shelve: removed redundant merge detection method

Differential Revision: https://phab.mercurial-scm.org/D6547

hgext/shelve.py

@@ -1,1147 +1,1139 b''
 # 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".
 """
 from __future__ import absolute_import
 
 import collections
 import errno
 import itertools
 import stat
 
 from mercurial.i18n import _
 from mercurial import (
     bookmarks,
     bundle2,
     bundlerepo,
     changegroup,
     cmdutil,
     discovery,
     error,
     exchange,
     hg,
     lock as lockmod,
     mdiff,
     merge,
     node as nodemod,
     patch,
     phases,
     pycompat,
     registrar,
     repair,
     scmutil,
     state as statemod,
     templatefilters,
     util,
     vfs as vfsmod,
 )
 
 from . import (
     rebase,
 )
 from mercurial.utils import (
     dateutil,
     stringutil,
 )
 
 cmdtable = {}
 command = registrar.command(cmdtable)
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' 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 = 'ships-with-hg-core'
 
 configtable = {}
 configitem = registrar.configitem(configtable)
 
 configitem('shelve', 'maxbackups',
     default=10,
 )
 
 backupdir = 'shelve-backup'
 shelvedir = 'shelved'
 shelvefileextensions = ['hg', 'patch', 'shelve']
 # universal extension is present in all types of shelves
 patchextension = 'patch'
 
 # we never need the user, so we use a
 # generic user for all shelve operations
 shelveuser = 'shelve@localhost'
 
 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 = vfsmod.vfs(repo.vfs.join(shelvedir))
         self.backupvfs = vfsmod.vfs(repo.vfs.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 error.Abort(_("shelved change '%s' not found") % self.name)
 
     def applybundle(self, tr):
         fp = self.opener()
         try:
             targetphase = phases.internal
             if not phases.supportinternal(self.repo):
                 targetphase = phases.secret
             gen = exchange.readbundle(self.repo.ui, fp, self.fname, self.vfs)
             pretip = self.repo['tip']
             bundle2.applybundle(self.repo, gen, tr,
                                 source='unshelve',
                                 url='bundle:' + self.vfs.join(self.fname),
                                 targetphase=targetphase)
             shelvectx = self.repo['tip']
             if pretip == shelvectx:
                 shelverev = tr.changes['revduplicates'][-1]
                 shelvectx = self.repo[shelverev]
             return shelvectx
         finally:
             fp.close()
 
     def bundlerepo(self):
         path = self.vfs.join(self.fname)
         return bundlerepo.instance(self.repo.baseui,
                                    'bundle://%s+%s' % (self.repo.root, path))
 
     def writebundle(self, bases, node):
         cgversion = changegroup.safeversion(self.repo)
         if cgversion == '01':
             btype = 'HG10BZ'
             compression = None
         else:
             btype = 'HG20'
             compression = 'BZ'
 
         repo = self.repo.unfiltered()
 
         outgoing = discovery.outgoing(repo, missingroots=bases,
                                       missingheads=[node])
         cg = changegroup.makechangegroup(repo, outgoing, cgversion, 'shelve')
 
         bundle2.writebundle(self.ui, cg, self.fname, btype, self.vfs,
                                 compression=compression)
 
     def writeinfo(self, info):
         scmutil.simplekeyvaluefile(self.vfs, self.fname).write(info)
 
     def readinfo(self):
         return scmutil.simplekeyvaluefile(self.vfs, self.fname).read()
 
 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 = 2
     _filename = 'shelvedstate'
     _keep = 'keep'
     _nokeep = 'nokeep'
     # colon is essential to differentiate from a real bookmark name
     _noactivebook = ':no-active-bookmark'
 
     @classmethod
     def _verifyandtransform(cls, d):
         """Some basic shelvestate syntactic verification and transformation"""
         try:
             d['originalwctx'] = nodemod.bin(d['originalwctx'])
             d['pendingctx'] = nodemod.bin(d['pendingctx'])
             d['parents'] = [nodemod.bin(h)
                             for h in d['parents'].split(' ')]
             d['nodestoremove'] = [nodemod.bin(h)
                                   for h in d['nodestoremove'].split(' ')]
         except (ValueError, TypeError, KeyError) as err:
             raise error.CorruptedState(pycompat.bytestr(err))
 
