view tests/test-rust-ancestor.py @ 47072:4c041c71ec01

revlog: introduce an explicit tracking of what the revlog is about

Since the dawn of time, people have been forced to rely to lossy introspection
of the index filename to determine what the purpose and role of the revlog they
encounter is. This is hacky, error prone, inflexible, abstraction-leaky,
<insert-your-own-complaints-here>.

In f63299ee7e4d Raphaël introduced a new attribute to track this information:
`revlog_kind`. However it is initialized in an odd place and various instances
end up not having it set. In addition is only tracking some of the information
we end up having to introspect in various pieces of code.

So we add a new attribute that holds more data and is more strictly enforced.
This work is done in collaboration with Raphaël.

The `revlog_kind` one will be removed/adapted in the next changeset. We expect
to be able to clean up various existing piece of code and to simplify coming
work around the newer revlog format.

Differential Revision: https://phab.mercurial-scm.org/D10352

from __future__ import absolute_import
import sys
import unittest

from mercurial.node import wdirrev
from mercurial import error

from mercurial.testing import revlog as revlogtesting

try:
    from mercurial import rustext

    rustext.__name__  # trigger immediate actual import
except ImportError:
    rustext = None
else:
    # this would fail already without appropriate ancestor.__package__
    from mercurial.rustext.ancestor import (
        AncestorsIterator,
        LazyAncestors,
        MissingAncestors,
    )
    from mercurial.rustext import dagop

try:
    from mercurial.cext import parsers as cparsers
except ImportError:
    cparsers = None


@unittest.skipIf(
    rustext is None,
    'The Rust version of the "ancestor" module is not available. It is needed'
    ' for this test.',
)
@unittest.skipIf(
    rustext is None,
    'The Rust or C version of the "parsers" module, which the "ancestor" module'
    ' relies on, is not available.',
)
class rustancestorstest(revlogtesting.RevlogBasedTestBase):
    """Test the correctness of binding to Rust code.

    This test is merely for the binding to Rust itself: extraction of
    Python variable, giving back the results etc.

    It is not meant to test the algorithmic correctness of the operations
    on ancestors it provides. Hence the very simple embedded index data is
    good enough.

    Algorithmic correctness is asserted by the Rust unit tests.
    """

    def testiteratorrevlist(self):
        idx = self.parseindex()
        # checking test assumption about the index binary data:
        self.assertEqual(
            {i: (r[5], r[6]) for i, r in enumerate(idx)},
            {0: (-1, -1), 1: (0, -1), 2: (1, -1), 3: (2, -1)},
        )
        ait = AncestorsIterator(idx, [3], 0, True)
        self.assertEqual([r for r in ait], [3, 2, 1, 0])

        ait = AncestorsIterator(idx, [3], 0, False)
        self.assertEqual([r for r in ait], [2, 1, 0])

    def testlazyancestors(self):
        idx = self.parseindex()
        start_count = sys.getrefcount(idx)  # should be 2 (see Python doc)
        self.assertEqual(
            {i: (r[5], r[6]) for i, r in enumerate(idx)},
            {0: (-1, -1), 1: (0, -1), 2: (1, -1), 3: (2, -1)},
        )
        lazy = LazyAncestors(idx, [3], 0, True)
        # we have two more references to the index:
        # - in its inner iterator for __contains__ and __bool__
        # - in the LazyAncestors instance itself (to spawn new iterators)
        self.assertEqual(sys.getrefcount(idx), start_count + 2)

        self.assertTrue(2 in lazy)
        self.assertTrue(bool(lazy))
        self.assertEqual(list(lazy), [3, 2, 1, 0])
        # a second time to validate that we spawn new iterators
        self.assertEqual(list(lazy), [3, 2, 1, 0])

        # now let's watch the refcounts closer
        ait = iter(lazy)
        self.assertEqual(sys.getrefcount(idx), start_count + 3)
        del ait
        self.assertEqual(sys.getrefcount(idx), start_count + 2)
        del lazy
        self.assertEqual(sys.getrefcount(idx), start_count)

        # let's check bool for an empty one
        self.assertFalse(LazyAncestors(idx, [0], 0, False))

    def testmissingancestors(self):
        idx = self.parseindex()
        missanc = MissingAncestors(idx, [1])
        self.assertTrue(missanc.hasbases())
        self.assertEqual(missanc.missingancestors([3]), [2, 3])
        missanc.addbases({2})
        self.assertEqual(missanc.bases(), {1, 2})
        self.assertEqual(missanc.missingancestors([3]), [3])
        self.assertEqual(missanc.basesheads(), {2})

    def testmissingancestorsremove(self):
        idx = self.parseindex()
        missanc = MissingAncestors(idx, [1])
        revs = {0, 1, 2, 3}
        missanc.removeancestorsfrom(revs)
        self.assertEqual(revs, {2, 3})

    def testrefcount(self):
        idx = self.parseindex()
        start_count = sys.getrefcount(idx)

        # refcount increases upon iterator init...
        ait = AncestorsIterator(idx, [3], 0, True)
        self.assertEqual(sys.getrefcount(idx), start_count + 1)
        self.assertEqual(next(ait), 3)

        # and decreases once the iterator is removed
        del ait
        self.assertEqual(sys.getrefcount(idx), start_count)

        # and removing ref to the index after iterator init is no issue
        ait = AncestorsIterator(idx, [3], 0, True)
        del idx
        self.assertEqual(list(ait), [3, 2, 1, 0])

    def testgrapherror(self):
        data = (
            revlogtesting.data_non_inlined[: 64 + 27]
            + b'\xf2'
            + revlogtesting.data_non_inlined[64 + 28 :]
        )
        idx = cparsers.parse_index2(data, False)[0]
        with self.assertRaises(rustext.GraphError) as arc:
            AncestorsIterator(idx, [1], -1, False)
        exc = arc.exception
        self.assertIsInstance(exc, ValueError)
        # rust-cpython issues appropriate str instances for Python 2 and 3
        self.assertEqual(exc.args, ('ParentOutOfRange', 1))

    def testwdirunsupported(self):
        # trying to access ancestors of the working directory raises
        # WdirUnsupported directly
        idx = self.parseindex()
        with self.assertRaises(error.WdirUnsupported):
            list(AncestorsIterator(idx, [wdirrev], -1, False))

    def testheadrevs(self):
        idx = self.parseindex()
        self.assertEqual(dagop.headrevs(idx, [1, 2, 3]), {3})


if __name__ == '__main__':
    import silenttestrunner

    silenttestrunner.main(__name__)