*** a/buildbot/steps/source/mtn.py.orig	2015-04-16 22:27:34.336585869 +0200
--- b/buildbot/steps/source/mtn.py	2015-04-17 14:33:35.539813501 +0200
***************
*** 319,325 ****
          return d
  
      def _checkDb(self):
!         d = self._dovccmd(['mtn', 'db', 'info', '--db', self.database], collectStdout=True)
  
          def checkInfo(stdout):
              if stdout.find("does not exist") > 0:
--- 319,327 ----
          return d
  
      def _checkDb(self):
!         d = self._dovccmd(['mtn', 'db', 'info', '--db', self.database],
!                           collectStdout=True,
!                           abandonOnFailure=False)
  
          def checkInfo(stdout):
              if stdout.find("does not exist") > 0:
***************
*** 337,352 ****
          d.addCallback(checkInfo)
          return d
  
      def _sourcedirIsUpdatable(self):
!         d = self.pathExists(self.build.path_module.join(self.workdir, '_MTN'))
  
!         def cont(res):
!             if res:
!                 d.addCallback(lambda _: self.pathExists('db.mtn'))
!             else:
!                 return False
!         d.addCallback(cont)
!         return d
  
      def finish(self, res):
          d = defer.succeed(res)
--- 339,358 ----
          d.addCallback(checkInfo)
          return d
  
+     @defer.inlineCallbacks
      def _sourcedirIsUpdatable(self):
!         workdir_path = self.build.path_module.join(self.workdir, '_MTN')
!         workdir_exists = yield self.pathExists(workdir_path)
  
!         db_path = self.build.path_module.join(self.workdir, self.database)
!         db_exists = yield self.pathExists(db_path)
! 
!         if not db_exists:
!             log.msg("Database does not exist, fallback to a fresh clone")
!         if not workdir_exists:
!             log.msg("Workdir does not exist, fallback to a fresh clone")
! 
!         defer.returnValue(db_exists and workdir_exists)
  
      def finish(self, res):
          d = defer.succeed(res)