Only delete source branch if it was forced.

marge/merge_request.py

@@ -117,6 +117,10 @@ def approved_by(self):
     def web_url(self):
         return self.info['web_url']
 
+    @property
+    def force_remove_source_branch(self):
+        return self.info['force_remove_source_branch']
+
     def refetch_info(self):
         self._info = self._api.call(GET('/projects/{0.project_id}/merge_requests/{0.iid}'.format(self)))
 

marge/single_merge_job.py

@@ -79,7 +79,7 @@ def update_merge_request_and_accept(self, approvals):
             self.ensure_mergeable_mr(merge_request)
 
             try:
-                merge_request.accept(remove_branch=True, sha=actual_sha)
+                merge_request.accept(remove_branch=merge_request.force_remove_source_branch, sha=actual_sha)
             except gitlab.NotAcceptable as err:
                 new_target_sha = Commit.last_on_branch(self._project.id, merge_request.target_branch, api).id
                 # target_branch has moved under us since we updated, just try again

pylintrc

@@ -30,7 +30,7 @@ max-line-length=110
 [DESIGN]
 max-args=10
 max-attributes=15
-max-public-methods=30
+max-public-methods=35
 
 [REPORTS]
 output-format=parseable

tests/gitlab_api_mock.py

@@ -54,6 +54,7 @@ def __init__(self, initial_master_sha='505e', gitlab_url=None, fork=False, merge
             'source_project_id': 1234,
             'target_project_id': 1234,
             'source_branch': 'useless_new_feature',
+            'force_remove_source_branch': True,
             'target_branch': 'master',
             'work_in_progress': False,
             'web_url': 'http://git.example.com/group/project/merge_request/666',

tests/test_merge_request.py

@@ -19,6 +19,7 @@
     'source_project_id': 5678,
     'target_project_id': 1234,
     'source_branch': 'useless_new_feature',
+    'force_remove_source_branch': True,
     'target_branch': 'master',
     'work_in_progress': False,
 }