localrepo: stop doing special dirstate backup at transaction open
Since the dirstate writes are already managed by the transaction, we already do
a backup of the dirstate when necessary (and even trigger one to keep `hg
rollback` happy).
We needs some special code to deal with the initial empty checkout, but it is
not too complicated.
Managing variable filename (as dirstate-v2 uses) at the "journalfile" level, is
complex and fragile (which is consistent with the fact these files are not
journal…). If we no longer do it, our life is significantly simpler.
In some sense, we apply the xkcd-1134¹ solution to our savebackup/restorebackup
problem.
[1] https://xkcd.com/1134/
(the change to test-hardlink are expect as decreasing the number of duplicated
backup drive the hardlink count down)
#!/usr/bin/env python
import hashlib
import os
import random
import shutil
import stat
import struct
import sys
import tempfile
import unittest
import silenttestrunner
from mercurial.node import sha1nodeconstants
from mercurial import (
pycompat,
ui as uimod,
)
# Load the local remotefilelog, not the system one
sys.path[0:0] = [os.path.join(os.path.dirname(__file__), '..')]
from hgext.remotefilelog import (
basepack,
historypack,
)
class histpacktests(unittest.TestCase):
def setUp(self):
self.tempdirs = []
def tearDown(self):
for d in self.tempdirs:
shutil.rmtree(d)
def makeTempDir(self):
tempdir = tempfile.mkdtemp()
self.tempdirs.append(tempdir)
return pycompat.fsencode(tempdir)
def getHash(self, content):
return hashlib.sha1(content).digest()
def getFakeHash(self):
return b''.join(
pycompat.bytechr(random.randint(0, 255)) for _ in range(20)
)
def createPack(self, revisions=None):
"""Creates and returns a historypack containing the specified revisions.
`revisions` is a list of tuples, where each tuple contains a filanem,
node, p1node, p2node, and linknode.
"""
if revisions is None:
revisions = [
(
b"filename",
self.getFakeHash(),
sha1nodeconstants.nullid,
sha1nodeconstants.nullid,
self.getFakeHash(),
None,
)
]
packdir = pycompat.fsencode(self.makeTempDir())
packer = historypack.mutablehistorypack(uimod.ui(), packdir, version=2)
for filename, node, p1, p2, linknode, copyfrom in revisions:
packer.add(filename, node, p1, p2, linknode, copyfrom)
path = packer.close()
return historypack.historypack(path)
def testAddSingle(self):
"""Test putting a single entry into a pack and reading it out."""
filename = b"foo"
node = self.getFakeHash()
p1 = self.getFakeHash()
p2 = self.getFakeHash()
linknode = self.getFakeHash()
revisions = [(filename, node, p1, p2, linknode, None)]
pack = self.createPack(revisions)
actual = pack.getancestors(filename, node)[node]
self.assertEqual(p1, actual[0])
self.assertEqual(p2, actual[1])
self.assertEqual(linknode, actual[2])
def testAddMultiple(self):
"""Test putting multiple unrelated revisions into a pack and reading
them out.
"""
revisions = []
for i in range(10):
filename = b"foo-%d" % i
node = self.getFakeHash()
p1 = self.getFakeHash()
p2 = self.getFakeHash()
linknode = self.getFakeHash()
revisions.append((filename, node, p1, p2, linknode, None))
pack = self.createPack(revisions)
for filename, node, p1, p2, linknode, copyfrom in revisions:
actual = pack.getancestors(filename, node)[node]
self.assertEqual(p1, actual[0])
self.assertEqual(p2, actual[1])
self.assertEqual(linknode, actual[2])
self.assertEqual(copyfrom, actual[3])
def testAddAncestorChain(self):
"""Test putting multiple revisions in into a pack and read the ancestor
chain.
"""
revisions = []
filename = b"foo"
lastnode = sha1nodeconstants.nullid
for i in range(10):
node = self.getFakeHash()
revisions.append(
(
filename,
node,
lastnode,
sha1nodeconstants.nullid,
sha1nodeconstants.nullid,
None,
)
)
lastnode = node
# revisions must be added in topological order, newest first
revisions = list(reversed(revisions))
pack = self.createPack(revisions)
# Test that the chain has all the entries
ancestors = pack.getancestors(revisions[0][0], revisions[0][1])
for filename, node, p1, p2, linknode, copyfrom in revisions:
ap1, ap2, alinknode, acopyfrom = ancestors[node]
self.assertEqual(ap1, p1)
self.assertEqual(ap2, p2)
self.assertEqual(alinknode, linknode)
self.assertEqual(acopyfrom, copyfrom)
def testPackMany(self):
"""Pack many related and unrelated ancestors."""
