hg: acquire wlock while updating the working directory via updatetotally

updatetotally() might be invoked outside wlock scope (e.g. invocation
via postincoming() at "hg unbundle" or "hg pull").

In such case, acquisition of wlock is needed for consistent view,
because parallel "hg update" and/or "hg bookmarks" might change
working directory status while executing updatetotally().

Strictly speaking, truly consistent updating should acquire also store
lock, because active bookmark might be moved to another one outside
wlock scope (e.g. pulling from other repository causes updating
current active one).

Acquisition of wlock in this patch ensures consistency in as same
level as past "hg update".

mercurial/hg.py

@@ -1,1008 +1,1008 b''
 # hg.py - repository classes for mercurial
 #
 # Copyright 2005-2007 Matt Mackall <[e-mail]>
 # Copyright 2006 Vadim Gelfer <[e-mail]>
 #
 # 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 errno
 import os
 import shutil
 
 from .i18n import _
 from .node import nullid
 
 from . import (
     bookmarks,
     bundlerepo,
     cmdutil,
     destutil,
     discovery,
     error,
     exchange,
     extensions,
     httppeer,
     localrepo,
     lock,
     merge as mergemod,
     node,
     phases,
     repoview,
     scmutil,
     sshpeer,
     statichttprepo,
     ui as uimod,
     unionrepo,
     url,
     util,
     verify as verifymod,
 )
 
 release = lock.release
 
 def _local(path):
     path = util.expandpath(util.urllocalpath(path))
     return (os.path.isfile(path) and bundlerepo or localrepo)
 
 def addbranchrevs(lrepo, other, branches, revs):
     peer = other.peer() # a courtesy to callers using a localrepo for other
     hashbranch, branches = branches
     if not hashbranch and not branches:
         x = revs or None
         if util.safehasattr(revs, 'first'):
             y = revs.first()
         elif revs:
             y = revs[0]
         else:
             y = None
         return x, y
     if revs:
         revs = list(revs)
     else:
         revs = []
 
     if not peer.capable('branchmap'):
         if branches:
             raise error.Abort(_("remote branch lookup not supported"))
         revs.append(hashbranch)
         return revs, revs[0]
     branchmap = peer.branchmap()
 
     def primary(branch):
         if branch == '.':
             if not lrepo:
                 raise error.Abort(_("dirstate branch not accessible"))
             branch = lrepo.dirstate.branch()
         if branch in branchmap:
             revs.extend(node.hex(r) for r in reversed(branchmap[branch]))
             return True
         else:
             return False
 
     for branch in branches:
         if not primary(branch):
             raise error.RepoLookupError(_("unknown branch '%s'") % branch)
     if hashbranch:
         if not primary(hashbranch):
             revs.append(hashbranch)
     return revs, revs[0]
 
 def parseurl(path, branches=None):
     '''parse url#branch, returning (url, (branch, branches))'''
 
     u = util.url(path)
     branch = None
     if u.fragment:
         branch = u.fragment
         u.fragment = None
     return str(u), (branch, branches or [])
 
 schemes = {
     'bundle': bundlerepo,
     'union': unionrepo,
     'file': _local,
     'http': httppeer,
     'https': httppeer,
     'ssh': sshpeer,
     'static-http': statichttprepo,
 }
 
 def _peerlookup(path):
     u = util.url(path)
     scheme = u.scheme or 'file'
     thing = schemes.get(scheme) or schemes['file']
     try:
         return thing(path)
     except TypeError:
         # we can't test callable(thing) because 'thing' can be an unloaded
         # module that implements __call__
         if not util.safehasattr(thing, 'instance'):
             raise
         return thing
 
 def islocal(repo):
     '''return true if repo (or path pointing to repo) is local'''
     if isinstance(repo, str):
         try:
             return _peerlookup(repo).islocal(repo)
         except AttributeError:
             return False
     return repo.local()
 
 def openpath(ui, path):
     '''open path with open if local, url.open if remote'''
     pathurl = util.url(path, parsequery=False, parsefragment=False)
     if pathurl.islocal():
         return util.posixfile(pathurl.localpath(), 'rb')
     else:
         return url.open(ui, path)
 
