--- a/sat/plugins/plugin_merge_req_mercurial.py	Tue Jan 22 18:52:16 2019 +0100
+++ b/sat/plugins/plugin_merge_req_mercurial.py	Fri Jan 25 09:06:29 2019 +0100
@@ -17,13 +17,13 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import re
+from twisted.python.procutils import which
+from sat.tools.common import async_process
+from sat.tools import utils
 from sat.core.i18n import _, D_
 from sat.core.constants import Const as C
 from sat.core import exceptions
-from twisted.internet import reactor, defer, protocol
-from twisted.python.failure import Failure
-from twisted.python.procutils import which
-import re
 from sat.core.log import getLogger
 log = getLogger(__name__)
 
@@ -42,66 +42,25 @@
 CLEAN_RE = re.compile(ur'[^\w -._]', flags=re.UNICODE)
 
 
-class MercurialProtocol(protocol.ProcessProtocol):
+class MercurialProtocol(async_process.CommandProtocol):
     """handle hg commands"""
-    hg = None
-
-    def __init__(self, deferred, stdin=None):
-        """
-        @param deferred(defer.Deferred): will be called when command is completed
-        @param stdin(str, None): if not None, will be push to standard input
-        """
-        self._stdin = stdin
-        self._deferred = deferred
-        self.data = []
-
-    def connectionMade(self):
-        if self._stdin is not None:
-            self.transport.write(self._stdin)
-            self.transport.closeStdin()
-
-    def outReceived(self, data):
-        self.data.append(data)
-
-    def errReceived(self, data):
-        self.data.append(data)
-
-    def processEnded(self, reason):
-        data = u''.join([d.decode('utf-8') for d in self.data])
-        if (reason.value.exitCode == 0):
-            log.debug(_('Mercurial command succeed'))
-            self._deferred.callback(data)
-        else:
-            msg = (_(u"Can't complete Mercurial command (error code: {code}): {message}")
-                   .format(code = reason.value.exitCode, message = data))
-            log.warning(msg)
-            self._deferred.errback(Failure(RuntimeError(msg)))
+    name = u"Mercurial"
+    command = None
 
     @classmethod
     def run(cls, path, command, *args, **kwargs):
         """Create a new MercurialRegisterProtocol and execute the given mercurial command.
 
         @param path(unicode): path to the repository
-        @param command(unicode): command to run
-        @param *args(unicode): command arguments
-        @param **kwargs: used because Python2 doesn't handle normal kw args after *args
-            can only be:
-            - stdin(unicode, None): data to push to standard input
-        @return ((D)):
+        @param command(unicode): hg command to run
         """
-        stdin = kwargs.pop('stdin', None)
-        if kwargs:
-            raise exceptions.InternalError(u'only stdin is allowed as keyword argument')
-        if stdin is not None:
-            stdin = stdin.encode('utf-8')
-        d = defer.Deferred()
-        mercurial_prot = MercurialProtocol(d, stdin=stdin)
-        cmd_args = [cls.hg, command.encode('utf-8')]
-        cmd_args.extend([a.encode('utf-8') for a in args])
-        reactor.spawnProcess(mercurial_prot,
-                             cls.hg,
-                             cmd_args,
-                             path=path.encode('utf-8'))
+        assert u"path" not in kwargs
+        kwargs["path"] = path
+        # FIXME: we have to use this workaround because Twisted's protocol.ProcessProtocol
+        #        is not using new style classes. This can be removed once moved to
+        #        Python 3 (super can be used normally then).
+        d = async_process.CommandProtocol.run.__func__(cls, command, *args, **kwargs)
+        d.addErrback(utils.logError)
         return d
 
 
@@ -111,7 +70,7 @@
     def __init__(self, host):
         log.info(_(u"Mercurial merge request handler initialization"))
         try:
-            MercurialProtocol.hg = which('hg')[0]
+            MercurialProtocol.command = which('hg')[0]
         except IndexError:
             raise exceptions.NotFound(_(u"Mercurial executable (hg) not found, "
                                         u"can't use Mercurial handler"))
@@ -119,6 +78,7 @@
         self._m = host.plugins['MERGE_REQUESTS']
         self._m.register('mercurial', self, self.data_types, SHORT_DESC)
 
+
     def check(self, repository):
         d = MercurialProtocol.run(repository, 'identify')
         d.addCallback(lambda __: True)