tests/test-annotate.py

bookmark: add a test for a race condition on push

Bookmark pointing to unknown nodes are ignored. Later these ignored bookmarks
are dropped when writing the file back on disk. On paper, this behavior should
be fine, but with the current implementation, it can lead to unexpected
bookmark deletions.

In theory, to make sure writer as a consistent view, taking the lock also
invalidate bookmark data we already loaded into memory.  However this
invalidation is incomplete. The data are stored in a `filecache` that preserve
them if the bookmark related file are untouched. In practice, the bookmark data
in memory also depends of the changelog content, because of the step checking
if the bookmarks refers to a node known to the changelog. So if the bookmark
data were loaded from an up to date bookmark file but filtered with an outdated
changelog file this go undetected.

This condition is fairly specific, but can occurs very often in practice.  We
introduce a test recreating the situation. The test comes in an independant
changeset to show it actually reproduce the situation. The fix will come soon
after.

A large share of the initial investigation of this race condition was made by
Valentin Gatien-Baron <[e-mail]>.

from __future__ import absolute_import
from __future__ import print_function

import unittest

from mercurial import (
    mdiff,
    pycompat,
)
from mercurial.dagop import (
    annotateline,
    _annotatedfile,
    _annotatepair,
)

def tr(a):
    return [annotateline(fctx, lineno, skip)
            for fctx, lineno, skip in zip(a.fctxs, a.linenos, a.skips)]

class AnnotateTests(unittest.TestCase):
    """Unit tests for annotate code."""

    def testannotatepair(self):
        self.maxDiff = None # camelcase-required

        oldfctx = b'old'
        p1fctx, p2fctx, childfctx = b'p1', b'p2', b'c'
        olddata = b'a\nb\n'
        p1data = b'a\nb\nc\n'
        p2data = b'a\nc\nd\n'
        childdata = b'a\nb2\nc\nc2\nd\n'
        diffopts = mdiff.diffopts()

        def decorate(text, fctx):
            n = text.count(b'\n')
            linenos = pycompat.rangelist(1, n + 1)
            return _annotatedfile([fctx] * n, linenos, [False] * n, text)

        # Basic usage

        oldann = decorate(olddata, oldfctx)
        p1ann = decorate(p1data, p1fctx)
        p1ann = _annotatepair([oldann], p1fctx, p1ann, False, diffopts)
        self.assertEqual(tr(p1ann), [
            annotateline(b'old', 1),
            annotateline(b'old', 2),
            annotateline(b'p1', 3),
        ])

        p2ann = decorate(p2data, p2fctx)
        p2ann = _annotatepair([oldann], p2fctx, p2ann, False, diffopts)
        self.assertEqual(tr(p2ann), [
            annotateline(b'old', 1),
            annotateline(b'p2', 2),
            annotateline(b'p2', 3),
        ])

        # Test with multiple parents (note the difference caused by ordering)

        childann = decorate(childdata, childfctx)
        childann = _annotatepair([p1ann, p2ann], childfctx, childann, False,
                                 diffopts)
        self.assertEqual(tr(childann), [
            annotateline(b'old', 1),
            annotateline(b'c', 2),
            annotateline(b'p2', 2),
            annotateline(b'c', 4),
            annotateline(b'p2', 3),
        ])

        childann = decorate(childdata, childfctx)
        childann = _annotatepair([p2ann, p1ann], childfctx, childann, False,
                                 diffopts)
        self.assertEqual(tr(childann), [
            annotateline(b'old', 1),
            annotateline(b'c', 2),
            annotateline(b'p1', 3),
            annotateline(b'c', 4),
            annotateline(b'p2', 3),
        ])

        # Test with skipchild (note the difference caused by ordering)

        childann = decorate(childdata, childfctx)
        childann = _annotatepair([p1ann, p2ann], childfctx, childann, True,
                                 diffopts)
        self.assertEqual(tr(childann), [
            annotateline(b'old', 1),
            annotateline(b'old', 2, True),
            # note that this line was carried over from earlier so it is *not*
            # marked skipped
            annotateline(b'p2', 2),
            annotateline(b'p2', 2, True),
            annotateline(b'p2', 3),
        ])

        childann = decorate(childdata, childfctx)
        childann = _annotatepair([p2ann, p1ann], childfctx, childann, True,
                                 diffopts)
        self.assertEqual(tr(childann), [
            annotateline(b'old', 1),
            annotateline(b'old', 2, True),
            annotateline(b'p1', 3),
            annotateline(b'p1', 3, True),
            annotateline(b'p2', 3),
        ])

if __name__ == '__main__':
    import silenttestrunner
    silenttestrunner.main(__name__)