discovery-helper: use reflink copy if available
A reflink copy will copy the files "as usual" but keep using the same data block
underneath. This is only supported by "copy on write" file system like btrfs or
zfs.
This will achieve similar performance that the existing hardlink clone that
Mercurial performs with the same initial space saving. However, it will behave
better on revlogs start being touch by strip. Instead of duplicating all data in
the touched revlogs, only the block actually affected by the strip will be
duplicated. This save a lot of space when building many variants of large
repositories.
The --reflink=always flag make sure the `cp` call fails if reflink copies are
not supported. Falling back to local clone.
from __future__ import absolute_import
import sys
import unittest
from mercurial import (
error,
node,
)
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
# picked from test-parse-index2, copied rather than imported
# so that it stays stable even if test-parse-index2 changes or disappears.
data_non_inlined = (
b'\x00\x00\x00\x01\x00\x00\x00\x00\x00\x01D\x19'
b'\x00\x07e\x12\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff\xff\xff'
b'\xff\xff\xff\xff\xd1\xf4\xbb\xb0\xbe\xfc\x13\xbd\x8c\xd3\x9d'
b'\x0f\xcd\xd9;\x8c\x07\x8cJ/\x00\x00\x00\x00\x00\x00\x00\x00\x00'
b'\x00\x00\x00\x00\x00\x00\x01D\x19\x00\x00\x00\x00\x00\xdf\x00'
b'\x00\x01q\x00\x00\x00\x01\x00\x00\x00\x01\x00\x00\x00\x00\xff'
b'\xff\xff\xff\xc1\x12\xb9\x04\x96\xa4Z1t\x91\xdfsJ\x90\xf0\x9bh'
b'\x07l&\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
b'\x00\x01D\xf8\x00\x00\x00\x00\x01\x1b\x00\x00\x01\xb8\x00\x00'
b'\x00\x01\x00\x00\x00\x02\x00\x00\x00\x01\xff\xff\xff\xff\x02\n'
b'\x0e\xc6&\xa1\x92\xae6\x0b\x02i\xfe-\xe5\xbao\x05\xd1\xe7\x00'
b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01F'
b'\x13\x00\x00\x00\x00\x01\xec\x00\x00\x03\x06\x00\x00\x00\x01'
b'\x00\x00\x00\x03\x00\x00\x00\x02\xff\xff\xff\xff\x12\xcb\xeby1'
b'\xb6\r\x98B\xcb\x07\xbd`\x8f\x92\xd9\xc4\x84\xbdK\x00\x00\x00'
b'\x00\x00\x00\x00\x00\x00\x00\x00\x00'
)
@unittest.skipIf(rustext is None or cparsers is None,
"rustext or the C Extension parsers module "
"ancestor relies on is not available")
class rustancestorstest(unittest.TestCase):
"""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 parseindex(self):
return cparsers.parse_index2(data_non_inlined, False)[0]
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 = (data_non_inlined[:64 + 27] +
b'\xf2' +
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, [node.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__)