Wait for merge status to resolve.

marge/job.py

@@ -190,6 +190,28 @@ def wait_for_ci_to_pass(self, merge_request, commit_sha=None):
 
         raise CannotMerge('CI is taking too long.')
 
+    def wait_for_merge_status_to_resolve(self, merge_request):
+        attempts = 3
+        waiting_time_in_secs = 5
+
+        log.info('Waiting for MR !%s to have merge_status can_be_merged', merge_request.iid)
+        for attempt in range(attempts):
+            merge_request.refetch_info()
+            merge_status = merge_request.merge_status
+
+            if merge_status == 'can_be_merged':
+                log.info('MR !%s can be merged on attempt %d', merge_request.iid, attempt)
+                return
+
+            if merge_status == 'cannot_be_merged':
+                log.info('MR !%s cannot be merged on attempt %d', merge_request.iid, attempt)
+                raise CannotMerge('GitLab believes this MR cannot be merged.')
+
+            if merge_status == 'unchecked':
+                log.info('MR !%s merge status currently unchecked on attempt %d.', merge_request.iid, attempt)
+
+            time.sleep(waiting_time_in_secs)
+
     def unassign_from_mr(self, merge_request):
         log.info('Unassigning from MR !%s', merge_request.iid)
         author_id = merge_request.author_id

marge/merge_request.py

@@ -63,6 +63,10 @@ def title(self):
     def state(self):
         return self.info['state']
 
+    @property
+    def merge_status(self):
+        return self.info['merge_status']
+
     @property
     def rebase_in_progress(self):
         return self.info.get('rebase_in_progress', False)

marge/single_merge_job.py

@@ -77,6 +77,8 @@ def update_merge_request_and_accept(self, approvals):
                 self.wait_for_ci_to_pass(merge_request, actual_sha)
                 time.sleep(2)
 
+            self.wait_for_merge_status_to_resolve(merge_request)
+
             self.ensure_mergeable_mr(merge_request)
 
             try:

tests/gitlab_api_mock.py

@@ -50,6 +50,7 @@ def __init__(self, initial_master_sha='505e', gitlab_url=None, fork=False, merge
             'assignees': [{'id': self.user_id}],
             'approved_by': [],
             'state': 'opened',
+            'merge_status': 'can_be_merged',
             'sha': self.commit_info['id'],
             'source_project_id': 1234,
             'target_project_id': 1234,