shelve: add utility to abort current transaction but keep dirstate

"hg shelve" and "hg unshelve" use aborting a current transaction to
discard temporary changes while (un)shelving.

This assumes that dirstate changes in a transaction scope are kept
even after aborting it. But this assumption will be broken by
"transactional dirstate". See the wiki page below for detail about it.

    https://mercurial.selenic.com/wiki/DirstateTransactionPlan

This patch adds utility function "_aborttransaction()" to abort
current transaction but keep dirstate changes for (un)shelving.

'dirstate.invalidate()' just after aborting a transaction should be
removed soon by subsequent patch, which writes or discards in-memory
dirstate changes at releasing transaction according to the result of
it.

BTW, there are some other ways below, which (seem to, at first glance)
resolve this issue. But this patch chose straightforward way for ease
of review and future refactorring.

  - commit transaction at first, and then rollback it

    It causes unintentional "dirty read" of running transaction to
    other processes at committing it.

  - use dirstateguard to save and restore shelved dirstate

    After DirstateTransactionPlan, making 'dirstate.write()' write
    in-memory changes into actual file requires
    'transaction.writepending()' while transaction running.

    It causes meaningless writing other in-memory changes out, even
    though they are never referred.

    In addition to it, it isn't desirable that scope of dirstateguard
    and transaction intersects each other.

  - get list of files changed from the parent, keep it in memory, and
    emulate that changes after aborting transaction

    This additional memory consumption may block aborting transaction
    in large repository (on small resource environment).

hgext/shelve.py

@@ -1,805 +1,834
 # shelve.py - save/restore working directory state
 #
 # 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.
 
 """save and restore changes to the working directory
 
 The "hg shelve" command saves changes made to the working directory
 and reverts those changes, resetting the working directory to a clean
 state.
 
 Later on, the "hg unshelve" command restores the changes saved by "hg
 shelve". Changes can be restored even after updating to a different
 parent, in which case Mercurial's merge machinery will resolve any
 conflicts if necessary.
 
 You can have more than one shelved change outstanding at a time; each
 shelved change has a distinct name. For details, see the help for "hg
 shelve".
 """
 
 import collections
 import itertools
 from mercurial.i18n import _
 from mercurial.node import nullid, nullrev, bin, hex
 from mercurial import changegroup, cmdutil, scmutil, phases, commands
 from mercurial import error, hg, mdiff, merge, patch, repair, util
 from mercurial import templatefilters, exchange, bundlerepo
 from mercurial import lock as lockmod
 from hgext import rebase
 import errno
 
 cmdtable = {}
 command = cmdutil.command(cmdtable)
 # Note for extension authors: ONLY specify testedwith = 'internal' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = 'internal'
 
 backupdir = 'shelve-backup'
 
 class shelvedfile(object):
     """Helper for the file storing a single shelve
 
     Handles common functions on shelve files (.hg/.patch) using
     the vfs layer"""
     def __init__(self, repo, name, filetype=None):
         self.repo = repo
         self.name = name
         self.vfs = scmutil.vfs(repo.join('shelved'))
         self.backupvfs = scmutil.vfs(repo.join(backupdir))
         self.ui = self.repo.ui
         if filetype:
             self.fname = name + '.' + filetype
         else:
             self.fname = name
 
     def exists(self):
         return self.vfs.exists(self.fname)
 
     def filename(self):
         return self.vfs.join(self.fname)
 
     def backupfilename(self):
         def gennames(base):
             yield base
             base, ext = base.rsplit('.', 1)
             for i in itertools.count(1):
                 yield '%s-%d.%s' % (base, i, ext)
 
         name = self.backupvfs.join(self.fname)
         for n in gennames(name):
             if not self.backupvfs.exists(n):
                 return n
 
     def movetobackup(self):
         if not self.backupvfs.isdir():
             self.backupvfs.makedir()
         util.rename(self.filename(), self.backupfilename())
 
     def stat(self):
         return self.vfs.stat(self.fname)
 
     def opener(self, mode='rb'):
         try:
             return self.vfs(self.fname, mode)
         except IOError as err:
             if err.errno != errno.ENOENT:
                 raise
             raise util.Abort(_("shelved change '%s' not found") % self.name)
 
     def applybundle(self):
         fp = self.opener()
         try:
             gen = exchange.readbundle(self.repo.ui, fp, self.fname, self.vfs)
             changegroup.addchangegroup(self.repo, gen, 'unshelve',
                                        'bundle:' + self.vfs.join(self.fname),
                                        targetphase=phases.secret)
         finally:
             fp.close()
 
