1 files changed, 45 insertions, 0 deletions
diff --git a/app/services/merge_requests/merge_when_pipeline_succeeds_service.rb b/app/services/merge_requests/merge_when_pipeline_succeeds_service.rb
new file mode 100644
index 00000000000..5616edf8b4a
--- /dev/null
+++ b/app/services/merge_requests/merge_when_pipeline_succeeds_service.rb
@@ -0,0 +1,45 @@
+module MergeRequests
+  class MergeWhenPipelineSucceedsService < MergeRequests::BaseService
+    # Marks the passed `merge_request` to be merged when the build succeeds or
+    # updates the params for the automatic merge
+    def execute(merge_request)
+      merge_request.merge_params.merge!(params)
+
+      # The service is also called when the merge params are updated.
+      already_approved = merge_request.merge_when_build_succeeds?
+
+      unless already_approved
+        merge_request.merge_when_build_succeeds = true
+        merge_request.merge_user                = @current_user
+
+        SystemNoteService.merge_when_build_succeeds(merge_request, @project, @current_user, merge_request.diff_head_commit)
+      end
+
+      merge_request.save
+    end
+
+    # Triggers the automatic merge of merge_request once the pipeline succeeds
+    def trigger(pipeline)
+      return unless pipeline.success?
+
+      pipeline_merge_requests(pipeline) do |merge_request|
+        next unless merge_request.merge_when_build_succeeds?
+        next unless merge_request.mergeable?
+
+        MergeWorker.perform_async(merge_request.id, merge_request.merge_user_id, merge_request.merge_params)
+      end
+    end
+
+    # Cancels the automatic merge
+    def cancel(merge_request)
+      if merge_request.merge_when_build_succeeds? && merge_request.open?
+        merge_request.reset_merge_when_build_succeeds
+        SystemNoteService.cancel_merge_when_build_succeeds(merge_request, @project, @current_user)
+
+        success
+      else
+        error("Can't cancel the automatic merge", 406)
+      end
+    end
+  end
+end