From 6823e7defb45dfd86d5258b40d6f82482d1ef451 Mon Sep 17 00:00:00 2001 From: Toon Claes Date: Mon, 24 Sep 2018 14:13:11 +0200 Subject: Work around a bug in Rails 5, where LIMIT causes trouble The original code caused Rails to generate invalid SQL. The problem lays in the `.arel` method in `ActiveRecord::Relation`. When there was a `limit` on the relation, the `LIMIT` statement was taken over to Arel, but the value wasn't. ```ruby relation = Event.limit(2) relation.to_sql #=> "SELECT `events`.* FROM `events` LIMIT 2" relation.arel.to_sql #=> "SELECT `events`.* FROM `events` LIMIT ?" ``` Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/51729 --- lib/gitlab/database/subquery.rb | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/lib/gitlab/database/subquery.rb b/lib/gitlab/database/subquery.rb index 2a6f39c6a27..36e4559b554 100644 --- a/lib/gitlab/database/subquery.rb +++ b/lib/gitlab/database/subquery.rb @@ -6,7 +6,15 @@ module Gitlab class << self def self_join(relation) t = relation.arel_table - t2 = relation.arel.as('t2') + t2 = if !Gitlab.rails5? + relation.arel.as('t2') + else + # Work around a bug in Rails 5, where LIMIT causes trouble + # See https://gitlab.com/gitlab-org/gitlab-ce/issues/51729 + r = relation.limit(nil).arel + r.take(relation.limit_value) if relation.limit_value + r.as('t2') + end relation.unscoped.joins(t.join(t2).on(t[:id].eq(t2[:id])).join_sources.first) end -- cgit v1.2.1