     @classmethod
     def _getversion(cls, repo):
         """Read version information from shelvestate file"""
         fp = repo.vfs(cls._filename)
         try:
             version = int(fp.readline().strip())
         except ValueError as err:
             raise error.CorruptedState(pycompat.bytestr(err))
         finally:
             fp.close()
         return version
 
     @classmethod
     def _readold(cls, repo):
         """Read the old position-based version of a shelvestate file"""
         # Order is important, because old shelvestate file uses it
         # to detemine values of fields (i.g. name is on the second line,
         # originalwctx is on the third and so forth). Please do not change.
         keys = ['version', 'name', 'originalwctx', 'pendingctx', 'parents',
                 'nodestoremove', 'branchtorestore', 'keep', 'activebook']
         # this is executed only seldomly, so it is not a big deal
         # that we open this file twice
         fp = repo.vfs(cls._filename)
         d = {}
         try:
             for key in keys:
                 d[key] = fp.readline().strip()
         finally:
             fp.close()
         return d
 
     @classmethod
     def load(cls, repo):
         version = cls._getversion(repo)
         if version < cls._version:
             d = cls._readold(repo)
         elif version == cls._version:
             d = scmutil.simplekeyvaluefile(
                 repo.vfs, cls._filename).read(firstlinenonkeyval=True)
         else:
             raise error.Abort(_('this version of shelve is incompatible '
                                 'with the version used in this repo'))
 
         cls._verifyandtransform(d)
         try:
             obj = cls()
             obj.name = d['name']
             obj.wctx = repo[d['originalwctx']]
             obj.pendingctx = repo[d['pendingctx']]
             obj.parents = d['parents']
             obj.nodestoremove = d['nodestoremove']
             obj.branchtorestore = d.get('branchtorestore', '')
             obj.keep = d.get('keep') == cls._keep
             obj.activebookmark = ''
             if d.get('activebook', '') != cls._noactivebook:
                 obj.activebookmark = d.get('activebook', '')
         except (error.RepoLookupError, KeyError) as err:
             raise error.CorruptedState(pycompat.bytestr(err))
 
         return obj
 
     @classmethod
     def save(cls, repo, name, originalwctx, pendingctx, nodestoremove,
              branchtorestore, keep=False, activebook=''):
         info = {
             "name": name,
             "originalwctx": nodemod.hex(originalwctx.node()),
             "pendingctx": nodemod.hex(pendingctx.node()),
             "parents": ' '.join([nodemod.hex(p)
                                  for p in repo.dirstate.parents()]),
             "nodestoremove": ' '.join([nodemod.hex(n)
                                       for n in nodestoremove]),
             "branchtorestore": branchtorestore,
             "keep": cls._keep if keep else cls._nokeep,
             "activebook": activebook or cls._noactivebook
         }
         scmutil.simplekeyvaluefile(
             repo.vfs, cls._filename).write(info,
                                            firstline=("%d" % cls._version))
 
     @classmethod
     def clear(cls, repo):
         repo.vfs.unlinkpath(cls._filename, ignoremissing=True)
 
 def cleanupoldbackups(repo):
     vfs = vfsmod.vfs(repo.vfs.join(backupdir))
     maxbackups = repo.ui.configint('shelve', 'maxbackups')
     hgfiles = [f for f in vfs.listdir()
                if f.endswith('.' + patchextension)]
     hgfiles = sorted([(vfs.stat(f)[stat.ST_MTIME], f) for f in hgfiles])
     if maxbackups > 0 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[:-(1 + len(patchextension))]
         for ext in shelvefileextensions:
             vfs.tryunlink(base + '.' + ext)
 
 def _backupactivebookmark(repo):
     activebookmark = repo._activebookmark
     if activebookmark:
         bookmarks.deactivate(repo)
     return activebookmark
 
 def _restoreactivebookmark(repo, mark):
     if mark:
         bookmarks.activate(repo, mark)
 
