view hgext/remotefilelog/shallowrepo.py @ 42377:0546ead39a7e stable

manifest: avoid corruption by dropping removed files with pure (issue5801)

Previously, removed files would simply be marked by overwriting the first byte
with NUL and dropping their entry in `self.position`.  But no effort was made to
ignore them when compacting the dictionary into text form.  This allowed them to
slip into the manifest revision, since the code seems to be trying to minimize
the string operations by copying as large a chunk as possible.  As part of this,
compact() walks the existing text based on entries in the `positions` list, and
consumed everything up to the next position entry.   This typically resulted in
a ValueError complaining about unsorted manifest entries.

Sometimes it seems that files do get dropped in large repos- it seems to
correspond to there being a new entry that would take the same slot.  A much
more trivial problem is that if the only changes were removals, `_compact()`
didn't even run because `__delitem__` doesn't add anything to `self.extradata`.
Now there's an explicit variable to flag this, both to allow `_compact()` to
run, and to avoid searching the manifest in cases where there are no removals.

In practice, this behavior was mostly obscured by the check in fastdelta() which
takes a different path that explicitly drops removed files if there are fewer
than 1000 changes.  However, timeless has a repo where after rebasing tens of
commits, a totally different path[1] is taken that bypasses the change count
check and hits this problem.

[1] https://www.mercurial-scm.org/repo/hg/file/2338bdea4474/mercurial/manifest.py#l1511

# shallowrepo.py - shallow repository that uses remote filelogs
#
# Copyright 2013 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import

import os

from mercurial.i18n import _
from mercurial.node import hex, nullid, nullrev
from mercurial import (
    encoding,
    error,
    localrepo,
    match,
    scmutil,
    sparse,
    util,
)
from mercurial.utils import procutil
from . import (
    connectionpool,
    constants,
    contentstore,
    datapack,
    fileserverclient,
    historypack,
    metadatastore,
    remotefilectx,
    remotefilelog,
    shallowutil,
)

if util.safehasattr(util, '_hgexecutable'):
    # Before 5be286db
    _hgexecutable = util.hgexecutable
else:
    from mercurial.utils import procutil
    _hgexecutable = procutil.hgexecutable

# These make*stores functions are global so that other extensions can replace
# them.
def makelocalstores(repo):
    """In-repo stores, like .hg/store/data; can not be discarded."""
    localpath = os.path.join(repo.svfs.vfs.base, 'data')
    if not os.path.exists(localpath):
        os.makedirs(localpath)

    # Instantiate local data stores
    localcontent = contentstore.remotefilelogcontentstore(
        repo, localpath, repo.name, shared=False)
    localmetadata = metadatastore.remotefilelogmetadatastore(
        repo, localpath, repo.name, shared=False)
    return localcontent, localmetadata

def makecachestores(repo):
    """Typically machine-wide, cache of remote data; can be discarded."""
    # Instantiate shared cache stores
    cachepath = shallowutil.getcachepath(repo.ui)
    cachecontent = contentstore.remotefilelogcontentstore(
        repo, cachepath, repo.name, shared=True)
    cachemetadata = metadatastore.remotefilelogmetadatastore(
        repo, cachepath, repo.name, shared=True)

    repo.sharedstore = cachecontent
    repo.shareddatastores.append(cachecontent)
    repo.sharedhistorystores.append(cachemetadata)

    return cachecontent, cachemetadata

def makeremotestores(repo, cachecontent, cachemetadata):
    """These stores fetch data from a remote server."""
    # Instantiate remote stores
    repo.fileservice = fileserverclient.fileserverclient(repo)
    remotecontent = contentstore.remotecontentstore(
        repo.ui, repo.fileservice, cachecontent)
    remotemetadata = metadatastore.remotemetadatastore(
        repo.ui, repo.fileservice, cachemetadata)
    return remotecontent, remotemetadata

