-id into a directory
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'content\n'))])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('unversion', 'a-id'),
             ('add', (u'a', 'a-id', 'directory', None))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        merge_obj = self.make_merge_obj(builder, 'E-id')
        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        # Only the kind was changed (content)
        self.assertEqual([('a-id', True,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'a', [u'a', u'a']), u'a', u'a'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_this_changed_kind(self):
        # Identical content, but THIS changes a file to a directory
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'content\n'))])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        builder.build_snapshot('D-id', ['B-id', 'C-id'],
            [('unversion', 'a-id'),
             ('add', (u'a', 'a-id', 'directory', None))])
        merge_obj = self.make_merge_obj(builder, 'E-id')
        entries = list(merge_obj._entries_lca())
        # Only the kind was changed (content)
        self.assertEqual([], entries)

    def test_interesting_files(self):
        # Two files modified, but we should filter one of them
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'content\n')),
             ('add', (u'b', 'b-id', 'file', 'content\n'))])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('modify', ('a-id', 'new-content\n')),
             ('modify', ('b-id', 'new-content\n'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        merge_obj = self.make_merge_obj(builder, 'E-id',
                                        interesting_files=['b'])
        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('b-id', True,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'b', [u'b', u'b']), u'b', u'b'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_interesting_file_in_this(self):
        # This renamed the file, but it should still match the entry in other
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'content\n')),
             ('add', (u'b', 'b-id', 'file', 'content\n'))])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('modify', ('a-id', 'new-content\n')),
             ('modify', ('b-id', 'new-content\n'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'],
            [('rename', ('b', 'c'))])
        merge_obj = self.make_merge_obj(builder, 'E-id',
                                        interesting_files=['c'])
        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('b-id', True,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'b', [u'b', u'b']), u'b', u'c'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_interesting_file_in_base(self):
        # This renamed the file, but it should still match the entry in BASE
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'content\n')),
             ('add', (u'c', 'c-id', 'file', 'content\n'))])
        builder.build_snapshot('B-id', ['A-id'],
            [('rename', ('c', 'b'))])
        builder.build_snapshot('C-id', ['A-id'],
            [('rename', ('c', 'b'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('modify', ('a-id', 'new-content\n')),
             ('modify', ('c-id', 'new-content\n'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        merge_obj = self.make_merge_obj(builder, 'E-id',
                                        interesting_files=['c'])
        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('c-id', True,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'c', [u'b', u'b']), u'b', u'b'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_interesting_file_in_lca(self):
        # This renamed the file, but it should still match the entry in LCA
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'content\n')),
             ('add', (u'b', 'b-id', 'file', 'content\n'))])
        builder.build_snapshot('B-id', ['A-id'],
            [('rename', ('b', 'c'))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('modify', ('a-id', 'new-content\n')),
             ('modify', ('b-id', 'new-content\n'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'],
            [('rename', ('c', 'b'))])
        merge_obj = self.make_merge_obj(builder, 'E-id',
                                        interesting_files=['c'])
        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('b-id', True,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'b', [u'c', u'b']), u'b', u'b'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_interesting_ids(self):
        # Two files modified, but we should filter one of them
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'content\n')),
             ('add', (u'b', 'b-id', 'file', 'content\n'))])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('modify', ('a-id', 'new-content\n')),
             ('modify', ('b-id', 'new-content\n'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        merge_obj = self.make_merge_obj(builder, 'E-id',
                                        interesting_ids=['b-id'])
        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('b-id', True,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'b', [u'b', u'b']), u'b', u'b'),
                           ((False, [False, False]), False, False)),
                         ], entries)



class TestMergerEntriesLCAOnDisk(tests.TestCaseWithTransport):

    def get_builder(self):
        builder = self.make_branch_builder('path')
        builder.start_series()
        self.addCleanup(builder.finish_series)
        return builder

    def get_wt_from_builder(self, builder):
        """Get a real WorkingTree from the builder."""
        the_branch = builder.get_branch()
        wt = the_branch.bzrdir.create_workingtree()
        # Note: This is a little bit ugly, but we are holding the branch
        #       write-locked as part of the build process, and we would like to
        #       maintain that. So we just force the WT to re-use the same
        #       branch object.
        wt._branch = the_branch
        wt.lock_write()
        self.addCleanup(wt.unlock)
        return wt

    def do_merge(self, builder, other_revision_id):
        wt = self.get_wt_from_builder(builder)
        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            wt, other_revision_id)
        merger.merge_type = _mod_merge.Merge3Merger
        return wt, merger.do_merge()

    def test_simple_lca(self):
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        builder.build_snapshot('D-id', ['B-id', 'C-id'],
            [('modify', ('a-id', 'a\nb\nc\nd\ne\nf\n'))])
        wt, conflicts = self.do_merge(builder, 'E-id')
        self.assertEqual(0, conflicts)
        # The merge should have simply update the contents of 'a'
        self.assertEqual('a\nb\nc\nd\ne\nf\n', wt.get_file_text('a-id'))

