hg: expose merge_state command to show conflicting files.

vcsserver/hg.py

@@ -1,829 +1,842 b''
 # RhodeCode VCSServer provides access to different vcs backends via network.
 # Copyright (C) 2014-2019 RhodeCode GmbH
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
 
 import io
 import logging
 import stat
 import urllib
 import urllib2
 import traceback
 
 from hgext import largefiles, rebase
 from hgext.strip import strip as hgext_strip
 from mercurial import commands
 from mercurial import unionrepo
 from mercurial import verify
 
 import vcsserver
 from vcsserver import exceptions
 from vcsserver.base import RepoFactory, obfuscate_qs, raise_from_original
 from vcsserver.hgcompat import (
     archival, bin, clone, config as hgconfig, diffopts, hex, get_ctx,
     hg_url as url_parser, httpbasicauthhandler, httpdigestauthhandler,
     makepeer, instance, match, memctx, exchange, memfilectx, nullrev, hg_merge,
     patch, peer, revrange, ui, hg_tag, Abort, LookupError, RepoError,
     RepoLookupError, InterventionRequired, RequirementError)
 
 log = logging.getLogger(__name__)
 
 
 def make_ui_from_config(repo_config):
 
     class LoggingUI(ui.ui):
         def status(self, *msg, **opts):
             log.info(' '.join(msg).rstrip('\n'))
             super(LoggingUI, self).status(*msg, **opts)
 
         def warn(self, *msg, **opts):
             log.warn(' '.join(msg).rstrip('\n'))
             super(LoggingUI, self).warn(*msg, **opts)
 
         def error(self, *msg, **opts):
             log.error(' '.join(msg).rstrip('\n'))
             super(LoggingUI, self).error(*msg, **opts)
 
         def note(self, *msg, **opts):
             log.info(' '.join(msg).rstrip('\n'))
             super(LoggingUI, self).note(*msg, **opts)
 
         def debug(self, *msg, **opts):
             log.debug(' '.join(msg).rstrip('\n'))
             super(LoggingUI, self).debug(*msg, **opts)
 
     baseui = LoggingUI()
 
     # clean the baseui object
     baseui._ocfg = hgconfig.config()
     baseui._ucfg = hgconfig.config()
     baseui._tcfg = hgconfig.config()
 
     for section, option, value in repo_config:
         baseui.setconfig(section, option, value)
 
     # make our hgweb quiet so it doesn't print output
     baseui.setconfig('ui', 'quiet', 'true')
 
     baseui.setconfig('ui', 'paginate', 'never')
     # for better Error reporting of Mercurial
     baseui.setconfig('ui', 'message-output', 'stderr')
 
     # force mercurial to only use 1 thread, otherwise it may try to set a
     # signal in a non-main thread, thus generating a ValueError.
     baseui.setconfig('worker', 'numcpus', 1)
 
     # If there is no config for the largefiles extension, we explicitly disable
     # it here. This overrides settings from repositories hgrc file. Recent
     # mercurial versions enable largefiles in hgrc on clone from largefile
     # repo.
     if not baseui.hasconfig('extensions', 'largefiles'):
         log.debug('Explicitly disable largefiles extension for repo.')
         baseui.setconfig('extensions', 'largefiles', '!')
 
     return baseui
 
 
 def reraise_safe_exceptions(func):
     """Decorator for converting mercurial exceptions to something neutral."""
     def wrapper(*args, **kwargs):
         try:
             return func(*args, **kwargs)
         except (Abort, InterventionRequired) as e:
             raise_from_original(exceptions.AbortException(e))
         except RepoLookupError as e:
             raise_from_original(exceptions.LookupException(e))
         except RequirementError as e:
             raise_from_original(exceptions.RequirementException(e))
         except RepoError as e:
             raise_from_original(exceptions.VcsException(e))
         except LookupError as e:
             raise_from_original(exceptions.LookupException(e))
         except Exception as e:
             if not hasattr(e, '_vcs_kind'):
                 log.exception("Unhandled exception in hg remote call")
                 raise_from_original(exceptions.UnhandledException(e))
 
             raise
     return wrapper
 
 
 class MercurialFactory(RepoFactory):
     repo_type = 'hg'
 
