view tests/test-manifest.py @ 34824:e2ad93bcc084

revlog: introduce an experimental flag to slice chunks reads when too sparse

Delta chains can become quite sparse if there is a lot of unrelated data between
relevant pieces. Right now, revlog always reads all the necessary data for the
delta chain in one single read. This can lead to a lot of unrelated data to be
read (see issue5482 for more details).
One can use the `experimental.maxdeltachainspan` option with a large value
(or -1) to easily produce a very sparse delta chain.

This change introduces the ability to slice the chunks retrieval into  multiple
reads, skipping large sections of unrelated data. Preliminary testing shows
interesting results. For example the peak memory consumption to read a manifest
on a large repository is reduced from 600MB to 250MB (200MB without
maxdeltachainspan). However, the slicing itself and the multiple reads can have
an negative impact on performance. This is why the new feature is hidden behind
an experimental flag.

Future changesets will add various parameters to control the slicing heuristics.
We hope to experiment a wide variety of repositories during 4.4 and hopefully
turn the feature on by default in 4.5.
As a first try, the algorithm itself is prone to deep changes. However, we wish
to define APIs and have a baseline to work on.

from __future__ import absolute_import

import binascii
import itertools
import silenttestrunner
import unittest

from mercurial import (
    manifest as manifestmod,
    match as matchmod,
)

EMTPY_MANIFEST = b''
EMTPY_MANIFEST_V2 = b'\0\n'

HASH_1 = b'1' * 40
BIN_HASH_1 = binascii.unhexlify(HASH_1)
HASH_2 = b'f' * 40
BIN_HASH_2 = binascii.unhexlify(HASH_2)
HASH_3 = b'1234567890abcdef0987654321deadbeef0fcafe'
BIN_HASH_3 = binascii.unhexlify(HASH_3)
A_SHORT_MANIFEST = (
    b'bar/baz/qux.py\0%(hash2)s%(flag2)s\n'
    b'foo\0%(hash1)s%(flag1)s\n'
    ) % {b'hash1': HASH_1,
         b'flag1': b'',
         b'hash2': HASH_2,
         b'flag2': b'l',
         }

# Same data as A_SHORT_MANIFEST
A_SHORT_MANIFEST_V2 = (
    b'\0\n'
    b'\x00bar/baz/qux.py\0%(flag2)s\n%(hash2)s\n'
    b'\x00foo\0%(flag1)s\n%(hash1)s\n'
    ) % {b'hash1': BIN_HASH_1,
         b'flag1': b'',
         b'hash2': BIN_HASH_2,
         b'flag2': b'l',
         }

# Same data as A_SHORT_MANIFEST
A_METADATA_MANIFEST = (
    b'\0foo\0bar\n'
    b'\x00bar/baz/qux.py\0%(flag2)s\0foo\0bar\n%(hash2)s\n' # flag and metadata
    b'\x00foo\0%(flag1)s\0foo\n%(hash1)s\n' # no flag, but metadata
    ) % {b'hash1': BIN_HASH_1,
         b'flag1': b'',
         b'hash2': BIN_HASH_2,
         b'flag2': b'l',
         }

A_STEM_COMPRESSED_MANIFEST = (
    b'\0\n'
    b'\x00bar/baz/qux.py\0%(flag2)s\n%(hash2)s\n'
    b'\x04qux/foo.py\0%(flag1)s\n%(hash1)s\n' # simple case of 4 stem chars
    b'\x0az.py\0%(flag1)s\n%(hash1)s\n' # tricky newline = 10 stem characters
    b'\x00%(verylongdir)sx/x\0\n%(hash1)s\n'
    b'\xffx/y\0\n%(hash2)s\n' # more than 255 stem chars
    ) % {b'hash1': BIN_HASH_1,
         b'flag1': b'',
         b'hash2': BIN_HASH_2,
         b'flag2': b'l',
         b'verylongdir': 255 * b'x',
         }