    def test_conflict_without_lca(self):
        # This test would cause a merge conflict, unless we use the lca trees
        # to determine the real ancestry
        #   A       Path at 'foo'
        #  / \
        # B   C     Path renamed to 'bar' in B
        # |\ /|
        # | X |
        # |/ \|
        # D   E     Path at 'bar' in D and E
        #     |
        #     F     Path at 'baz' in F, which supersedes 'bar' and 'foo'
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'],
            [('rename', ('foo', 'bar'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], # merge the rename
            [('rename', ('foo', 'bar'))])
        builder.build_snapshot('F-id', ['E-id'],
            [('rename', ('bar', 'baz'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        wt, conflicts = self.do_merge(builder, 'F-id')
        self.assertEqual(0, conflicts)
        # The merge should simply recognize that the final rename takes
        # precedence
        self.assertEqual('baz', wt.id2path('foo-id'))

    def test_other_deletes_lca_renames(self):
        # This test would cause a merge conflict, unless we use the lca trees
        # to determine the real ancestry
        #   A       Path at 'foo'
        #  / \
        # B   C     Path renamed to 'bar' in B
        # |\ /|
        # | X |
        # |/ \|
        # D   E     Path at 'bar' in D and E
        #     |
        #     F     F deletes 'bar'
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'],
            [('rename', ('foo', 'bar'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], # merge the rename
            [('rename', ('foo', 'bar'))])
        builder.build_snapshot('F-id', ['E-id'],
            [('unversion', 'foo-id')])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        wt, conflicts = self.do_merge(builder, 'F-id')
        self.assertEqual(0, conflicts)
        self.assertRaises(errors.NoSuchId, wt.id2path, 'foo-id')

    def test_executable_changes(self):
        #   A       Path at 'foo'
        #  / \
        # B   C
        # |\ /|
        # | X |
        # |/ \|
        # D   E
        #     |
        #     F     Executable bit changed
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        # Have to use a real WT, because BranchBuilder doesn't support exec bit
        wt = self.get_wt_from_builder(builder)
        tt = transform.TreeTransform(wt)
        try:
            tt.set_executability(True, tt.trans_id_tree_file_id('foo-id'))
            tt.apply()
        except:
            tt.finalize()
            raise
        self.assertTrue(wt.is_executable('foo-id'))
        wt.commit('F-id', rev_id='F-id')
        # Reset to D, so that we can merge F
        wt.set_parent_ids(['D-id'])
        wt.branch.set_last_revision_info(3, 'D-id')
        wt.revert()
        self.assertFalse(wt.is_executable('foo-id'))
        conflicts = wt.merge_from_branch(wt.branch, to_revision='F-id')
        self.assertEqual(0, conflicts)
        self.assertTrue(wt.is_executable('foo-id'))

    def test_create_symlink(self):
        self.requireFeature(tests.SymlinkFeature)
        #   A
        #  / \
        # B   C
        # |\ /|
        # | X |
        # |/ \|
        # D   E
        #     |
        #     F     Add a symlink 'foo' => 'bar'
        # Have to use a real WT, because BranchBuilder and MemoryTree don't
        # have symlink support
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'], [])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        # Have to use a real WT, because BranchBuilder doesn't support exec bit
        wt = self.get_wt_from_builder(builder)
        os.symlink('bar', 'path/foo')
        wt.add(['foo'], ['foo-id'])
        self.assertEqual('bar', wt.get_symlink_target('foo-id'))
        wt.commit('add symlink', rev_id='F-id')
        # Reset to D, so that we can merge F
        wt.set_parent_ids(['D-id'])
        wt.branch.set_last_revision_info(3, 'D-id')
        wt.revert()
        self.assertIs(None, wt.path2id('foo'))
        conflicts = wt.merge_from_branch(wt.branch, to_revision='F-id')
        self.assertEqual(0, conflicts)
        self.assertEqual('foo-id', wt.path2id('foo'))
        self.assertEqual('bar', wt.get_symlink_target('foo-id'))

    def test_both_sides_revert(self):
        # Both sides of a criss-cross revert the text to the lca
        #       A    base, introduces 'foo'
        #       |\
        #       B C  B modifies 'foo', C modifies 'foo'
        #       |X|
        #       D E  D reverts to B, E reverts to C
        # This should conflict
        # This must be done with a real WorkingTree, because normally their
        # inventory contains "None" rather than a real sha1
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'A content\n'))])
        builder.build_snapshot('B-id', ['A-id'],
            [('modify', ('foo-id', 'B content\n'))])
        builder.build_snapshot('C-id', ['A-id'],
            [('modify', ('foo-id', 'C content\n'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'], [])
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        wt, conflicts = self.do_merge(builder, 'E-id')
        self.assertEqual(1, conflicts)
        self.assertEqualDiff('<<<<<<< TREE\n'
                             'B content\n'
                             '=======\n'
                             'C content\n'
                             '>>>>>>> MERGE-SOURCE\n',
                             wt.get_file_text('foo-id'))

    def test_modified_symlink(self):
        self.requireFeature(tests.SymlinkFeature)
        #   A       Create symlink foo => bar
        #  / \
        # B   C     B relinks foo => baz
        # |\ /|
        # | X |
        # |/ \|
        # D   E     D & E have foo => baz
        #     |
        #     F     F changes it to bing
        #
        # Merging D & F should result in F cleanly overriding D, because D's
        # value actually comes from B