     def _create_config(self, config, hooks=True):
         if not hooks:
             hooks_to_clean = frozenset((
                 'changegroup.repo_size', 'preoutgoing.pre_pull',
                 'outgoing.pull_logger', 'prechangegroup.pre_push'))
             new_config = []
             for section, option, value in config:
                 if section == 'hooks' and option in hooks_to_clean:
                     continue
                 new_config.append((section, option, value))
             config = new_config
 
         baseui = make_ui_from_config(config)
         return baseui
 
     def _create_repo(self, wire, create):
         baseui = self._create_config(wire["config"])
         return instance(baseui, wire["path"], create)
 
 
 class HgRemote(object):
 
     def __init__(self, factory):
         self._factory = factory
 
         self._bulk_methods = {
             "affected_files": self.ctx_files,
             "author": self.ctx_user,
             "branch": self.ctx_branch,
             "children": self.ctx_children,
             "date": self.ctx_date,
             "message": self.ctx_description,
             "parents": self.ctx_parents,
             "status": self.ctx_status,
             "obsolete": self.ctx_obsolete,
             "phase": self.ctx_phase,
             "hidden": self.ctx_hidden,
             "_file_paths": self.ctx_list,
         }
 
     def _get_ctx(self, repo, ref):
         return get_ctx(repo, ref)
 
     @reraise_safe_exceptions
     def discover_hg_version(self):
         from mercurial import util
         return util.version()
 
     @reraise_safe_exceptions
     def archive_repo(self, archive_path, mtime, file_info, kind):
         if kind == "tgz":
             archiver = archival.tarit(archive_path, mtime, "gz")
         elif kind == "tbz2":
             archiver = archival.tarit(archive_path, mtime, "bz2")
         elif kind == 'zip':
             archiver = archival.zipit(archive_path, mtime)
         else:
             raise exceptions.ArchiveException()(
                 'Remote does not support: "%s".' % kind)
 
         for f_path, f_mode, f_is_link, f_content in file_info:
             archiver.addfile(f_path, f_mode, f_is_link, f_content)
         archiver.done()
 
     @reraise_safe_exceptions
     def bookmarks(self, wire):
         repo = self._factory.repo(wire)
         return dict(repo._bookmarks)
 
     @reraise_safe_exceptions
     def branches(self, wire, normal, closed):
         repo = self._factory.repo(wire)
         iter_branches = repo.branchmap().iterbranches()
         bt = {}
         for branch_name, _heads, tip, is_closed in iter_branches:
             if normal and not is_closed:
                 bt[branch_name] = tip
             if closed and is_closed:
                 bt[branch_name] = tip
 
         return bt
 
     @reraise_safe_exceptions
     def bulk_request(self, wire, rev, pre_load):
         result = {}
         for attr in pre_load:
             try:
                 method = self._bulk_methods[attr]
                 result[attr] = method(wire, rev)
             except KeyError as e:
                 raise exceptions.VcsException(e)(
                     'Unknown bulk attribute: "%s"' % attr)
         return result
 
     @reraise_safe_exceptions
     def clone(self, wire, source, dest, update_after_clone=False, hooks=True):
         baseui = self._factory._create_config(wire["config"], hooks=hooks)
         clone(baseui, source, dest, noupdate=not update_after_clone)
 
     @reraise_safe_exceptions
     def commitctx(
             self, wire, message, parents, commit_time, commit_timezone,
             user, files, extra, removed, updated):
 
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         publishing = baseui.configbool('phases', 'publish')
         if publishing:
             new_commit = 'public'
         else:
             new_commit = 'draft'
 
         def _filectxfn(_repo, ctx, path):
             """
             Marks given path as added/changed/removed in a given _repo. This is
             for internal mercurial commit function.
             """
 
             # check if this path is removed
             if path in removed:
                 # returning None is a way to mark node for removal
                 return None
 
             # check if this path is added
             for node in updated:
                 if node['path'] == path:
                     return memfilectx(
                         _repo,
                         changectx=ctx,
                         path=node['path'],
                         data=node['content'],
                         islink=False,
                         isexec=bool(node['mode'] & stat.S_IXUSR),
                         copied=False)
 
             raise exceptions.AbortException()(
                 "Given path haven't been marked as added, "
                 "changed or removed (%s)" % path)
 
         with repo.ui.configoverride({('phases', 'new-commit'): new_commit}):
 
             commit_ctx = memctx(
                 repo=repo,
                 parents=parents,
                 text=message,
                 files=files,
                 filectxfn=_filectxfn,
                 user=user,
                 date=(commit_time, commit_timezone),
                 extra=extra)
 
             n = repo.commitctx(commit_ctx)
             new_id = hex(n)
 
             return new_id
 
     @reraise_safe_exceptions
     def ctx_branch(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         return ctx.branch()
 
