Ignore milestone_id from epics table 1/3

app/models/concerns/issuable.rb

@@ -173,7 +173,7 @@ module Issuable
     private
 
     def milestone_is_valid
-      errors.add(:milestone_id, message: "is invalid") if milestone_id.present? && !milestone_available?
+      errors.add(:milestone_id, message: "is invalid") if respond_to?(:milestone_id) && milestone_id.present? && !milestone_available?
     end
 
     def description_max_length_for_new_records_is_valid

app/models/epic.rb

@@ -3,6 +3,8 @@
 # Placeholder class for model that is implemented in EE
 # It reserves '&' as a reference prefix, but the table does not exists in CE
 class Epic < ApplicationRecord
+  self.ignored_columns += %i[milestone_id]
+
   def self.link_reference_pattern
     nil
   end

app/services/issuable/clone/attributes_rewriter.rb

@@ -10,7 +10,13 @@ module Issuable
       end
 
       def execute
-        new_entity.update(milestone: cloneable_milestone, labels: cloneable_labels)
+        update_attributes = { labels: cloneable_labels }
+
+        milestone = cloneable_milestone
+        update_attributes[:milestone] = milestone if milestone.present?
+
+        new_entity.update(update_attributes)
+
         copy_resource_label_events
       end
 

changelogs/unreleased/remove_milestone_id_from_epics.yml

+---
+title: Remove milestone_id from epics
+merge_request: 20187
+author: Lee Tickett
+type: other

config/pseudonymizer.yml

@@ -47,7 +47,6 @@ tables:
   epics:
     whitelist:
     - id
-    - milestone_id
     - group_id
     - author_id
     - assignee_id

ee/spec/services/ee/issuable/clone/attributes_rewriter_spec.rb

@@ -30,11 +30,11 @@ describe Issuable::Clone::AttributesRewriter do
       end
 
       context 'setting milestones' do
-        it 'sets milestone attribute as nil' do
+        it 'ignores milestone attribute' do
           milestone = create(:milestone, title: 'milestone', group: group)
           original_issue.update(milestone: milestone)
 
-          expect(new_epic).to receive(:update).with(labels: [], milestone: nil)
+          expect(new_epic).to receive(:update).with(labels: [])
 
           subject.execute
         end