        # Have to use a real WT, because BranchBuilder and MemoryTree don't
        # have symlink support
        wt = self.make_branch_and_tree('path')
        wt.lock_write()
        self.addCleanup(wt.unlock)
        os.symlink('bar', 'path/foo')
        wt.add(['foo'], ['foo-id'])
        wt.commit('add symlink', rev_id='A-id')
        os.remove('path/foo')
        os.symlink('baz', 'path/foo')
        wt.commit('foo => baz', rev_id='B-id')
        wt.set_last_revision('A-id')
        wt.branch.set_last_revision_info(1, 'A-id')
        wt.revert()
        wt.commit('C', rev_id='C-id')
        wt.merge_from_branch(wt.branch, 'B-id')
        self.assertEqual('baz', wt.get_symlink_target('foo-id'))
        wt.commit('E merges C & B', rev_id='E-id')
        os.remove('path/foo')
        os.symlink('bing', 'path/foo')
        wt.commit('F foo => bing', rev_id='F-id')
        wt.set_last_revision('B-id')
        wt.branch.set_last_revision_info(2, 'B-id')
        wt.revert()
        wt.merge_from_branch(wt.branch, 'C-id')
        wt.commit('D merges B & C', rev_id='D-id')
        conflicts = wt.merge_from_branch(wt.branch, to_revision='F-id')
        self.assertEqual(0, conflicts)
        self.assertEqual('bing', wt.get_symlink_target('foo-id'))

    def test_renamed_symlink(self):
        self.requireFeature(tests.SymlinkFeature)
        #   A       Create symlink foo => bar
        #  / \
        # B   C     B renames foo => barry
        # |\ /|
        # | X |
        # |/ \|
        # D   E     D & E have barry
        #     |
        #     F     F renames barry to blah
        #
        # Merging D & F should result in F cleanly overriding D, because D's
        # value actually comes from B

        wt = self.make_branch_and_tree('path')
        wt.lock_write()
        self.addCleanup(wt.unlock)
        os.symlink('bar', 'path/foo')
        wt.add(['foo'], ['foo-id'])
        wt.commit('A add symlink', rev_id='A-id')
        wt.rename_one('foo', 'barry')
        wt.commit('B foo => barry', rev_id='B-id')
        wt.set_last_revision('A-id')
        wt.branch.set_last_revision_info(1, 'A-id')
        wt.revert()
        wt.commit('C', rev_id='C-id')
        wt.merge_from_branch(wt.branch, 'B-id')
        self.assertEqual('barry', wt.id2path('foo-id'))
        self.assertEqual('bar', wt.get_symlink_target('foo-id'))
        wt.commit('E merges C & B', rev_id='E-id')
        wt.rename_one('barry', 'blah')
        wt.commit('F barry => blah', rev_id='F-id')
        wt.set_last_revision('B-id')
        wt.branch.set_last_revision_info(2, 'B-id')
        wt.revert()
        wt.merge_from_branch(wt.branch, 'C-id')
        wt.commit('D merges B & C', rev_id='D-id')
        self.assertEqual('barry', wt.id2path('foo-id'))
        # Check the output of the Merger object directly
        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            wt, 'F-id')
        merger.merge_type = _mod_merge.Merge3Merger
        merge_obj = merger.make_merger()
        root_id = wt.path2id('')
        entries = list(merge_obj._entries_lca())
        # No content change, just a path change
        self.assertEqual([('foo-id', False,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'foo', [u'barry', u'foo']), u'blah', u'barry'),
                           ((False, [False, False]), False, False)),
                         ], entries)
        conflicts = wt.merge_from_branch(wt.branch, to_revision='F-id')
        self.assertEqual(0, conflicts)
        self.assertEqual('blah', wt.id2path('foo-id'))