A_DEEPER_MANIFEST = (
    b'a/b/c/bar.py\0%(hash3)s%(flag1)s\n'
    b'a/b/c/bar.txt\0%(hash1)s%(flag1)s\n'
    b'a/b/c/foo.py\0%(hash3)s%(flag1)s\n'
    b'a/b/c/foo.txt\0%(hash2)s%(flag2)s\n'
    b'a/b/d/baz.py\0%(hash3)s%(flag1)s\n'
    b'a/b/d/qux.py\0%(hash1)s%(flag2)s\n'
    b'a/b/d/ten.txt\0%(hash3)s%(flag2)s\n'
    b'a/b/dog.py\0%(hash3)s%(flag1)s\n'
    b'a/b/fish.py\0%(hash2)s%(flag1)s\n'
    b'a/c/london.py\0%(hash3)s%(flag2)s\n'
    b'a/c/paper.txt\0%(hash2)s%(flag2)s\n'
    b'a/c/paris.py\0%(hash2)s%(flag1)s\n'
    b'a/d/apple.py\0%(hash3)s%(flag1)s\n'
    b'a/d/pizza.py\0%(hash3)s%(flag2)s\n'
    b'a/green.py\0%(hash1)s%(flag2)s\n'
    b'a/purple.py\0%(hash2)s%(flag1)s\n'
    b'app.py\0%(hash3)s%(flag1)s\n'
    b'readme.txt\0%(hash2)s%(flag1)s\n'
    ) % {b'hash1': HASH_1,
         b'flag1': b'',
         b'hash2': HASH_2,
         b'flag2': b'l',
         b'hash3': HASH_3,
         }

HUGE_MANIFEST_ENTRIES = 200001

izip = getattr(itertools, 'izip', zip)
if 'xrange' not in globals():
    xrange = range

A_HUGE_MANIFEST = b''.join(sorted(
    b'file%d\0%s%s\n' % (i, h, f) for i, h, f in
    izip(xrange(200001),
         itertools.cycle((HASH_1, HASH_2)),
         itertools.cycle((b'', b'x', b'l')))))

class basemanifesttests(object):
    def parsemanifest(self, text):
        raise NotImplementedError('parsemanifest not implemented by test case')

    def testEmptyManifest(self):
        m = self.parsemanifest(EMTPY_MANIFEST)
        self.assertEqual(0, len(m))
        self.assertEqual([], list(m))

    def testEmptyManifestv2(self):
        m = self.parsemanifest(EMTPY_MANIFEST_V2)
        self.assertEqual(0, len(m))
        self.assertEqual([], list(m))

    def testManifest(self):
        m = self.parsemanifest(A_SHORT_MANIFEST)
        self.assertEqual([b'bar/baz/qux.py', b'foo'], list(m))
        self.assertEqual(BIN_HASH_2, m[b'bar/baz/qux.py'])
        self.assertEqual(b'l', m.flags(b'bar/baz/qux.py'))
        self.assertEqual(BIN_HASH_1, m[b'foo'])
        self.assertEqual(b'', m.flags(b'foo'))
        with self.assertRaises(KeyError):
            m[b'wat']

    def testParseManifestV2(self):
        m1 = self.parsemanifest(A_SHORT_MANIFEST)
        m2 = self.parsemanifest(A_SHORT_MANIFEST_V2)
        # Should have same content as A_SHORT_MANIFEST
        self.assertEqual(m1.text(), m2.text())

    def testParseManifestMetadata(self):
        # Metadata is for future-proofing and should be accepted but ignored
        m = self.parsemanifest(A_METADATA_MANIFEST)
        self.assertEqual(A_SHORT_MANIFEST, m.text())

    def testParseManifestStemCompression(self):
        m = self.parsemanifest(A_STEM_COMPRESSED_MANIFEST)
        self.assertIn(b'bar/baz/qux.py', m)
        self.assertIn(b'bar/qux/foo.py', m)
        self.assertIn(b'bar/qux/foz.py', m)
        self.assertIn(256 * b'x' + b'/x', m)
        self.assertIn(256 * b'x' + b'/y', m)
        self.assertEqual(A_STEM_COMPRESSED_MANIFEST, m.text(usemanifestv2=True))

    def testTextV2(self):
        m1 = self.parsemanifest(A_SHORT_MANIFEST)
        v2text = m1.text(usemanifestv2=True)
        self.assertEqual(A_SHORT_MANIFEST_V2, v2text)

    def testSetItem(self):
        want = BIN_HASH_1

        m = self.parsemanifest(EMTPY_MANIFEST)
        m[b'a'] = want
        self.assertIn(b'a', m)
        self.assertEqual(want, m[b'a'])
        self.assertEqual(b'a\0' + HASH_1 + b'\n', m.text())

