[29652] Avoid duplicated deferred parent insertion

When the parent work package is not in the current page,
but the grandparent is, the parent was added once per child
to the deferred render list and that list is not kept unique.

https://community.openproject.com/wp/29652

frontend/src/app/components/wp-fast-table/builders/modes/hierarchy/hierarchy-render-pass.ts

@@ -115,11 +115,14 @@ export class HierarchyRenderPass extends PrimaryRenderPass {
 
       if (inTable) {
         // Get the current elements
-        const elements = this.deferred[parent.id] || [];
+        let elements = this.deferred[parent.id] || [];
         // Append to them the child and all children below
         let newElements:WorkPackageResource[] = ancestorChain.slice(i + 1, ancestorChain.length);
         newElements = newElements.map(child => this.wpCacheService.state(child.id).value!);
-        this.deferred[parent.id] = elements.concat(newElements);
+        // Append all new elements
+        elements = elements.concat(newElements);
+        // Remove duplicates (Regression #29652)
+        this.deferred[parent.id] = _.uniqBy(elements, el => el.id);
         return true;
       }
       // Otherwise, continue the chain upwards

spec/features/work_packages/table/hierarchy/hierarchy_parent_below_spec.rb

@@ -92,4 +92,53 @@ describe 'Work Package table hierarchy parent below', js: true do
       wp_table.expect_work_package_order(child.id, grandparent.id)
     end
   end
+
+  describe 'grand-parent of 2+ children visible anywhere on the page, but parent is not (Regression #29652)' do
+    let(:child) { FactoryBot.create(:work_package, subject: 'AA Child WP', project: project, type: type_task) }
+    let(:child2) { FactoryBot.create(:work_package, subject: 'BB Child WP', project: project, type: type_task) }
+    let(:parent) { FactoryBot.create(:work_package, subject: 'ZZ Parent WP', project: project, type: type_task) }
+    let(:grandparent) { FactoryBot.create(:work_package, subject: 'Grandparent', project: project, type: type_task) }
+
+    let(:query) do
+      query              = FactoryBot.build(:query, user: user, project: project)
+      query.column_names = %w(id subject)
+      query.sort_criteria = [%w(subject asc)]
+      query.show_hierarchies = true
+
+      query.save!
+      query
+    end
+
+    before do
+      child
+      parent
+      grandparent
+
+      child.update(parent_id: parent.id)
+      child2.update(parent_id: parent.id)
+      parent.update(parent_id: grandparent.id)
+
+      allow(Setting).to receive(:per_page_options).and_return '3'
+      query
+    end
+
+    it 'shows hierarchy correctly' do
+      wp_table.visit_query query
+
+      wp_table.expect_work_package_listed(child, child2, parent, grandparent)
+
+      # Expect pagination to be correct
+      expect(page).to have_selector('.pagination--item.-current', text: '3')
+
+      # Expect count to be correct (one additional parent shown)
+      expect(page).to have_selector('.wp-table--row', count: 4)
+
+      # Double order result from regression
+      wp_table.expect_work_package_order(grandparent.id, parent.id, child.id, child2.id)
+
+      # Enable hierarchy mode, should sort according to spec above
+      hierarchy.expect_hierarchy_at(grandparent, parent)
+      hierarchy.expect_leaf_at(child, child2)
+    end
+  end
 end