    def test_symlink_no_content_change(self):
        self.requireFeature(tests.SymlinkFeature)
        #   A       Create symlink foo => bar
        #  / \
        # B   C     B relinks foo => baz
        # |\ /|
        # | X |
        # |/ \|
        # D   E     D & E have foo => baz
        # |
        # F         F has foo => bing
        #
        # Merging E into F should not cause a conflict, because E doesn't have
        # a content change relative to the LCAs (it does relative to A)
        wt = self.make_branch_and_tree('path')
        wt.lock_write()
        self.addCleanup(wt.unlock)
        os.symlink('bar', 'path/foo')
        wt.add(['foo'], ['foo-id'])
        wt.commit('add symlink', rev_id='A-id')
        os.remove('path/foo')
        os.symlink('baz', 'path/foo')
        wt.commit('foo => baz', rev_id='B-id')
        wt.set_last_revision('A-id')
        wt.branch.set_last_revision_info(1, 'A-id')
        wt.revert()
        wt.commit('C', rev_id='C-id')
        wt.merge_from_branch(wt.branch, 'B-id')
        self.assertEqual('baz', wt.get_symlink_target('foo-id'))
        wt.commit('E merges C & B', rev_id='E-id')
        wt.set_last_revision('B-id')
        wt.branch.set_last_revision_info(2, 'B-id')
        wt.revert()
        wt.merge_from_branch(wt.branch, 'C-id')
        wt.commit('D merges B & C', rev_id='D-id')
        os.remove('path/foo')
        os.symlink('bing', 'path/foo')
        wt.commit('F foo => bing', rev_id='F-id')

        # Check the output of the Merger object directly
        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            wt, 'E-id')
        merger.merge_type = _mod_merge.Merge3Merger
        merge_obj = merger.make_merger()
        # Nothing interesting happened in OTHER relative to BASE
        self.assertEqual([], list(merge_obj._entries_lca()))
        # Now do a real merge, just to test the rest of the stack
        conflicts = wt.merge_from_branch(wt.branch, to_revision='E-id')
        self.assertEqual(0, conflicts)
        self.assertEqual('bing', wt.get_symlink_target('foo-id'))

    def test_symlink_this_changed_kind(self):
        self.requireFeature(tests.SymlinkFeature)
        #   A       Nothing
        #  / \
        # B   C     B creates symlink foo => bar
        # |\ /|
        # | X |
        # |/ \|
        # D   E     D changes foo into a file, E has foo => bing
        #
        # Mostly, this is trying to test that we don't try to os.readlink() on
        # a file, or when there is nothing there
        wt = self.make_branch_and_tree('path')
        wt.lock_write()
        self.addCleanup(wt.unlock)
        wt.commit('base', rev_id='A-id')
        os.symlink('bar', 'path/foo')
        wt.add(['foo'], ['foo-id'])
        wt.commit('add symlink foo => bar', rev_id='B-id')
        wt.set_last_revision('A-id')
        wt.branch.set_last_revision_info(1, 'A-id')
        wt.revert()
        wt.commit('C', rev_id='C-id')
        wt.merge_from_branch(wt.branch, 'B-id')
        self.assertEqual('bar', wt.get_symlink_target('foo-id'))
        os.remove('path/foo')
        # We have to change the link in E, or it won't try to do a comparison
        os.symlink('bing', 'path/foo')
        wt.commit('E merges C & B, overrides to bing', rev_id='E-id')
        wt.set_last_revision('B-id')
        wt.branch.set_last_revision_info(2, 'B-id')
        wt.revert()
        wt.merge_from_branch(wt.branch, 'C-id')
        os.remove('path/foo')
        self.build_tree_contents([('path/foo', 'file content\n')])
        # XXX: workaround, WT doesn't detect kind changes unless you do
        # iter_changes()
        list(wt.iter_changes(wt.basis_tree()))
        wt.commit('D merges B & C, makes it a file', rev_id='D-id')

        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            wt, 'E-id')
        merger.merge_type = _mod_merge.Merge3Merger
        merge_obj = merger.make_merger()
        entries = list(merge_obj._entries_lca())
        root_id = wt.path2id('')
        self.assertEqual([('foo-id', True,
                           ((None, [root_id, None]), root_id, root_id),
                           ((None, [u'foo', None]), u'foo', u'foo'),
                           ((None, [False, None]), False, False)),
                         ], entries)

    def test_symlink_all_wt(self):
        """Check behavior if all trees are Working Trees."""
        self.requireFeature(tests.SymlinkFeature)
        # The big issue is that entry.symlink_target is None for WorkingTrees.
        # So we need to make sure we handle that case correctly.
        #   A   foo => bar
        #   |\
        #   B C B relinks foo => baz
        #   |X|
        #   D E D & E have foo => baz
        #     |
        #     F F changes it to bing
        # Merging D & F should result in F cleanly overriding D, because D's
        # value actually comes from B