        m = self.parsemanifest(A_SHORT_MANIFEST)
        m[b'a'] = want
        self.assertEqual(want, m[b'a'])
        self.assertEqual(b'a\0' + HASH_1 + b'\n' + A_SHORT_MANIFEST,
                         m.text())

    def testSetFlag(self):
        want = b'x'

        m = self.parsemanifest(EMTPY_MANIFEST)
        # first add a file; a file-less flag makes no sense
        m[b'a'] = BIN_HASH_1
        m.setflag(b'a', want)
        self.assertEqual(want, m.flags(b'a'))
        self.assertEqual(b'a\0' + HASH_1 + want + b'\n', m.text())

        m = self.parsemanifest(A_SHORT_MANIFEST)
        # first add a file; a file-less flag makes no sense
        m[b'a'] = BIN_HASH_1
        m.setflag(b'a', want)
        self.assertEqual(want, m.flags(b'a'))
        self.assertEqual(b'a\0' + HASH_1 + want + b'\n' + A_SHORT_MANIFEST,
                         m.text())

    def testCopy(self):
        m = self.parsemanifest(A_SHORT_MANIFEST)
        m[b'a'] = BIN_HASH_1
        m2 = m.copy()
        del m
        del m2 # make sure we don't double free() anything

    def testCompaction(self):
        unhex = binascii.unhexlify
        h1, h2 = unhex(HASH_1), unhex(HASH_2)
        m = self.parsemanifest(A_SHORT_MANIFEST)
        m[b'alpha'] = h1
        m[b'beta'] = h2
        del m[b'foo']
        want = b'alpha\0%s\nbar/baz/qux.py\0%sl\nbeta\0%s\n' % (
            HASH_1, HASH_2, HASH_2)
        self.assertEqual(want, m.text())
        self.assertEqual(3, len(m))
        self.assertEqual([b'alpha', b'bar/baz/qux.py', b'beta'], list(m))
        self.assertEqual(h1, m[b'alpha'])
        self.assertEqual(h2, m[b'bar/baz/qux.py'])
        self.assertEqual(h2, m[b'beta'])
        self.assertEqual(b'', m.flags(b'alpha'))
        self.assertEqual(b'l', m.flags(b'bar/baz/qux.py'))
        self.assertEqual(b'', m.flags(b'beta'))
        with self.assertRaises(KeyError):
            m[b'foo']

    def testSetGetNodeSuffix(self):
        clean = self.parsemanifest(A_SHORT_MANIFEST)
        m = self.parsemanifest(A_SHORT_MANIFEST)
        h = m[b'foo']
        f = m.flags(b'foo')
        want = h + b'a'
        # Merge code wants to set 21-byte fake hashes at times
        m[b'foo'] = want
        self.assertEqual(want, m[b'foo'])
        self.assertEqual([(b'bar/baz/qux.py', BIN_HASH_2),
                          (b'foo', BIN_HASH_1 + b'a')],
                         list(m.iteritems()))
        # Sometimes it even tries a 22-byte fake hash, but we can
        # return 21 and it'll work out
        m[b'foo'] = want + b'+'
        self.assertEqual(want, m[b'foo'])
        # make sure the suffix survives a copy
        match = matchmod.match(b'', b'', [b're:foo'])
        m2 = m.matches(match)
        self.assertEqual(want, m2[b'foo'])
        self.assertEqual(1, len(m2))
        m2 = m.copy()
        self.assertEqual(want, m2[b'foo'])
        # suffix with iteration
        self.assertEqual([(b'bar/baz/qux.py', BIN_HASH_2),
                          (b'foo', want)],
                         list(m.iteritems()))

