Fix a wrong MR status when merge_when_build_succeeds & project.only_allow_merge_if_build_succeeds are true

The issue was that `MergeRequest#mergeable?` returns false when the CI
state is not success and project.only_allow_merge_if_build_succeeds is
true. In this case `Projects::MergeRequestsController#merge` would
return the `:failed` status when enabling `merge_when_build_succeeds`,
thus leading to a weird state and the MR never automatically merged.

The fix is to disable the CI state check in the controller safeguard
that early return the `:failed` status.

Signed-off-by: Rémy Coutable <remy@rymai.me>

1 files changed, 12 insertions, 0 deletions

diff --git a/spec/controllers/projects/merge_requests_controller_spec.rb b/spec/controllers/projects/merge_requests_controller_spec.rb
index 4b408c03703..5e66106122c 100644
--- a/spec/controllers/projects/merge_requests_controller_spec.rb
+++ b/spec/controllers/projects/merge_requests_controller_spec.rb
@@ -264,6 +264,18 @@ describe Projects::MergeRequestsController do
 
           merge_when_build_succeeds
         end
+
+        context 'when project.only_allow_merge_if_build_succeeds? is true' do
+          before do
+            project.update_column(:only_allow_merge_if_build_succeeds, true)
+          end
+
+          it 'returns :merge_when_build_succeeds' do
+            merge_when_build_succeeds
+
+            expect(assigns(:status)).to eq(:merge_when_build_succeeds)
+          end
+        end
       end
     end
   end