 # a list of (ui, repo) functions called for wire peer initialization
 wirepeersetupfuncs = []
 
 def _peerorrepo(ui, path, create=False):
     """return a repository object for the specified path"""
     obj = _peerlookup(path).instance(ui, path, create)
     ui = getattr(obj, "ui", ui)
     for name, module in extensions.extensions(ui):
         hook = getattr(module, 'reposetup', None)
         if hook:
             hook(ui, obj)
     if not obj.local():
         for f in wirepeersetupfuncs:
             f(ui, obj)
     return obj
 
 def repository(ui, path='', create=False):
     """return a repository object for the specified path"""
     peer = _peerorrepo(ui, path, create)
     repo = peer.local()
     if not repo:
         raise error.Abort(_("repository '%s' is not local") %
                          (path or peer.url()))
     return repo.filtered('visible')
 
 def peer(uiorrepo, opts, path, create=False):
     '''return a repository peer for the specified path'''
     rui = remoteui(uiorrepo, opts)
     return _peerorrepo(rui, path, create).peer()
 
 def defaultdest(source):
     '''return default destination of clone if none is given
 
     >>> defaultdest('foo')
     'foo'
     >>> defaultdest('/foo/bar')
     'bar'
     >>> defaultdest('/')
     ''
     >>> defaultdest('')
     ''
     >>> defaultdest('http://example.org/')
     ''
     >>> defaultdest('http://example.org/foo/')
     'foo'
     '''
     path = util.url(source).path
     if not path:
         return ''
     return os.path.basename(os.path.normpath(path))
 
 def share(ui, source, dest=None, update=True, bookmarks=True):
     '''create a shared repository'''
 
     if not islocal(source):
         raise error.Abort(_('can only share local repositories'))
 
     if not dest:
         dest = defaultdest(source)
     else:
         dest = ui.expandpath(dest)
 
     if isinstance(source, str):
         origsource = ui.expandpath(source)
         source, branches = parseurl(origsource)
         srcrepo = repository(ui, source)
         rev, checkout = addbranchrevs(srcrepo, srcrepo, branches, None)
     else:
         srcrepo = source.local()
         origsource = source = srcrepo.url()
         checkout = None
 
     sharedpath = srcrepo.sharedpath # if our source is already sharing
 
     destwvfs = scmutil.vfs(dest, realpath=True)
     destvfs = scmutil.vfs(os.path.join(destwvfs.base, '.hg'), realpath=True)
 
     if destvfs.lexists():
         raise error.Abort(_('destination already exists'))
 
     if not destwvfs.isdir():
         destwvfs.mkdir()
     destvfs.makedir()
 
     requirements = ''
     try:
         requirements = srcrepo.vfs.read('requires')
     except IOError as inst:
         if inst.errno != errno.ENOENT:
             raise
 
     requirements += 'shared\n'
     destvfs.write('requires', requirements)
     destvfs.write('sharedpath', sharedpath)
 
     r = repository(ui, destwvfs.base)
     postshare(srcrepo, r, bookmarks=bookmarks)
     _postshareupdate(r, update, checkout=checkout)
 
 def postshare(sourcerepo, destrepo, bookmarks=True):
     """Called after a new shared repo is created.
 
     The new repo only has a requirements file and pointer to the source.
     This function configures additional shared data.
 
     Extensions can wrap this function and write additional entries to
     destrepo/.hg/shared to indicate additional pieces of data to be shared.
     """
     default = sourcerepo.ui.config('paths', 'default')
     if default:
         fp = destrepo.vfs("hgrc", "w", text=True)
         fp.write("[paths]\n")
         fp.write("default = %s\n" % default)
         fp.close()
 
     if bookmarks:
         fp = destrepo.vfs('shared', 'w')
         fp.write('bookmarks\n')
         fp.close()
 
 def _postshareupdate(repo, update, checkout=None):
     """Maybe perform a working directory update after a shared repo is created.
 
