tests/test-manifest.py

localrepo: experimental support for non-zlib revlog compression

The final part of integrating the compression manager APIs into
revlog storage is the plumbing for repositories to advertise they
are using non-zlib storage and for revlogs to instantiate a non-zlib
compression engine.

The main intent of the compression manager work was to zstd all
of the things. Adding zstd to revlogs has proved to be more involved
than other places because revlogs are... special. Very small inputs
and the use of delta chains (which are themselves a form of
compression) are a completely different use case from streaming
compression, which bundles and the wire protocol employ. I've
conducted numerous experiments with zstd in revlogs and have yet
to formalize compression settings and a storage architecture that
I'm confident I won't regret later. In other words, I'm not yet
ready to commit to a new mechanism for using zstd - or any other
compression format - in revlogs.

That being said, having some support for zstd (and other compression
formats) in revlogs in core is beneficial. It can allow others to
conduct experiments.

This patch introduces *highly experimental* support for non-zlib
compression formats in revlogs. Introduced is a config option to
control which compression engine to use. Also introduced is a namespace
of "exp-compression-*" requirements to denote support for non-zlib
compression in revlogs. I've prefixed the namespace with "exp-"
(short for "experimental") because I'm not confident of the
requirements "schema" and in no way want to give the illusion of
supporting these requirements in the future. I fully intend to drop
support for these requirements once we figure out what we're doing
with zstd in revlogs.

A good portion of the patch is teaching the requirements system
about registered compression engines and passing the requested
compression engine as an opener option so revlogs can instantiate
the proper compression engine for new operations.

That's a verbose way of saying "we can now use zstd in revlogs!"

On an `hg pull` conversion of the mozilla-unified repo with no extra
redelta settings (like aggressivemergedeltas), we can see the impact
of zstd vs zlib in revlogs:

$ hg perfrevlogchunks -c
! chunk
! wall 2.032052 comb 2.040000 user 1.990000 sys 0.050000 (best of 5)
! wall 1.866360 comb 1.860000 user 1.820000 sys 0.040000 (best of 6)

! chunk batch
! wall 1.877261 comb 1.870000 user 1.860000 sys 0.010000 (best of 6)
! wall 1.705410 comb 1.710000 user 1.690000 sys 0.020000 (best of 6)

$ hg perfrevlogchunks -m
! chunk
! wall 2.721427 comb 2.720000 user 2.640000 sys 0.080000 (best of 4)
! wall 2.035076 comb 2.030000 user 1.950000 sys 0.080000 (best of 5)

! chunk batch
! wall 2.614561 comb 2.620000 user 2.580000 sys 0.040000 (best of 4)
! wall 1.910252 comb 1.910000 user 1.880000 sys 0.030000 (best of 6)

$ hg perfrevlog -c -d 1
! wall 4.812885 comb 4.820000 user 4.800000 sys 0.020000 (best of 3)
! wall 4.699621 comb 4.710000 user 4.700000 sys 0.010000 (best of 3)

$ hg perfrevlog -m -d 1000
! wall 34.252800 comb 34.250000 user 33.730000 sys 0.520000 (best of 3)
! wall 24.094999 comb 24.090000 user 23.320000 sys 0.770000 (best of 3)

Only modest wins for the changelog. But manifest reading is
significantly faster. What's going on?

One reason might be data volume. zstd decompresses faster. So given
more bytes, it will put more distance between it and zlib.

Another reason is size. In the current design, zstd revlogs are
*larger*:

debugcreatestreamclonebundle (size in bytes)
zlib: 1,638,852,492
zstd: 1,680,601,332

I haven't investigated this fully, but I reckon a significant cause of
larger revlogs is that the zstd frame/header has more bytes than
zlib's. For very small inputs or data that doesn't compress well, we'll
tend to store more uncompressed chunks than with zlib (because the
compressed size isn't smaller than original). This will make revlog
reading faster because it is doing less decompression.

Moving on to bundle performance:

$ hg bundle -a -t none-v2 (total CPU time)
zlib: 102.79s
zstd:  97.75s

So, marginal CPU decrease for reading all chunks in all revlogs
(this is somewhat disappointing).

