unionrepo: read-only operations on a union of two localrepos

unionrepo is just like bundlerepo without bundles.

The implementation is very similar to bundlerepo, but I don't see any obvious
way to generalize it.

Some most obvious use cases for this would be log and diff across local repos,
as a kind of preview of pulls, for instance:

  $ hg -R union:repo1+repo2 heads
  $ hg -R union:repo1+repo2 log -r REPO1REV -r REPO2REV
  $ hg -R union:repo1+repo2 log -r '::REPO1REV-::REPO2REV'
  $ hg -R union:repo1+repo2 log -r 'ancestor(REPO1REV,REPO2REV)'
  $ hg -R union:repo1+repo2 diff -r REPO1REV -r REPO2REV

This is going to be used in RhodeCode, and Bitbucket already uses something
similar. Having a core implementation would be beneficial.

mercurial/unionrepo.py

@@ -0,0 +1,208 b''
+# unionrepo.py - repository class for viewing union of repository changesets
+#
+# Derived from bundlerepo.py
+# Copyright 2006, 2007 Benoit Boissinot <[e-mail]>
+# Copyright 2013 Unity Technologies, Mads Kiilerich <[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.
+
+"""Repository class for "in-memory pull" of one local repository to another,
+allowing operations like diff and log with revsets.
+"""
+
+from node import nullid
+from i18n import _
+import os
+import util, mdiff, cmdutil, scmutil
+import localrepo, changelog, manifest, filelog, revlog
+
+class unionrevlog(revlog.revlog):
+    def __init__(self, opener, indexfile, revlog2, linkmapper):
+        # How it works:
+        # To retrieve a revision, we just need to know the node id so we can
+        # look it up in revlog2.
+        #
+        # To differentiate a rev in the second revlog from a rev in the revlog,
+        # we check revision against repotiprev.
+        opener = scmutil.readonlyvfs(opener)
+        revlog.revlog.__init__(self, opener, indexfile)
+        self.revlog2 = revlog2
+
+        n = len(self)
+        self.repotiprev = n - 1
+        self.bundlerevs = set() # used by 'bundle()' revset expression
+        for rev2 in self.revlog2:
+            rev = self.revlog2.index[rev2]
+            # rev numbers - in revlog2, very different from self.rev
+            _start, _csize, _rsize, _base, linkrev, p1rev, p2rev, node = rev
+
+            if linkmapper is None: # link is to same revlog
+                assert linkrev == rev2 # we never link back
+                link = n
+            else: # rev must be mapped from repo2 cl to unified cl by linkmapper
+                link = linkmapper(linkrev)
+
+            if node in self.nodemap:
+                # this happens for the common revlog revisions
+                self.bundlerevs.add(self.nodemap[node])
+                continue
+
+            p1node = self.revlog2.node(p1rev)
+            p2node = self.revlog2.node(p2rev)
+
+            e = (None, None, None, None,
+                 link, self.rev(p1node), self.rev(p2node), node)
+            self.index.insert(-1, e)
+            self.nodemap[node] = n
+            self.bundlerevs.add(n)
+            n += 1
+
+    def _chunk(self, rev):
+        if rev <= self.repotiprev:
+            return revlog.revlog._chunk(self, rev)
+        return self.revlog2._chunk(self.node(rev))
+
+    def revdiff(self, rev1, rev2):
+        """return or calculate a delta between two revisions"""
+        if rev1 > self.repotiprev and rev2 > self.repotiprev:
+            return self.revlog2.revdiff(
+                self.revlog2.rev(self.node(rev1)),
+                self.revlog2.rev(self.node(rev2)))
+        elif rev1 <= self.repotiprev and rev2 <= self.repotiprev:
+            return revlog.revlog.revdiff(self, rev1, rev2)
+
+        return mdiff.textdiff(self.revision(self.node(rev1)),
+                              self.revision(self.node(rev2)))
+
+    def revision(self, nodeorrev):
+        """return an uncompressed revision of a given node or revision
+        number.
+        """
+        if isinstance(nodeorrev, int):
+            rev = nodeorrev
+            node = self.node(rev)
+        else:
+            node = nodeorrev
+            rev = self.rev(node)
+
+        if node == nullid:
+            return ""
+
+        if rev > self.repotiprev:
