pull-requests: add merge check that detects WIP marker in title. This will prevent merges in such case.

Usually WIP in title means unfinished task that needs still some work.

This pattern is present in Gitlab/Github and is already quite common.

rhodecode/model/pull_request.py

@@ -1614,6 +1614,7 @@ class MergeCheck(object):
     PERM_CHECK = 'perm'
     REVIEW_CHECK = 'review'
     MERGE_CHECK = 'merge'
+    WIP_CHECK = 'wip'
 
     def __init__(self):
         self.review_status = None
@@ -1638,6 +1639,15 @@ class MergeCheck(object):
         _ = translator
         merge_check = cls()
 
+        # title has WIP:
+        if pull_request.work_in_progress:
+            log.debug("MergeCheck: cannot merge, title has wip: marker.")
+
+            msg = _('WIP marker in title prevents from accidental merge.')
+            merge_check.push_error('error', msg, cls.WIP_CHECK, pull_request.title)
+            if fail_early:
+                return merge_check
+
         # permissions to merge
         user_allowed_to_merge = PullRequestModel().check_user_merge(
             pull_request, auth_user)