 def _aborttransaction(repo, tr):
     '''Abort current transaction for shelve/unshelve, but keep dirstate
     '''
     dirstatebackupname = 'dirstate.shelve'
     repo.dirstate.savebackup(tr, dirstatebackupname)
     tr.abort()
     repo.dirstate.restorebackup(None, dirstatebackupname)
 
 def getshelvename(repo, parent, opts):
     """Decide on the name this shelve is going to have"""
     def gennames():
         yield label
         for i in itertools.count(1):
             yield '%s-%02d' % (label, i)
     name = opts.get('name')
     label = repo._activebookmark or parent.branch() or 'default'
     # slashes aren't allowed in filenames, therefore we rename it
     label = label.replace('/', '_')
     label = label.replace('\\', '_')
     # filenames must not start with '.' as it should not be hidden
     if label.startswith('.'):
         label = label.replace('.', '_', 1)
 
     if name:
         if shelvedfile(repo, name, patchextension).exists():
             e = _("a shelved change named '%s' already exists") % name
             raise error.Abort(e)
 
         # ensure we are not creating a subdirectory or a hidden file
         if '/' in name or '\\' in name:
             raise error.Abort(_('shelved change names can not contain slashes'))
         if name.startswith('.'):
             raise error.Abort(_("shelved change names can not start with '.'"))
 
     else:
         for n in gennames():
             if not shelvedfile(repo, n, patchextension).exists():
                 name = n
                 break
 
     return name
 
 def mutableancestors(ctx):
     """return all mutable ancestors for ctx (included)
 
     Much faster than the revset ancestors(ctx) & draft()"""
     seen = {nodemod.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)
 
 def getcommitfunc(extra, interactive, editor=False):
     def commitfunc(ui, repo, message, match, opts):
         hasmq = util.safehasattr(repo, 'mq')
         if hasmq:
             saved, repo.mq.checkapplied = repo.mq.checkapplied, False
 
         targetphase = phases.internal
         if not phases.supportinternal(repo):
             targetphase = phases.secret
         overrides = {('phases', 'new-commit'): targetphase}
         try:
             editor_ = False
             if editor:
                 editor_ = cmdutil.getcommiteditor(editform='shelve.shelve',
                                                   **pycompat.strkwargs(opts))
             with repo.ui.configoverride(overrides):
                 return repo.commit(message, shelveuser, opts.get('date'),
                                    match, editor=editor_, extra=extra)
         finally:
             if hasmq:
                 repo.mq.checkapplied = saved
 
     def interactivecommitfunc(ui, repo, *pats, **opts):
         opts = pycompat.byteskwargs(opts)
         match = scmutil.match(repo['.'], pats, {})
         message = opts['message']
         return commitfunc(ui, repo, message, match, opts)
 
     return interactivecommitfunc if interactive else commitfunc
 
 def _nothingtoshelvemessaging(ui, repo, pats, opts):
     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"))
 
 def _shelvecreatedcommit(repo, node, name, match):
     info = {'node': nodemod.hex(node)}
     shelvedfile(repo, name, 'shelve').writeinfo(info)
     bases = list(mutableancestors(repo[node]))
     shelvedfile(repo, name, 'hg').writebundle(bases, node)
     with shelvedfile(repo, name, patchextension).opener('wb') as fp:
         cmdutil.exportfile(repo, [node], fp, opts=mdiff.diffopts(git=True),
                            match=match)
 
 def _includeunknownfiles(repo, pats, opts, extra):
     s = repo.status(match=scmutil.match(repo[None], pats, opts),
                     unknown=True)
     if s.unknown:
         extra['shelve_unknown'] = '\0'.join(s.unknown)
         repo[None].add(s.unknown)
 
 def _finishshelve(repo, tr):
     if phases.supportinternal(repo):
         tr.close()
     else:
         _aborttransaction(repo, tr)
 
 def createcmd(ui, repo, pats, opts):
     """subcommand that creates a new shelve"""
     with repo.wlock():
         cmdutil.checkunfinished(repo)
         return _docreatecmd(ui, repo, pats, opts)
 
 def _docreatecmd(ui, repo, pats, opts):
     wctx = repo[None]
     parents = wctx.parents()
-    if len(parents) > 1:
-        raise error.Abort(_('cannot shelve while merging'))
     parent = parents[0]
     origbranch = wctx.branch()
 