+            text = self.revlog2.revision(node)
+            self._cache = (node, rev, text)
+        else:
+            text = revlog.revlog.revision(self, rev)
+            # already cached
+        return text
+
+    def addrevision(self, text, transaction, link, p1=None, p2=None, d=None):
+        raise NotImplementedError
+    def addgroup(self, revs, linkmapper, transaction):
+        raise NotImplementedError
+    def strip(self, rev, minlink):
+        raise NotImplementedError
+    def checksize(self):
+        raise NotImplementedError
+
+class unionchangelog(unionrevlog, changelog.changelog):
+    def __init__(self, opener, opener2):
+        changelog.changelog.__init__(self, opener)
+        linkmapper = None
+        changelog2 = changelog.changelog(opener2)
+        unionrevlog.__init__(self, opener, self.indexfile, changelog2,
+                             linkmapper)
+
+class unionmanifest(unionrevlog, manifest.manifest):
+    def __init__(self, opener, opener2, linkmapper):
+        manifest.manifest.__init__(self, opener)
+        manifest2 = manifest.manifest(opener2)
+        unionrevlog.__init__(self, opener, self.indexfile, manifest2,
+                             linkmapper)
+
+class unionfilelog(unionrevlog, filelog.filelog):
+    def __init__(self, opener, path, opener2, linkmapper, repo):
+        filelog.filelog.__init__(self, opener, path)
+        filelog2 = filelog.filelog(opener2, path)
+        unionrevlog.__init__(self, opener, self.indexfile, filelog2,
+                             linkmapper)
+        self._repo = repo
+
+    def _file(self, f):
+        self._repo.file(f)
+
+class unionpeer(localrepo.localpeer):
+    def canpush(self):
+        return False
+
+class unionrepository(localrepo.localrepository):
+    def __init__(self, ui, path, path2):
+        localrepo.localrepository.__init__(self, ui, path)
+        self.ui.setconfig('phases', 'publish', False)
+
+        self._url = 'union:%s+%s' % (util.expandpath(path),
+                                     util.expandpath(path2))
+        self.repo2 = localrepo.localrepository(ui, path2)
+
+    @localrepo.unfilteredpropertycache
+    def changelog(self):
+        return unionchangelog(self.sopener, self.repo2.sopener)
+
+    def _clrev(self, rev2):
+        """map from repo2 changelog rev to temporary rev in self.changelog"""
+        node = self.repo2.changelog.node(rev2)
+        return self.changelog.rev(node)
+
+    @localrepo.unfilteredpropertycache
+    def manifest(self):
+        return unionmanifest(self.sopener, self.repo2.sopener,
+                             self._clrev)
+
+    def url(self):
+        return self._url
+
+    def file(self, f):
+        return unionfilelog(self.sopener, f, self.repo2.sopener,
+                            self._clrev, self)
+
+    def close(self):
+        self.repo2.close()
+
+    def cancopy(self):
+        return False
+
+    def peer(self):
+        return unionpeer(self)
+
+    def getcwd(self):
+        return os.getcwd() # always outside the repo
+
+def instance(ui, path, create):
+    if create:
+        raise util.Abort(_('cannot create new union repository'))
+    parentpath = ui.config("bundle", "mainreporoot", "")
+    if not parentpath:
+        # try to find the correct path to the working directory repo
+        parentpath = cmdutil.findrepo(os.getcwd())
+        if parentpath is None:
+            parentpath = ''
+    if parentpath:
+        # Try to make the full path relative so we get a nice, short URL.
+        # In particular, we don't want temp dir names in test outputs.
+        cwd = os.getcwd()
+        if parentpath == cwd:
+            parentpath = ''
+        else:
+            cwd = os.path.join(cwd,'')
+            if parentpath.startswith(cwd):
+                parentpath = parentpath[len(cwd):]
+    if path.startswith('union:'):
+        s = path.split(":", 1)[1].split("+", 1)
+        if len(s) == 1:
+            repopath, repopath2 = parentpath, s[0]
+        else:
+            repopath, repopath2 = s
+    else:
+        repopath, repopath2 = parentpath, path
+    return unionrepository(ui, repopath, repopath2)