        # shows up in diff
        self.assertEqual({b'foo': ((want, f), (h, b''))}, m.diff(clean))
        self.assertEqual({b'foo': ((h, b''), (want, f))}, clean.diff(m))

    def testMatchException(self):
        m = self.parsemanifest(A_SHORT_MANIFEST)
        match = matchmod.match(b'', b'', [b're:.*'])
        def filt(path):
            if path == b'foo':
                assert False
            return True
        match.matchfn = filt
        with self.assertRaises(AssertionError):
            m.matches(match)

    def testRemoveItem(self):
        m = self.parsemanifest(A_SHORT_MANIFEST)
        del m[b'foo']
        with self.assertRaises(KeyError):
            m[b'foo']
        self.assertEqual(1, len(m))
        self.assertEqual(1, len(list(m)))
        # now restore and make sure everything works right
        m[b'foo'] = b'a' * 20
        self.assertEqual(2, len(m))
        self.assertEqual(2, len(list(m)))

    def testManifestDiff(self):
        MISSING = (None, b'')
        addl = b'z-only-in-left\0' + HASH_1 + b'\n'
        addr = b'z-only-in-right\0' + HASH_2 + b'x\n'
        left = self.parsemanifest(
            A_SHORT_MANIFEST.replace(HASH_1, HASH_3 + b'x') + addl)
        right = self.parsemanifest(A_SHORT_MANIFEST + addr)
        want = {
            b'foo': ((BIN_HASH_3, b'x'),
                     (BIN_HASH_1, b'')),
            b'z-only-in-left': ((BIN_HASH_1, b''), MISSING),
            b'z-only-in-right': (MISSING, (BIN_HASH_2, b'x')),
            }
        self.assertEqual(want, left.diff(right))

        want = {
            b'bar/baz/qux.py': (MISSING, (BIN_HASH_2, b'l')),
            b'foo': (MISSING, (BIN_HASH_3, b'x')),
            b'z-only-in-left': (MISSING, (BIN_HASH_1, b'')),
            }
        self.assertEqual(want, self.parsemanifest(EMTPY_MANIFEST).diff(left))

        want = {
            b'bar/baz/qux.py': ((BIN_HASH_2, b'l'), MISSING),
            b'foo': ((BIN_HASH_3, b'x'), MISSING),
            b'z-only-in-left': ((BIN_HASH_1, b''), MISSING),
            }
        self.assertEqual(want, left.diff(self.parsemanifest(EMTPY_MANIFEST)))
        copy = right.copy()
        del copy[b'z-only-in-right']
        del right[b'foo']
        want = {
            b'foo': (MISSING, (BIN_HASH_1, b'')),
            b'z-only-in-right': ((BIN_HASH_2, b'x'), MISSING),
            }
        self.assertEqual(want, right.diff(copy))

        short = self.parsemanifest(A_SHORT_MANIFEST)
        pruned = short.copy()
        del pruned[b'foo']
        want = {
            b'foo': ((BIN_HASH_1, b''), MISSING),
            }
        self.assertEqual(want, short.diff(pruned))
        want = {
            b'foo': (MISSING, (BIN_HASH_1, b'')),
            }
        self.assertEqual(want, pruned.diff(short))
        want = {
            b'bar/baz/qux.py': None,
            b'foo': (MISSING, (BIN_HASH_1, b'')),
            }
        self.assertEqual(want, pruned.diff(short, clean=True))

    def testReversedLines(self):
        backwards = b''.join(
            l + b'\n' for l in reversed(A_SHORT_MANIFEST.split(b'\n')) if l)
        try:
            self.parsemanifest(backwards)
            self.fail('Should have raised ValueError')
        except ValueError as v:
            self.assertIn('Manifest lines not in sorted order.', str(v))

    def testNoTerminalNewline(self):
        try:
            self.parsemanifest(A_SHORT_MANIFEST + b'wat')
            self.fail('Should have raised ValueError')
        except ValueError as v:
            self.assertIn('Manifest did not end in a newline.', str(v))

    def testNoNewLineAtAll(self):
        try:
            self.parsemanifest(b'wat')
            self.fail('Should have raised ValueError')
        except ValueError as v:
            self.assertIn('Manifest did not end in a newline.', str(v))

    def testHugeManifest(self):
        m = self.parsemanifest(A_HUGE_MANIFEST)
        self.assertEqual(HUGE_MANIFEST_ENTRIES, len(m))
        self.assertEqual(len(m), len(list(m)))

    def testMatchesMetadata(self):
        '''Tests matches() for a few specific files to make sure that both
        the set of files as well as their flags and nodeids are correct in
        the resulting manifest.'''
        m = self.parsemanifest(A_HUGE_MANIFEST)

        match = matchmod.match(b'/', b'',
                [b'file1', b'file200', b'file300'], exact=True)
        m2 = m.matches(match)