     ``update`` can be a boolean or a revision to update to.
     """
     if not update:
         return
 
     repo.ui.status(_("updating working directory\n"))
     if update is not True:
         checkout = update
     for test in (checkout, 'default', 'tip'):
         if test is None:
             continue
         try:
             uprev = repo.lookup(test)
             break
         except error.RepoLookupError:
             continue
     _update(repo, uprev)
 
 def copystore(ui, srcrepo, destpath):
     '''copy files from store of srcrepo in destpath
 
     returns destlock
     '''
     destlock = None
     try:
         hardlink = None
         num = 0
         closetopic = [None]
         def prog(topic, pos):
             if pos is None:
                 closetopic[0] = topic
             else:
                 ui.progress(topic, pos + num)
         srcpublishing = srcrepo.publishing()
         srcvfs = scmutil.vfs(srcrepo.sharedpath)
         dstvfs = scmutil.vfs(destpath)
         for f in srcrepo.store.copylist():
             if srcpublishing and f.endswith('phaseroots'):
                 continue
             dstbase = os.path.dirname(f)
             if dstbase and not dstvfs.exists(dstbase):
                 dstvfs.mkdir(dstbase)
             if srcvfs.exists(f):
                 if f.endswith('data'):
                     # 'dstbase' may be empty (e.g. revlog format 0)
                     lockfile = os.path.join(dstbase, "lock")
                     # lock to avoid premature writing to the target
                     destlock = lock.lock(dstvfs, lockfile)
                 hardlink, n = util.copyfiles(srcvfs.join(f), dstvfs.join(f),
                                              hardlink, progress=prog)
                 num += n
         if hardlink:
             ui.debug("linked %d files\n" % num)
             if closetopic[0]:
                 ui.progress(closetopic[0], None)
         else:
             ui.debug("copied %d files\n" % num)
             if closetopic[0]:
                 ui.progress(closetopic[0], None)
         return destlock
     except: # re-raises
         release(destlock)
         raise
 
 def clonewithshare(ui, peeropts, sharepath, source, srcpeer, dest, pull=False,
                    rev=None, update=True, stream=False):
     """Perform a clone using a shared repo.
 
     The store for the repository will be located at <sharepath>/.hg. The
     specified revisions will be cloned or pulled from "source". A shared repo
     will be created at "dest" and a working copy will be created if "update" is
     True.
     """
     revs = None
     if rev:
         if not srcpeer.capable('lookup'):
             raise error.Abort(_("src repository does not support "
                                "revision lookup and so doesn't "
                                "support clone by revision"))
         revs = [srcpeer.lookup(r) for r in rev]
 
     # Obtain a lock before checking for or cloning the pooled repo otherwise
     # 2 clients may race creating or populating it.
     pooldir = os.path.dirname(sharepath)
     # lock class requires the directory to exist.
     try:
         util.makedir(pooldir, False)
     except OSError as e:
         if e.errno != errno.EEXIST:
             raise
 
     poolvfs = scmutil.vfs(pooldir)
     basename = os.path.basename(sharepath)
 
     with lock.lock(poolvfs, '%s.lock' % basename):
         if os.path.exists(sharepath):
             ui.status(_('(sharing from existing pooled repository %s)\n') %
                       basename)
         else:
             ui.status(_('(sharing from new pooled repository %s)\n') % basename)
             # Always use pull mode because hardlinks in share mode don't work
             # well. Never update because working copies aren't necessary in
             # share mode.
             clone(ui, peeropts, source, dest=sharepath, pull=True,
                   rev=rev, update=False, stream=stream)
 
     sharerepo = repository(ui, path=sharepath)
     share(ui, sharerepo, dest=dest, update=False, bookmarks=False)
 
     # We need to perform a pull against the dest repo to fetch bookmarks
     # and other non-store data that isn't shared by default. In the case of
     # non-existing shared repo, this means we pull from the remote twice. This
     # is a bit weird. But at the time it was implemented, there wasn't an easy
     # way to pull just non-changegroup data.
     destrepo = repository(ui, path=dest)
     exchange.pull(destrepo, srcpeer, heads=revs)
 
     _postshareupdate(destrepo, update)
 
     return srcpeer, peer(ui, peeropts, dest)
 
 def clone(ui, peeropts, source, dest=None, pull=False, rev=None,
           update=True, stream=False, branch=None, shareopts=None):
     """Make a copy of an existing repository.
 
     Create a copy of an existing repository in a new directory.  The
     source and destination are URLs, as passed to the repository
     function.  Returns a pair of repository peers, the source and
     newly created destination.
 
