Add index to the title, details and instructions

This allows us to search the fields using MySQL’s fulltext search
functions. Because we can’t index JSON fields using fulltext, we have
to create a virtual column which casts the JSON as text. I tried some
MySQL-fu to try and extract all the JSON values, but we can’t do it
recursively. This should be enough anyway, as it’s what we’re only
searching across the JSON at the moment.

db/migrate/20250220131003_add_fulltext_index_to_content_block_editions.rb

@@ -0,0 +1,17 @@
+class AddFulltextIndexToContentBlockEditions < ActiveRecord::Migration[8.0]
+  INDEX_NAME = "title_details_instructions_to_publishers".freeze
+
+  def up
+    change_table :content_block_editions, bulk: true do |t|
+      t.virtual :details_for_indexing, type: :text, as: "JSON_UNQUOTE(details)", stored: true
+      t.index %i[title details_for_indexing instructions_to_publishers], name: INDEX_NAME, type: :fulltext
+    end
+  end
+
+  def down
+    change_table :content_block_editions, bulk: true do |t|
+      t.remove :details_for_indexing
+    end
+    remove_index :content_block_editions, name: INDEX_NAME
+  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: 2025_01_29_095918) do
+ActiveRecord::Schema[8.0].define(version: 2025_02_20_131003) do
   create_table "assets", charset: "utf8mb4", collation: "utf8mb4_unicode_ci", force: :cascade do |t|
     t.string "asset_manager_id", null: false
     t.string "variant", null: false
@@ -236,7 +236,9 @@
     t.text "internal_change_note"
     t.text "change_note"
     t.boolean "major_change"
+    t.virtual "details_for_indexing", type: :text, as: "json_unquote(`details`)", stored: true
     t.index ["document_id"], name: "index_content_block_editions_on_document_id"
+    t.index ["title", "details_for_indexing", "instructions_to_publishers"], name: "title_details_instructions_to_publishers", type: :fulltext
     t.index ["user_id"], name: "index_content_block_editions_on_user_id"
   end