2 files changed, 7 insertions, 5 deletions
diff --git a/activerecord/lib/active_record/associations/join_dependency.rb b/activerecord/lib/active_record/associations/join_dependency.rb
index be56d27021..d316db2145 100644
--- a/activerecord/lib/active_record/associations/join_dependency.rb
+++ b/activerecord/lib/active_record/associations/join_dependency.rb
@@ -232,11 +232,6 @@ module ActiveRecord
             else
               model = construct_model(ar_parent, node, row, model_cache, id)
 
-              if node.reflection.scope &&
-                  node.reflection.scope_for(node.base_klass.unscoped).readonly_value
-                model.readonly!
-              end
-
               seen[ar_parent.object_id][node][id] = model
               construct(model, node, row, seen, model_cache)
             end
@@ -257,6 +252,7 @@ module ActiveRecord
             other.target = model
           end
 
+          model.readonly! if node.readonly?
           model
         end
     end
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
index 6e5e950e90..4583d89cba 100644
--- a/activerecord/lib/active_record/associations/join_dependency/join_association.rb
+++ b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
@@ -54,6 +54,12 @@ module ActiveRecord
           @tables = tables
           @table  = tables.first
         end
+
+        def readonly?
+          return @readonly if defined?(@readonly)
+
+          @readonly = reflection.scope && reflection.scope_for(base_klass.unscoped).readonly_value
+        end
       end
     end
   end