2 files changed, 2 insertions, 6 deletions
diff --git a/activerecord/lib/active_record/attribute_set.rb b/activerecord/lib/active_record/attribute_set.rb
index fdce68ce45..0c9793d470 100644
--- a/activerecord/lib/active_record/attribute_set.rb
+++ b/activerecord/lib/active_record/attribute_set.rb
@@ -24,7 +24,7 @@ module ActiveRecord
     end
 
     def keys
-      attributes.initialized_keys
+      attributes.each_key.select { |name| self[name].initialized? }
     end
 
     def fetch_value(name)
diff --git a/activerecord/lib/active_record/attribute_set/builder.rb b/activerecord/lib/active_record/attribute_set/builder.rb
index 3a76f5262d..0f3c285a80 100644
--- a/activerecord/lib/active_record/attribute_set/builder.rb
+++ b/activerecord/lib/active_record/attribute_set/builder.rb
@@ -20,7 +20,7 @@ module ActiveRecord
   end
 
   class LazyAttributeHash # :nodoc:
-    delegate :select, :transform_values, to: :materialize
+    delegate :select, :transform_values, :each_key, to: :materialize
 
     def initialize(types, values, additional_types)
       @types = types
@@ -45,10 +45,6 @@ module ActiveRecord
       delegate_hash[key] = value
     end
 
-    def initialized_keys
-      delegate_hash.keys | values.keys
-    end
-
     def initialize_dup(_)
       @delegate_hash = delegate_hash.transform_values(&:dup)
       super