     @reraise_safe_exceptions
     def ctx_children(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         return [child.rev() for child in ctx.children()]
 
     @reraise_safe_exceptions
     def ctx_date(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         return ctx.date()
 
     @reraise_safe_exceptions
     def ctx_description(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         return ctx.description()
 
     @reraise_safe_exceptions
     def ctx_files(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         return ctx.files()
 
     @reraise_safe_exceptions
     def ctx_list(self, path, revision):
         repo = self._factory.repo(path)
         ctx = self._get_ctx(repo, revision)
         return list(ctx)
 
     @reraise_safe_exceptions
     def ctx_parents(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         return [parent.rev() for parent in ctx.parents()]
 
     @reraise_safe_exceptions
     def ctx_phase(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         # public=0, draft=1, secret=3
         return ctx.phase()
 
     @reraise_safe_exceptions
     def ctx_obsolete(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         return ctx.obsolete()
 
     @reraise_safe_exceptions
     def ctx_hidden(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         return ctx.hidden()
 
     @reraise_safe_exceptions
     def ctx_substate(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         return ctx.substate
 
     @reraise_safe_exceptions
     def ctx_status(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         status = repo[ctx.p1().node()].status(other=ctx.node())
         # object of status (odd, custom named tuple in mercurial) is not
         # correctly serializable, we make it a list, as the underling
         # API expects this to be a list
         return list(status)
 
     @reraise_safe_exceptions
     def ctx_user(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         return ctx.user()
 
     @reraise_safe_exceptions
     def check_url(self, url, config):
         _proto = None
         if '+' in url[:url.find('://')]:
             _proto = url[0:url.find('+')]
             url = url[url.find('+') + 1:]
         handlers = []
         url_obj = url_parser(url)
         test_uri, authinfo = url_obj.authinfo()
         url_obj.passwd = '*****' if url_obj.passwd else url_obj.passwd
         url_obj.query = obfuscate_qs(url_obj.query)
 
         cleaned_uri = str(url_obj)
         log.info("Checking URL for remote cloning/import: %s", cleaned_uri)
 
         if authinfo:
             # create a password manager
             passmgr = urllib2.HTTPPasswordMgrWithDefaultRealm()
             passmgr.add_password(*authinfo)
 
             handlers.extend((httpbasicauthhandler(passmgr),
                              httpdigestauthhandler(passmgr)))
 
         o = urllib2.build_opener(*handlers)
         o.addheaders = [('Content-Type', 'application/mercurial-0.1'),
                         ('Accept', 'application/mercurial-0.1')]
 
         q = {"cmd": 'between'}
         q.update({'pairs': "%s-%s" % ('0' * 40, '0' * 40)})
         qs = '?%s' % urllib.urlencode(q)
         cu = "%s%s" % (test_uri, qs)
         req = urllib2.Request(cu, None, {})
 
         try:
             log.debug("Trying to open URL %s", cleaned_uri)
             resp = o.open(req)
             if resp.code != 200:
                 raise exceptions.URLError()('Return Code is not 200')
         except Exception as e:
             log.warning("URL cannot be opened: %s", cleaned_uri, exc_info=True)
             # means it cannot be cloned
             raise exceptions.URLError(e)("[%s] org_exc: %s" % (cleaned_uri, e))
 
         # now check if it's a proper hg repo, but don't do it for svn
         try:
             if _proto == 'svn':
                 pass
             else:
                 # check for pure hg repos
                 log.debug(
                     "Verifying if URL is a Mercurial repository: %s",
                     cleaned_uri)
                 ui = make_ui_from_config(config)
                 peer_checker = makepeer(ui, url)
                 peer_checker.lookup('tip')
         except Exception as e:
             log.warning("URL is not a valid Mercurial repository: %s",
                         cleaned_uri)
             raise exceptions.URLError(e)(
                 "url [%s] does not look like an hg repo org_exc: %s"
                 % (cleaned_uri, e))
 
         log.info("URL is a valid Mercurial repository: %s", cleaned_uri)
         return True
 