        w = (b'file1\0%sx\n'
             b'file200\0%sl\n'
             b'file300\0%s\n') % (HASH_2, HASH_1, HASH_1)
        self.assertEqual(w, m2.text())

    def testMatchesNonexistentFile(self):
        '''Tests matches() for a small set of specific files, including one
        nonexistent file to make sure in only matches against existing files.
        '''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match(b'/', b'',
                [b'a/b/c/bar.txt', b'a/b/d/qux.py',
                 b'readme.txt', b'nonexistent'],
                exact=True)
        m2 = m.matches(match)

        self.assertEqual(
                [b'a/b/c/bar.txt', b'a/b/d/qux.py', b'readme.txt'],
                m2.keys())

    def testMatchesNonexistentDirectory(self):
        '''Tests matches() for a relpath match on a directory that doesn't
        actually exist.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match(b'/', b'', [b'a/f'], default=b'relpath')
        m2 = m.matches(match)

        self.assertEqual([], m2.keys())

    def testMatchesExactLarge(self):
        '''Tests matches() for files matching a large list of exact files.
        '''
        m = self.parsemanifest(A_HUGE_MANIFEST)

        flist = m.keys()[80:300]
        match = matchmod.match(b'/', b'', flist, exact=True)
        m2 = m.matches(match)

        self.assertEqual(flist, m2.keys())

    def testMatchesFull(self):
        '''Tests matches() for what should be a full match.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match(b'/', b'', [b''])
        m2 = m.matches(match)

        self.assertEqual(m.keys(), m2.keys())

    def testMatchesDirectory(self):
        '''Tests matches() on a relpath match on a directory, which should
        match against all files within said directory.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match(b'/', b'', [b'a/b'], default=b'relpath')
        m2 = m.matches(match)

        self.assertEqual([
            b'a/b/c/bar.py', b'a/b/c/bar.txt', b'a/b/c/foo.py',
            b'a/b/c/foo.txt',
            b'a/b/d/baz.py', b'a/b/d/qux.py', b'a/b/d/ten.txt', b'a/b/dog.py',
            b'a/b/fish.py'], m2.keys())

    def testMatchesExactPath(self):
        '''Tests matches() on an exact match on a directory, which should
        result in an empty manifest because you can't perform an exact match
        against a directory.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match(b'/', b'', [b'a/b'], exact=True)
        m2 = m.matches(match)

        self.assertEqual([], m2.keys())

    def testMatchesCwd(self):
        '''Tests matches() on a relpath match with the current directory ('.')
        when not in the root directory.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match(b'/', b'a/b', [b'.'], default=b'relpath')
        m2 = m.matches(match)

        self.assertEqual([
            b'a/b/c/bar.py', b'a/b/c/bar.txt', b'a/b/c/foo.py',
            b'a/b/c/foo.txt', b'a/b/d/baz.py', b'a/b/d/qux.py',
            b'a/b/d/ten.txt', b'a/b/dog.py', b'a/b/fish.py'], m2.keys())

    def testMatchesWithPattern(self):
        '''Tests matches() for files matching a pattern that reside
        deeper than the specified directory.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match(b'/', b'', [b'a/b/*/*.txt'])
        m2 = m.matches(match)

        self.assertEqual(
                [b'a/b/c/bar.txt', b'a/b/c/foo.txt', b'a/b/d/ten.txt'],
                m2.keys())

class testmanifestdict(unittest.TestCase, basemanifesttests):
    def parsemanifest(self, text):
        return manifestmod.manifestdict(text)

class testtreemanifest(unittest.TestCase, basemanifesttests):
    def parsemanifest(self, text):
        return manifestmod.treemanifest(b'', text)

    def testWalkSubtrees(self):
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        dirs = [s._dir for s in m.walksubtrees()]
        self.assertEqual(
            sorted([
                b'', b'a/', b'a/c/', b'a/d/', b'a/b/', b'a/b/c/', b'a/b/d/']),
            sorted(dirs)
        )

        match = matchmod.match(b'/', b'', [b'path:a/b/'])
        dirs = [s._dir for s in m.walksubtrees(matcher=match)]
        self.assertEqual(
            sorted([b'a/b/', b'a/b/c/', b'a/b/d/']),
            sorted(dirs)
        )

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