Merge pull request #36647 from giraffate/fix_exists_with_distinct_and…

…_offset_and_order_in_postgresql

Fix `relation.exists?` with giving `distinct`, `offset` and `order` for joined table

activerecord/lib/active_record/relation/finder_methods.rb

@@ -360,7 +360,7 @@ def offset_index
 
       def construct_relation_for_exists(conditions)
         if distinct_value && offset_value
-          relation = limit(1)
+          relation = except(:order).limit!(1)
         else
           relation = except(:select, :distinct, :order)._select!(ONE_AS_ONE).limit!(1)
         end

activerecord/test/cases/finder_test.rb

@@ -260,6 +260,11 @@ def test_exists_with_distinct_and_offset_and_select
     assert_not Post.select(:body).distinct.offset(4).exists?
   end
 
+  def test_exists_with_distinct_and_offset_and_eagerload_and_order
+    assert Post.eager_load(:comments).distinct.offset(10).merge(Comment.order(post_id: :asc)).exists?
+    assert_not Post.eager_load(:comments).distinct.offset(11).merge(Comment.order(post_id: :asc)).exists?
+  end
+
   # Ensure +exists?+ runs without an error by excluding distinct value.
   # See https://github.com/rails/rails/pull/26981.
   def test_exists_with_order_and_distinct