     def bundlerepo(self):
         return bundlerepo.bundlerepository(self.repo.baseui, self.repo.root,
                                            self.vfs.join(self.fname))
     def writebundle(self, bases, node):
         btype = 'HG10BZ'
         cgversion = '01'
         compression = None
         if 'generaldelta' in self.repo.requirements:
             btype = 'HG20'
             cgversion = '02'
             compression = 'BZ'
 
         cg = changegroup.changegroupsubset(self.repo, bases, [node], 'shelve',
                                            version=cgversion)
         changegroup.writebundle(self.ui, cg, self.fname, btype, self.vfs,
                                 compression=compression)
 
 class shelvedstate(object):
     """Handle persistence during unshelving operations.
 
     Handles saving and restoring a shelved state. Ensures that different
     versions of a shelved state are possible and handles them appropriately.
     """
     _version = 1
     _filename = 'shelvedstate'
 
     @classmethod
     def load(cls, repo):
         fp = repo.vfs(cls._filename)
         try:
             version = int(fp.readline().strip())
 
             if version != cls._version:
                 raise util.Abort(_('this version of shelve is incompatible '
                                    'with the version used in this repo'))
             name = fp.readline().strip()
             wctx = fp.readline().strip()
             pendingctx = fp.readline().strip()
             parents = [bin(h) for h in fp.readline().split()]
             stripnodes = [bin(h) for h in fp.readline().split()]
         finally:
             fp.close()
 
         obj = cls()
         obj.name = name
         obj.wctx = repo[bin(wctx)]
         obj.pendingctx = repo[bin(pendingctx)]
         obj.parents = parents
         obj.stripnodes = stripnodes
 
         return obj
 
     @classmethod
     def save(cls, repo, name, originalwctx, pendingctx, stripnodes):
         fp = repo.vfs(cls._filename, 'wb')
         fp.write('%i\n' % cls._version)
         fp.write('%s\n' % name)
         fp.write('%s\n' % hex(originalwctx.node()))
         fp.write('%s\n' % hex(pendingctx.node()))
         fp.write('%s\n' % ' '.join([hex(p) for p in repo.dirstate.parents()]))
         fp.write('%s\n' % ' '.join([hex(n) for n in stripnodes]))
         fp.close()
 
     @classmethod
     def clear(cls, repo):
         util.unlinkpath(repo.join(cls._filename), ignoremissing=True)
 
 def cleanupoldbackups(repo):
     vfs = scmutil.vfs(repo.join(backupdir))
     maxbackups = repo.ui.configint('shelve', 'maxbackups', 10)
     hgfiles = [f for f in vfs.listdir() if f.endswith('.hg')]
     hgfiles = sorted([(vfs.stat(f).st_mtime, f) for f in hgfiles])
     if 0 < maxbackups and maxbackups < len(hgfiles):
         bordermtime = hgfiles[-maxbackups][0]
     else:
         bordermtime = None
     for mtime, f in hgfiles[:len(hgfiles) - maxbackups]:
         if mtime == bordermtime:
             # keep it, because timestamp can't decide exact order of backups
             continue
         base = f[:-3]
         for ext in 'hg patch'.split():
             try:
                 vfs.unlink(base + '.' + ext)
             except OSError as err:
                 if err.errno != errno.ENOENT:
                     raise
 
+def _aborttransaction(repo):
+    '''Abort current transaction for shelve/unshelve, but keep dirstate
+    '''
+    backupname = 'dirstate.shelve'
+    dirstatebackup = None
+    try:
+        # create backup of (un)shelved dirstate, because aborting transaction
+        # should restore dirstate to one at the beginning of the
+        # transaction, which doesn't include the result of (un)shelving
+        fp = repo.vfs.open(backupname, "w")
+        dirstatebackup = backupname
+        # clearing _dirty/_dirtypl of dirstate by _writedirstate below
+        # is unintentional. but it doesn't cause problem in this case,
+        # because no code path refers them until transaction is aborted.
+        repo.dirstate._writedirstate(fp) # write in-memory changes forcibly
+
+        tr = repo.currenttransaction()
+        tr.abort()
+
+        # TODO: this should be done via transaction.abort()
+        repo.dirstate.invalidate() # prevent wlock from writing changes out
+
+        # restore to backuped dirstate
+        repo.vfs.rename(dirstatebackup, 'dirstate')
+        dirstatebackup = None
+    finally:
+        if dirstatebackup:
+            repo.vfs.unlink(dirstatebackup)
+
 def createcmd(ui, repo, pats, opts):
     """subcommand that creates a new shelve"""
 
     def publicancestors(ctx):
         """Compute the public ancestors of a commit.
 
