Merge pull request rails#52969 from ghiculescu/am-serializable_hash-order

Ensure consistent sort order in `ActiveModel#serializable_hash` when using `only` option

Author: jhawthorn

activemodel/lib/active_model/serialization.rb

@@ -128,7 +128,7 @@ def serializable_hash(options = nil)
       return serializable_attributes(attribute_names) if options.blank?
 
       if only = options[:only]
-        attribute_names &= Array(only).map(&:to_s)
+        attribute_names = Array(only).map(&:to_s) & attribute_names
       elsif except = options[:except]
         attribute_names -= Array(except).map(&:to_s)
       end

activemodel/test/cases/serialization_test.rb

@@ -62,6 +62,11 @@ def test_method_serializable_hash_should_work_with_only_option
     assert_equal expected, @user.serializable_hash(only: [:name])
   end
 
+  def test_method_serializable_hash_should_work_with_only_option_with_order_of_given_keys
+    expected = { "name" => "David", "email" => "[email protected]" }
+    assert_equal expected.keys, @user.serializable_hash(only: [:name, :email]).keys
+  end
+
   def test_method_serializable_hash_should_work_with_except_option
     expected = { "gender" => "male", "email" => "[email protected]" }
     assert_equal expected, @user.serializable_hash(except: [:name])