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)
import difflib
import random
import unittest
from mercurial import linelog
vecratio = 3 # number of replacelines / number of replacelines_vec
maxlinenum = 0xFFFFFF
maxb1 = 0xFFFFFF
maxdeltaa = 10
maxdeltab = 10
def _genedits(seed, endrev):
lines = []
random.seed(seed)
for rev in range(0, endrev):
n = len(lines)
a1 = random.randint(0, n)
a2 = random.randint(a1, min(n, a1 + maxdeltaa))
b1 = random.randint(0, maxb1)
b2 = random.randint(b1, b1 + maxdeltab)
usevec = not bool(random.randint(0, vecratio))
if usevec:
blines = [
(random.randint(0, rev), random.randint(0, maxlinenum))
for _ in range(b1, b2)
]
else:
blines = [(rev, bidx) for bidx in range(b1, b2)]
lines[a1:a2] = blines
yield lines, rev, a1, a2, b1, b2, blines, usevec
class linelogtests(unittest.TestCase):
def testlinelogencodedecode(self):
program = [
linelog._eof(0, 0),
linelog._jge(41, 42),
linelog._jump(0, 43),
linelog._eof(0, 0),
linelog._jl(44, 45),
linelog._line(46, 47),
]
ll = linelog.linelog(program, maxrev=100)
enc = ll.encode()
# round-trips okay
self.assertEqual(linelog.linelog.fromdata(enc)._program, ll._program)
self.assertEqual(linelog.linelog.fromdata(enc), ll)
# This encoding matches the encoding used by hg-experimental's
# linelog file, or is supposed to if it doesn't.
self.assertEqual(
enc,
(
b'\x00\x00\x01\x90\x00\x00\x00\x06'
b'\x00\x00\x00\xa4\x00\x00\x00*'
b'\x00\x00\x00\x00\x00\x00\x00+'
b'\x00\x00\x00\x00\x00\x00\x00\x00'
b'\x00\x00\x00\xb1\x00\x00\x00-'
b'\x00\x00\x00\xba\x00\x00\x00/'
),
)
def testsimpleedits(self):
ll = linelog.linelog()
# Initial revision: add lines 0, 1, and 2
ll.replacelines(1, 0, 0, 0, 3)
self.assertEqual(
[(l.rev, l.linenum) for l in ll.annotate(1)],
[
(1, 0),
(1, 1),
(1, 2),
],
)
# Replace line 1 with a new line
ll.replacelines(2, 1, 2, 1, 2)
self.assertEqual(
[(l.rev, l.linenum) for l in ll.annotate(2)],
[
(1, 0),
(2, 1),
(1, 2),
],
)
# delete a line out of 2
ll.replacelines(3, 1, 2, 0, 0)
self.assertEqual(
[(l.rev, l.linenum) for l in ll.annotate(3)],
[
(1, 0),
(1, 2),
],
)
# annotation of 1 is unchanged
self.assertEqual(
[(l.rev, l.linenum) for l in ll.annotate(1)],
[
(1, 0),
(1, 1),
(1, 2),
],
)
ll.annotate(3) # set internal state to revision 3
start = ll.getoffset(0)
end = ll.getoffset(1)
self.assertEqual(
ll.getalllines(start, end),
[
(1, 0),
(2, 1),
(1, 1),
],
)
self.assertEqual(
ll.getalllines(),
[
(1, 0),
(2, 1),
(1, 1),
(1, 2),
],
)
def testparseclinelogfile(self):
# This data is what the replacements in testsimpleedits
# produce when fed to the original linelog.c implementation.
data = (
b'\x00\x00\x00\x0c\x00\x00\x00\x0f'
b'\x00\x00\x00\x00\x00\x00\x00\x02'
b'\x00\x00\x00\x05\x00\x00\x00\x06'
b'\x00\x00\x00\x06\x00\x00\x00\x00'
b'\x00\x00\x00\x00\x00\x00\x00\x07'
b'\x00\x00\x00\x06\x00\x00\x00\x02'
b'\x00\x00\x00\x00\x00\x00\x00\x00'
b'\x00\x00\x00\t\x00\x00\x00\t'
b'\x00\x00\x00\x00\x00\x00\x00\x0c'
b'\x00\x00\x00\x08\x00\x00\x00\x05'
b'\x00\x00\x00\x06\x00\x00\x00\x01'
b'\x00\x00\x00\x00\x00\x00\x00\x05'
b'\x00\x00\x00\x0c\x00\x00\x00\x05'
b'\x00\x00\x00\n\x00\x00\x00\x01'
b'\x00\x00\x00\x00\x00\x00\x00\t'
)
llc = linelog.linelog.fromdata(data)
self.assertEqual(
[(l.rev, l.linenum) for l in llc.annotate(1)],
[
(1, 0),
(1, 1),
(1, 2),
],
)
self.assertEqual(
[(l.rev, l.linenum) for l in llc.annotate(2)],
[
(1, 0),
(2, 1),
(1, 2),
],
)
self.assertEqual(
[(l.rev, l.linenum) for l in llc.annotate(3)],
[
(1, 0),
(1, 2),
],
)
# Check we emit the same bytecode.
ll = linelog.linelog()
# Initial revision: add lines 0, 1, and 2
ll.replacelines(1, 0, 0, 0, 3)
# Replace line 1 with a new line
ll.replacelines(2, 1, 2, 1, 2)
# delete a line out of 2
ll.replacelines(3, 1, 2, 0, 0)
diff = '\n ' + '\n '.join(
difflib.unified_diff(
ll.debugstr().splitlines(),
llc.debugstr().splitlines(),
'python',
'c',
lineterm='',
)
)
self.assertEqual(ll._program, llc._program, 'Program mismatch: ' + diff)
# Done as a secondary step so we get a better result if the
# program is where the mismatch is.
self.assertEqual(ll, llc)
self.assertEqual(ll.encode(), data)
def testanothersimplecase(self):
ll = linelog.linelog()
ll.replacelines(3, 0, 0, 0, 2)
ll.replacelines(4, 0, 2, 0, 0)
self.assertEqual([(l.rev, l.linenum) for l in ll.annotate(4)], [])
self.assertEqual(
[(l.rev, l.linenum) for l in ll.annotate(3)], [(3, 0), (3, 1)]
)
# rev 2 is empty because contents were only ever introduced in rev 3
self.assertEqual([(l.rev, l.linenum) for l in ll.annotate(2)], [])
def testrandomedits(self):
# Inspired by original linelog tests.
seed = random.random()
numrevs = 2000
ll = linelog.linelog()
# Populate linelog
for lines, rev, a1, a2, b1, b2, blines, usevec in _genedits(
seed, numrevs
):
if usevec:
ll.replacelines_vec(rev, a1, a2, blines)
else:
ll.replacelines(rev, a1, a2, b1, b2)
ll.annotate(rev)
self.assertEqual(ll.annotateresult, lines)
# Verify we can get back these states by annotating each rev
for lines, rev, a1, a2, b1, b2, blines, usevec in _genedits(
seed, numrevs
):
ar = ll.annotate(rev)
self.assertEqual([(l.rev, l.linenum) for l in ar], lines)
def testinfinitebadprogram(self):
ll = linelog.linelog.fromdata(
b'\x00\x00\x00\x00\x00\x00\x00\x02' # header
b'\x00\x00\x00\x00\x00\x00\x00\x01' # JUMP to self
)
with self.assertRaises(linelog.LineLogError):
# should not be an infinite loop and raise
ll.annotate(1)
if __name__ == '__main__':
import silenttestrunner
silenttestrunner.main(__name__)