     @reraise_safe_exceptions
     def diff(
             self, wire, rev1, rev2, file_filter, opt_git, opt_ignorews,
             context):
         repo = self._factory.repo(wire)
 
         if file_filter:
             match_filter = match(file_filter[0], '', [file_filter[1]])
         else:
             match_filter = file_filter
         opts = diffopts(git=opt_git, ignorews=opt_ignorews, context=context)
 
         try:
             return "".join(patch.diff(
                 repo, node1=rev1, node2=rev2, match=match_filter, opts=opts))
         except RepoLookupError as e:
             raise exceptions.LookupException(e)()
 
     @reraise_safe_exceptions
     def node_history(self, wire, revision, path, limit):
         repo = self._factory.repo(wire)
 
         ctx = self._get_ctx(repo, revision)
         fctx = ctx.filectx(path)
 
         def history_iter():
             limit_rev = fctx.rev()
             for obj in reversed(list(fctx.filelog())):
                 obj = fctx.filectx(obj)
                 if limit_rev >= obj.rev():
                     yield obj
 
         history = []
         for cnt, obj in enumerate(history_iter()):
             if limit and cnt >= limit:
                 break
             history.append(hex(obj.node()))
 
         return [x for x in history]
 
     @reraise_safe_exceptions
     def node_history_untill(self, wire, revision, path, limit):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         fctx = ctx.filectx(path)
 
         file_log = list(fctx.filelog())
         if limit:
             # Limit to the last n items
             file_log = file_log[-limit:]
 
         return [hex(fctx.filectx(cs).node()) for cs in reversed(file_log)]
 
     @reraise_safe_exceptions
     def fctx_annotate(self, wire, revision, path):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         fctx = ctx.filectx(path)
 
         result = []
         for i, annotate_obj in enumerate(fctx.annotate(), 1):
             ln_no = i
             sha = hex(annotate_obj.fctx.node())
             content = annotate_obj.text
             result.append((ln_no, sha, content))
         return result
 
     @reraise_safe_exceptions
     def fctx_data(self, wire, revision, path):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         fctx = ctx.filectx(path)
         return fctx.data()
 
     @reraise_safe_exceptions
     def fctx_flags(self, wire, revision, path):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         fctx = ctx.filectx(path)
         return fctx.flags()
 
     @reraise_safe_exceptions
     def fctx_size(self, wire, revision, path):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         fctx = ctx.filectx(path)
         return fctx.size()
 
     @reraise_safe_exceptions
     def get_all_commit_ids(self, wire, name):
         repo = self._factory.repo(wire)
         repo = repo.filtered(name)
         revs = map(lambda x: hex(x[7]), repo.changelog.index)
         return revs
 
     @reraise_safe_exceptions
     def get_config_value(self, wire, section, name, untrusted=False):
         repo = self._factory.repo(wire)
         return repo.ui.config(section, name, untrusted=untrusted)
 
     @reraise_safe_exceptions
     def get_config_bool(self, wire, section, name, untrusted=False):
         repo = self._factory.repo(wire)
         return repo.ui.configbool(section, name, untrusted=untrusted)
 
     @reraise_safe_exceptions
     def get_config_list(self, wire, section, name, untrusted=False):
         repo = self._factory.repo(wire)
         return repo.ui.configlist(section, name, untrusted=untrusted)
 
     @reraise_safe_exceptions
     def is_large_file(self, wire, path):
         return largefiles.lfutil.isstandin(path)
 
     @reraise_safe_exceptions
     def in_largefiles_store(self, wire, sha):
         repo = self._factory.repo(wire)
         return largefiles.lfutil.instore(repo, sha)
 
     @reraise_safe_exceptions
     def in_user_cache(self, wire, sha):
         repo = self._factory.repo(wire)
         return largefiles.lfutil.inusercache(repo.ui, sha)
 
     @reraise_safe_exceptions
     def store_path(self, wire, sha):
         repo = self._factory.repo(wire)
         return largefiles.lfutil.storepath(repo, sha)
 
     @reraise_safe_exceptions
     def link(self, wire, sha, path):
         repo = self._factory.repo(wire)
         largefiles.lfutil.link(
             largefiles.lfutil.usercachepath(repo.ui, sha), path)
 
     @reraise_safe_exceptions
     def localrepository(self, wire, create=False):
         self._factory.repo(wire, create=create)
 