     if parent.node() != nodemod.nullid:
         desc = "changes to: %s" % parent.description().split('\n', 1)[0]
     else:
         desc = '(changes in empty repository)'
 
     if not opts.get('message'):
         opts['message'] = desc
 
     lock = tr = activebookmark = None
     try:
         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('shelve', report=lambda x: None)
 
         interactive = opts.get('interactive', False)
         includeunknown = (opts.get('unknown', False) and
                           not opts.get('addremove', False))
 
         name = getshelvename(repo, parent, opts)
         activebookmark = _backupactivebookmark(repo)
         extra = {'internal': 'shelve'}
         if includeunknown:
             _includeunknownfiles(repo, pats, opts, extra)
 
         if _iswctxonnewbranch(repo) and not _isbareshelve(pats, opts):
             # In non-bare shelve we don't store newly created branch
             # at bundled commit
             repo.dirstate.setbranch(repo['.'].branch())
 
         commitfunc = getcommitfunc(extra, interactive, editor=True)
         if not interactive:
             node = cmdutil.commit(ui, repo, commitfunc, pats, opts)
         else:
             node = cmdutil.dorecord(ui, repo, commitfunc, None,
                                     False, cmdutil.recordfilter, *pats,
                                     **pycompat.strkwargs(opts))
         if not node:
             _nothingtoshelvemessaging(ui, repo, pats, opts)
             return 1
 
         # Create a matcher so that prefetch doesn't attempt to fetch
         # the entire repository pointlessly, and as an optimisation
         # for movedirstate, if needed.
         match = scmutil.matchfiles(repo, repo[node].files())
         _shelvecreatedcommit(repo, node, name, match)
 
         if ui.formatted():
             desc = stringutil.ellipsis(desc, ui.termwidth())
         ui.status(_('shelved as %s\n') % name)
         if opts['keep']:
             with repo.dirstate.parentchange():
                 scmutil.movedirstate(repo, parent, match)
         else:
             hg.update(repo, parent.node())
         if origbranch != repo['.'].branch() and not _isbareshelve(pats, opts):
             repo.dirstate.setbranch(origbranch)
 
         _finishshelve(repo, tr)
     finally:
         _restoreactivebookmark(repo, activebookmark)
         lockmod.release(tr, lock)
 
 def _isbareshelve(pats, opts):
     return (not pats
             and not opts.get('interactive', False)
             and not opts.get('include', False)
             and not opts.get('exclude', False))
 
 def _iswctxonnewbranch(repo):
     return repo[None].branch() != repo['.'].branch()
 
 def cleanupcmd(ui, repo):
     """subcommand that deletes all shelves"""
 
     with repo.wlock():
         for (name, _type) in repo.vfs.readdir(shelvedir):
             suffix = name.rsplit('.', 1)[-1]
             if suffix in shelvefileextensions:
                 shelvedfile(repo, name).movetobackup()
             cleanupoldbackups(repo)
 
 def deletecmd(ui, repo, pats):
     """subcommand that deletes a specific shelve"""
     if not pats:
         raise error.Abort(_('no shelved changes specified!'))
     with repo.wlock():
         try:
             for name in pats:
                 for suffix in shelvefileextensions:
                     shfile = shelvedfile(repo, name, suffix)
                     # patch file is necessary, as it should
                     # be present for any kind of shelve,
                     # but the .hg file is optional as in future we
                     # will add obsolete shelve with does not create a
                     # bundle
                     if shfile.exists() or suffix == patchextension:
                         shfile.movetobackup()
             cleanupoldbackups(repo)
         except OSError as err:
             if err.errno != errno.ENOENT:
                 raise
             raise error.Abort(_("shelved change '%s' not found") % name)
 
 def listshelves(repo):
     """return all shelves in repo as list of (time, filename)"""
     try:
         names = repo.vfs.readdir(shelvedir)
     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 != patchextension:
             continue
         st = shelvedfile(repo, name).stat()
         info.append((st[stat.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'
     ui.pager('shelve')
     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
         date = dateutil.makedate(mtime)
         age = '(%s)' % templatefilters.age(date, abbrev=True)
         ui.write(age, label='shelve.age')
         ui.write(' ' * (12 - len(age)))
         used += 12
         with open(name + '.' + patchextension, 'rb') as fp:
             while True:
                 line = fp.readline()
                 if not line:
                     break
                 if not line.startswith('#'):
                     desc = line.rstrip()
                     if ui.formatted():
                         desc = stringutil.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):
                     ui.write(chunk, label=label)
 