         Much faster than the revset ancestors(ctx) & draft()"""
         seen = set([nullrev])
         visit = collections.deque()
         visit.append(ctx)
         while visit:
             ctx = visit.popleft()
             yield ctx.node()
             for parent in ctx.parents():
                 rev = parent.rev()
                 if rev not in seen:
                     seen.add(rev)
                     if parent.mutable():
                         visit.append(parent)
 
     wctx = repo[None]
     parents = wctx.parents()
     if len(parents) > 1:
         raise util.Abort(_('cannot shelve while merging'))
     parent = parents[0]
 
     # we never need the user, so we use a generic user for all shelve operations
     user = 'shelve@localhost'
     label = repo._activebookmark or parent.branch() or 'default'
 
     # slashes aren't allowed in filenames, therefore we rename it
     label = label.replace('/', '_')
 
     def gennames():
         yield label
         for i in xrange(1, 100):
             yield '%s-%02d' % (label, i)
 
     def commitfunc(ui, repo, message, match, opts):
         hasmq = util.safehasattr(repo, 'mq')
         if hasmq:
             saved, repo.mq.checkapplied = repo.mq.checkapplied, False
         backup = repo.ui.backupconfig('phases', 'new-commit')
         try:
             repo.ui. setconfig('phases', 'new-commit', phases.secret)
             editor = cmdutil.getcommiteditor(editform='shelve.shelve', **opts)
             return repo.commit(message, user, opts.get('date'), match,
                                editor=editor)
         finally:
             repo.ui.restoreconfig(backup)
             if hasmq:
                 repo.mq.checkapplied = saved
 
     if parent.node() != nullid:
         desc = "changes to '%s'" % parent.description().split('\n', 1)[0]
     else:
         desc = '(changes in empty repository)'
 
     if not opts['message']:
         opts['message'] = desc
 
     name = opts['name']
 
     wlock = lock = tr = None
     try:
         wlock = repo.wlock()
         lock = repo.lock()
 
         # use an uncommitted transaction to generate the bundle to avoid
         # pull races. ensure we don't print the abort message to stderr.
         tr = repo.transaction('commit', report=lambda x: None)
 
         if name:
             if shelvedfile(repo, name, 'hg').exists():
                 raise util.Abort(_("a shelved change named '%s' already exists")
                                  % name)
         else:
             for n in gennames():
                 if not shelvedfile(repo, n, 'hg').exists():
                     name = n
                     break
             else:
                 raise util.Abort(_("too many shelved changes named '%s'") %
                                  label)
 
         # ensure we are not creating a subdirectory or a hidden file
         if '/' in name or '\\' in name:
             raise util.Abort(_('shelved change names may not contain slashes'))
         if name.startswith('.'):
             raise util.Abort(_("shelved change names may not start with '.'"))
         interactive = opts.get('interactive', False)
 
         def interactivecommitfunc(ui, repo, *pats, **opts):
             match = scmutil.match(repo['.'], pats, {})
             message = opts['message']
             return commitfunc(ui, repo, message, match, opts)
         if not interactive:
             node = cmdutil.commit(ui, repo, commitfunc, pats, opts)
         else:
             node = cmdutil.dorecord(ui, repo, interactivecommitfunc, None,
                                     False, cmdutil.recordfilter, *pats, **opts)
         if not node:
             stat = repo.status(match=scmutil.match(repo[None], pats, opts))
             if stat.deleted:
                 ui.status(_("nothing changed (%d missing files, see "
                             "'hg status')\n") % len(stat.deleted))
             else:
                 ui.status(_("nothing changed\n"))
             return 1
 
         bases = list(publicancestors(repo[node]))
         shelvedfile(repo, name, 'hg').writebundle(bases, node)
         cmdutil.export(repo, [node],
                        fp=shelvedfile(repo, name, 'patch').opener('wb'),
                        opts=mdiff.diffopts(git=True))
 