def makepackstores(repo):
    """Packs are more efficient (to read from) cache stores."""
    # Instantiate pack stores
    packpath = shallowutil.getcachepackpath(repo,
                                            constants.FILEPACK_CATEGORY)
    packcontentstore = datapack.datapackstore(repo.ui, packpath)
    packmetadatastore = historypack.historypackstore(repo.ui, packpath)

    repo.shareddatastores.append(packcontentstore)
    repo.sharedhistorystores.append(packmetadatastore)
    shallowutil.reportpackmetrics(repo.ui, 'filestore', packcontentstore,
        packmetadatastore)
    return packcontentstore, packmetadatastore

def makeunionstores(repo):
    """Union stores iterate the other stores and return the first result."""
    repo.shareddatastores = []
    repo.sharedhistorystores = []

    packcontentstore, packmetadatastore = makepackstores(repo)
    cachecontent, cachemetadata = makecachestores(repo)
    localcontent, localmetadata = makelocalstores(repo)
    remotecontent, remotemetadata = makeremotestores(repo, cachecontent,
                                                     cachemetadata)

    # Instantiate union stores
    repo.contentstore = contentstore.unioncontentstore(
        packcontentstore, cachecontent,
        localcontent, remotecontent, writestore=localcontent)
    repo.metadatastore = metadatastore.unionmetadatastore(
        packmetadatastore, cachemetadata, localmetadata, remotemetadata,
        writestore=localmetadata)

    fileservicedatawrite = cachecontent
    fileservicehistorywrite = cachemetadata
    repo.fileservice.setstore(repo.contentstore, repo.metadatastore,
                              fileservicedatawrite, fileservicehistorywrite)
    shallowutil.reportpackmetrics(repo.ui, 'filestore',
        packcontentstore, packmetadatastore)

def wraprepo(repo):
    class shallowrepository(repo.__class__):
        @util.propertycache
        def name(self):
            return self.ui.config('remotefilelog', 'reponame')

        @util.propertycache
        def fallbackpath(self):
            path = repo.ui.config("remotefilelog", "fallbackpath",
                                  repo.ui.config('paths', 'default'))
            if not path:
                raise error.Abort("no remotefilelog server "
                    "configured - is your .hg/hgrc trusted?")

            return path

        def maybesparsematch(self, *revs, **kwargs):
            '''
            A wrapper that allows the remotefilelog to invoke sparsematch() if
            this is a sparse repository, or returns None if this is not a
            sparse repository.
            '''
            if revs:
                ret = sparse.matcher(repo, revs=revs)
            else:
                ret = sparse.matcher(repo)

            if ret.always():
                return None
            return ret

        def file(self, f):
            if f[0] == '/':
                f = f[1:]

            if self.shallowmatch(f):
                return remotefilelog.remotefilelog(self.svfs, f, self)
            else:
                return super(shallowrepository, self).file(f)

        def filectx(self, path, *args, **kwargs):
            if self.shallowmatch(path):
                return remotefilectx.remotefilectx(self, path, *args, **kwargs)
            else:
                return super(shallowrepository, self).filectx(path, *args,
                                                              **kwargs)

        @localrepo.unfilteredmethod
        def commitctx(self, ctx, error=False):
            """Add a new revision to current repository.
            Revision information is passed via the context argument.
            """

            # some contexts already have manifest nodes, they don't need any
            # prefetching (for example if we're just editing a commit message
            # we can reuse manifest
            if not ctx.manifestnode():
                # prefetch files that will likely be compared
                m1 = ctx.p1().manifest()
                files = []
                for f in ctx.modified() + ctx.added():
                    fparent1 = m1.get(f, nullid)
                    if fparent1 != nullid:
                        files.append((f, hex(fparent1)))
                self.fileservice.prefetch(files)
            return super(shallowrepository, self).commitctx(ctx,
                                                            error=error)