 def patchcmds(ui, repo, pats, opts):
     """subcommand that displays shelves"""
     if len(pats) == 0:
         shelves = listshelves(repo)
         if not shelves:
             raise error.Abort(_("there are no shelves to show"))
         mtime, name = shelves[0]
         sname = util.split(name)[1]
         pats = [sname]
 
     for shelfname in pats:
         if not shelvedfile(repo, shelfname, patchextension).exists():
             raise error.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 error.Abort(_('working directory parents do not match unshelve '
                            'state'))
 
 def unshelveabort(ui, repo, state, opts):
     """subcommand that abort an in-progress unshelve"""
     with repo.lock():
         try:
             checkparents(repo, state)
 
             merge.update(repo, state.pendingctx, branchmerge=False, force=True)
             if (state.activebookmark
                     and state.activebookmark in repo._bookmarks):
                 bookmarks.activate(repo, state.activebookmark)
 
             if repo.vfs.exists('unshelverebasestate'):
                 repo.vfs.rename('unshelverebasestate', 'rebasestate')
                 rebase.clearstatus(repo)
 
             mergefiles(ui, repo, state.wctx, state.pendingctx)
             if not phases.supportinternal(repo):
                 repair.strip(ui, repo, state.nodestoremove, backup=False,
                              topic='shelve')
         finally:
             shelvedstate.clear(repo)
             ui.warn(_("unshelve of '%s' aborted\n") % state.name)
 
 def mergefiles(ui, repo, wctx, shelvectx):
     """updates to wctx and merges the changes from shelvectx into the
     dirstate."""
     with ui.configoverride({('ui', 'quiet'): True}):
         hg.update(repo, wctx.node())
         ui.pushbuffer(True)
         cmdutil.revert(ui, repo, shelvectx, repo.dirstate.parents())
         ui.popbuffer()
 
 def restorebranch(ui, repo, branchtorestore):
     if branchtorestore and branchtorestore != repo.dirstate.branch():
         repo.dirstate.setbranch(branchtorestore)
         ui.status(_('marked working directory as branch %s\n')
                   % branchtorestore)
 
 def unshelvecleanup(ui, repo, name, opts):
     """remove related files after an unshelve"""
     if not opts.get('keep'):
         for filetype in shelvefileextensions:
             shfile = shelvedfile(repo, name, filetype)
             if shfile.exists():
                 shfile.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.
     with repo.lock():
         checkparents(repo, state)
         ms = merge.mergestate.read(repo)
         if list(ms.unresolved()):
             raise error.Abort(
                 _("unresolved conflicts, can't continue"),
                 hint=_("see 'hg resolve', then 'hg unshelve --continue'"))
 
         shelvectx = repo[state.parents[1]]
         pendingctx = state.pendingctx
 
         with repo.dirstate.parentchange():
             repo.setparents(state.pendingctx.node(), nodemod.nullid)
             repo.dirstate.write(repo.currenttransaction())
 
         targetphase = phases.internal
         if not phases.supportinternal(repo):
             targetphase = phases.secret
         overrides = {('phases', 'new-commit'): targetphase}
         with repo.ui.configoverride(overrides, 'unshelve'):
             with repo.dirstate.parentchange():
                 repo.setparents(state.parents[0], nodemod.nullid)
                 newnode = repo.commit(text=shelvectx.description(),
                                       extra=shelvectx.extra(),
                                       user=shelvectx.user(),
                                       date=shelvectx.date())
 
         if newnode is None:
             # If it ended up being a no-op commit, then the normal
             # merge state clean-up path doesn't happen, so do it
             # here. Fix issue5494
             merge.mergestate.clean(repo)
             shelvectx = state.pendingctx
             msg = _('note: unshelved changes already existed '
                     'in the working copy\n')
             ui.status(msg)
         else:
             # only strip the shelvectx if we produced one
             state.nodestoremove.append(newnode)
             shelvectx = repo[newnode]
 
