Mercurial > hg
view tests/test-bdiff.py @ 48038:52018f8ef020 stable
persistent-nodemap: introduce a test to highlight possible race
Weakness in the current file caching of the changelog means that a writer can
end up using an outdated docket. This might result in "committed"
persistent-nodemap data from a previous writer to be overwritten by a later
writer. This break the strong "append only" assumption of the persistent nodemap
and can result in confused reader.
The race windows are quite narrow. See the test documentation for details.
The issues is fixed in the next changeset.
Differential Revision: https://phab.mercurial-scm.org/D11481
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
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date | Tue, 21 Sep 2021 21:18:50 +0200 |
parents | 2372284d9457 |
children | 6000f5b25c9b |
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from __future__ import absolute_import, print_function 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__)