 
         if ui.formatted():
             desc = util.ellipsis(desc, ui.termwidth())
         ui.status(_('shelved as %s\n') % name)
         hg.update(repo, parent.node())
     finally:
         if tr:
             tr.abort()
         lockmod.release(lock, wlock)
 
 def cleanupcmd(ui, repo):
     """subcommand that deletes all shelves"""
 
     wlock = None
     try:
         wlock = repo.wlock()
         for (name, _type) in repo.vfs.readdir('shelved'):
             suffix = name.rsplit('.', 1)[-1]
             if suffix in ('hg', 'patch'):
                 shelvedfile(repo, name).movetobackup()
             cleanupoldbackups(repo)
     finally:
         lockmod.release(wlock)
 
 def deletecmd(ui, repo, pats):
     """subcommand that deletes a specific shelve"""
     if not pats:
         raise util.Abort(_('no shelved changes specified!'))
     wlock = repo.wlock()
     try:
         for name in pats:
             for suffix in 'hg patch'.split():
                 shelvedfile(repo, name, suffix).movetobackup()
         cleanupoldbackups(repo)
     except OSError as err:
         if err.errno != errno.ENOENT:
             raise
         raise util.Abort(_("shelved change '%s' not found") % name)
     finally:
         lockmod.release(wlock)
 
 def listshelves(repo):
     """return all shelves in repo as list of (time, filename)"""
     try:
         names = repo.vfs.readdir('shelved')
     except OSError as err:
         if err.errno != errno.ENOENT:
             raise
         return []
     info = []
     for (name, _type) in names:
         pfx, sfx = name.rsplit('.', 1)
         if not pfx or sfx != 'patch':
             continue
         st = shelvedfile(repo, name).stat()
         info.append((st.st_mtime, shelvedfile(repo, pfx).filename()))
     return sorted(info, reverse=True)
 
 def listcmd(ui, repo, pats, opts):
     """subcommand that displays the list of shelves"""
     pats = set(pats)
     width = 80
     if not ui.plain():
         width = ui.termwidth()
     namelabel = 'shelve.newest'
     for mtime, name in listshelves(repo):
         sname = util.split(name)[1]
         if pats and sname not in pats:
             continue
         ui.write(sname, label=namelabel)
         namelabel = 'shelve.name'
         if ui.quiet:
             ui.write('\n')
             continue
         ui.write(' ' * (16 - len(sname)))
         used = 16
         age = '(%s)' % templatefilters.age(util.makedate(mtime), abbrev=True)
         ui.write(age, label='shelve.age')
         ui.write(' ' * (12 - len(age)))
         used += 12
         fp = open(name + '.patch', 'rb')
         try:
             while True:
                 line = fp.readline()
                 if not line:
                     break
                 if not line.startswith('#'):
                     desc = line.rstrip()
                     if ui.formatted():
                         desc = util.ellipsis(desc, width - used)
                     ui.write(desc)
                     break
             ui.write('\n')
             if not (opts['patch'] or opts['stat']):
                 continue
             difflines = fp.readlines()
             if opts['patch']:
                 for chunk, label in patch.difflabel(iter, difflines):
                     ui.write(chunk, label=label)
             if opts['stat']:
                 for chunk, label in patch.diffstatui(difflines, width=width,
                                                      git=True):
                     ui.write(chunk, label=label)
         finally:
             fp.close()
 
 def singlepatchcmds(ui, repo, pats, opts, subcommand):
     """subcommand that displays a single shelf"""
     if len(pats) != 1:
         raise util.Abort(_("--%s expects a single shelf") % subcommand)
     shelfname = pats[0]
 
     if not shelvedfile(repo, shelfname, 'patch').exists():
         raise util.Abort(_("cannot find shelf %s") % shelfname)
 
     listcmd(ui, repo, pats, opts)
 
 def checkparents(repo, state):
     """check parent while resuming an unshelve"""
     if state.parents != repo.dirstate.parents():
         raise util.Abort(_('working directory parents do not match unshelve '
                            'state'))
 
 def pathtofiles(repo, files):
     cwd = repo.getcwd()
     return [repo.pathto(f, cwd) for f in files]
 
 def unshelveabort(ui, repo, state, opts):
     """subcommand that abort an in-progress unshelve"""
     wlock = repo.wlock()
     lock = None
     try:
         checkparents(repo, state)
 
         util.rename(repo.join('unshelverebasestate'),
                     repo.join('rebasestate'))
         try:
             rebase.rebase(ui, repo, **{
                 'abort' : True
             })
         except Exception:
             util.rename(repo.join('rebasestate'),
                         repo.join('unshelverebasestate'))
             raise
 
