Merge pull request #36120 from kamipo/should_maintain_join_type

Fix merging left_joins to maintain its own `join_type` context

2 files changed, 5 insertions, 0 deletions

diff --git a/activerecord/test/cases/associations/left_outer_join_association_test.rb b/activerecord/test/cases/associations/left_outer_join_association_test.rb
index 0a8863c35d..d44c6407f5 100644
--- a/activerecord/test/cases/associations/left_outer_join_association_test.rb
+++ b/activerecord/test/cases/associations/left_outer_join_association_test.rb
@@ -32,6 +32,10 @@ class LeftOuterJoinAssociationTest < ActiveRecord::TestCase
     assert_equal 17, Post.left_outer_joins(:comments).count
   end
 
+  def test_merging_left_joins_should_be_left_joins
+    assert_equal 5, Author.left_joins(:posts).merge(Post.no_comments).count
+  end
+
   def test_left_joins_aliases_left_outer_joins
     assert_equal Post.left_outer_joins(:comments).to_sql, Post.left_joins(:comments).to_sql
   end
diff --git a/activerecord/test/models/post.rb b/activerecord/test/models/post.rb
index 090b576a5d..50c0dddcf2 100644
--- a/activerecord/test/models/post.rb
+++ b/activerecord/test/models/post.rb
@@ -43,6 +43,7 @@ class Post < ActiveRecord::Base
   has_one :first_comment, -> { order("id ASC") }, class_name: "Comment"
   has_one :last_comment, -> { order("id desc") }, class_name: "Comment"
 
+  scope :no_comments, -> { left_joins(:comments).where(comments: { id: nil }) }
   scope :with_special_comments, -> { joins(:comments).where(comments: { type: "SpecialComment" }) }
   scope :with_very_special_comments, -> { joins(:comments).where(comments: { type: "VerySpecialComment" }) }
   scope :with_post, ->(post_id) { joins(:comments).where(comments: { post_id: post_id }) }