fix: Convert cached_label_list to text (#9143)

db/migrate/20240322071629_convert_cached_label_list_to_text.rb

@@ -0,0 +1,32 @@
+class ConvertCachedLabelListToText < ActiveRecord::Migration[7.0]
+  def up
+    change_column :conversations, :cached_label_list, :text
+  end
+
+  def down
+    # This might cause data loss if the text is longer than 255 characters
+    # lets start by truncating the data to 255 characters
+    Conversation.where('LENGTH(cached_label_list) > 255').find_in_batches do |conversation_batch|
+      Conversation.transaction do
+        conversation_batch.each do |conversation|
+          conversation.update!(cached_label_list: truncate_list(conversation.cached_label_list))
+        end
+      end
+    end
+
+    change_column :conversations, :cached_label_list, :string
+  end
+
+  private
+
+  # Truncate the list to 255 characters or less
+  # by removing the last element until the length is less than 255
+  def truncate_list(label_list)
+    labels = label_list.split(',')
+
+    # we add the `labels.length - 1` to account for the commas
+    labels.pop while (labels.join(',').length + labels.length - 1) > 255
+
+    labels.join(',')
+  end
+end