     The location of the source is added to the new repository's
     .hg/hgrc file, as the default to be used for future pulls and
     pushes.
 
     If an exception is raised, the partly cloned/updated destination
     repository will be deleted.
 
     Arguments:
 
     source: repository object or URL
 
     dest: URL of destination repository to create (defaults to base
     name of source repository)
 
     pull: always pull from source repository, even in local case or if the
     server prefers streaming
 
     stream: stream raw data uncompressed from repository (fast over
     LAN, slow over WAN)
 
     rev: revision to clone up to (implies pull=True)
 
     update: update working directory after clone completes, if
     destination is local repository (True means update to default rev,
     anything else is treated as a revision)
 
     branch: branches to clone
 
     shareopts: dict of options to control auto sharing behavior. The "pool" key
     activates auto sharing mode and defines the directory for stores. The
     "mode" key determines how to construct the directory name of the shared
     repository. "identity" means the name is derived from the node of the first
     changeset in the repository. "remote" means the name is derived from the
     remote's path/URL. Defaults to "identity."
     """
 
     if isinstance(source, str):
         origsource = ui.expandpath(source)
         source, branch = parseurl(origsource, branch)
         srcpeer = peer(ui, peeropts, source)
     else:
         srcpeer = source.peer() # in case we were called with a localrepo
         branch = (None, branch or [])
         origsource = source = srcpeer.url()
     rev, checkout = addbranchrevs(srcpeer, srcpeer, branch, rev)
 
     if dest is None:
         dest = defaultdest(source)
         if dest:
             ui.status(_("destination directory: %s\n") % dest)
     else:
         dest = ui.expandpath(dest)
 
     dest = util.urllocalpath(dest)
     source = util.urllocalpath(source)
 
     if not dest:
         raise error.Abort(_("empty destination path is not valid"))
 
     destvfs = scmutil.vfs(dest, expandpath=True)
     if destvfs.lexists():
         if not destvfs.isdir():
             raise error.Abort(_("destination '%s' already exists") % dest)
         elif destvfs.listdir():
             raise error.Abort(_("destination '%s' is not empty") % dest)
 
     shareopts = shareopts or {}
     sharepool = shareopts.get('pool')
     sharenamemode = shareopts.get('mode')
     if sharepool and islocal(dest):
         sharepath = None
         if sharenamemode == 'identity':
             # Resolve the name from the initial changeset in the remote
             # repository. This returns nullid when the remote is empty. It
             # raises RepoLookupError if revision 0 is filtered or otherwise
             # not available. If we fail to resolve, sharing is not enabled.
             try:
                 rootnode = srcpeer.lookup('0')
                 if rootnode != node.nullid:
                     sharepath = os.path.join(sharepool, node.hex(rootnode))
                 else:
                     ui.status(_('(not using pooled storage: '
                                 'remote appears to be empty)\n'))
             except error.RepoLookupError:
                 ui.status(_('(not using pooled storage: '
                             'unable to resolve identity of remote)\n'))
         elif sharenamemode == 'remote':
             sharepath = os.path.join(sharepool, util.sha1(source).hexdigest())
         else:
             raise error.Abort('unknown share naming mode: %s' % sharenamemode)
 
         if sharepath:
             return clonewithshare(ui, peeropts, sharepath, source, srcpeer,
                                   dest, pull=pull, rev=rev, update=update,
                                   stream=stream)
 
     srclock = destlock = cleandir = None
     srcrepo = srcpeer.local()
     try:
         abspath = origsource
         if islocal(origsource):
             abspath = os.path.abspath(util.urllocalpath(origsource))
 
         if islocal(dest):
             cleandir = dest
 
         copy = False
         if (srcrepo and srcrepo.cancopy() and islocal(dest)
             and not phases.hassecret(srcrepo)):
             copy = not pull and not rev
 
         if copy:
             try:
                 # we use a lock here because if we race with commit, we
                 # can end up with extra data in the cloned revlogs that's
                 # not pointed to by changesets, thus causing verify to
                 # fail
                 srclock = srcrepo.lock(wait=False)
             except error.LockError:
                 copy = False
 
