Correctly find nested association reflections for rails#37356

Follow up of rails#37434.

Author: kamipo

activerecord/lib/active_record/relation/finder_methods.rb

@@ -376,8 +376,16 @@ def apply_join_dependency(eager_loading: group_values.empty?)
         )
         relation = except(:includes, :eager_load, :preload).joins!(join_dependency)
 
-        reflections = join_dependency.reflections + joins_values.map { |joins_value| reflect_on_association(joins_value) }.reject(&:blank?)
-        if eager_loading && !using_limitable_reflections?(reflections)
+        if eager_loading && !(
+            using_limitable_reflections?(join_dependency.reflections) &&
+            using_limitable_reflections?(
+              construct_join_dependency(
+                select_association_list(joins_values).concat(
+                  select_association_list(left_outer_joins_values)
+                ), nil
+              ).reflections
+            )
+        )
           if has_limit_or_offset?
             limited_ids = limited_ids_for(relation)
             limited_ids.empty? ? relation.none! : relation.where!(primary_key => limited_ids)

activerecord/lib/active_record/relation/query_methods.rb

@@ -1083,15 +1083,23 @@ def build_from
         end
       end
 
-      def valid_association_list(associations)
+      def select_association_list(associations)
+        result = []
         associations.each do |association|
           case association
           when Hash, Symbol, Array
-            # valid
+            result << association
           else
-            raise ArgumentError, "only Hash, Symbol and Array are allowed"
+            yield if block_given?
           end
         end
+        result
+      end
+
+      def valid_association_list(associations)
+        select_association_list(associations) do
+          raise ArgumentError, "only Hash, Symbol and Array are allowed"
+        end
       end
 
       def build_left_outer_joins(manager, outer_joins, aliases)

activerecord/test/cases/finder_test.rb

@@ -1330,9 +1330,15 @@ def test_with_limiting_with_custom_select
   end
 
   def test_eager_load_for_no_has_many_with_limit_and_joins_for_has_many
-    relation = Post.eager_load(:author).joins(:comments)
+    relation = Post.eager_load(:author).joins(comments: :post)
     assert_equal 5, relation.to_a.size
-    assert_equal relation.limit(5).to_a.size, relation.to_a.size
+    assert_equal 5, relation.limit(5).to_a.size
+  end
+
+  def test_eager_load_for_no_has_many_with_limit_and_left_joins_for_has_many
+    relation = Post.eager_load(:author).left_joins(comments: :post)
+    assert_equal 11, relation.to_a.size
+    assert_equal 11, relation.limit(11).to_a.size
   end
 
   def test_find_one_message_on_primary_key