Use Rails serialize method to save/load cached fields in Item

Just packing some serialization complexity away into its own thing, so
the model code doesn't need to sweat it!

app/models/item.rb

@@ -10,6 +10,9 @@ class Item < ApplicationRecord
 
   SwfAssetType = 'object'
 
+  serialize :cached_compatible_body_ids, coder: Serializers::IntegerSet
+  serialize :cached_occupied_zone_ids, coder: Serializers::IntegerSet
+
   has_many :closet_hangers
   has_one :contribution, as: :contributed, inverse_of: :contributed
   has_one :nc_mall_record
@@ -258,8 +261,8 @@ class Item < ApplicationRecord
   end
 
   def update_cached_fields
-    self.cached_occupied_zone_ids = occupied_zone_ids.sort.join(",")
-    self.cached_compatible_body_ids = compatible_body_ids.sort.join(",")
+    self.cached_occupied_zone_ids = occupied_zone_ids
+    self.cached_compatible_body_ids = compatible_body_ids
     self.save!
   end
 

db/migrate/20241003004726_allow_null_in_items_cached_fields.rb

@@ -0,0 +1,9 @@
+class AllowNullInItemsCachedFields < ActiveRecord::Migration[7.2]
+  def change
+    # This is a bit more compatible with ActiveRecord's `serialize` utility,
+    # which seems pretty insistent that empty arrays should be saved as `NULL`,
+    # rather than the empty string our serializer would return if called :(
+    change_column_null :items, :cached_compatible_body_ids, true
+    change_column_null :items, :cached_occupied_zone_ids, true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.2].define(version: 2024_10_01_052510) do
+ActiveRecord::Schema[7.2].define(version: 2024_10_03_004726) do
   create_table "alt_styles", charset: "utf8mb4", collation: "utf8mb4_unicode_520_ci", force: :cascade do |t|
     t.integer "species_id", null: false
     t.integer "color_id", null: false
@@ -137,8 +137,8 @@ ActiveRecord::Schema[7.2].define(version: 2024_10_01_052510) do
     t.text "description", size: :medium, null: false
     t.string "rarity", default: "", null: false
     t.integer "dyeworks_base_item_id"
-    t.string "cached_occupied_zone_ids", default: "", null: false
-    t.text "cached_compatible_body_ids", default: "", null: false
+    t.string "cached_occupied_zone_ids", default: ""
+    t.text "cached_compatible_body_ids", default: ""
     t.index ["dyeworks_base_item_id"], name: "index_items_on_dyeworks_base_item_id"
     t.index ["modeling_status_hint", "created_at", "id"], name: "items_modeling_status_hint_and_created_at_and_id"
     t.index ["modeling_status_hint", "created_at"], name: "items_modeling_status_hint_and_created_at"

lib/serializers/integer_set.rb

@@ -0,0 +1,11 @@
+module Serializers
+	module IntegerSet
+		def self.dump(array)
+			array.sort.join(",")
+		end
+
+		def self.load(string)
+			(string || "").split(",").map(&:to_i)
+		end
+	end
+end