Fix unexpected exception by failed to find an actual head pipeline

Add changelog

1 files changed, 4 insertions, 3 deletions

diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 5310f2ee765..a9d1ece0d7e 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -1108,9 +1108,10 @@ class MergeRequest < ActiveRecord::Base
   end
 
   def update_head_pipeline
-    self.head_pipeline = find_actual_head_pipeline
-
-    update_column(:head_pipeline_id, head_pipeline.id) if head_pipeline_id_changed?
+    find_actual_head_pipeline.try do |pipeline|
+      self.head_pipeline = pipeline
+      update_column(:head_pipeline_id, head_pipeline.id) if head_pipeline_id_changed?
+    end
   end
 
   def merge_request_pipeline_exists?