         if copy:
             srcrepo.hook('preoutgoing', throw=True, source='clone')
             hgdir = os.path.realpath(os.path.join(dest, ".hg"))
             if not os.path.exists(dest):
                 os.mkdir(dest)
             else:
                 # only clean up directories we create ourselves
                 cleandir = hgdir
             try:
                 destpath = hgdir
                 util.makedir(destpath, notindexed=True)
             except OSError as inst:
                 if inst.errno == errno.EEXIST:
                     cleandir = None
                     raise error.Abort(_("destination '%s' already exists")
                                      % dest)
                 raise
 
             destlock = copystore(ui, srcrepo, destpath)
             # copy bookmarks over
             srcbookmarks = srcrepo.join('bookmarks')
             dstbookmarks = os.path.join(destpath, 'bookmarks')
             if os.path.exists(srcbookmarks):
                 util.copyfile(srcbookmarks, dstbookmarks)
 
             # Recomputing branch cache might be slow on big repos,
             # so just copy it
             def copybranchcache(fname):
                 srcbranchcache = srcrepo.join('cache/%s' % fname)
                 dstbranchcache = os.path.join(dstcachedir, fname)
                 if os.path.exists(srcbranchcache):
                     if not os.path.exists(dstcachedir):
                         os.mkdir(dstcachedir)
                     util.copyfile(srcbranchcache, dstbranchcache)
 
             dstcachedir = os.path.join(destpath, 'cache')
             # In local clones we're copying all nodes, not just served
             # ones. Therefore copy all branch caches over.
             copybranchcache('branch2')
             for cachename in repoview.filtertable:
                 copybranchcache('branch2-%s' % cachename)
 
             # we need to re-init the repo after manually copying the data
             # into it
             destpeer = peer(srcrepo, peeropts, dest)
             srcrepo.hook('outgoing', source='clone',
                           node=node.hex(node.nullid))
         else:
             try:
                 destpeer = peer(srcrepo or ui, peeropts, dest, create=True)
                                 # only pass ui when no srcrepo
             except OSError as inst:
                 if inst.errno == errno.EEXIST:
                     cleandir = None
                     raise error.Abort(_("destination '%s' already exists")
                                      % dest)
                 raise
 
             revs = None
             if rev:
                 if not srcpeer.capable('lookup'):
                     raise error.Abort(_("src repository does not support "
                                        "revision lookup and so doesn't "
                                        "support clone by revision"))
                 revs = [srcpeer.lookup(r) for r in rev]
                 checkout = revs[0]
             local = destpeer.local()
             if local:
                 if not stream:
                     if pull:
                         stream = False
                     else:
                         stream = None
                 # internal config: ui.quietbookmarkmove
                 quiet = local.ui.backupconfig('ui', 'quietbookmarkmove')
                 try:
                     local.ui.setconfig(
                         'ui', 'quietbookmarkmove', True, 'clone')
                     exchange.pull(local, srcpeer, revs,
                                   streamclonerequested=stream)
                 finally:
                     local.ui.restoreconfig(quiet)
             elif srcrepo:
                 exchange.push(srcrepo, destpeer, revs=revs,
                               bookmarks=srcrepo._bookmarks.keys())
             else:
                 raise error.Abort(_("clone from remote to remote not supported")
                                  )
 
         cleandir = None
 
         destrepo = destpeer.local()
         if destrepo:
             template = uimod.samplehgrcs['cloned']
             fp = destrepo.vfs("hgrc", "w", text=True)
             u = util.url(abspath)
             u.passwd = None
             defaulturl = str(u)
             fp.write(template % defaulturl)
             fp.close()
 
             destrepo.ui.setconfig('paths', 'default', defaulturl, 'clone')
 
