tests/test-simplekeyvaluefile.py

dirs: fix out-of-bounds access in Py3

The hack for mutating Python's variable-length integers that was
ported to py3 in cb3048746dae (dirs: port PyInt code to work on Python
3, 2016-10-08) was reading from ob_digit[1] instead of ob_digit[0] for
some reason. Space for ob_digit[1] would only be allocated for
integers larger than 30 bits, so we ended up writing to unallocated
memory. Also, we would write an integer that's 2^30 times too large,
so we would never free these integers.

Found by AddressSanitizer.

Differential Revision: https://phab.mercurial-scm.org/D7597

from __future__ import absolute_import

import unittest
import silenttestrunner

from mercurial import (
    error,
    scmutil,
)


class mockfile(object):
    def __init__(self, name, fs):
        self.name = name
        self.fs = fs

    def __enter__(self):
        return self

    def __exit__(self, *args, **kwargs):
        pass

    def write(self, text):
        self.fs.contents[self.name] = text

    def read(self):
        return self.fs.contents[self.name]


class mockvfs(object):
    def __init__(self):
        self.contents = {}

    def read(self, path):
        return mockfile(path, self).read()

    def readlines(self, path):
        # lines need to contain the trailing '\n' to mock the real readlines
        return [l for l in mockfile(path, self).read().splitlines(True)]

    def __call__(self, path, mode, atomictemp):
        return mockfile(path, self)


class testsimplekeyvaluefile(unittest.TestCase):
    def setUp(self):
        self.vfs = mockvfs()

    def testbasicwritingiandreading(self):
        dw = {b'key1': b'value1', b'Key2': b'value2'}
        scmutil.simplekeyvaluefile(self.vfs, b'kvfile').write(dw)
        self.assertEqual(
            sorted(self.vfs.read(b'kvfile').split(b'\n')),
            [b'', b'Key2=value2', b'key1=value1'],
        )
        dr = scmutil.simplekeyvaluefile(self.vfs, b'kvfile').read()
        self.assertEqual(dr, dw)

    if not getattr(unittest.TestCase, 'assertRaisesRegex', False):
        # Python 3.7 deprecates the regex*p* version, but 2.7 lacks
        # the regex version.
        assertRaisesRegex = (  # camelcase-required
            unittest.TestCase.assertRaisesRegexp
        )

    def testinvalidkeys(self):
        d = {b'0key1': b'value1', b'Key2': b'value2'}
        with self.assertRaisesRegex(
            error.ProgrammingError, 'keys must start with a letter.*'
        ):
            scmutil.simplekeyvaluefile(self.vfs, b'kvfile').write(d)

        d = {b'key1@': b'value1', b'Key2': b'value2'}
        with self.assertRaisesRegex(error.ProgrammingError, 'invalid key.*'):
            scmutil.simplekeyvaluefile(self.vfs, b'kvfile').write(d)

    def testinvalidvalues(self):
        d = {b'key1': b'value1', b'Key2': b'value2\n'}
        with self.assertRaisesRegex(error.ProgrammingError, 'invalid val.*'):
            scmutil.simplekeyvaluefile(self.vfs, b'kvfile').write(d)

    def testcorruptedfile(self):
        self.vfs.contents[b'badfile'] = b'ababagalamaga\n'
        with self.assertRaisesRegex(
            error.CorruptedState, 'dictionary.*element.*'
        ):
            scmutil.simplekeyvaluefile(self.vfs, b'badfile').read()

    def testfirstline(self):
        dw = {b'key1': b'value1'}
        scmutil.simplekeyvaluefile(self.vfs, b'fl').write(dw, firstline=b'1.0')
        self.assertEqual(self.vfs.read(b'fl'), b'1.0\nkey1=value1\n')
        dr = scmutil.simplekeyvaluefile(self.vfs, b'fl').read(
            firstlinenonkeyval=True
        )
        self.assertEqual(dr, {b'__firstline': b'1.0', b'key1': b'value1'})


if __name__ == "__main__":
    silenttestrunner.main(__name__)