view tests/test-simplemerge.py @ 32697:19b9fc40cc51

revlog: skeleton support for version 2 revlogs

There are a number of improvements we want to make to revlogs
that will require a new version - version 2. It is unclear what the
full set of improvements will be or when we'll be done with them.
What I do know is that the process will likely take longer than a
single release, will require input from various stakeholders to
evaluate changes, and will have many contentious debates and
bikeshedding.

It is unrealistic to develop revlog version 2 up front: there
are just too many uncertainties that we won't know until things
are implemented and experiments are run. Some changes will also
be invasive and prone to bit rot, so sitting on dozens of patches
is not practical.

This commit introduces skeleton support for version 2 revlogs in
a way that is flexible and not bound by backwards compatibility
concerns.

An experimental repo requirement for denoting revlog v2 has been
added. The requirement string has a sub-version component to it.
This will allow us to declare multiple requirements in the course
of developing revlog v2. Whenever we change the in-development
revlog v2 format, we can tweak the string, creating a new
requirement and locking out old clients. This will allow us to
make as many backwards incompatible changes and experiments to
revlog v2 as we want. In other words, we can land code and make
meaningful progress towards revlog v2 while still maintaining
extreme format flexibility up until the point we freeze the
format and remove the experimental labels.

To enable the new repo requirement, you must supply an experimental
and undocumented config option. But not just any boolean flag
will do: you need to explicitly use a value that no sane person
should ever type. This is an additional guard against enabling
revlog v2 on an installation it shouldn't be enabled on. The
specific scenario I'm trying to prevent is say a user with a
4.4 client with a frozen format enabling the option but then
downgrading to 4.3 and accidentally creating repos with an
outdated and unsupported repo format. Requiring a "challenge"
string should prevent this.

Because the format is not yet finalized and I don't want to take
any chances, revlog v2's version is currently 0xDEAD. I figure
squatting on a value we're likely never to use as an actual revlog
version to mean "internal testing only" is acceptable. And
"dead" is easily recognized as something meaningful.

There is a bunch of cleanup that is needed before work on revlog
v2 begins in earnest. I plan on doing that work once this patch
is accepted and we're comfortable with the idea of starting down
this path.

# Copyright (C) 2004, 2005 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, see <http://www.gnu.org/licenses/>.

from __future__ import absolute_import

import unittest
from mercurial import (
    error,
    simplemerge,
    util,
)

TestCase = unittest.TestCase
# bzr compatible interface, for the tests
class Merge3(simplemerge.Merge3Text):
    """3-way merge of texts.

    Given BASE, OTHER, THIS, tries to produce a combined text
    incorporating the changes from both BASE->OTHER and BASE->THIS.
    All three will typically be sequences of lines."""
    def __init__(self, base, a, b):
        basetext = '\n'.join([i.strip('\n') for i in base] + [''])
        atext = '\n'.join([i.strip('\n') for i in a] + [''])
        btext = '\n'.join([i.strip('\n') for i in b] + [''])
        if util.binary(basetext) or util.binary(atext) or util.binary(btext):
            raise error.Abort("don't know how to merge binary files")
        simplemerge.Merge3Text.__init__(self, basetext, atext, btext,
                                        base, a, b)

CantReprocessAndShowBase = simplemerge.CantReprocessAndShowBase

def split_lines(t):
    return util.stringio(t).readlines()

############################################################
# test case data from the gnu diffutils manual
# common base
TZU = split_lines("""     The Nameless is the origin of Heaven and Earth;
     The named is the mother of all things.

     Therefore let there always be non-being,
       so we may see their subtlety,
     And let there always be being,
       so we may see their outcome.
     The two are the same,
     But after they are produced,
       they have different names.
     They both may be called deep and profound.
     Deeper and more profound,
     The door of all subtleties!
""")

LAO = split_lines("""     The Way that can be told of is not the eternal Way;
     The name that can be named is not the eternal name.
     The Nameless is the origin of Heaven and Earth;
     The Named is the mother of all things.
     Therefore let there always be non-being,
       so we may see their subtlety,
     And let there always be being,
       so we may see their outcome.
     The two are the same,
     But after they are produced,
       they have different names.
""")


TAO = split_lines("""     The Way that can be told of is not the eternal Way;
     The name that can be named is not the eternal name.
     The Nameless is the origin of Heaven and Earth;
     The named is the mother of all things.

     Therefore let there always be non-being,
       so we may see their subtlety,
     And let there always be being,
       so we may see their result.
     The two are the same,
     But after they are produced,
       they have different names.