tests/test-unionrepo.t

@@ -0,0 +1,148 b''
+Test unionrepo functionality
+
+Create one repository
+
+  $ hg init repo1
+  $ cd repo1
+  $ touch repo1-0
+  $ echo repo1-0 > f
+  $ hg ci -Aqmrepo1-0
+  $ touch repo1-1
+  $ echo repo1-1 >> f
+  $ hg ci -Aqmrepo1-1
+  $ touch repo1-2
+  $ echo repo1-2 >> f
+  $ hg ci -Aqmrepo1-2
+  $ hg log --template '{rev}:{node|short}  {desc|firstline}\n'
+  2:68c0685446a3  repo1-2
+  1:8a58db72e69d  repo1-1
+  0:f093fec0529b  repo1-0
+  $ tip1=`hg id -q`
+  $ cd ..
+
+- and a clone with a not-completely-trivial history
+
+  $ hg clone -q repo1 --rev 0 repo2
+  $ cd repo2
+  $ touch repo2-1
+  $ sed '1irepo2-1 at top' f > f.tmp
+  $ mv f.tmp f
+  $ hg ci -Aqmrepo2-1
+  $ touch repo2-2
+  $ hg pull -q ../repo1 -r 1
+  $ hg merge -q
+  $ hg ci -Aqmrepo2-2-merge
+  $ touch repo2-3
+  $ echo repo2-3 >> f
+  $ hg ci -mrepo2-3
+  $ hg log --template '{rev}:{node|short}  {desc|firstline}\n'
+  4:2f0d178c469c  repo2-3
+  3:9e6fb3e0b9da  repo2-2-merge
+  2:8a58db72e69d  repo1-1
+  1:c337dba826e7  repo2-1
+  0:f093fec0529b  repo1-0
+  $ cd ..
+
+revisions from repo2 appear as appended / pulled to repo1
+
+  $ hg -R union:repo1+repo2 log --template '{rev}:{node|short}  {desc|firstline}\n'
+  5:2f0d178c469c  repo2-3
+  4:9e6fb3e0b9da  repo2-2-merge
+  3:c337dba826e7  repo2-1
+  2:68c0685446a3  repo1-2
+  1:8a58db72e69d  repo1-1
+  0:f093fec0529b  repo1-0
+
+manifest can be retrieved for revisions in both repos
+
+  $ hg -R union:repo1+repo2 mani -r $tip1
+  f
+  repo1-0
+  repo1-1
+  repo1-2
+  $ hg -R union:repo1+repo2 mani -r 4
+  f
+  repo1-0
+  repo1-1
+  repo2-1
+  repo2-2
+
+files can be retrieved form both repos
+
+  $ hg -R repo1 cat repo1/f -r2
+  repo1-0
+  repo1-1
+  repo1-2
+
+  $ hg -R union:repo1+repo2 cat -r$tip1 repo1/f
+  repo1-0
+  repo1-1
+  repo1-2
+
+  $ hg -R union:repo1+repo2 cat -r4 $TESTTMP/repo1/f
+  repo2-1 at top
+  repo1-0
+  repo1-1
+
+files can be compared across repos
+
+  $ hg -R union:repo1+repo2 diff -r$tip1 -rtip
+  diff -r 68c0685446a3 -r 2f0d178c469c f
+  --- a/f	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/f	Thu Jan 01 00:00:00 1970 +0000
+  @@ -1,3 +1,4 @@
+  +repo2-1 at top
+   repo1-0
+   repo1-1
+  -repo1-2
+  +repo2-3
+
+heads from both repos are found correctly
+
+  $ hg -R union:repo1+repo2 heads --template '{rev}:{node|short}  {desc|firstline}\n'
+  5:2f0d178c469c  repo2-3
+  2:68c0685446a3  repo1-2
+
+revsets works across repos
+
+  $ hg -R union:repo1+repo2 id -r "ancestor($tip1, 5)"
+  8a58db72e69d
+
+annotate works - an indication that linkrevs works
+
+  $ hg --cwd repo1 -R union:../repo2 annotate $TESTTMP/repo1/f -r tip
+  3: repo2-1 at top
+  0: repo1-0
+  1: repo1-1
+  5: repo2-3
+
+union repos can be cloned ... and clones works correctly
+
+  $ hg clone -U union:repo1+repo2 repo3
+  requesting all changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 6 changesets with 11 changes to 6 files (+1 heads)
+
+  $ hg -R repo3 paths
+  default = union:repo1+repo2
+
+  $ hg -R repo3 verify
+  checking changesets
+  checking manifests
+  crosschecking files in changesets and manifests
+  checking files
+  6 files, 6 changesets, 11 total revisions
+
+  $ hg -R repo3 heads --template '{rev}:{node|short}  {desc|firstline}\n'
+  5:2f0d178c469c  repo2-3
+  2:68c0685446a3  repo1-2
+
+  $ hg -R repo3 log --template '{rev}:{node|short}  {desc|firstline}\n'
+  5:2f0d178c469c  repo2-3
+  4:9e6fb3e0b9da  repo2-2-merge
+  3:c337dba826e7  repo2-1
+  2:68c0685446a3  repo1-2
+  1:8a58db72e69d  repo1-1
+  0:f093fec0529b  repo1-0