         hg.updaterepo(repo, pendingctx.node(), overwrite=False)
 
         if repo.vfs.exists('unshelverebasestate'):
             repo.vfs.rename('unshelverebasestate', 'rebasestate')
             rebase.clearstatus(repo)
 
         mergefiles(ui, repo, state.wctx, shelvectx)
         restorebranch(ui, repo, state.branchtorestore)
 
         if not phases.supportinternal(repo):
             repair.strip(ui, repo, state.nodestoremove, backup=False,
                          topic='shelve')
         _restoreactivebookmark(repo, state.activebookmark)
         shelvedstate.clear(repo)
         unshelvecleanup(ui, repo, state.name, opts)
         ui.status(_("unshelve of '%s' complete\n") % state.name)
 
 def _commitworkingcopychanges(ui, repo, opts, tmpwctx):
     """Temporarily commit working copy changes before moving unshelve commit"""
     # Store pending changes in a commit and remember added in case a shelve
     # contains unknown files that are part of the pending change
     s = repo.status()
     addedbefore = frozenset(s.added)
     if not (s.modified or s.added or s.removed):
         return tmpwctx, addedbefore
     ui.status(_("temporarily committing pending changes "
                 "(restore with 'hg unshelve --abort')\n"))
     extra = {'internal': 'shelve'}
     commitfunc = getcommitfunc(extra=extra, interactive=False,
                                editor=False)
     tempopts = {}
     tempopts['message'] = "pending changes temporary commit"
     tempopts['date'] = opts.get('date')
     with ui.configoverride({('ui', 'quiet'): True}):
         node = cmdutil.commit(ui, repo, commitfunc, [], tempopts)
     tmpwctx = repo[node]
     return tmpwctx, addedbefore
 
 def _unshelverestorecommit(ui, repo, tr, basename):
     """Recreate commit in the repository during the unshelve"""
     repo = repo.unfiltered()
     node = None
     if shelvedfile(repo, basename, 'shelve').exists():
         node = shelvedfile(repo, basename, 'shelve').readinfo()['node']
     if node is None or node not in repo:
         with ui.configoverride({('ui', 'quiet'): True}):
             shelvectx = shelvedfile(repo, basename, 'hg').applybundle(tr)
         # We might not strip the unbundled changeset, so we should keep track of
         # the unshelve node in case we need to reuse it (eg: unshelve --keep)
         if node is None:
             info = {'node': nodemod.hex(shelvectx.node())}
             shelvedfile(repo, basename, 'shelve').writeinfo(info)
     else:
         shelvectx = repo[node]
 
     return repo, shelvectx
 
 def _rebaserestoredcommit(ui, repo, opts, tr, oldtiprev, basename, pctx,
                           tmpwctx, shelvectx, branchtorestore,
                           activebookmark):
     """Rebase restored commit from its original location to a destination"""
     # 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.p1().node():
         return shelvectx
 
     overrides = {
         ('ui', 'forcemerge'): opts.get('tool', ''),
         ('phases', 'new-commit'): phases.secret,
     }
     with repo.ui.configoverride(overrides, 'unshelve'):
         ui.status(_('rebasing shelved changes\n'))
         stats = merge.graft(repo, shelvectx, shelvectx.p1(),
                            labels=['shelve', 'working-copy'],
                            keepconflictparent=True)
         if stats.unresolvedcount:
             tr.close()
 
             nodestoremove = [repo.changelog.node(rev)
                              for rev in pycompat.xrange(oldtiprev, len(repo))]
             shelvedstate.save(repo, basename, pctx, tmpwctx, nodestoremove,
                               branchtorestore, opts.get('keep'), activebookmark)
             raise error.InterventionRequired(
                 _("unresolved conflicts (see 'hg resolve', then "
                   "'hg unshelve --continue')"))
 
         with repo.dirstate.parentchange():
             repo.setparents(tmpwctx.node(), nodemod.nullid)
             newnode = repo.commit(text=shelvectx.description(),
                                   extra=shelvectx.extra(),
                                   user=shelvectx.user(),
                                   date=shelvectx.date())
 
