Fix `stale_state` for nested `has_many :through` associations

Need reloading when through record has replaced.

1 files changed, 13 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/associations/through_association.rb b/activerecord/lib/active_record/associations/through_association.rb
index 806397f83a..54673b74f7 100644
--- a/activerecord/lib/active_record/associations/through_association.rb
+++ b/activerecord/lib/active_record/associations/through_association.rb
@@ -4,9 +4,20 @@ module ActiveRecord
   module Associations
     # = Active Record Through Association
     module ThroughAssociation #:nodoc:
-      delegate :source_reflection, :through_reflection, to: :reflection
+      delegate :source_reflection, to: :reflection
 
       private
+        def through_reflection
+          @through_reflection ||= begin
+            refl = reflection.through_reflection
+
+            while refl.through_reflection?
+              refl = refl.through_reflection
+            end
+
+            refl
+          end
+        end
 
         # We merge in these scopes for two reasons:
         #
@@ -68,7 +79,7 @@ module ActiveRecord
         end
 
         def foreign_key_present?
-          through_reflection.belongs_to_or_through? && !owner[through_reflection.foreign_key].nil?
+          through_reflection.belongs_to? && !owner[through_reflection.foreign_key].nil?
         end
 
         def ensure_mutable