mercurial/hg.py

@@ -1,632 +1,633 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 i18n import _
 from lock import release
 from node import hex, nullid
-import localrepo, bundlerepo, httppeer, sshpeer, statichttprepo, bookmarks
-import lock, util, extensions, error, node, scmutil, phases, url
+import localrepo, bundlerepo, unionrepo, httppeer, sshpeer, statichttprepo
+import bookmarks, lock, util, extensions, error, node, scmutil, phases, url
 import cmdutil, discovery
 import merge as mergemod
 import verify as verifymod
 import errno, os, shutil
 
 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:
         return revs or None, revs and revs[0] or None
     revs = revs and list(revs) or []
     if not peer.capable('branchmap'):
         if branches:
             raise util.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 util.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:
         return thing
 
 def islocal(repo):
     '''return true if repo or path 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'''
     if islocal(path):
         return util.posixfile(util.urllocalpath(path), 'rb')
     else:
         return url.open(ui, path)
 
 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():
         hook = getattr(module, 'reposetup', None)
         if hook:
             hook(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 util.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'''
     return os.path.basename(os.path.normpath(util.url(source).path or ''))
 
 def share(ui, source, dest=None, update=True):
     '''create a shared repository'''
 
     if not islocal(source):
         raise util.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
 
     root = os.path.realpath(dest)
     roothg = os.path.join(root, '.hg')
 
     if os.path.exists(roothg):
         raise util.Abort(_('destination already exists'))
 
     if not os.path.isdir(root):
         os.mkdir(root)
     util.makedir(roothg, notindexed=True)
 
     requirements = ''
     try:
         requirements = srcrepo.opener.read('requires')
     except IOError, inst:
         if inst.errno != errno.ENOENT:
             raise
 
     requirements += 'shared\n'
     util.writefile(os.path.join(roothg, 'requires'), requirements)
     util.writefile(os.path.join(roothg, 'sharedpath'), sharedpath)
 
     r = repository(ui, root)
 
     default = srcrepo.ui.config('paths', 'default')
     if default:
         fp = r.opener("hgrc", "w", text=True)
         fp.write("[paths]\n")
         fp.write("default = %s\n" % default)
         fp.close()
 
     if update:
         r.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 = r.lookup(test)
                 break
             except error.RepoLookupError:
                 continue
         _update(r, uprev)
 
 def copystore(ui, srcrepo, destpath):
     '''copy files from store of srcrepo in destpath
 
     returns destlock
     '''
     destlock = None
     try:
         hardlink = None
         num = 0
         srcpublishing = srcrepo.ui.configbool('phases', 'publish', True)
         for f in srcrepo.store.copylist():
             if srcpublishing and f.endswith('phaseroots'):
                 continue
             src = os.path.join(srcrepo.sharedpath, f)
             dst = os.path.join(destpath, f)
             dstbase = os.path.dirname(dst)
             if dstbase and not os.path.exists(dstbase):
                 os.mkdir(dstbase)
             if os.path.exists(src):
                 if dst.endswith('data'):
                     # lock to avoid premature writing to the target
                     destlock = lock.lock(os.path.join(dstbase, "lock"))
                 hardlink, n = util.copyfiles(src, dst, hardlink)
                 num += n
         if hardlink:
             ui.debug("linked %d files\n" % num)
         else:
             ui.debug("copied %d files\n" % num)
         return destlock
     except: # re-raises
         release(destlock)
         raise
 
 def clone(ui, peeropts, source, dest=None, pull=False, rev=None,
           update=True, stream=False, branch=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
 
     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
     """
 
