view tests/test-manifest.py @ 44118:f81c17ec303c

hgdemandimport: apply lazy module loading to sys.meta_path finders

Python's `sys.meta_path` finders are the primary objects whose job it
is to find a module at import time. When `import` is called, Python
iterates objects in this list and calls `o.find_spec(...)` to find
a `ModuleSpec` (or None if the module couldn't be found by that
finder). If no meta path finder can find a module, import fails.

One of the default meta path finders is `PathFinder`. Its job is to
import modules from the filesystem and is probably the most important
importer. This finder looks at `sys.path` and `sys.path_hooks` to do
its job.

The `ModuleSpec` returned by `MetaPathImporter.find_spec()` has a
`loader` attribute, which defines the concrete module loader to use.
`sys.path_hooks` is a hook point for teaching `PathFinder` to
instantiate custom loader types.

Previously, we injected a custom `sys.path_hook` that told `PathFinder`
to wrap the default loaders with a loader that creates a module object
that is lazy.

This approach worked. But its main limitation was that it only applied
to the `PathFinder` meta path importer. There are other meta path
importers that are registered. And in the case of PyOxidizer loading
modules from memory, `PathFinder` doesn't come into play since
PyOxidizer's own meta path importer was handling all imports.

This commit changes our approach to lazy module loading by proxying
all meta path importers. Specifically, we overload the `find_spec()`
method to swap in a wrapped loader on the `ModuleSpec` before it
is returned. The end result of this is all meta path importers should
be lazy.

As much as I would have loved to utilize .__class__ manipulation to
achieve this, some meta path importers are implemented in C/Rust
in such a way that they cannot be monkeypatched. This is why we
use __getattribute__ to define a proxy.

Also, this change could theoretically open us up to regressions in
meta path importers whose loader is creating module objects which
can't be monkeypatched. But I'm not aware of any of these in the
wild. So I think we'll be safe.

According to hyperfine, this change yields a decent startup time win of
5-6ms:

```
Benchmark #1: ~/.pyenv/versions/3.6.10/bin/python ./hg version
  Time (mean ± σ):      86.8 ms ±   0.5 ms    [User: 78.0 ms, System: 8.7 ms]
  Range (min … max):    86.0 ms …  89.1 ms    50 runs

  Time (mean ± σ):      81.1 ms ±   2.7 ms    [User: 74.5 ms, System: 6.5 ms]
  Range (min … max):    77.8 ms …  90.5 ms    50 runs

Benchmark #2: ~/.pyenv/versions/3.7.6/bin/python ./hg version
  Time (mean ± σ):      78.9 ms ±   0.6 ms    [User: 70.2 ms, System: 8.7 ms]
  Range (min … max):    78.1 ms …  81.2 ms    50 runs

  Time (mean ± σ):      73.4 ms ±   0.6 ms    [User: 65.3 ms, System: 8.0 ms]
  Range (min … max):    72.4 ms …  75.7 ms    50 runs

Benchmark #3: ~/.pyenv/versions/3.8.1/bin/python ./hg version
  Time (mean ± σ):      78.1 ms ±   0.6 ms    [User: 70.2 ms, System: 7.9 ms]
  Range (min … max):    77.4 ms …  80.9 ms    50 runs

  Time (mean ± σ):      72.1 ms ±   0.4 ms    [User: 64.4 ms, System: 7.6 ms]
  Range (min … max):    71.4 ms …  74.1 ms    50 runs
```

Differential Revision: https://phab.mercurial-scm.org/D7954

from __future__ import absolute_import

import binascii
import itertools
import silenttestrunner
import unittest
import zlib

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

EMTPY_MANIFEST = b''

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',}

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 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 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.items()),
        )
        # 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(util.localpath(b'/repo'), 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.items())
        )

        # 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(util.localpath(b'/repo'), 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.exact([b'file1', b'file200', b'file300'])
        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.exact(
            [b'a/b/c/bar.txt', b'a/b/d/qux.py', b'readme.txt', b'nonexistent']
        )
        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(
            util.localpath(b'/repo'), 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.exact(flist)
        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(util.localpath(b'/repo'), 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(
            util.localpath(b'/repo'), 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.exact([b'a/b'])
        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(
            util.localpath(b'/repo'), 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(util.localpath(b'/repo'), 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)

    def testObviouslyBogusManifest(self):
        # This is a 163k manifest that came from oss-fuzz. It was a
        # timeout there, but when run normally it doesn't seem to
        # present any particular slowness.
        data = zlib.decompress(
            b'x\x9c\xed\xce;\n\x83\x00\x10\x04\xd0\x8deNa\x93~\xf1\x03\xc9q\xf4'
            b'\x14\xeaU\xbdB\xda\xd4\xe6Cj\xc1FA\xde+\x86\xe9f\xa2\xfci\xbb\xfb'
            b'\xa3\xef\xea\xba\xca\x7fk\x86q\x9a\xc6\xc8\xcc&\xb3\xcf\xf8\xb8|#'
            b'\x8a9\x00\xd8\xe6v\xf4\x01N\xe1\n\x00\x00\x00\x00\x00\x00\x00\x00'
            b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
            b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
            b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
            b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
            b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
            b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
            b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
            b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
            b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
            b'\x00\x00\xc0\x8aey\x1d}\x01\xd8\xe0\xb9\xf3\xde\x1b\xcf\x17'
            b'\xac\xbe'
        )
        with self.assertRaises(ValueError):
            self.parsemanifest(data)


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(util.localpath(b'/repo'), 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__)