             if update:
                 if update is not True:
                     checkout = srcpeer.lookup(update)
                 uprev = None
                 status = None
                 if checkout is not None:
                     try:
                         uprev = destrepo.lookup(checkout)
                     except error.RepoLookupError:
                         if update is not True:
                             try:
                                 uprev = destrepo.lookup(update)
                             except error.RepoLookupError:
                                 pass
                 if uprev is None:
                     try:
                         uprev = destrepo._bookmarks['@']
                         update = '@'
                         bn = destrepo[uprev].branch()
                         if bn == 'default':
                             status = _("updating to bookmark @\n")
                         else:
                             status = (_("updating to bookmark @ on branch %s\n")
                                       % bn)
                     except KeyError:
                         try:
                             uprev = destrepo.branchtip('default')
                         except error.RepoLookupError:
                             uprev = destrepo.lookup('tip')
                 if not status:
                     bn = destrepo[uprev].branch()
                     status = _("updating to branch %s\n") % bn
                 destrepo.ui.status(status)
                 _update(destrepo, uprev)
                 if update in destrepo._bookmarks:
                     bookmarks.activate(destrepo, update)
     finally:
         release(srclock, destlock)
         if cleandir is not None:
             shutil.rmtree(cleandir, True)
         if srcpeer is not None:
             srcpeer.close()
     return srcpeer, destpeer
 
 def _showstats(repo, stats, quietempty=False):
     if quietempty and not any(stats):
         return
     repo.ui.status(_("%d files updated, %d files merged, "
                      "%d files removed, %d files unresolved\n") % stats)
 
 def updaterepo(repo, node, overwrite):
     """Update the working directory to node.
 
     When overwrite is set, changes are clobbered, merged else
 
     returns stats (see pydoc mercurial.merge.applyupdates)"""
     return mergemod.update(repo, node, False, overwrite,
                            labels=['working copy', 'destination'])
 
 def update(repo, node, quietempty=False):
     """update the working directory to node, merging linear changes"""
     stats = updaterepo(repo, node, False)
     _showstats(repo, stats, quietempty)
     if stats[3]:
         repo.ui.status(_("use 'hg resolve' to retry unresolved file merges\n"))
     return stats[3] > 0
 
 # naming conflict in clone()
 _update = update
 
 def clean(repo, node, show_stats=True, quietempty=False):
     """forcibly switch the working directory to node, clobbering changes"""
     stats = updaterepo(repo, node, True)
     util.unlinkpath(repo.join('graftstate'), ignoremissing=True)
     if show_stats:
         _showstats(repo, stats, quietempty)
     return stats[3] > 0
 
 # naming conflict in updatetotally()
 _clean = clean
 
 def updatetotally(ui, repo, checkout, brev, clean=False, check=False):
     """Update the working directory with extra care for non-file components
 
     This takes care of non-file components below:
 
     :bookmark: might be advanced or (in)activated
 
     This takes arguments below:
 
     :checkout: to which revision the working directory is updated
     :brev: a name, which might be a bookmark to be activated after updating
     :clean: whether changes in the working directory can be discarded
     :check: whether changes in the working directory should be checked
 
     This returns whether conflict is detected at updating or not.
     """
-    if True:
+    with repo.wlock():
         movemarkfrom = None
         warndest = False
         if checkout is None:
             updata = destutil.destupdate(repo, clean=clean, check=check)
             checkout, movemarkfrom, brev = updata
             warndest = True
 
         if clean:
             ret = _clean(repo, checkout)
         else:
             ret = _update(repo, checkout)
 
         if not ret and movemarkfrom:
             if movemarkfrom == repo['.'].node():
                 pass # no-op update
             elif bookmarks.update(repo, [movemarkfrom], repo['.'].node()):
                 ui.status(_("updating bookmark %s\n") % repo._activebookmark)
             else:
                 # this can happen with a non-linear update
                 ui.status(_("(leaving bookmark %s)\n") %
                           repo._activebookmark)
                 bookmarks.deactivate(repo)
         elif brev in repo._bookmarks:
             if brev != repo._activebookmark:
                 ui.status(_("(activating bookmark %s)\n") % brev)
             bookmarks.activate(repo, brev)
         elif brev:
             if repo._activebookmark:
                 ui.status(_("(leaving bookmark %s)\n") %
                           repo._activebookmark)
             bookmarks.deactivate(repo)
 
         if warndest:
             destutil.statusotherdests(ui, repo)
 
     return ret
 
 def merge(repo, node, force=None, remind=True, mergeforce=False):
     """Branch merge with node, resolving changes. Return true if any
     unresolved conflicts."""
     stats = mergemod.update(repo, node, True, force, mergeforce=mergeforce)
     _showstats(repo, stats)
     if stats[3]:
         repo.ui.status(_("use 'hg resolve' to retry unresolved file merges "
                          "or 'hg update -C .' to abandon\n"))
     elif remind:
         repo.ui.status(_("(branch merge, don't forget to commit)\n"))
     return stats[3] > 0
 