         lock = repo.lock()
 
         mergefiles(ui, repo, state.wctx, state.pendingctx)
 
         repair.strip(ui, repo, state.stripnodes, backup=False, topic='shelve')
         shelvedstate.clear(repo)
         ui.warn(_("unshelve of '%s' aborted\n") % state.name)
     finally:
         lockmod.release(lock, wlock)
 
 def mergefiles(ui, repo, wctx, shelvectx):
     """updates to wctx and merges the changes from shelvectx into the
     dirstate."""
     oldquiet = ui.quiet
     try:
         ui.quiet = True
         hg.update(repo, wctx.node())
         files = []
         files.extend(shelvectx.files())
         files.extend(shelvectx.parents()[0].files())
 
         # revert will overwrite unknown files, so move them out of the way
         for file in repo.status(unknown=True).unknown:
             if file in files:
                 util.rename(file, file + ".orig")
         ui.pushbuffer(True)
         cmdutil.revert(ui, repo, shelvectx, repo.dirstate.parents(),
                        *pathtofiles(repo, files),
                        **{'no_backup': True})
         ui.popbuffer()
     finally:
         ui.quiet = oldquiet
 
 def unshelvecleanup(ui, repo, name, opts):
     """remove related files after an unshelve"""
     if not opts['keep']:
         for filetype in 'hg patch'.split():
             shelvedfile(repo, name, filetype).movetobackup()
         cleanupoldbackups(repo)
 
 def unshelvecontinue(ui, repo, state, opts):
     """subcommand to continue an in-progress unshelve"""
     # We're finishing off a merge. First parent is our original
     # parent, second is the temporary "fake" commit we're unshelving.
     wlock = repo.wlock()
     lock = None
     try:
         checkparents(repo, state)
         ms = merge.mergestate(repo)
         if [f for f in ms if ms[f] == 'u']:
             raise util.Abort(
                 _("unresolved conflicts, can't continue"),
                 hint=_("see 'hg resolve', then 'hg unshelve --continue'"))
 
         lock = repo.lock()
 
         util.rename(repo.join('unshelverebasestate'),
                     repo.join('rebasestate'))
         try:
             rebase.rebase(ui, repo, **{
                 'continue' : True
             })
         except Exception:
             util.rename(repo.join('rebasestate'),
                         repo.join('unshelverebasestate'))
             raise
 
         shelvectx = repo['tip']
         if not shelvectx in state.pendingctx.children():
             # rebase was a no-op, so it produced no child commit
             shelvectx = state.pendingctx
         else:
             # only strip the shelvectx if the rebase produced it
             state.stripnodes.append(shelvectx.node())
 
         mergefiles(ui, repo, state.wctx, shelvectx)
 
         repair.strip(ui, repo, state.stripnodes, backup=False, topic='shelve')
         shelvedstate.clear(repo)
         unshelvecleanup(ui, repo, state.name, opts)
         ui.status(_("unshelve of '%s' complete\n") % state.name)
     finally:
         lockmod.release(lock, wlock)
 
 @command('unshelve',
          [('a', 'abort', None,
            _('abort an incomplete unshelve operation')),
           ('c', 'continue', None,
            _('continue an incomplete unshelve operation')),
           ('', 'keep', None,
            _('keep shelve after unshelving')),
           ('', 'date', '',
            _('set date for temporary commits (DEPRECATED)'), _('DATE'))],
          _('hg unshelve [SHELVED]'))
 def unshelve(ui, repo, *shelved, **opts):
     """restore a shelved change to the working directory
 
     This command accepts an optional name of a shelved change to
     restore. If none is given, the most recent shelved change is used.
 
     If a shelved change is applied successfully, the bundle that
     contains the shelved changes is moved to a backup location
     (.hg/shelve-backup).
 
     Since you can restore a shelved change on top of an arbitrary
     commit, it is possible that unshelving will result in a conflict
     between your changes and the commits you are unshelving onto. If
     this occurs, you must resolve the conflict, then use
     ``--continue`` to complete the unshelve operation. (The bundle
     will not be moved until you successfully complete the unshelve.)
 
     (Alternatively, you can use ``--abort`` to abandon an unshelve
     that causes a conflict. This reverts the unshelved changes, and
     leaves the bundle in place.)
 
