Merge pull request rails#37434 from giraffate/fix_eager_loading_with_limit_and_join_has_many

Fix eager load for no :has_many with limit and joins for :has_many

Author: kamipo

activerecord/lib/active_record/relation/finder_methods.rb

@@ -376,7 +376,8 @@ def apply_join_dependency(eager_loading: group_values.empty?)
         )
         relation = except(:includes, :eager_load, :preload).joins!(join_dependency)
 
-        if eager_loading && !using_limitable_reflections?(join_dependency.reflections)
+        reflections = join_dependency.reflections + joins_values.map { |joins_value| reflect_on_association(joins_value) }.reject(&:blank?)
+        if eager_loading && !using_limitable_reflections?(reflections)
           if has_limit_or_offset?
             limited_ids = limited_ids_for(relation)
             limited_ids.empty? ? relation.none! : relation.where!(primary_key => limited_ids)

activerecord/test/cases/finder_test.rb

@@ -1329,6 +1329,12 @@ def test_with_limiting_with_custom_select
     assert_equal [0, 1, 1], posts.map(&:author_id).sort
   end
 
+  def test_eager_load_for_no_has_many_with_limit_and_joins_for_has_many
+    relation = Post.eager_load(:author).joins(:comments)
+    assert_equal 5, relation.to_a.size
+    assert_equal relation.limit(5).to_a.size, relation.to_a.size
+  end
+
   def test_find_one_message_on_primary_key
     e = assert_raises(ActiveRecord::RecordNotFound) do
       Car.find(0)