        wt = self.make_branch_and_tree('path')
        wt.lock_write()
        self.addCleanup(wt.unlock)
        os.symlink('bar', 'path/foo')
        wt.add(['foo'], ['foo-id'])
        wt.commit('add symlink', rev_id='A-id')
        os.remove('path/foo')
        os.symlink('baz', 'path/foo')
        wt.commit('foo => baz', rev_id='B-id')
        wt.set_last_revision('A-id')
        wt.branch.set_last_revision_info(1, 'A-id')
        wt.revert()
        wt.commit('C', rev_id='C-id')
        wt.merge_from_branch(wt.branch, 'B-id')
        self.assertEqual('baz', wt.get_symlink_target('foo-id'))
        wt.commit('E merges C & B', rev_id='E-id')
        os.remove('path/foo')
        os.symlink('bing', 'path/foo')
        wt.commit('F foo => bing', rev_id='F-id')
        wt.set_last_revision('B-id')
        wt.branch.set_last_revision_info(2, 'B-id')
        wt.revert()
        wt.merge_from_branch(wt.branch, 'C-id')
        wt.commit('D merges B & C', rev_id='D-id')
        wt_base = wt.bzrdir.sprout('base', 'A-id').open_workingtree()
        wt_base.lock_read()
        self.addCleanup(wt_base.unlock)
        wt_lca1 = wt.bzrdir.sprout('b-tree', 'B-id').open_workingtree()
        wt_lca1.lock_read()
        self.addCleanup(wt_lca1.unlock)
        wt_lca2 = wt.bzrdir.sprout('c-tree', 'C-id').open_workingtree()
        wt_lca2.lock_read()
        self.addCleanup(wt_lca2.unlock)
        wt_other = wt.bzrdir.sprout('other', 'F-id').open_workingtree()
        wt_other.lock_read()
        self.addCleanup(wt_other.unlock)
        merge_obj = _mod_merge.Merge3Merger(wt, wt, wt_base,
            wt_other, lca_trees=[wt_lca1, wt_lca2], do_merge=False)
        entries = list(merge_obj._entries_lca())
        root_id = wt.path2id('')
        self.assertEqual([('foo-id', True,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'foo', [u'foo', u'foo']), u'foo', u'foo'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_other_reverted_path_to_base(self):
        #   A       Path at 'foo'
        #  / \
        # B   C     Path at 'bar' in B
        # |\ /|
        # | X |
        # |/ \|
        # D   E     Path at 'bar'
        #     |
        #     F     Path at 'foo'
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'a\nb\nc\n'))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'],
            [('rename', ('foo', 'bar'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('rename', ('foo', 'bar'))]) # merge the rename
        builder.build_snapshot('F-id', ['E-id'],
            [('rename', ('bar', 'foo'))]) # Rename back to BASE
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        wt, conflicts = self.do_merge(builder, 'F-id')
        self.assertEqual(0, conflicts)
        self.assertEqual('foo', wt.id2path('foo-id'))

    def test_other_reverted_content_to_base(self):
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'base content\n'))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'],
            [('modify', ('foo-id', 'B content\n'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('modify', ('foo-id', 'B content\n'))]) # merge the content
        builder.build_snapshot('F-id', ['E-id'],
            [('modify', ('foo-id', 'base content\n'))]) # Revert back to BASE
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        wt, conflicts = self.do_merge(builder, 'F-id')
        self.assertEqual(0, conflicts)
        # TODO: We need to use the per-file graph to properly select a BASE
        #       before this will work. Or at least use the LCA trees to find
        #       the appropriate content base. (which is B, not A).
        self.assertEqual('base content\n', wt.get_file_text('foo-id'))

    def test_other_modified_content(self):
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'foo', 'foo-id', 'file', 'base content\n'))])
        builder.build_snapshot('C-id', ['A-id'], [])
        builder.build_snapshot('B-id', ['A-id'],
            [('modify', ('foo-id', 'B content\n'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('modify', ('foo-id', 'B content\n'))]) # merge the content
        builder.build_snapshot('F-id', ['E-id'],
            [('modify', ('foo-id', 'F content\n'))]) # Override B content
        builder.build_snapshot('D-id', ['B-id', 'C-id'], [])
        wt, conflicts = self.do_merge(builder, 'F-id')
        self.assertEqual(0, conflicts)
        self.assertEqual('F content\n', wt.get_file_text('foo-id'))