     After a successful unshelve, the shelved changes are stored in a
     backup directory. Only the N most recent backups are kept. N
     defaults to 10 but can be overridden using the ``shelve.maxbackups``
     configuration option.
 
     .. container:: verbose
 
        Timestamp in seconds is used to decide order of backups. More
        than ``maxbackups`` backups are kept, if same timestamp
        prevents from deciding exact order of them, for safety.
     """
     abortf = opts['abort']
     continuef = opts['continue']
     if not abortf and not continuef:
         cmdutil.checkunfinished(repo)
 
     if abortf or continuef:
         if abortf and continuef:
             raise util.Abort(_('cannot use both abort and continue'))
         if shelved:
             raise util.Abort(_('cannot combine abort/continue with '
                                'naming a shelved change'))
 
         try:
             state = shelvedstate.load(repo)
         except IOError as err:
             if err.errno != errno.ENOENT:
                 raise
             raise util.Abort(_('no unshelve operation underway'))
 
         if abortf:
             return unshelveabort(ui, repo, state, opts)
         elif continuef:
             return unshelvecontinue(ui, repo, state, opts)
     elif len(shelved) > 1:
         raise util.Abort(_('can only unshelve one change at a time'))
     elif not shelved:
         shelved = listshelves(repo)
         if not shelved:
             raise util.Abort(_('no shelved changes to apply!'))
         basename = util.split(shelved[0][1])[1]
         ui.status(_("unshelving change '%s'\n") % basename)
     else:
         basename = shelved[0]
 
     if not shelvedfile(repo, basename, 'patch').exists():
         raise util.Abort(_("shelved change '%s' not found") % basename)
 
     oldquiet = ui.quiet
     wlock = lock = tr = None
     try:
         wlock = repo.wlock()
         lock = repo.lock()
 
         tr = repo.transaction('unshelve', report=lambda x: None)
         oldtiprev = len(repo)
 
         pctx = repo['.']
         tmpwctx = pctx
         # The goal is to have a commit structure like so:
         # ...-> pctx -> tmpwctx -> shelvectx
         # where tmpwctx is an optional commit with the user's pending changes
         # and shelvectx is the unshelved changes. Then we merge it all down
         # to the original pctx.
 
         # Store pending changes in a commit
         s = repo.status()
         if s.modified or s.added or s.removed or s.deleted:
             ui.status(_("temporarily committing pending changes "
                         "(restore with 'hg unshelve --abort')\n"))
             def commitfunc(ui, repo, message, match, opts):
                 hasmq = util.safehasattr(repo, 'mq')
                 if hasmq:
                     saved, repo.mq.checkapplied = repo.mq.checkapplied, False
 
                 backup = repo.ui.backupconfig('phases', 'new-commit')
                 try:
                     repo.ui. setconfig('phases', 'new-commit', phases.secret)
                     return repo.commit(message, 'shelve@localhost',
                                        opts.get('date'), match)
                 finally:
                     repo.ui.restoreconfig(backup)
                     if hasmq:
                         repo.mq.checkapplied = saved
 
             tempopts = {}
             tempopts['message'] = "pending changes temporary commit"
             tempopts['date'] = opts.get('date')
             ui.quiet = True
             node = cmdutil.commit(ui, repo, commitfunc, [], tempopts)
             tmpwctx = repo[node]
 
         ui.quiet = True
         shelvedfile(repo, basename, 'hg').applybundle()
 
         ui.quiet = oldquiet
 
         shelvectx = repo['tip']
 
         # If the shelve is not immediately on top of the commit
         # we'll be merging with, rebase it to be on top.
         if tmpwctx.node() != shelvectx.parents()[0].node():
             ui.status(_('rebasing shelved changes\n'))
             try:
                 rebase.rebase(ui, repo, **{
                     'rev' : [shelvectx.rev()],
                     'dest' : str(tmpwctx.rev()),
                     'keep' : True,
                 })
             except error.InterventionRequired:
                 tr.close()
 
                 stripnodes = [repo.changelog.node(rev)
                               for rev in xrange(oldtiprev, len(repo))]
                 shelvedstate.save(repo, basename, pctx, tmpwctx, stripnodes)
 
                 util.rename(repo.join('rebasestate'),
                             repo.join('unshelverebasestate'))
                 raise error.InterventionRequired(
                     _("unresolved conflicts (see 'hg resolve', then "
                       "'hg unshelve --continue')"))
 
