tests/test-check-interfaces.py

rust: fix unsound `OwningDirstateMap`

As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.

The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.

I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.

In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.

Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.

Differential Revision: https://phab.mercurial-scm.org/D12429

# Test that certain objects conform to well-defined interfaces.

from __future__ import absolute_import, print_function

from mercurial import encoding

encoding.environ[b'HGREALINTERFACES'] = b'1'

import os
import subprocess
import sys

# Only run if tests are run in a repo
if subprocess.call(
    [sys.executable, '%s/hghave' % os.environ['TESTDIR'], 'test-repo']
):
    sys.exit(80)

from mercurial.interfaces import (
    dirstate as intdirstate,
    repository,
)
from mercurial.thirdparty.zope import interface as zi
from mercurial.thirdparty.zope.interface import verify as ziverify
from mercurial import (
    bundlerepo,
    dirstate,
    filelog,
    httppeer,
    localrepo,
    manifest,
    pycompat,
    revlog,
    sshpeer,
    statichttprepo,
    ui as uimod,
    unionrepo,
    vfs as vfsmod,
    wireprotoserver,
    wireprototypes,
    wireprotov1peer,
)

testdir = os.path.dirname(__file__)
rootdir = pycompat.fsencode(os.path.normpath(os.path.join(testdir, '..')))

sys.path[0:0] = [testdir]
import simplestorerepo

del sys.path[0]


def checkzobject(o, allowextra=False):
    """Verify an object with a zope interface."""
    ifaces = zi.providedBy(o)
    if not ifaces:
        print('%r does not provide any zope interfaces' % o)
        return

    # Run zope.interface's built-in verification routine. This verifies that
    # everything that is supposed to be present is present.
    for iface in ifaces:
        ziverify.verifyObject(iface, o)

    if allowextra:
        return

    # Now verify that the object provides no extra public attributes that
    # aren't declared as part of interfaces.
    allowed = set()
    for iface in ifaces:
        allowed |= set(iface.names(all=True))

    public = {a for a in dir(o) if not a.startswith('_')}

    for attr in sorted(public - allowed):
        print(
            'public attribute not declared in interfaces: %s.%s'
            % (o.__class__.__name__, attr)
        )


# Facilitates testing localpeer.
class dummyrepo(object):
    def __init__(self):
        self.ui = uimod.ui()
        self._wanted_sidedata = set()

    def filtered(self, name):
        pass

    def _restrictcapabilities(self, caps):
        pass


class dummyopener(object):
    handlers = []


# Facilitates testing sshpeer without requiring a server.
class badpeer(httppeer.httppeer):
    def __init__(self):
        super(badpeer, self).__init__(
            None, None, None, dummyopener(), None, None
        )
        self.badattribute = True

    def badmethod(self):
        pass


class dummypipe(object):
    def close(self):
        pass

    @property
    def closed(self):
        pass


def main():
    ui = uimod.ui()
    # Needed so we can open a local repo with obsstore without a warning.
    ui.setconfig(b'experimental', b'evolution.createmarkers', True)

    checkzobject(badpeer())

    ziverify.verifyClass(repository.ipeerbase, httppeer.httppeer)
    checkzobject(httppeer.httppeer(None, None, None, dummyopener(), None, None))

    ziverify.verifyClass(repository.ipeerbase, localrepo.localpeer)
    checkzobject(localrepo.localpeer(dummyrepo()))

    ziverify.verifyClass(
        repository.ipeercommandexecutor, localrepo.localcommandexecutor
    )
    checkzobject(localrepo.localcommandexecutor(None))

    ziverify.verifyClass(
        repository.ipeercommandexecutor, wireprotov1peer.peerexecutor
    )
    checkzobject(wireprotov1peer.peerexecutor(None))

    ziverify.verifyClass(repository.ipeerbase, sshpeer.sshv1peer)
    checkzobject(
        sshpeer.sshv1peer(
            ui,
            b'ssh://localhost/foo',
            b'',
            dummypipe(),
            dummypipe(),
            None,
            None,
        )
    )