     @reraise_safe_exceptions
     def lookup(self, wire, revision, both):
 
         repo = self._factory.repo(wire)
 
         if isinstance(revision, int):
             # NOTE(marcink):
             # since Mercurial doesn't support negative indexes properly
             # we need to shift accordingly by one to get proper index, e.g
             # repo[-1] => repo[-2]
             # repo[0]  => repo[-1]
             if revision <= 0:
                 revision = revision + -1
         try:
             ctx = self._get_ctx(repo, revision)
         except (TypeError, RepoLookupError) as e:
             e._org_exc_tb = traceback.format_exc()
             raise exceptions.LookupException(e)(revision)
         except LookupError as e:
             e._org_exc_tb = traceback.format_exc()
             raise exceptions.LookupException(e)(e.name)
 
         if not both:
             return ctx.hex()
 
         ctx = repo[ctx.hex()]
         return ctx.hex(), ctx.rev()
 
     @reraise_safe_exceptions
     def pull(self, wire, url, commit_ids=None):
         repo = self._factory.repo(wire)
         # Disable any prompts for this repo
         repo.ui.setconfig('ui', 'interactive', 'off', '-y')
 
         remote = peer(repo, {}, url)
         # Disable any prompts for this remote
         remote.ui.setconfig('ui', 'interactive', 'off', '-y')
 
         if commit_ids:
             commit_ids = [bin(commit_id) for commit_id in commit_ids]
 
         return exchange.pull(
             repo, remote, heads=commit_ids, force=None).cgresult
 
     @reraise_safe_exceptions
     def sync_push(self, wire, url):
         if not self.check_url(url, wire['config']):
             return
 
         repo = self._factory.repo(wire)
 
         # Disable any prompts for this repo
         repo.ui.setconfig('ui', 'interactive', 'off', '-y')
 
         bookmarks = dict(repo._bookmarks).keys()
         remote = peer(repo, {}, url)
         # Disable any prompts for this remote
         remote.ui.setconfig('ui', 'interactive', 'off', '-y')
 
         return exchange.push(
             repo, remote, newbranch=True, bookmarks=bookmarks).cgresult
 
     @reraise_safe_exceptions
     def revision(self, wire, rev):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, rev)
         return ctx.rev()
 
     @reraise_safe_exceptions
     def rev_range(self, wire, filter):
         repo = self._factory.repo(wire)
         revisions = [rev for rev in revrange(repo, filter)]
         return revisions
 
     @reraise_safe_exceptions
     def rev_range_hash(self, wire, node):
         repo = self._factory.repo(wire)
 
         def get_revs(repo, rev_opt):
             if rev_opt:
                 revs = revrange(repo, rev_opt)
                 if len(revs) == 0:
                     return (nullrev, nullrev)
                 return max(revs), min(revs)
             else:
                 return len(repo) - 1, 0
 
         stop, start = get_revs(repo, [node + ':'])
         revs = [hex(repo[r].node()) for r in xrange(start, stop + 1)]
         return revs
 
     @reraise_safe_exceptions
     def revs_from_revspec(self, wire, rev_spec, *args, **kwargs):
         other_path = kwargs.pop('other_path', None)
 
         # case when we want to compare two independent repositories
         if other_path and other_path != wire["path"]:
             baseui = self._factory._create_config(wire["config"])
             repo = unionrepo.makeunionrepository(baseui, other_path, wire["path"])
         else:
             repo = self._factory.repo(wire)
         return list(repo.revs(rev_spec, *args))
 
     @reraise_safe_exceptions
     def strip(self, wire, revision, update, backup):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         hgext_strip(
             repo.baseui, repo, ctx.node(), update=update, backup=backup)
 
     @reraise_safe_exceptions
     def verify(self, wire,):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         baseui.setconfig('ui', 'quiet', 'false')
         output = io.BytesIO()
 
         def write(data, **unused_kwargs):
             output.write(data)
         baseui.write = write
 
         repo.ui = baseui
         verify.verify(repo)
         return output.getvalue()
 
     @reraise_safe_exceptions
     def tag(self, wire, name, revision, message, local, user,
             tag_time, tag_timezone):
         repo = self._factory.repo(wire)
         ctx = self._get_ctx(repo, revision)
         node = ctx.node()
 
         date = (tag_time, tag_timezone)
         try:
             hg_tag.tag(repo, name, node, message, local, user, date)
         except Abort as e:
             log.exception("Tag operation aborted")
             # Exception can contain unicode which we convert
             raise exceptions.AbortException(e)(repr(e))
 
