The existing behavior is to keep routing => nil in event fields. This commit rollback the changes to satisfy that condition

Author: andsel

lib/logstash/outputs/elasticsearch.rb

@@ -554,11 +554,13 @@ def common_event_params(event)
     #      }
     params[:pipeline] = target_pipeline unless (target_pipeline.nil? || target_pipeline.empty?)
 
-    params[:version] = resolve_version(event, event_version)
-    params[:version_type] = resolve_version_type(event, event_version_type)
+    resolved_version = resolve_version(event, event_version)
+    resolved_version_type = resolve_version_type(event, event_version_type)
+    # avoid to add nil valued key-value pairs
+    params[:version] = resolved_version unless resolved_version.nil?
+    params[:version_type] = resolved_version_type unless resolved_version_type.nil?
 
-    # purge nil valued key-value pairs
-    params.compact
+    params
   end
 
   def resolve_version(event, event_version)

spec/unit/outputs/elasticsearch_spec.rb

@@ -372,7 +372,7 @@
 
         context "when the event DOESN'T contain an integration metadata routing" do
           it "plugin's default id mechanism is used" do
-            expect(subject.send(:event_action_tuple, event)[1]).to_not include(:routing)
+            expect(subject.send(:event_action_tuple, event)[1]).to include(:routing => nil)
           end
         end
       end