From 060e09dfb3637b03ef026c5e6b69432c08995c47 Mon Sep 17 00:00:00 2001 From: Ryuta Kamizono Date: Thu, 28 Mar 2019 09:56:40 +0900 Subject: Fix `count(:all)` with eager loading and explicit select and order This follows up ebc09ed9ad9a04338138739226a1a92c7a2707ee. We've still experienced a regression for `size` (`count(:all)`) with eager loading and explicit select and order when upgrading Rails to 5.1. In that case, the eager loading enforces `distinct` to subselect but still keep the custom select, it would cause the ORDER BY with DISTINCT issue. ``` % ARCONN=postgresql bundle exec ruby -w -Itest test/cases/relations_test.rb -n test_size_with_eager_loading_and_custom_select_and_order Using postgresql Run options: -n test_size_with_eager_loading_and_custom_select_and_order --seed 8356 # Running: E Error: RelationTest#test_size_with_eager_loading_and_custom_select_and_order: ActiveRecord::StatementInvalid: PG::InvalidColumnReference: ERROR: for SELECT DISTINCT, ORDER BY expressions must appear in select list LINE 1: ..." ON "comments"."post_id" = "posts"."id" ORDER BY comments.i... ^ ``` As another problem on `distinct` is enforced, the result of `count` becomes fewer than expected if `select` is given explicitly. e.g. ```ruby Post.select(:type).count # => 11 Post.select(:type).distinct.count # => 3 ``` As long as `distinct` is enforced, we need to care to keep the result of `count`. This fixes both the `count` with eager loading problems. --- activerecord/test/cases/relations_test.rb | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'activerecord/test/cases/relations_test.rb') diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb index 131e034c66..2417775ef1 100644 --- a/activerecord/test/cases/relations_test.rb +++ b/activerecord/test/cases/relations_test.rb @@ -985,6 +985,12 @@ class RelationTest < ActiveRecord::TestCase assert_queries(1) { assert_equal 11, posts.load.size } end + def test_size_with_eager_loading_and_custom_select_and_order + posts = Post.includes(:comments).order("comments.id").select(:type) + assert_queries(1) { assert_equal 11, posts.size } + assert_queries(1) { assert_equal 11, posts.load.size } + end + def test_size_with_eager_loading_and_custom_order_and_distinct posts = Post.includes(:comments).order("comments.id").distinct assert_queries(1) { assert_equal 11, posts.size } -- cgit v1.2.3