Use ids instead of pluck(:id) (#32977).

git-svn-id: http://svn.redmine.org/redmine/trunk@21208 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/user.rb

@@ -952,7 +952,7 @@ class User < Principal
     Watcher.where('user_id = ?', id).delete_all
     WikiContent.where(['author_id = ?', id]).update_all(['author_id = ?', substitute.id])
     WikiContentVersion.where(['author_id = ?', id]).update_all(['author_id = ?', substitute.id])
-    user_custom_field_ids = CustomField.where(field_format: 'user').pluck(:id)
+    user_custom_field_ids = CustomField.where(field_format: 'user').ids
     if user_custom_field_ids.any?
       CustomValue.where(custom_field_id: user_custom_field_ids, value: self.id.to_s).delete_all
     end

db/migrate/20210801211024_remove_orphaned_user_custom_values.rb

@@ -1,8 +1,8 @@
 class RemoveOrphanedUserCustomValues < ActiveRecord::Migration[6.1]
   def up
-    user_custom_field_ids = CustomField.where(field_format: 'user').pluck(:id)
+    user_custom_field_ids = CustomField.where(field_format: 'user').ids
     if user_custom_field_ids.any?
-      user_ids = Principal.pluck(:id)
+      user_ids = Principal.ids
       CustomValue.
         where(custom_field_id: user_custom_field_ids).
         where.not(value: [nil, ''] + user_ids).