    def test_all_wt(self):
        """Check behavior if all trees are Working Trees."""
        # The big issue is that entry.revision is None for WorkingTrees. (as is
        # entry.text_sha1, etc. So we need to make sure we handle that case
        # correctly.
        #   A   Content of 'foo', path of 'a'
        #   |\
        #   B C B modifies content, C renames 'a' => 'b'
        #   |X|
        #   D E E updates content, renames 'b' => 'c'
        builder = self.get_builder()
        builder.build_snapshot('A-id', None,
            [('add', (u'', 'a-root-id', 'directory', None)),
             ('add', (u'a', 'a-id', 'file', 'base content\n')),
             ('add', (u'foo', 'foo-id', 'file', 'base content\n'))])
        builder.build_snapshot('B-id', ['A-id'],
            [('modify', ('foo-id', 'B content\n'))])
        builder.build_snapshot('C-id', ['A-id'],
            [('rename', ('a', 'b'))])
        builder.build_snapshot('E-id', ['C-id', 'B-id'],
            [('rename', ('b', 'c')),
             ('modify', ('foo-id', 'E content\n'))])
        builder.build_snapshot('D-id', ['B-id', 'C-id'],
            [('rename', ('a', 'b'))]) # merged change
        wt_this = self.get_wt_from_builder(builder)
        wt_base = wt_this.bzrdir.sprout('base', 'A-id').open_workingtree()
        wt_base.lock_read()
        self.addCleanup(wt_base.unlock)
        wt_lca1 = wt_this.bzrdir.sprout('b-tree', 'B-id').open_workingtree()
        wt_lca1.lock_read()
        self.addCleanup(wt_lca1.unlock)
        wt_lca2 = wt_this.bzrdir.sprout('c-tree', 'C-id').open_workingtree()
        wt_lca2.lock_read()
        self.addCleanup(wt_lca2.unlock)
        wt_other = wt_this.bzrdir.sprout('other', 'E-id').open_workingtree()
        wt_other.lock_read()
        self.addCleanup(wt_other.unlock)
        merge_obj = _mod_merge.Merge3Merger(wt_this, wt_this, wt_base,
            wt_other, lca_trees=[wt_lca1, wt_lca2], do_merge=False)
        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('a-id', False,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'a', [u'a', u'b']), u'c', u'b'),
                           ((False, [False, False]), False, False)),
                          ('foo-id', True,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'foo', [u'foo', u'foo']), u'foo', u'foo'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_nested_tree_unmodified(self):
        # Tested with a real WT, because BranchBuilder/MemoryTree don't handle
        # 'tree-reference'
        wt = self.make_branch_and_tree('tree',
            format='dirstate-with-subtree')
        wt.lock_write()
        self.addCleanup(wt.unlock)
        sub_tree = self.make_branch_and_tree('tree/sub-tree',
            format='dirstate-with-subtree')
        wt.set_root_id('a-root-id')
        sub_tree.set_root_id('sub-tree-root')
        self.build_tree_contents([('tree/sub-tree/file', 'text1')])
        sub_tree.add('file')
        sub_tree.commit('foo', rev_id='sub-A-id')
        wt.add_reference(sub_tree)
        wt.commit('set text to 1', rev_id='A-id', recursive=None)
        # Now create a criss-cross merge in the parent, without modifying the
        # subtree
        wt.commit('B', rev_id='B-id', recursive=None)
        wt.set_last_revision('A-id')
        wt.branch.set_last_revision_info(1, 'A-id')
        wt.commit('C', rev_id='C-id', recursive=None)
        wt.merge_from_branch(wt.branch, to_revision='B-id')
        wt.commit('E', rev_id='E-id', recursive=None)
        wt.set_parent_ids(['B-id', 'C-id'])
        wt.branch.set_last_revision_info(2, 'B-id')
        wt.commit('D', rev_id='D-id', recursive=None)

        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            wt, 'E-id')
        merger.merge_type = _mod_merge.Merge3Merger
        merge_obj = merger.make_merger()
        entries = list(merge_obj._entries_lca())
        self.assertEqual([], entries)

    def test_nested_tree_subtree_modified(self):
        # Tested with a real WT, because BranchBuilder/MemoryTree don't handle
        # 'tree-reference'
        wt = self.make_branch_and_tree('tree',
            format='dirstate-with-subtree')
        wt.lock_write()
        self.addCleanup(wt.unlock)
        sub_tree = self.make_branch_and_tree('tree/sub',
            format='dirstate-with-subtree')
        wt.set_root_id('a-root-id')
        sub_tree.set_root_id('sub-tree-root')
        self.build_tree_contents([('tree/sub/file', 'text1')])
        sub_tree.add('file')
        sub_tree.commit('foo', rev_id='sub-A-id')
        wt.add_reference(sub_tree)
        wt.commit('set text to 1', rev_id='A-id', recursive=None)
        # Now create a criss-cross merge in the parent, without modifying the
        # subtree
        wt.commit('B', rev_id='B-id', recursive=None)
        wt.set_last_revision('A-id')
        wt.branch.set_last_revision_info(1, 'A-id')
        wt.commit('C', rev_id='C-id', recursive=None)
        wt.merge_from_branch(wt.branch, to_revision='B-id')
        self.build_tree_contents([('tree/sub/file', 'text2')])
        sub_tree.commit('modify contents', rev_id='sub-B-id')
        wt.commit('E', rev_id='E-id', recursive=None)
        wt.set_parent_ids(['B-id', 'C-id'])
        wt.branch.set_last_revision_info(2, 'B-id')
        wt.commit('D', rev_id='D-id', recursive=None)