         if newnode is None:
             # If it ended up being a no-op commit, then the normal
             # merge state clean-up path doesn't happen, so do it
             # here. Fix issue5494
             merge.mergestate.clean(repo)
             shelvectx = tmpwctx
             msg = _('note: unshelved changes already existed '
                     'in the working copy\n')
             ui.status(msg)
         else:
             shelvectx = repo[newnode]
             hg.updaterepo(repo, tmpwctx.node(), False)
 
     return shelvectx
 
 def _forgetunknownfiles(repo, shelvectx, addedbefore):
     # Forget any files that were unknown before the shelve, unknown before
     # unshelve started, but are now added.
     shelveunknown = shelvectx.extra().get('shelve_unknown')
     if not shelveunknown:
         return
     shelveunknown = frozenset(shelveunknown.split('\0'))
     addedafter = frozenset(repo.status().added)
     toforget = (addedafter & shelveunknown) - addedbefore
     repo[None].forget(toforget)
 
 def _finishunshelve(repo, oldtiprev, tr, activebookmark):
     _restoreactivebookmark(repo, activebookmark)
     # 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)
     _aborttransaction(repo, tr)
 
 def _checkunshelveuntrackedproblems(ui, repo, shelvectx):
     """Check potential problems which may result from working
     copy having untracked changes."""
     wcdeleted = set(repo.status().deleted)
     shelvetouched = set(shelvectx.files())
     intersection = wcdeleted.intersection(shelvetouched)
     if intersection:
         m = _("shelved change touches missing files")
         hint = _("run hg status to see which files are missing")
         raise error.Abort(m, hint=hint)
 
 @command('unshelve',
          [('a', 'abort', None,
            _('abort an incomplete unshelve operation')),
           ('c', 'continue', None,
            _('continue an incomplete unshelve operation')),
           ('k', 'keep', None,
            _('keep shelve after unshelving')),
           ('n', 'name', '',
            _('restore shelved change with given name'), _('NAME')),
           ('t', 'tool', '', _('specify merge tool')),
           ('', 'date', '',
            _('set date for temporary commits (DEPRECATED)'), _('DATE'))],
          _('hg unshelve [[-n] SHELVED]'),
          helpcategory=command.CATEGORY_WORKING_DIRECTORY)
 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.)
 
     If bare shelved change (when no files are specified, without interactive,
     include and exclude option) was done on newly created branch it would
     restore branch information to the working directory.
 
     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.
     """
     with repo.wlock():
         return _dounshelve(ui, repo, *shelved, **opts)
 
 def _dounshelve(ui, repo, *shelved, **opts):
     opts = pycompat.byteskwargs(opts)
     abortf = opts.get('abort')
     continuef = opts.get('continue')
     if not abortf and not continuef:
         cmdutil.checkunfinished(repo)
     shelved = list(shelved)
     if opts.get("name"):
         shelved.append(opts["name"])
 
     if abortf or continuef:
         if abortf and continuef:
             raise error.Abort(_('cannot use both abort and continue'))
         if shelved:
             raise error.Abort(_('cannot combine abort/continue with '
                                'naming a shelved change'))
         if abortf and opts.get('tool', False):
             ui.warn(_('tool option will be ignored\n'))
 
         try:
             state = shelvedstate.load(repo)
             if opts.get('keep') is None:
                 opts['keep'] = state.keep
         except IOError as err:
             if err.errno != errno.ENOENT:
                 raise
             cmdutil.wrongtooltocontinue(repo, _('unshelve'))
         except error.CorruptedState as err:
             ui.debug(pycompat.bytestr(err) + '\n')
             if continuef:
                 msg = _('corrupted shelved state file')
                 hint = _('please run hg unshelve --abort to abort unshelve '
                          'operation')
                 raise error.Abort(msg, hint=hint)
             elif abortf:
                 msg = _('could not read shelved state file, your working copy '
                         'may be in an unexpected state\nplease update to some '
                         'commit\n')
                 ui.warn(msg)
                 shelvedstate.clear(repo)
             return
 
         if abortf:
             return unshelveabort(ui, repo, state, opts)
         elif continuef:
             return unshelvecontinue(ui, repo, state, opts)
     elif len(shelved) > 1:
         raise error.Abort(_('can only unshelve one change at a time'))
-
-    # abort unshelve while merging (issue5123)
-    parents = repo[None].parents()
-    if len(parents) > 1:
-        raise error.Abort(_('cannot unshelve while merging'))
-
     elif not shelved:
         shelved = listshelves(repo)
         if not shelved:
             raise error.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, patchextension).exists():
         raise error.Abort(_("shelved change '%s' not found") % basename)
 
     repo = repo.unfiltered()
     lock = tr = None
     try:
         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.
 