     @reraise_safe_exceptions
     def tags(self, wire):
         repo = self._factory.repo(wire)
         return repo.tags()
 
     @reraise_safe_exceptions
     def update(self, wire, node=None, clean=False):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         commands.update(baseui, repo, node=node, clean=clean)
 
     @reraise_safe_exceptions
     def identify(self, wire):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         output = io.BytesIO()
         baseui.write = output.write
         # This is required to get a full node id
         baseui.debugflag = True
         commands.identify(baseui, repo, id=True)
 
         return output.getvalue()
 
     @reraise_safe_exceptions
     def pull_cmd(self, wire, source, bookmark=None, branch=None, revision=None,
                  hooks=True):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'], hooks=hooks)
 
         # Mercurial internally has a lot of logic that checks ONLY if
         # option is defined, we just pass those if they are defined then
         opts = {}
         if bookmark:
             opts['bookmark'] = bookmark
         if branch:
             opts['branch'] = branch
         if revision:
             opts['rev'] = revision
 
         commands.pull(baseui, repo, source, **opts)
 
     @reraise_safe_exceptions
     def heads(self, wire, branch=None):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         output = io.BytesIO()
 
         def write(data, **unused_kwargs):
             output.write(data)
 
         baseui.write = write
         if branch:
             args = [branch]
         else:
             args = []
         commands.heads(baseui, repo, template='{node} ', *args)
 
         return output.getvalue()
 
     @reraise_safe_exceptions
     def ancestor(self, wire, revision1, revision2):
         repo = self._factory.repo(wire)
         changelog = repo.changelog
         lookup = repo.lookup
         a = changelog.ancestor(lookup(revision1), lookup(revision2))
         return hex(a)
 
     @reraise_safe_exceptions
     def push(self, wire, revisions, dest_path, hooks=True,
              push_branches=False):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'], hooks=hooks)
         commands.push(baseui, repo, dest=dest_path, rev=revisions,
                       new_branch=push_branches)
 
     @reraise_safe_exceptions
     def merge(self, wire, revision):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         repo.ui.setconfig('ui', 'merge', 'internal:dump')
 
         # In case of sub repositories are used mercurial prompts the user in
         # case of merge conflicts or different sub repository sources. By
         # setting the interactive flag to `False` mercurial doesn't prompt the
         # used but instead uses a default value.
         repo.ui.setconfig('ui', 'interactive', False)
+        commands.merge(baseui, repo, rev=revision)
 
-        commands.merge(baseui, repo, rev=revision)
+    @reraise_safe_exceptions
+    def merge_state(self, wire):
+        repo = self._factory.repo(wire)
+        repo.ui.setconfig('ui', 'merge', 'internal:dump')
+
+        # In case of sub repositories are used mercurial prompts the user in
+        # case of merge conflicts or different sub repository sources. By
+        # setting the interactive flag to `False` mercurial doesn't prompt the
+        # used but instead uses a default value.
+        repo.ui.setconfig('ui', 'interactive', False)
+        ms = hg_merge.mergestate(repo)
+        return [x for x in ms.unresolved()]
 
     @reraise_safe_exceptions
     def commit(self, wire, message, username, close_branch=False):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         repo.ui.setconfig('ui', 'username', username)
         commands.commit(baseui, repo, message=message, close_branch=close_branch)
 
+
     @reraise_safe_exceptions
     def rebase(self, wire, source=None, dest=None, abort=False):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         repo.ui.setconfig('ui', 'merge', 'internal:dump')
         rebase.rebase(
             baseui, repo, base=source, dest=dest, abort=abort, keep=not abort)
 
     @reraise_safe_exceptions
     def bookmark(self, wire, bookmark, revision=None):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         commands.bookmark(baseui, repo, bookmark, rev=revision, force=True)
 
     @reraise_safe_exceptions
     def install_hooks(self, wire, force=False):
         # we don't need any special hooks for Mercurial
         pass
 
     @reraise_safe_exceptions
     def get_hooks_info(self, wire):
         return {
             'pre_version': vcsserver.__version__,
             'post_version': vcsserver.__version__,
         }