        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            wt, 'E-id')
        merger.merge_type = _mod_merge.Merge3Merger
        merge_obj = merger.make_merger()
        entries = list(merge_obj._entries_lca())
        # Nothing interesting about this sub-tree, because content changes are
        # computed at a higher level
        self.assertEqual([], entries)

    def test_nested_tree_subtree_renamed(self):
        # Tested with a real WT, because BranchBuilder/MemoryTree don't handle
        # 'tree-reference'
        wt = self.make_branch_and_tree('tree',
            format='dirstate-with-subtree')
        wt.lock_write()
        self.addCleanup(wt.unlock)
        sub_tree = self.make_branch_and_tree('tree/sub',
            format='dirstate-with-subtree')
        wt.set_root_id('a-root-id')
        sub_tree.set_root_id('sub-tree-root')
        self.build_tree_contents([('tree/sub/file', 'text1')])
        sub_tree.add('file')
        sub_tree.commit('foo', rev_id='sub-A-id')
        wt.add_reference(sub_tree)
        wt.commit('set text to 1', rev_id='A-id', recursive=None)
        # Now create a criss-cross merge in the parent, without modifying the
        # subtree
        wt.commit('B', rev_id='B-id', recursive=None)
        wt.set_last_revision('A-id')
        wt.branch.set_last_revision_info(1, 'A-id')
        wt.commit('C', rev_id='C-id', recursive=None)
        wt.merge_from_branch(wt.branch, to_revision='B-id')
        wt.rename_one('sub', 'alt_sub')
        wt.commit('E', rev_id='E-id', recursive=None)
        wt.set_last_revision('B-id')
        wt.revert()
        wt.set_parent_ids(['B-id', 'C-id'])
        wt.branch.set_last_revision_info(2, 'B-id')
        wt.commit('D', rev_id='D-id', recursive=None)

        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            wt, 'E-id')
        merger.merge_type = _mod_merge.Merge3Merger
        merge_obj = merger.make_merger()
        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('sub-tree-root', False,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'sub', [u'sub', u'sub']), u'alt_sub', u'sub'),
                           ((False, [False, False]), False, False)),
                         ], entries)

    def test_nested_tree_subtree_renamed_and_modified(self):
        # Tested with a real WT, because BranchBuilder/MemoryTree don't handle
        # 'tree-reference'
        wt = self.make_branch_and_tree('tree',
            format='dirstate-with-subtree')
        wt.lock_write()
        self.addCleanup(wt.unlock)
        sub_tree = self.make_branch_and_tree('tree/sub',
            format='dirstate-with-subtree')
        wt.set_root_id('a-root-id')
        sub_tree.set_root_id('sub-tree-root')
        self.build_tree_contents([('tree/sub/file', 'text1')])
        sub_tree.add('file')
        sub_tree.commit('foo', rev_id='sub-A-id')
        wt.add_reference(sub_tree)
        wt.commit('set text to 1', rev_id='A-id', recursive=None)
        # Now create a criss-cross merge in the parent, without modifying the
        # subtree
        wt.commit('B', rev_id='B-id', recursive=None)
        wt.set_last_revision('A-id')
        wt.branch.set_last_revision_info(1, 'A-id')
        wt.commit('C', rev_id='C-id', recursive=None)
        wt.merge_from_branch(wt.branch, to_revision='B-id')
        self.build_tree_contents([('tree/sub/file', 'text2')])
        sub_tree.commit('modify contents', rev_id='sub-B-id')
        wt.rename_one('sub', 'alt_sub')
        wt.commit('E', rev_id='E-id', recursive=None)
        wt.set_last_revision('B-id')
        wt.revert()
        wt.set_parent_ids(['B-id', 'C-id'])
        wt.branch.set_last_revision_info(2, 'B-id')
        wt.commit('D', rev_id='D-id', recursive=None)

        merger = _mod_merge.Merger.from_revision_ids(progress.DummyProgress(),
            wt, 'E-id')
        merger.merge_type = _mod_merge.Merge3Merger
        merge_obj = merger.make_merger()
        entries = list(merge_obj._entries_lca())
        root_id = 'a-root-id'
        self.assertEqual([('sub-tree-root', False,
                           ((root_id, [root_id, root_id]), root_id, root_id),
                           ((u'sub', [u'sub', u'sub']), u'alt_sub', u'sub'),
                           ((False, [False, False]), False, False)),
                         ], entries)


class TestLCAMultiWay(tests.TestCase):

    def assertLCAMultiWay(self, expected, base, lcas, other, this,
                          allow_overriding_lca=True):
        self.assertEqual(expected, _mod_merge.Merge3Merger._lca_multi_way(
                                (base, lcas), other, this,
                                allow_overriding_lca=allow_overriding_lca))

    def test_other_equal_equal_lcas(self):
        """Test when OTHER=LCA and all LCAs are identical."""
        self.assertLCAMultiWay('this',
            'bval', ['bval', 'bval'], 'bval', 'bval')
        self.assertLCAMultiWay('this',
            'bval', ['lcaval', 'lcaval'], 'lcaval', 'bval')
        self.assertLCAMultiWay('this',
            'bval', ['lcaval', 'lcaval', 'lcaval'], 'lcaval', 'bval')
        self.assertLCAMultiWay('this',
            'bval', ['lcaval', 'lcaval', 'lcaval'], 'lcaval', 'tval')
        self.assertLCAMultiWay('this',
            'bval', ['lcaval', 'lcaval', 'lcaval'], 'lcaval', None)