             # refresh ctx after rebase completes
             shelvectx = repo['tip']
 
             if not shelvectx in tmpwctx.children():
                 # rebase was a no-op, so it produced no child commit
                 shelvectx = tmpwctx
 
         mergefiles(ui, repo, pctx, shelvectx)
         shelvedstate.clear(repo)
 
         # The transaction aborting will strip all the commits for us,
         # but it doesn't update the inmemory structures, so addchangegroup
         # hooks still fire and try to operate on the missing commits.
         # Clean up manually to prevent this.
         repo.unfiltered().changelog.strip(oldtiprev, tr)
 
         unshelvecleanup(ui, repo, basename, opts)
     finally:
         ui.quiet = oldquiet
         if tr:
             tr.release()
         lockmod.release(lock, wlock)
 
 @command('shelve',
          [('A', 'addremove', None,
            _('mark new/missing files as added/removed before shelving')),
           ('', 'cleanup', None,
            _('delete all shelved changes')),
           ('', 'date', '',
            _('shelve with the specified commit date'), _('DATE')),
           ('d', 'delete', None,
            _('delete the named shelved change(s)')),
           ('e', 'edit', False,
            _('invoke editor on commit messages')),
           ('l', 'list', None,
            _('list current shelves')),
           ('m', 'message', '',
            _('use text as shelve message'), _('TEXT')),
           ('n', 'name', '',
            _('use the given name for the shelved commit'), _('NAME')),
           ('p', 'patch', None,
            _('show patch')),
           ('i', 'interactive', None,
            _('interactive mode, only works while creating a shelve')),
           ('', 'stat', None,
            _('output diffstat-style summary of changes'))] + commands.walkopts,
          _('hg shelve [OPTION]... [FILE]...'))
 def shelvecmd(ui, repo, *pats, **opts):
     '''save and set aside changes from the working directory
 
     Shelving takes files that "hg status" reports as not clean, saves
     the modifications to a bundle (a shelved change), and reverts the
     files so that their state in the working directory becomes clean.
 
     To restore these changes to the working directory, using "hg
     unshelve"; this will work even if you switch to a different
     commit.
 
     When no files are specified, "hg shelve" saves all not-clean
     files. If specific files or directories are named, only changes to
     those files are shelved.
 
     Each shelved change has a name that makes it easier to find later.
     The name of a shelved change defaults to being based on the active
     bookmark, or if there is no active bookmark, the current named
     branch.  To specify a different name, use ``--name``.
 
     To see a list of existing shelved changes, use the ``--list``
     option. For each shelved change, this will print its name, age,
     and description; use ``--patch`` or ``--stat`` for more details.
 
     To delete specific shelved changes, use ``--delete``. To delete
     all shelved changes, use ``--cleanup``.
     '''
     cmdutil.checkunfinished(repo)
 
     allowables = [
         ('addremove', set(['create'])), # 'create' is pseudo action
         ('cleanup', set(['cleanup'])),
 #       ('date', set(['create'])), # ignored for passing '--date "0 0"' in tests
         ('delete', set(['delete'])),
         ('edit', set(['create'])),
         ('list', set(['list'])),
         ('message', set(['create'])),
         ('name', set(['create'])),
         ('patch', set(['patch', 'list'])),
         ('stat', set(['stat', 'list'])),
     ]
     def checkopt(opt):
         if opts[opt]:
             for i, allowable in allowables:
                 if opts[i] and opt not in allowable:
                     raise util.Abort(_("options '--%s' and '--%s' may not be "
                                        "used together") % (opt, i))
             return True
     if checkopt('cleanup'):
         if pats:
             raise util.Abort(_("cannot specify names when using '--cleanup'"))
         return cleanupcmd(ui, repo)
     elif checkopt('delete'):
         return deletecmd(ui, repo, pats)
     elif checkopt('list'):
         return listcmd(ui, repo, pats, opts)
     elif checkopt('patch'):
         return singlepatchcmds(ui, repo, pats, opts, subcommand='patch')
     elif checkopt('stat'):
         return singlepatchcmds(ui, repo, pats, opts, subcommand='stat')
     else:
         return createcmd(ui, repo, pats, opts)
 
 def extsetup(ui):
     cmdutil.unfinishedstates.append(
         [shelvedstate._filename, False, False,
          _('unshelve already in progress'),
          _("use 'hg unshelve --continue' or 'hg unshelve --abort'")])