Automatically update MR merge-ref along merge status

This couples the code that transitions the `MergeRequest#merge_status`
and refs/merge-requests/:iid/merge ref update.

In general, instead of directly telling `MergeToRefService` to update
the merge ref, we should rely on `MergeabilityCheckService` to keep
both the merge status and merge ref synced. Now, if the merge_status is
`can_be_merged` it means the merge-ref is also updated to the latest.

We've also updated the logic to be more systematic and less user-based.

1 files changed, 8 insertions, 7 deletions

diff --git a/app/services/service_response.rb b/app/services/service_response.rb
index 1de30e68d87..f3437ba16de 100644
--- a/app/services/service_response.rb
+++ b/app/services/service_response.rb
@@ -1,19 +1,20 @@
 # frozen_string_literal: true
 
 class ServiceResponse
-  def self.success(message: nil)
-    new(status: :success, message: message)
+  def self.success(message: nil, payload: {})
+    new(status: :success, message: message, payload: payload)
   end
 
-  def self.error(message:, http_status: nil)
-    new(status: :error, message: message, http_status: http_status)
+  def self.error(message:, payload: {}, http_status: nil)
+    new(status: :error, message: message, payload: payload, http_status: http_status)
   end
 
-  attr_reader :status, :message, :http_status
+  attr_reader :status, :message, :http_status, :payload
 
-  def initialize(status:, message: nil, http_status: nil)
+  def initialize(status:, message: nil, payload: {}, http_status: nil)
     self.status = status
     self.message = message
+    self.payload = payload
     self.http_status = http_status
   end
 
@@ -27,5 +28,5 @@ class ServiceResponse
 
   private
 
-  attr_writer :status, :message, :http_status
+  attr_writer :status, :message, :http_status, :payload
 end