settings: Read 'rebase-merge' config option and pass it to the VCS insntacen on merge.

rhodecode/model/pull_request.py

@@ -425,6 +425,7 b' class PullRequestModel(BaseModel):'
         workspace_id = self._workspace_id(pull_request)
         protocol = rhodecode.CONFIG.get('vcs.hooks.protocol')
         use_direct_calls = rhodecode.CONFIG.get('vcs.hooks.direct_calls')
+        use_rebase = self._use_rebase_for_merging(pull_request)
 
         callback_daemon, extras = prepare_callback_daemon(
             extras, protocol=protocol, use_direct_calls=use_direct_calls)
@@ -437,7 +438,7 b' class PullRequestModel(BaseModel):'
             merge_state = target_vcs.merge(
                 target_ref, source_vcs, pull_request.source_ref_parts,
                 workspace_id, user_name=user.username,
-                user_email=user.email, message=message)
+                user_email=user.email, message=message, use_rebase=use_rebase)
         return merge_state
 
     def _comment_and_close_pr(self, pull_request, user, merge_state):
@@ -955,9 +956,10 b' class PullRequestModel(BaseModel):'
     def _refresh_merge_state(self, pull_request, target_vcs, target_reference):
         workspace_id = self._workspace_id(pull_request)
         source_vcs = pull_request.source_repo.scm_instance()
+        use_rebase = self._use_rebase_for_merging(pull_request)
         merge_state = target_vcs.merge(
             target_reference, source_vcs, pull_request.source_ref_parts,
-            workspace_id, dry_run=True)
+            workspace_id, dry_run=True, use_rebase=use_rebase)
 
         # Do not store the response if there was an unknown error.
         if merge_state.failure_reason != MergeFailureReason.UNKNOWN:
@@ -1126,6 +1128,11 b' class PullRequestModel(BaseModel):'
         settings = settings_model.get_general_settings()
         return settings.get('rhodecode_pr_merge_enabled', False)
 
+    def _use_rebase_for_merging(self, pull_request):
+        settings_model = VcsSettingsModel(repo=pull_request.target_repo)
+        settings = settings_model.get_general_settings()
+        return settings.get('rhodecode_hg_use_rebase_for_merging', False)
+
     def _log_action(self, action, user, pull_request):
         action_logger(
             user,