 def _incoming(displaychlist, subreporecurse, ui, repo, source,
         opts, buffered=False):
     """
     Helper for incoming / gincoming.
     displaychlist gets called with
         (remoterepo, incomingchangesetlist, displayer) parameters,
     and is supposed to contain only code that can't be unified.
     """
     source, branches = parseurl(ui.expandpath(source), opts.get('branch'))
     other = peer(repo, opts, source)
     ui.status(_('comparing with %s\n') % util.hidepassword(source))
     revs, checkout = addbranchrevs(repo, other, branches, opts.get('rev'))
 
     if revs:
         revs = [other.lookup(rev) for rev in revs]
     other, chlist, cleanupfn = bundlerepo.getremotechanges(ui, repo, other,
                                 revs, opts["bundle"], opts["force"])
     try:
         if not chlist:
             ui.status(_("no changes found\n"))
             return subreporecurse()
 
         displayer = cmdutil.show_changeset(ui, other, opts, buffered)
         displaychlist(other, chlist, displayer)
         displayer.close()
     finally:
         cleanupfn()
     subreporecurse()
     return 0 # exit code is zero since we found incoming changes
 
 def incoming(ui, repo, source, opts):
     def subreporecurse():
         ret = 1
         if opts.get('subrepos'):
             ctx = repo[None]
             for subpath in sorted(ctx.substate):
                 sub = ctx.sub(subpath)
                 ret = min(ret, sub.incoming(ui, source, opts))
         return ret
 
     def display(other, chlist, displayer):
         limit = cmdutil.loglimit(opts)
         if opts.get('newest_first'):
             chlist.reverse()
         count = 0
         for n in chlist:
             if limit is not None and count >= limit:
                 break
             parents = [p for p in other.changelog.parents(n) if p != nullid]
             if opts.get('no_merges') and len(parents) == 2:
                 continue
             count += 1
             displayer.show(other[n])
     return _incoming(display, subreporecurse, ui, repo, source, opts)
 
 def _outgoing(ui, repo, dest, opts):
     dest = ui.expandpath(dest or 'default-push', dest or 'default')
     dest, branches = parseurl(dest, opts.get('branch'))
     ui.status(_('comparing with %s\n') % util.hidepassword(dest))
     revs, checkout = addbranchrevs(repo, repo, branches, opts.get('rev'))
     if revs:
         revs = [repo.lookup(rev) for rev in scmutil.revrange(repo, revs)]
 
     other = peer(repo, opts, dest)
     outgoing = discovery.findcommonoutgoing(repo.unfiltered(), other, revs,
                                             force=opts.get('force'))
     o = outgoing.missing
     if not o:
         scmutil.nochangesfound(repo.ui, repo, outgoing.excluded)
     return o, other
 
 def outgoing(ui, repo, dest, opts):
     def recurse():
         ret = 1
         if opts.get('subrepos'):
             ctx = repo[None]
             for subpath in sorted(ctx.substate):
                 sub = ctx.sub(subpath)
                 ret = min(ret, sub.outgoing(ui, dest, opts))
         return ret
 
     limit = cmdutil.loglimit(opts)
     o, other = _outgoing(ui, repo, dest, opts)
     if not o:
         cmdutil.outgoinghooks(ui, repo, other, opts, o)
         return recurse()
 
     if opts.get('newest_first'):
         o.reverse()
     displayer = cmdutil.show_changeset(ui, repo, opts)
     count = 0
     for n in o:
         if limit is not None and count >= limit:
             break
         parents = [p for p in repo.changelog.parents(n) if p != nullid]
         if opts.get('no_merges') and len(parents) == 2:
             continue
         count += 1
         displayer.show(repo[n])
     displayer.close()
     cmdutil.outgoinghooks(ui, repo, other, opts, o)
     recurse()
     return 0 # exit code is zero since we found outgoing changes
 
 def verify(repo):
     """verify the consistency of a repository"""
     ret = verifymod.verify(repo)
 
     # Broken subrepo references in hidden csets don't seem worth worrying about,
     # since they can't be pushed/pulled, and --hidden can be used if they are a
     # concern.
 