        def backgroundprefetch(self, revs, base=None, repack=False, pats=None,
                               opts=None):
            """Runs prefetch in background with optional repack
            """
            cmd = [_hgexecutable(), '-R', repo.origroot, 'prefetch']
            if repack:
                cmd.append('--repack')
            if revs:
                cmd += ['-r', revs]
            procutil.runbgcommand(cmd, encoding.environ)

        def prefetch(self, revs, base=None, pats=None, opts=None):
            """Prefetches all the necessary file revisions for the given revs
            Optionally runs repack in background
            """
            with repo._lock(repo.svfs, 'prefetchlock', True, None, None,
                            _('prefetching in %s') % repo.origroot):
                self._prefetch(revs, base, pats, opts)

        def _prefetch(self, revs, base=None, pats=None, opts=None):
            fallbackpath = self.fallbackpath
            if fallbackpath:
                # If we know a rev is on the server, we should fetch the server
                # version of those files, since our local file versions might
                # become obsolete if the local commits are stripped.
                localrevs = repo.revs('outgoing(%s)', fallbackpath)
                if base is not None and base != nullrev:
                    serverbase = list(repo.revs('first(reverse(::%s) - %ld)',
                                                base, localrevs))
                    if serverbase:
                        base = serverbase[0]
            else:
                localrevs = repo

            mfl = repo.manifestlog
            mfrevlog = mfl.getstorage('')
            if base is not None:
                mfdict = mfl[repo[base].manifestnode()].read()
                skip = set(mfdict.iteritems())
            else:
                skip = set()

            # Copy the skip set to start large and avoid constant resizing,
            # and since it's likely to be very similar to the prefetch set.
            files = skip.copy()
            serverfiles = skip.copy()
            visited = set()
            visited.add(nullrev)
            revcount = len(revs)
            progress = self.ui.makeprogress(_('prefetching'), total=revcount)
            progress.update(0)
            for rev in sorted(revs):
                ctx = repo[rev]
                if pats:
                    m = scmutil.match(ctx, pats, opts)
                sparsematch = repo.maybesparsematch(rev)

                mfnode = ctx.manifestnode()
                mfrev = mfrevlog.rev(mfnode)

                # Decompressing manifests is expensive.
                # When possible, only read the deltas.
                p1, p2 = mfrevlog.parentrevs(mfrev)
                if p1 in visited and p2 in visited:
                    mfdict = mfl[mfnode].readfast()
                else:
                    mfdict = mfl[mfnode].read()

                diff = mfdict.iteritems()
                if pats:
                    diff = (pf for pf in diff if m(pf[0]))
                if sparsematch:
                    diff = (pf for pf in diff if sparsematch(pf[0]))
                if rev not in localrevs:
                    serverfiles.update(diff)
                else:
                    files.update(diff)

                visited.add(mfrev)
                progress.increment()

            files.difference_update(skip)
            serverfiles.difference_update(skip)
            progress.complete()

            # Fetch files known to be on the server
            if serverfiles:
                results = [(path, hex(fnode)) for (path, fnode) in serverfiles]
                repo.fileservice.prefetch(results, force=True)

            # Fetch files that may or may not be on the server
            if files:
                results = [(path, hex(fnode)) for (path, fnode) in files]
                repo.fileservice.prefetch(results)

        def close(self):
            super(shallowrepository, self).close()
            self.connectionpool.close()

    repo.__class__ = shallowrepository

    repo.shallowmatch = match.always()

    makeunionstores(repo)

    repo.includepattern = repo.ui.configlist("remotefilelog", "includepattern",
                                             None)
    repo.excludepattern = repo.ui.configlist("remotefilelog", "excludepattern",
                                             None)
    if not util.safehasattr(repo, 'connectionpool'):
        repo.connectionpool = connectionpool.connectionpool(repo)

    if repo.includepattern or repo.excludepattern:
        repo.shallowmatch = match.match(repo.root, '', None,
            repo.includepattern, repo.excludepattern)