     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)
         ui.status(_("destination directory: %s\n") % dest)
     else:
         dest = ui.expandpath(dest)
 
     dest = util.urllocalpath(dest)
     source = util.urllocalpath(source)
 
     if not dest:
         raise util.Abort(_("empty destination path is not valid"))
     if os.path.exists(dest):
         if not os.path.isdir(dest):
             raise util.Abort(_("destination '%s' already exists") % dest)
         elif os.listdir(dest):
             raise util.Abort(_("destination '%s' is not empty") % dest)
 
     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, inst:
                 if inst.errno == errno.EEXIST:
                     cleandir = None
                     raise util.Abort(_("destination '%s' already exists")
                                      % dest)
                 raise
 
             destlock = copystore(ui, srcrepo, destpath)
 
             # Recomputing branch cache might be slow on big repos,
             # so just copy it
             dstcachedir = os.path.join(destpath, 'cache')
             srcbranchcache = srcrepo.sjoin('cache/branchheads')
             dstbranchcache = os.path.join(dstcachedir, 'branchheads')
             if os.path.exists(srcbranchcache):
                 if not os.path.exists(dstcachedir):
                     os.mkdir(dstcachedir)
                 util.copyfile(srcbranchcache, dstbranchcache)
 
             # 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, inst:
                 if inst.errno == errno.EEXIST:
                     cleandir = None
                     raise util.Abort(_("destination '%s' already exists")
                                      % dest)
                 raise
 
             revs = None
             if rev:
                 if not srcpeer.capable('lookup'):
                     raise util.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]
             if destpeer.local():
                 destpeer.local().clone(srcpeer, heads=revs, stream=stream)
             elif srcrepo:
                 srcrepo.push(destpeer, revs=revs)
             else:
                 raise util.Abort(_("clone from remote to remote not supported"))
 
         cleandir = None
 
         # clone all bookmarks except divergent ones
         destrepo = destpeer.local()
         if destrepo and srcpeer.capable("pushkey"):
             rb = srcpeer.listkeys('bookmarks')
             marks = destrepo._bookmarks
             for k, n in rb.iteritems():
                 try:
                     m = destrepo.lookup(n)
                     marks[k] = m
                 except error.RepoLookupError:
                     pass
             if rb:
                 marks.write()
         elif srcrepo and destpeer.capable("pushkey"):
             for k, n in srcrepo._bookmarks.iteritems():
                 destpeer.pushkey('bookmarks', k, '', hex(n))
 
         if destrepo:
             fp = destrepo.opener("hgrc", "w", text=True)
             fp.write("[paths]\n")
             u = util.url(abspath)
             u.passwd = None
             defaulturl = str(u)
             fp.write("default = %s\n" % defaulturl)
             fp.close()
 
             destrepo.ui.setconfig('paths', 'default', defaulturl)
 
             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:
                         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.setcurrent(destrepo, update)
 
         return srcpeer, destpeer
     finally:
         release(srclock, destlock)
         if cleandir is not None:
             shutil.rmtree(cleandir, True)
         if srcpeer is not None:
             srcpeer.close()
 
 def _showstats(repo, stats):
     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, None)
 
 def update(repo, node):
     """update the working directory to node, merging linear changes"""
     stats = updaterepo(repo, node, False)
     _showstats(repo, stats)
     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):
     """forcibly switch the working directory to node, clobbering changes"""
     stats = updaterepo(repo, node, True)
     if show_stats:
         _showstats(repo, stats)
     return stats[3] > 0
 
 def merge(repo, node, force=None, remind=True):
     """Branch merge with node, resolving changes. Return true if any
     unresolved conflicts."""
     stats = mergemod.update(repo, node, True, force, False)
     _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)
 
         # XXX once graphlog extension makes it into core,
         # should be replaced by a if graph/else
         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 None
     return o
 
 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 = _outgoing(ui, repo, dest, opts)
     if o is None:
         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()
     recurse()
     return 0 # exit code is zero since we found outgoing changes
 
 def revert(repo, node, choose):
     """revert changes to revision in node without updating dirstate"""
     return mergemod.update(repo, node, False, True, choose)[3] > 0
 
 def verify(repo):
     """verify the consistency of a repository"""
     return verifymod.verify(repo)
 
 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)
 
     # copy bundle-specific options
     r = src.config('bundle', 'mainreporoot')
     if r:
         dst.setconfig('bundle', 'mainreporoot', r)
 
     # 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)
     v = src.config('web', 'cacerts')
     if v:
         dst.setconfig('web', 'cacerts', util.expandpath(v))
 
     return dst