view tests/test-bdiff.py @ 51316:178e50edb4f8

changelog: stop useless enforcing split at the end of transaction

Changelogs are no longer created inline, and existing changelogs are
automatically split. Since we now enforce splitting at the start of any write,
we don't need to enforce splitting at the end of the transaction.

This has the nice side effect of killing the only user of "side_write".

import collections
import struct
import unittest

from mercurial import mdiff


class diffreplace(collections.namedtuple('diffreplace', 'start end from_ to')):
    def __repr__(self):
        return 'diffreplace(%r, %r, %r, %r)' % self


class BdiffTests(unittest.TestCase):
    def assert_bdiff_applies(self, a, b):
        d = mdiff.textdiff(a, b)
        c = a
        if d:
            c = mdiff.patches(a, [d])
        self.assertEqual(
            c,
            b,
            (
                "bad diff+patch result from\n  %r to\n  "
                "%r: \nbdiff: %r\npatched: %r" % (a, b, d, c[:200])
            ),
        )

    def assert_bdiff(self, a, b):
        self.assert_bdiff_applies(a, b)
        self.assert_bdiff_applies(b, a)

    def test_bdiff_basic(self):
        cases = [
            (b"a\nc\n\n\n\n", b"a\nb\n\n\n"),
            (b"a\nb\nc\n", b"a\nc\n"),
            (b"", b""),
            (b"a\nb\nc", b"a\nb\nc"),
            (b"a\nb\nc\nd\n", b"a\nd\n"),
            (b"a\nb\nc\nd\n", b"a\nc\ne\n"),
            (b"a\nb\nc\n", b"a\nc\n"),
            (b"a\n", b"c\na\nb\n"),
            (b"a\n", b""),
            (b"a\n", b"b\nc\n"),
            (b"a\n", b"c\na\n"),
            (b"", b"adjfkjdjksdhfksj"),
            (b"", b"ab"),
            (b"", b"abc"),
            (b"a", b"a"),
            (b"ab", b"ab"),
            (b"abc", b"abc"),
            (b"a\n", b"a\n"),
            (b"a\nb", b"a\nb"),
        ]
        for a, b in cases:
            self.assert_bdiff(a, b)

    def showdiff(self, a, b):
        bin = mdiff.textdiff(a, b)
        pos = 0
        q = 0
        actions = []
        while pos < len(bin):
            p1, p2, l = struct.unpack(">lll", bin[pos : pos + 12])
            pos += 12
            if p1:
                actions.append(a[q:p1])
            actions.append(diffreplace(p1, p2, a[p1:p2], bin[pos : pos + l]))
            pos += l
            q = p2
        if q < len(a):
            actions.append(a[q:])
        return actions

    def test_issue1295(self):
        cases = [
            (
                b"x\n\nx\n\nx\n\nx\n\nz\n",
                b"x\n\nx\n\ny\n\nx\n\nx\n\nz\n",
                [
                    b'x\n\nx\n\n',
                    diffreplace(6, 6, b'', b'y\n\n'),
                    b'x\n\nx\n\nz\n',
                ],
            ),
            (
                b"x\n\nx\n\nx\n\nx\n\nz\n",
                b"x\n\nx\n\ny\n\nx\n\ny\n\nx\n\nz\n",
                [
                    b'x\n\nx\n\n',
                    diffreplace(6, 6, b'', b'y\n\n'),
                    b'x\n\n',
                    diffreplace(9, 9, b'', b'y\n\n'),
                    b'x\n\nz\n',
                ],
            ),
        ]
        for old, new, want in cases:
            self.assertEqual(self.showdiff(old, new), want)

    def test_issue1295_varies_on_pure(self):
        # we should pick up abbbc. rather than bc.de as the longest match
        got = self.showdiff(
            b"a\nb\nb\nb\nc\n.\nd\ne\n.\nf\n",
            b"a\nb\nb\na\nb\nb\nb\nc\n.\nb\nc\n.\nd\ne\nf\n",
        )
        want_c = [
            b'a\nb\nb\n',
            diffreplace(6, 6, b'', b'a\nb\nb\nb\nc\n.\n'),
            b'b\nc\n.\nd\ne\n',
            diffreplace(16, 18, b'.\n', b''),
            b'f\n',
        ]
        want_pure = [
            diffreplace(0, 0, b'', b'a\nb\nb\n'),
            b'a\nb\nb\nb\nc\n.\n',
            diffreplace(12, 12, b'', b'b\nc\n.\n'),
            b'd\ne\n',
            diffreplace(16, 18, b'.\n', b''),
            b'f\n',
        ]
        self.assertTrue(
            got in (want_c, want_pure),
            'got: %r, wanted either %r or %r' % (got, want_c, want_pure),
        )

    def test_fixws(self):
        cases = [
            (b" \ta\r b\t\n", b"ab\n", 1),
            (b" \ta\r b\t\n", b" a b\n", 0),
            (b"", b"", 1),
            (b"", b"", 0),
        ]
        for a, b, allws in cases:
            c = mdiff.fixws(a, allws)
            self.assertEqual(
                c, b, 'fixws(%r) want %r got %r (allws=%r)' % (a, b, c, allws)
            )

    def test_nice_diff_for_trivial_change(self):
        self.assertEqual(
            self.showdiff(
                b''.join(b'<%d\n-\n' % i for i in range(5)),
                b''.join(b'>%d\n-\n' % i for i in range(5)),
            ),
            [
                diffreplace(0, 3, b'<0\n', b'>0\n'),
                b'-\n',
                diffreplace(5, 8, b'<1\n', b'>1\n'),
                b'-\n',
                diffreplace(10, 13, b'<2\n', b'>2\n'),
                b'-\n',
                diffreplace(15, 18, b'<3\n', b'>3\n'),
                b'-\n',
                diffreplace(20, 23, b'<4\n', b'>4\n'),
                b'-\n',
            ],
        )

    def test_prefer_appending(self):
        # 1 line to 3 lines
        self.assertEqual(
            self.showdiff(b'a\n', b'a\n' * 3),
            [b'a\n', diffreplace(2, 2, b'', b'a\na\n')],
        )
        # 1 line to 5 lines
        self.assertEqual(
            self.showdiff(b'a\n', b'a\n' * 5),
            [b'a\n', diffreplace(2, 2, b'', b'a\na\na\na\n')],
        )

    def test_prefer_removing_trailing(self):
        # 3 lines to 1 line
        self.assertEqual(
            self.showdiff(b'a\n' * 3, b'a\n'),
            [b'a\n', diffreplace(2, 6, b'a\na\n', b'')],
        )
        # 5 lines to 1 line
        self.assertEqual(
            self.showdiff(b'a\n' * 5, b'a\n'),
            [b'a\n', diffreplace(2, 10, b'a\na\na\na\n', b'')],
        )


if __name__ == '__main__':
    import silenttestrunner

    silenttestrunner.main(__name__)