    ziverify.verifyClass(repository.ipeerbase, bundlerepo.bundlepeer)
    checkzobject(bundlerepo.bundlepeer(dummyrepo()))

    ziverify.verifyClass(repository.ipeerbase, statichttprepo.statichttppeer)
    checkzobject(statichttprepo.statichttppeer(dummyrepo()))

    ziverify.verifyClass(repository.ipeerbase, unionrepo.unionpeer)
    checkzobject(unionrepo.unionpeer(dummyrepo()))

    ziverify.verifyClass(
        repository.ilocalrepositorymain, localrepo.localrepository
    )
    ziverify.verifyClass(
        repository.ilocalrepositoryfilestorage, localrepo.revlogfilestorage
    )
    repo = localrepo.makelocalrepository(ui, rootdir)
    checkzobject(repo)

    ziverify.verifyClass(
        wireprototypes.baseprotocolhandler, wireprotoserver.sshv1protocolhandler
    )
    ziverify.verifyClass(
        wireprototypes.baseprotocolhandler,
        wireprotoserver.httpv1protocolhandler,
    )

    sshv1 = wireprotoserver.sshv1protocolhandler(None, None, None)
    checkzobject(sshv1)

    httpv1 = wireprotoserver.httpv1protocolhandler(None, None, None)
    checkzobject(httpv1)

    ziverify.verifyClass(repository.ifilestorage, filelog.filelog)
    ziverify.verifyClass(repository.imanifestdict, manifest.manifestdict)
    ziverify.verifyClass(repository.imanifestdict, manifest.treemanifest)
    ziverify.verifyClass(
        repository.imanifestrevisionstored, manifest.manifestctx
    )
    ziverify.verifyClass(
        repository.imanifestrevisionwritable, manifest.memmanifestctx
    )
    ziverify.verifyClass(
        repository.imanifestrevisionstored, manifest.treemanifestctx
    )
    ziverify.verifyClass(
        repository.imanifestrevisionwritable, manifest.memtreemanifestctx
    )
    ziverify.verifyClass(repository.imanifestlog, manifest.manifestlog)
    ziverify.verifyClass(repository.imanifeststorage, manifest.manifestrevlog)

    ziverify.verifyClass(
        repository.irevisiondelta, simplestorerepo.simplestorerevisiondelta
    )
    ziverify.verifyClass(repository.ifilestorage, simplestorerepo.filestorage)
    ziverify.verifyClass(
        repository.iverifyproblem, simplestorerepo.simplefilestoreproblem
    )

    ziverify.verifyClass(intdirstate.idirstate, dirstate.dirstate)

    vfs = vfsmod.vfs(b'.')
    fl = filelog.filelog(vfs, b'dummy.i')
    checkzobject(fl, allowextra=True)

    # Conforms to imanifestlog.
    ml = manifest.manifestlog(
        vfs,
        repo,
        manifest.manifestrevlog(repo.nodeconstants, repo.svfs),
        repo.narrowmatch(),
    )
    checkzobject(ml)
    checkzobject(repo.manifestlog)

    # Conforms to imanifestrevision.
    mctx = ml[repo[0].manifestnode()]
    checkzobject(mctx)

    # Conforms to imanifestrevisionwritable.
    checkzobject(mctx.copy())

    # Conforms to imanifestdict.
    checkzobject(mctx.read())

    mrl = manifest.manifestrevlog(repo.nodeconstants, vfs)
    checkzobject(mrl)

    ziverify.verifyClass(repository.irevisiondelta, revlog.revlogrevisiondelta)

    rd = revlog.revlogrevisiondelta(
        node=b'',
        p1node=b'',
        p2node=b'',
        basenode=b'',
        linknode=b'',
        flags=b'',
        baserevisionsize=None,
        revision=b'',
        sidedata=b'',
        delta=None,
        protocol_flags=b'',
    )
    checkzobject(rd)

    ziverify.verifyClass(repository.iverifyproblem, revlog.revlogproblem)
    checkzobject(revlog.revlogproblem())


main()