Joined tables in association scope doesn't use the same aliases with the parent relation's aliases

Building association scope in join dependency should respect the parent
relation's aliases to avoid using the same alias name more than once.

Fixes #30681.

2 files changed, 5 insertions, 0 deletions

diff --git a/activerecord/test/cases/associations/has_many_through_associations_test.rb b/activerecord/test/cases/associations/has_many_through_associations_test.rb
index 521b388cee..c6a4ac356f 100644
--- a/activerecord/test/cases/associations/has_many_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -1250,6 +1250,10 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     TenantMembership.current_member = nil
   end
 
+  def test_has_many_trough_with_scope_that_has_joined_same_table_with_parent_relation
+    assert_equal authors(:david), Author.joins(:comments_for_first_author).take
+  end
+
   def test_has_many_through_with_unscope_should_affect_to_through_scope
     assert_equal [comments(:eager_other_comment1)], authors(:mary).unordered_comments
   end
diff --git a/activerecord/test/models/author.rb b/activerecord/test/models/author.rb
index 3371fcbfcc..e9eba9be2e 100644
--- a/activerecord/test/models/author.rb
+++ b/activerecord/test/models/author.rb
@@ -22,6 +22,7 @@ class Author < ActiveRecord::Base
   has_many :comments_containing_the_letter_e, through: :posts, source: :comments
   has_many :comments_with_order_and_conditions, -> { order("comments.body").where("comments.body like 'Thank%'") }, through: :posts, source: :comments
   has_many :comments_with_include, -> { includes(:post).where(posts: { type: "Post" }) }, through: :posts, source: :comments
+  has_many :comments_for_first_author, -> { for_first_author }, through: :posts, source: :comments
 
   has_many :first_posts
   has_many :comments_on_first_posts, -> { order("posts.id desc, comments.id asc") }, through: :first_posts, source: :comments