     # pathto() is needed for -R case
     revs = repo.revs("filelog(%s)",
                      util.pathto(repo.root, repo.getcwd(), '.hgsubstate'))
 
     if revs:
         repo.ui.status(_('checking subrepo links\n'))
         for rev in revs:
             ctx = repo[rev]
             try:
                 for subpath in ctx.substate:
                     ret = ctx.sub(subpath).verify() or ret
             except Exception:
                 repo.ui.warn(_('.hgsubstate is corrupt in revision %s\n') %
                              node.short(ctx.node()))
 
     return ret
 
 def remoteui(src, opts):
     'build a remote ui from ui or repo and opts'
     if util.safehasattr(src, 'baseui'): # looks like a repository
         dst = src.baseui.copy() # drop repo-specific config
         src = src.ui # copy target options from repo
     else: # assume it's a global ui object
         dst = src.copy() # keep all global options
 
     # copy ssh-specific options
     for o in 'ssh', 'remotecmd':
         v = opts.get(o) or src.config('ui', o)
         if v:
             dst.setconfig("ui", o, v, 'copied')
 
     # copy bundle-specific options
     r = src.config('bundle', 'mainreporoot')
     if r:
         dst.setconfig('bundle', 'mainreporoot', r, 'copied')
 
     # copy selected local settings to the remote ui
     for sect in ('auth', 'hostfingerprints', 'http_proxy'):
         for key, val in src.configitems(sect):
             dst.setconfig(sect, key, val, 'copied')
     v = src.config('web', 'cacerts')
     if v == '!':
         dst.setconfig('web', 'cacerts', v, 'copied')
     elif v:
         dst.setconfig('web', 'cacerts', util.expandpath(v), 'copied')
 
     return dst
 
 # Files of interest
 # Used to check if the repository has changed looking at mtime and size of
 # these files.
 foi = [('spath', '00changelog.i'),
        ('spath', 'phaseroots'), # ! phase can change content at the same size
        ('spath', 'obsstore'),
        ('path', 'bookmarks'), # ! bookmark can change content at the same size
       ]
 
 class cachedlocalrepo(object):
     """Holds a localrepository that can be cached and reused."""
 
     def __init__(self, repo):
         """Create a new cached repo from an existing repo.
 
         We assume the passed in repo was recently created. If the
         repo has changed between when it was created and when it was
         turned into a cache, it may not refresh properly.
         """
         assert isinstance(repo, localrepo.localrepository)
         self._repo = repo
         self._state, self.mtime = self._repostate()
         self._filtername = repo.filtername
 
     def fetch(self):
         """Refresh (if necessary) and return a repository.
 
         If the cached instance is out of date, it will be recreated
         automatically and returned.
 
         Returns a tuple of the repo and a boolean indicating whether a new
         repo instance was created.
         """
         # We compare the mtimes and sizes of some well-known files to
         # determine if the repo changed. This is not precise, as mtimes
         # are susceptible to clock skew and imprecise filesystems and
         # file content can change while maintaining the same size.
 
         state, mtime = self._repostate()
         if state == self._state:
             return self._repo, False
 
         repo = repository(self._repo.baseui, self._repo.url())
         if self._filtername:
             self._repo = repo.filtered(self._filtername)
         else:
             self._repo = repo.unfiltered()
         self._state = state
         self.mtime = mtime
 
         return self._repo, True
 
     def _repostate(self):
         state = []
         maxmtime = -1
         for attr, fname in foi:
             prefix = getattr(self._repo, attr)
             p = os.path.join(prefix, fname)
             try:
                 st = os.stat(p)
             except OSError:
                 st = os.stat(prefix)
             state.append((st.st_mtime, st.st_size))
             maxmtime = max(maxmtime, st.st_mtime)
 
         return tuple(state), maxmtime
 
     def copy(self):
         """Obtain a copy of this class instance.
 
         A new localrepository instance is obtained. The new instance should be
         completely independent of the original.
         """
         repo = repository(self._repo.baseui, self._repo.origroot)
         if self._filtername:
             repo = repo.filtered(self._filtername)
         else:
             repo = repo.unfiltered()
         c = cachedlocalrepo(repo)
         c._state = self._state
         c.mtime = self.mtime
         return c