# Build a random pack file
allentries = {}
ancestorcounts = {}
revisions = []
random.seed(0)
for i in range(100):
filename = b"filename-%d" % i
entries = []
p2 = sha1nodeconstants.nullid
linknode = sha1nodeconstants.nullid
for j in range(random.randint(1, 100)):
node = self.getFakeHash()
p1 = sha1nodeconstants.nullid
if len(entries) > 0:
p1 = entries[random.randint(0, len(entries) - 1)]
entries.append(node)
revisions.append((filename, node, p1, p2, linknode, None))
allentries[(filename, node)] = (p1, p2, linknode)
if p1 == sha1nodeconstants.nullid:
ancestorcounts[(filename, node)] = 1
else:
newcount = ancestorcounts[(filename, p1)] + 1
ancestorcounts[(filename, node)] = newcount
# Must add file entries in reverse topological order
revisions = list(reversed(revisions))
pack = self.createPack(revisions)
# Verify the pack contents
for (filename, node) in allentries:
ancestors = pack.getancestors(filename, node)
self.assertEqual(ancestorcounts[(filename, node)], len(ancestors))
for anode, (ap1, ap2, alinknode, copyfrom) in ancestors.items():
ep1, ep2, elinknode = allentries[(filename, anode)]
self.assertEqual(ap1, ep1)
self.assertEqual(ap2, ep2)
self.assertEqual(alinknode, elinknode)
self.assertEqual(copyfrom, None)
def testGetNodeInfo(self):
revisions = []
filename = b"foo"
lastnode = sha1nodeconstants.nullid
for i in range(10):
node = self.getFakeHash()
revisions.append(
(
filename,
node,
lastnode,
sha1nodeconstants.nullid,
sha1nodeconstants.nullid,
None,
)
)
lastnode = node
pack = self.createPack(revisions)
# Test that getnodeinfo returns the expected results
for filename, node, p1, p2, linknode, copyfrom in revisions:
ap1, ap2, alinknode, acopyfrom = pack.getnodeinfo(filename, node)
self.assertEqual(ap1, p1)
self.assertEqual(ap2, p2)
self.assertEqual(alinknode, linknode)
self.assertEqual(acopyfrom, copyfrom)
def testGetMissing(self):
"""Test the getmissing() api."""
revisions = []
filename = b"foo"
for i in range(10):
node = self.getFakeHash()
p1 = self.getFakeHash()
p2 = self.getFakeHash()
linknode = self.getFakeHash()
revisions.append((filename, node, p1, p2, linknode, None))
pack = self.createPack(revisions)
missing = pack.getmissing([(filename, revisions[0][1])])
self.assertFalse(missing)
missing = pack.getmissing(
[(filename, revisions[0][1]), (filename, revisions[1][1])]
)
self.assertFalse(missing)
fakenode = self.getFakeHash()
missing = pack.getmissing(
[(filename, revisions[0][1]), (filename, fakenode)]
)
self.assertEqual(missing, [(filename, fakenode)])
# Test getmissing on a non-existant filename
missing = pack.getmissing([(b"bar", fakenode)])
self.assertEqual(missing, [(b"bar", fakenode)])
def testAddThrows(self):
pack = self.createPack()
try:
pack.add(
b'filename',
sha1nodeconstants.nullid,
sha1nodeconstants.nullid,
sha1nodeconstants.nullid,
sha1nodeconstants.nullid,
None,
)
self.assertTrue(False, "historypack.add should throw")
except RuntimeError:
pass
def testBadVersionThrows(self):
pack = self.createPack()
path = pack.path + b'.histpack'
with open(path, 'rb') as f:
raw = f.read()
raw = struct.pack('!B', 255) + raw[1:]
os.chmod(path, os.stat(path).st_mode | stat.S_IWRITE)
with open(path, 'wb+') as f:
f.write(raw)
try:
historypack.historypack(pack.path)
self.assertTrue(False, "bad version number should have thrown")
except RuntimeError:
pass
def testLargePack(self):
"""Test creating and reading from a large pack with over X entries.
This causes it to use a 2^16 fanout table instead."""
total = basepack.SMALLFANOUTCUTOFF + 1
revisions = []
for i in range(total):
filename = b"foo-%d" % i
node = self.getFakeHash()
p1 = self.getFakeHash()
p2 = self.getFakeHash()
linknode = self.getFakeHash()
revisions.append((filename, node, p1, p2, linknode, None))
pack = self.createPack(revisions)
self.assertEqual(pack.params.fanoutprefix, basepack.LARGEFANOUTPREFIX)
for filename, node, p1, p2, linknode, copyfrom in revisions:
actual = pack.getancestors(filename, node)[node]
self.assertEqual(p1, actual[0])
self.assertEqual(p2, actual[1])
self.assertEqual(linknode, actual[2])
self.assertEqual(copyfrom, actual[3])
# TODO:
# histpack store:
# - repack two packs into one
if __name__ == '__main__':
if pycompat.iswindows:
sys.exit(80) # Skip on Windows
silenttestrunner.main(__name__)