Handle relative position on issue move or clone

When an issue is moved or cloned to different project we need
to ensure that we either reset the relative position, if it is
moved to a different hierarchy so that we do not carry over large
relative position or we keep the same if it remains within the same
hierarchy just a different project as we want to keep the position on
group boards in that case.

app/services/issuable/clone/base_service.rb

@@ -3,12 +3,13 @@
 module Issuable
   module Clone
     class BaseService < IssuableBaseService
-      attr_reader :original_entity, :new_entity
+      attr_reader :original_entity, :new_entity, :target_project
 
       alias_method :old_project, :project
 
-      def execute(original_entity, new_project = nil)
+      def execute(original_entity, target_project = nil)
         @original_entity = original_entity
+        @target_project = target_project
 
         # Using transaction because of a high resources footprint
         # on rewriting notes (unfolding references)
@@ -77,6 +78,12 @@ module Issuable
           new_entity.project.group
         end
       end
+
+      def relative_position
+        return if original_entity.project.root_ancestor.id != target_project.root_ancestor.id
+
+        original_entity.relative_position
+      end
     end
   end
 end

app/services/issues/clone_service.rb

@@ -47,6 +47,7 @@ module Issues
       new_params = {
         id: nil,
         iid: nil,
+        relative_position: relative_position,
         project: target_project,
         author: current_user,
         assignee_ids: original_entity.assignee_ids

app/services/issues/move_service.rb

@@ -50,6 +50,7 @@ module Issues
       new_params = {
         id: nil,
         iid: nil,
+        relative_position: relative_position,
         project: target_project,
         author: original_entity.author,
         assignee_ids: original_entity.assignee_ids,

changelogs/unreleased/fix-relative-position-on-move-and-copy-issue.yml

+---
+title: Handle relative position on issue move or clone
+merge_request: 55555
+author:
+type: fixed

spec/services/issues/clone_service_spec.rb

@@ -280,6 +280,12 @@ RSpec.describe Issues::CloneService do
           expect(new_issue.designs.first.notes.size).to eq(1)
         end
       end
+
+      context 'issue relative position' do
+        let(:subject) { clone_service.execute(old_issue, new_project) }
+
+        it_behaves_like 'copy or reset relative position'
+      end
     end
 
     describe 'clone permissions' do

spec/services/issues/move_service_spec.rb

@@ -244,6 +244,12 @@ RSpec.describe Issues::MoveService do
           expect(new_issue.designs.first.notes.size).to eq(1)
         end
       end
+
+      context 'issue relative position' do
+        let(:subject) { move_service.execute(old_issue, new_project) }
+
+        it_behaves_like 'copy or reset relative position'
+      end
     end
 
     describe 'move permissions' do

spec/support/services/issues/move_and_clone_services_shared_examples.rb

+# frozen_string_literal: true
+
+RSpec.shared_examples 'copy or reset relative position' do
+  before do
+    # ensure we have a relative position and it is known
+    old_issue.update!(relative_position: 1000)
+  end
+
+  context 'when moved to a project within same group hierarchy' do
+    it 'does not reset the relative_position' do
+      expect(subject.relative_position).to eq(1000)
+    end
+  end
+
+  context 'when moved to a project in a different group hierarchy' do
+    let_it_be(:new_project) { create(:project, group: create(:group)) }
+
+    it 'does reset the relative_position' do
+      expect(subject.relative_position).to be_nil
+    end
+  end
+end