$ hg bundle -a -t <engine>-v2 (total CPU time)
zlib: 191.59s
zstd: 115.36s

This last test effectively measures the difference between zlib->zlib
and zstd->zstd for revlogs to bundle. This is a rough approximation of
what a server does during `hg clone`.

There are some promising results for zstd. But not enough for me to
feel comfortable advertising it to users. We'll get there...

from __future__ import absolute_import

import binascii
import itertools
import silenttestrunner
import unittest

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

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

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

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

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

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

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

HUGE_MANIFEST_ENTRIES = 200001

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

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

    def assertIn(self, thing, container, msg=None):
        # assertIn new in 2.7, use it if available, otherwise polyfill
        sup = getattr(unittest.TestCase, 'assertIn', False)
        if sup:
            return sup(self, thing, container, msg=msg)
        if not msg:
            msg = 'Expected %r in %r' % (thing, container)
        self.assert_(thing in container, msg)

    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(['bar/baz/qux.py', 'foo'], list(m))
        self.assertEqual(BIN_HASH_2, m['bar/baz/qux.py'])
        self.assertEqual('l', m.flags('bar/baz/qux.py'))
        self.assertEqual(BIN_HASH_1, m['foo'])
        self.assertEqual('', m.flags('foo'))
        self.assertRaises(KeyError, lambda : m['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('bar/baz/qux.py', m)
        self.assertIn('bar/qux/foo.py', m)
        self.assertIn('bar/qux/foz.py', m)
        self.assertIn(256 * 'x' + '/x', m)
        self.assertIn(256 * 'x' + '/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['a'] = want
        self.assertIn('a', m)
        self.assertEqual(want, m['a'])
        self.assertEqual('a\0' + HASH_1 + '\n', m.text())

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

    def testSetFlag(self):
        want = 'x'

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

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

    def testCopy(self):
        m = self.parsemanifest(A_SHORT_MANIFEST)
        m['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['alpha'] = h1
        m['beta'] = h2
        del m['foo']
        want = '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(['alpha', 'bar/baz/qux.py', 'beta'], list(m))
        self.assertEqual(h1, m['alpha'])
        self.assertEqual(h2, m['bar/baz/qux.py'])
        self.assertEqual(h2, m['beta'])
        self.assertEqual('', m.flags('alpha'))
        self.assertEqual('l', m.flags('bar/baz/qux.py'))
        self.assertEqual('', m.flags('beta'))
        self.assertRaises(KeyError, lambda : m['foo'])

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

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

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

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

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

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

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

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

    def testReversedLines(self):
        backwards = ''.join(
            l + '\n' for l in reversed(A_SHORT_MANIFEST.split('\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 + '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('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('/', '',
                ['file1', 'file200', 'file300'], exact=True)
        m2 = m.matches(match)

        w = ('file1\0%sx\n'
             'file200\0%sl\n'
             '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('/', '',
                ['a/b/c/bar.txt', 'a/b/d/qux.py', 'readme.txt', 'nonexistent'],
                exact=True)
        m2 = m.matches(match)

        self.assertEqual(
                ['a/b/c/bar.txt', 'a/b/d/qux.py', '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('/', '', ['a/f'], default='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('/', '', 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('/', '', [''])
        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('/', '', ['a/b'], default='relpath')
        m2 = m.matches(match)

        self.assertEqual([
            'a/b/c/bar.py', 'a/b/c/bar.txt', 'a/b/c/foo.py', 'a/b/c/foo.txt',
            'a/b/d/baz.py', 'a/b/d/qux.py', 'a/b/d/ten.txt', 'a/b/dog.py',
            '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('/', '', ['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('/', 'a/b', ['.'], default='relpath')
        m2 = m.matches(match)

        self.assertEqual([
            'a/b/c/bar.py', 'a/b/c/bar.txt', 'a/b/c/foo.py', 'a/b/c/foo.txt',
            'a/b/d/baz.py', 'a/b/d/qux.py', 'a/b/d/ten.txt', 'a/b/dog.py',
            '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('/', '', ['a/b/*/*.txt'])
        m2 = m.matches(match)

        self.assertEqual(
                ['a/b/c/bar.txt', 'a/b/c/foo.txt', '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('', text)

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