    def test_other_equal_this(self):
        """Test when other and this are identical."""
        self.assertLCAMultiWay('this',
            'bval', ['bval', 'bval'], 'oval', 'oval')
        self.assertLCAMultiWay('this',
            'bval', ['lcaval', 'lcaval'], 'oval', 'oval')
        self.assertLCAMultiWay('this',
            'bval', ['cval', 'dval'], 'oval', 'oval')
        self.assertLCAMultiWay('this',
            'bval', [None, 'lcaval'], 'oval', 'oval')
        self.assertLCAMultiWay('this',
            None, [None, 'lcaval'], 'oval', 'oval')
        self.assertLCAMultiWay('this',
            None, ['lcaval', 'lcaval'], 'oval', 'oval')
        self.assertLCAMultiWay('this',
            None, ['cval', 'dval'], 'oval', 'oval')
        self.assertLCAMultiWay('this',
            None, ['cval', 'dval'], None, None)
        self.assertLCAMultiWay('this',
            None, ['cval', 'dval', 'eval', 'fval'], 'oval', 'oval')

    def test_no_lcas(self):
        self.assertLCAMultiWay('this',
            'bval', [], 'bval', 'tval')
        self.assertLCAMultiWay('other',
            'bval', [], 'oval', 'bval')
        self.assertLCAMultiWay('conflict',
            'bval', [], 'oval', 'tval')
        self.assertLCAMultiWay('this',
            'bval', [], 'oval', 'oval')

    def test_lca_supersedes_other_lca(self):
        """If one lca == base, the other lca takes precedence"""
        self.assertLCAMultiWay('this',
            'bval', ['bval', 'lcaval'], 'lcaval', 'tval')
        self.assertLCAMultiWay('this',
            'bval', ['bval', 'lcaval'], 'lcaval', 'bval')
        # This is actually considered a 'revert' because the 'lcaval' in LCAS
        # supersedes the BASE val (in the other LCA) but then OTHER reverts it
        # back to bval.
        self.assertLCAMultiWay('other',
            'bval', ['bval', 'lcaval'], 'bval', 'lcaval')
        self.assertLCAMultiWay('conflict',
            'bval', ['bval', 'lcaval'], 'bval', 'tval')

    def test_other_and_this_pick_different_lca(self):
        # OTHER and THIS resolve the lca conflict in different ways
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val'], 'lca1val', 'lca2val')
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val', 'lca3val'], 'lca1val', 'lca2val')
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val', 'bval'], 'lca1val', 'lca2val')

    def test_other_in_lca(self):
        # OTHER takes a value of one of the LCAs, THIS takes a new value, which
        # theoretically supersedes both LCA values and 'wins'
        self.assertLCAMultiWay('this',
            'bval', ['lca1val', 'lca2val'], 'lca1val', 'newval')
        self.assertLCAMultiWay('this',
            'bval', ['lca1val', 'lca2val', 'lca3val'], 'lca1val', 'newval')
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val'], 'lca1val', 'newval',
            allow_overriding_lca=False)
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val', 'lca3val'], 'lca1val', 'newval',
            allow_overriding_lca=False)
        # THIS reverted back to BASE, but that is an explicit supersede of all
        # LCAs
        self.assertLCAMultiWay('this',
            'bval', ['lca1val', 'lca2val', 'lca3val'], 'lca1val', 'bval')
        self.assertLCAMultiWay('this',
            'bval', ['lca1val', 'lca2val', 'bval'], 'lca1val', 'bval')
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val', 'lca3val'], 'lca1val', 'bval',
            allow_overriding_lca=False)
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val', 'bval'], 'lca1val', 'bval',
            allow_overriding_lca=False)

    def test_this_in_lca(self):
        # THIS takes a value of one of the LCAs, OTHER takes a new value, which
        # theoretically supersedes both LCA values and 'wins'
        self.assertLCAMultiWay('other',
            'bval', ['lca1val', 'lca2val'], 'oval', 'lca1val')
        self.assertLCAMultiWay('other',
            'bval', ['lca1val', 'lca2val'], 'oval', 'lca2val')
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val'], 'oval', 'lca1val',
            allow_overriding_lca=False)
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val'], 'oval', 'lca2val',
            allow_overriding_lca=False)
        # OTHER reverted back to BASE, but that is an explicit supersede of all
        # LCAs
        self.assertLCAMultiWay('other',
            'bval', ['lca1val', 'lca2val', 'lca3val'], 'bval', 'lca3val')
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val', 'lca3val'], 'bval', 'lca3val',
            allow_overriding_lca=False)

    def test_all_differ(self):
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val'], 'oval', 'tval')
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val', 'lca2val'], 'oval', 'tval')
        self.assertLCAMultiWay('conflict',
            'bval', ['lca1val', 'lca2val', 'lca3val'], 'oval', 'tval')