       -- The Way of Lao-Tzu, tr. Wing-tsit Chan

""")

MERGED_RESULT = split_lines("""\
     The Way that can be told of is not the eternal Way;
     The name that can be named is not the eternal name.
     The Nameless is the origin of Heaven and Earth;
     The Named is the mother of all things.
     Therefore let there always be non-being,
       so we may see their subtlety,
     And let there always be being,
       so we may see their result.
     The two are the same,
     But after they are produced,
       they have different names.
<<<<<<< LAO
=======

       -- The Way of Lao-Tzu, tr. Wing-tsit Chan

>>>>>>> TAO
""")

class TestMerge3(TestCase):
    def log(self, msg):
        pass

    def test_no_changes(self):
        """No conflicts because nothing changed"""
        m3 = Merge3(['aaa', 'bbb'],
                    ['aaa', 'bbb'],
                    ['aaa', 'bbb'])

        self.assertEquals(m3.find_unconflicted(),
                          [(0, 2)])

        self.assertEquals(list(m3.find_sync_regions()),
                          [(0, 2,
                            0, 2,
                            0, 2),
                           (2, 2,  2, 2,  2, 2)])

        self.assertEquals(list(m3.merge_regions()),
                          [('unchanged', 0, 2)])

        self.assertEquals(list(m3.merge_groups()),
                          [('unchanged', ['aaa', 'bbb'])])

    def test_front_insert(self):
        m3 = Merge3(['zz'],
                    ['aaa', 'bbb', 'zz'],
                    ['zz'])

        # todo: should use a sentinel at end as from get_matching_blocks
        # to match without zz
        self.assertEquals(list(m3.find_sync_regions()),
                          [(0, 1,  2, 3,  0, 1),
                           (1, 1,  3, 3,  1, 1)])

        self.assertEquals(list(m3.merge_regions()),
                          [('a', 0, 2),
                           ('unchanged', 0, 1)])

        self.assertEquals(list(m3.merge_groups()),
                          [('a', ['aaa', 'bbb']),
                           ('unchanged', ['zz'])])

    def test_null_insert(self):
        m3 = Merge3([],
                    ['aaa', 'bbb'],
                    [])
        # todo: should use a sentinel at end as from get_matching_blocks
        # to match without zz
        self.assertEquals(list(m3.find_sync_regions()),
                          [(0, 0,  2, 2,  0, 0)])

        self.assertEquals(list(m3.merge_regions()),
                          [('a', 0, 2)])

        self.assertEquals(list(m3.merge_lines()),
                          ['aaa', 'bbb'])

    def test_no_conflicts(self):
        """No conflicts because only one side changed"""
        m3 = Merge3(['aaa', 'bbb'],
                    ['aaa', '111', 'bbb'],
                    ['aaa', 'bbb'])

        self.assertEquals(m3.find_unconflicted(),
                          [(0, 1), (1, 2)])

        self.assertEquals(list(m3.find_sync_regions()),
                          [(0, 1,  0, 1,  0, 1),
                           (1, 2,  2, 3,  1, 2),
                           (2, 2,  3, 3,  2, 2)])

        self.assertEquals(list(m3.merge_regions()),
                          [('unchanged', 0, 1),
                           ('a', 1, 2),
                           ('unchanged', 1, 2)])

    def test_append_a(self):
        m3 = Merge3(['aaa\n', 'bbb\n'],
                    ['aaa\n', 'bbb\n', '222\n'],
                    ['aaa\n', 'bbb\n'])

        self.assertEquals(''.join(m3.merge_lines()),
                          'aaa\nbbb\n222\n')

    def test_append_b(self):
        m3 = Merge3(['aaa\n', 'bbb\n'],
                    ['aaa\n', 'bbb\n'],
                    ['aaa\n', 'bbb\n', '222\n'])

        self.assertEquals(''.join(m3.merge_lines()),
                          'aaa\nbbb\n222\n')

    def test_append_agreement(self):
        m3 = Merge3(['aaa\n', 'bbb\n'],
                    ['aaa\n', 'bbb\n', '222\n'],
                    ['aaa\n', 'bbb\n', '222\n'])

        self.assertEquals(''.join(m3.merge_lines()),
                          'aaa\nbbb\n222\n')

    def test_append_clash(self):
        m3 = Merge3(['aaa\n', 'bbb\n'],
                    ['aaa\n', 'bbb\n', '222\n'],
                    ['aaa\n', 'bbb\n', '333\n'])

        ml = m3.merge_lines(name_a='a',
                            name_b='b',
                            start_marker='<<',
                            mid_marker='--',
                            end_marker='>>')
        self.assertEquals(''.join(ml),
                          'aaa\n'
                          'bbb\n'
                          '<< a\n'
                          '222\n'
                          '--\n'
                          '333\n'
                          '>> b\n'
                         )