         activebookmark = _backupactivebookmark(repo)
         tmpwctx, addedbefore = _commitworkingcopychanges(ui, repo, opts,
                                                          tmpwctx)
         repo, shelvectx = _unshelverestorecommit(ui, repo, tr, basename)
         _checkunshelveuntrackedproblems(ui, repo, shelvectx)
         branchtorestore = ''
         if shelvectx.branch() != shelvectx.p1().branch():
             branchtorestore = shelvectx.branch()
 
         shelvectx = _rebaserestoredcommit(ui, repo, opts, tr, oldtiprev,
                                           basename, pctx, tmpwctx,
                                           shelvectx, branchtorestore,
                                           activebookmark)
         overrides = {('ui', 'forcemerge'): opts.get('tool', '')}
         with ui.configoverride(overrides, 'unshelve'):
             mergefiles(ui, repo, pctx, shelvectx)
         restorebranch(ui, repo, branchtorestore)
         _forgetunknownfiles(repo, shelvectx, addedbefore)
 
         shelvedstate.clear(repo)
         _finishunshelve(repo, oldtiprev, tr, activebookmark)
         unshelvecleanup(ui, repo, basename, opts)
     finally:
         if tr:
             tr.release()
         lockmod.release(lock)
 
 @command('shelve',
          [('A', 'addremove', None,
            _('mark new/missing files as added/removed before shelving')),
           ('u', 'unknown', None,
            _('store unknown files in the shelve')),
           ('', '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')),
           ('k', 'keep', False,
            _('shelve, but keep changes in the working directory')),
           ('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,
            _('output patches for changes (provide the names of the shelved '
              'changes as positional arguments)')),
           ('i', 'interactive', None,
            _('interactive mode, only works while creating a shelve')),
           ('', 'stat', None,
            _('output diffstat-style summary of changes (provide the names of '
              'the shelved changes as positional arguments)')
            )] + cmdutil.walkopts,
          _('hg shelve [OPTION]... [FILE]...'),
          helpcategory=command.CATEGORY_WORKING_DIRECTORY)
 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.
 
     In bare shelve (when no files are specified, without interactive,
     include and exclude option), shelving remembers information if the
     working directory was on newly created branch, in other words working
     directory was on different branch than its first parent. In this
     situation unshelving restores branch information to the working directory.
 
     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``.
     '''
     opts = pycompat.byteskwargs(opts)
     allowables = [
         ('addremove', {'create'}), # 'create' is pseudo action
         ('unknown', {'create'}),
         ('cleanup', {'cleanup'}),
 #       ('date', {'create'}), # ignored for passing '--date "0 0"' in tests
         ('delete', {'delete'}),
         ('edit', {'create'}),
         ('keep', {'create'}),
         ('list', {'list'}),
         ('message', {'create'}),
         ('name', {'create'}),
         ('patch', {'patch', 'list'}),
         ('stat', {'stat', 'list'}),
     ]
     def checkopt(opt):
         if opts.get(opt):
             for i, allowable in allowables:
                 if opts[i] and opt not in allowable:
                     raise error.Abort(_("options '--%s' and '--%s' may not be "
                                        "used together") % (opt, i))
             return True
     if checkopt('cleanup'):
         if pats:
             raise error.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') or checkopt('stat'):
         return patchcmds(ui, repo, pats, opts)
     else:
         return createcmd(ui, repo, pats, opts)
 
 def extsetup(ui):
     statemod.addunfinished(
         'unshelve', fname=shelvedstate._filename, continueflag=True,
         cmdmsg=_('unshelve already in progress')
     )