1 files changed, 116 insertions, 0 deletions
diff --git a/lib/gitlab/issuable/clone/copy_resource_events_service.rb b/lib/gitlab/issuable/clone/copy_resource_events_service.rb
new file mode 100644
index 00000000000..563805fcb01
--- /dev/null
+++ b/lib/gitlab/issuable/clone/copy_resource_events_service.rb
@@ -0,0 +1,116 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Issuable
+    module Clone
+      class CopyResourceEventsService
+        attr_reader :current_user, :original_entity, :new_entity
+
+        def initialize(current_user, original_entity, new_entity)
+          @current_user = current_user
+          @original_entity = original_entity
+          @new_entity = new_entity
+        end
+
+        def execute
+          copy_resource_label_events
+          copy_resource_milestone_events
+          copy_resource_state_events
+        end
+
+        private
+
+        def copy_resource_label_events
+          copy_events(ResourceLabelEvent.table_name, original_entity.resource_label_events) do |event|
+            event.attributes
+              .except('id', 'reference', 'reference_html')
+              .merge(entity_key => new_entity.id, 'action' => ResourceLabelEvent.actions[event.action])
+          end
+        end
+
+        def copy_resource_milestone_events
+          return unless milestone_events_supported?
+
+          copy_events(ResourceMilestoneEvent.table_name, original_entity.resource_milestone_events) do |event|
+            if event.remove?
+              event_attributes_with_milestone(event, nil)
+            else
+              destination_milestone = matching_milestone(event.milestone_title)
+
+              event_attributes_with_milestone(event, destination_milestone) if destination_milestone.present?
+            end
+          end
+        end
+
+        def copy_resource_state_events
+          return unless state_events_supported?
+
+          copy_events(ResourceStateEvent.table_name, original_entity.resource_state_events) do |event|
+            event.attributes
+              .except(*blocked_state_event_attributes)
+              .merge(entity_key => new_entity.id,
+                    'state' => ResourceStateEvent.states[event.state])
+          end
+        end
+
+        # Overriden on EE::Gitlab::Issuable::Clone::CopyResourceEventsService
+        def blocked_state_event_attributes
+          ['id']
+        end
+
+        def event_attributes_with_milestone(event, milestone)
+          event.attributes
+            .except('id')
+            .merge(entity_key => new_entity.id,
+                    'milestone_id' => milestone&.id,
+                    'action' => ResourceMilestoneEvent.actions[event.action],
+                    'state' => ResourceMilestoneEvent.states[event.state])
+        end
+
+        def copy_events(table_name, events_to_copy)
+          events_to_copy.find_in_batches do |batch|
+            events = batch.map do |event|
+              yield(event)
+            end.compact
+
+            ApplicationRecord.legacy_bulk_insert(table_name, events) # rubocop:disable Gitlab/BulkInsert
+          end
+        end
+
+        def entity_key
+          new_entity.class.name.underscore.foreign_key
+        end
+
+        def milestone_events_supported?
+          both_respond_to?(:resource_milestone_events)
+        end
+
+        def state_events_supported?
+          both_respond_to?(:resource_state_events)
+        end
+
+        def both_respond_to?(method)
+          original_entity.respond_to?(method) &&
+            new_entity.respond_to?(method)
+        end
+
+        def matching_milestone(title)
+          return if title.blank? || !new_entity.supports_milestone?
+
+          params = { title: title, project_ids: new_entity.project&.id, group_ids: group&.id }
+
+          milestones = MilestonesFinder.new(params).execute
+          milestones.first
+        end
+
+        def group
+          if new_entity.project&.group && current_user.can?(:read_group, new_entity.project.group)
+            new_entity.project.group
+          end
+        end
+      end
+    end
+  end
+end
+
+Gitlab::Issuable::Clone::CopyResourceEventsService.prepend_mod