    def test_insert_agreement(self):
        m3 = Merge3(['aaa\n', 'bbb\n'],
                    ['aaa\n', '222\n', 'bbb\n'],
                    ['aaa\n', '222\n', 'bbb\n'])

        ml = m3.merge_lines(name_a='a',
                            name_b='b',
                            start_marker='<<',
                            mid_marker='--',
                            end_marker='>>')
        self.assertEquals(''.join(ml), 'aaa\n222\nbbb\n')


    def test_insert_clash(self):
        """Both try to insert lines in the same place."""
        m3 = Merge3(['aaa\n', 'bbb\n'],
                    ['aaa\n', '111\n', 'bbb\n'],
                    ['aaa\n', '222\n', 'bbb\n'])

        self.assertEquals(m3.find_unconflicted(),
                          [(0, 1), (1, 2)])

        self.assertEquals(list(m3.find_sync_regions()),
                          [(0, 1,  0, 1,  0, 1),
                           (1, 2,  2, 3,  2, 3),
                           (2, 2,  3, 3,  3, 3)])

        self.assertEquals(list(m3.merge_regions()),
                          [('unchanged', 0, 1),
                           ('conflict', 1, 1,  1, 2,  1, 2),
                           ('unchanged', 1, 2)])

        self.assertEquals(list(m3.merge_groups()),
                          [('unchanged', ['aaa\n']),
                           ('conflict', [], ['111\n'], ['222\n']),
                           ('unchanged', ['bbb\n']),
                           ])

        ml = m3.merge_lines(name_a='a',
                            name_b='b',
                            start_marker='<<',
                            mid_marker='--',
                            end_marker='>>')
        self.assertEquals(''.join(ml),
'''aaa
<< a
111
--
222
>> b
bbb
''')

    def test_replace_clash(self):
        """Both try to insert lines in the same place."""
        m3 = Merge3(['aaa', '000', 'bbb'],
                    ['aaa', '111', 'bbb'],
                    ['aaa', '222', 'bbb'])

        self.assertEquals(m3.find_unconflicted(),
                          [(0, 1), (2, 3)])

        self.assertEquals(list(m3.find_sync_regions()),
                          [(0, 1,  0, 1,  0, 1),
                           (2, 3,  2, 3,  2, 3),
                           (3, 3,  3, 3,  3, 3)])

    def test_replace_multi(self):
        """Replacement with regions of different size."""
        m3 = Merge3(['aaa', '000', '000', 'bbb'],
                    ['aaa', '111', '111', '111', 'bbb'],
                    ['aaa', '222', '222', '222', '222', 'bbb'])

        self.assertEquals(m3.find_unconflicted(),
                          [(0, 1), (3, 4)])


        self.assertEquals(list(m3.find_sync_regions()),
                          [(0, 1,  0, 1,  0, 1),
                           (3, 4,  4, 5,  5, 6),
                           (4, 4,  5, 5,  6, 6)])

    def test_merge_poem(self):
        """Test case from diff3 manual"""
        m3 = Merge3(TZU, LAO, TAO)
        ml = list(m3.merge_lines('LAO', 'TAO'))
        self.log('merge result:')
        self.log(''.join(ml))
        self.assertEquals(ml, MERGED_RESULT)

    def test_binary(self):
        with self.assertRaises(error.Abort):
            Merge3(['\x00'], ['a'], ['b'])

    def test_dos_text(self):
        base_text = 'a\r\n'
        this_text = 'b\r\n'
        other_text = 'c\r\n'
        m3 = Merge3(base_text.splitlines(True), other_text.splitlines(True),
                    this_text.splitlines(True))
        m_lines = m3.merge_lines('OTHER', 'THIS')
        self.assertEqual('<<<<<<< OTHER\r\nc\r\n=======\r\nb\r\n'
            '>>>>>>> THIS\r\n'.splitlines(True), list(m_lines))

    def test_mac_text(self):
        base_text = 'a\r'
        this_text = 'b\r'
        other_text = 'c\r'
        m3 = Merge3(base_text.splitlines(True), other_text.splitlines(True),
                    this_text.splitlines(True))
        m_lines = m3.merge_lines('OTHER', 'THIS')
        self.assertEqual('<<<<<<< OTHER\rc\r=======\rb\r'
            '>>>>>>> THIS\r'.splitlines(True), list(m_lines))

if __name__ == '__main__':
    # hide the timer
    import time
    orig = time.time
    try:
        time.time = lambda: 0
        unittest.main()
    finally:
        time.time = orig