From a1c2c27c833ae9ae3e88a80a2ba5d9dcdc27a1d3 Mon Sep 17 00:00:00 2001
From: Andreas Pfohl <a.pfohl@openproject.com>
Date: Mon, 4 Nov 2024 14:26:56 +0100
Subject: [PATCH] [58520] Fixed hashed subtree flattening

---
 .../hierarchy/hierarchical_item_service.rb    |  4 +++
 .../hierarchy_item_collection_representer.rb  |  5 ---
 .../v3/custom_fields/hierarchy/items_api.rb   | 31 +++++++++----------
 3 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/app/services/custom_fields/hierarchy/hierarchical_item_service.rb b/app/services/custom_fields/hierarchy/hierarchical_item_service.rb
index e0274491d148..472c56975df2 100644
--- a/app/services/custom_fields/hierarchy/hierarchical_item_service.rb
+++ b/app/services/custom_fields/hierarchy/hierarchical_item_service.rb
@@ -117,6 +117,10 @@ def soft_delete_item(item)
         raise NotImplementedError
       end
 
+      def hashed_subtree(item:, depth:)
+        Success(item.hash_tree(limit_depth: depth + 1))
+      end
+
       private
 
       def create_root_item(custom_field)
diff --git a/lib/api/v3/custom_fields/hierarchy/hierarchy_item_collection_representer.rb b/lib/api/v3/custom_fields/hierarchy/hierarchy_item_collection_representer.rb
index 562dad207cda..badb8cad2e77 100644
--- a/lib/api/v3/custom_fields/hierarchy/hierarchy_item_collection_representer.rb
+++ b/lib/api/v3/custom_fields/hierarchy/hierarchy_item_collection_representer.rb
@@ -31,11 +31,6 @@ module V3
     module CustomFields
       module Hierarchy
         class HierarchyItemCollectionRepresenter < ::API::Decorators::UnpaginatedCollection
-          property :count, getter: ->(*) { count.size }
-
-          def model_count(models)
-            super.size
-          end
         end
       end
     end
diff --git a/lib/api/v3/custom_fields/hierarchy/items_api.rb b/lib/api/v3/custom_fields/hierarchy/items_api.rb
index 04da904acee8..f8da3cb04145 100644
--- a/lib/api/v3/custom_fields/hierarchy/items_api.rb
+++ b/lib/api/v3/custom_fields/hierarchy/items_api.rb
@@ -31,6 +31,8 @@ module V3
     module CustomFields
       module Hierarchy
         class ItemsAPI < ::API::OpenProjectAPI
+          include Dry::Monads[:result]
+
           helpers do
             def start_item(root, parent)
               return root if parent.nil?
@@ -42,28 +44,18 @@ def start_item(root, parent)
               start
             end
 
-            def item_list(item, depth)
-              return item.self_and_descendants_preordered if depth.nil?
-
-              d = parse_int(depth)
-              raise ::API::Errors::InvalidQuery.new("Depth must be a natural number.") if d.nil? || d < 0
-
-              # t = flatten_tree_hash item.hash_tree(limit_depth: d + 1)
-
-              item.self_and_descendants_preordered
-            end
-
             def flatten_tree_hash(hash)
-              flat_list = hash.keys
-
-              queue = hash.values
+              flat_list = []
+              queue = [hash]
 
               # {:a => {:b => {:c1 => {:d1 => {}}, :c2 => {:d2 => {}}}, :b2 => {}}}
 
               while queue.any?
                 current = queue.shift
-                flat_list += current.keys
-                queue.unshift(current.values)
+                item, children = current.shift
+                flat_list << item
+                queue.unshift(current) unless current.empty?
+                queue.unshift(children) unless children.empty?
               end
 
               flat_list
@@ -99,7 +91,12 @@ def parse_int(str)
 
               self_link = api_v3_paths.custom_field_items(@custom_field.id, params[:parent], params[:depth])
               start = start_item(root_item.first, params[:parent])
-              models = item_list(start, params[:depth])
+
+              models = ::CustomFields::Hierarchy::HierarchicalItemService
+                         .new.hashed_subtree(item: start,
+                                             depth: parse_int(params[:depth])).fmap do |subtree|
+                flatten_tree_hash(subtree)
+              end.value!
               HierarchyItemCollectionRepresenter.new(models, self_link:, current_user:)
             end
           end