From 2f8c596d1beb46acd8a74f0e6d5c1c48a29dcee9 Mon Sep 17 00:00:00 2001
From: Sean Griffin <sean@thoughtbot.com>
Date: Tue, 10 Feb 2015 08:20:54 -0700
Subject: [PATCH] Maintain a consistent order in
 `ActiveRecord::Base#attributes`

Fixes #18871
---
 .../lib/active_record/attribute_set/builder.rb       | 12 +++++++++++-
 activerecord/test/cases/attribute_set_test.rb        | 10 ++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/activerecord/lib/active_record/attribute_set/builder.rb b/activerecord/lib/active_record/attribute_set/builder.rb
index 0f3c285a80..e85777c335 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, :each_key, to: :materialize
+    delegate :transform_values, :each_key, to: :materialize
 
     def initialize(types, values, additional_types)
       @types = types
@@ -50,6 +50,16 @@ module ActiveRecord
       super
     end
 
+    def select
+      keys = types.keys | values.keys | delegate_hash.keys
+      keys.each_with_object({}) do |key, hash|
+        attribute = self[key]
+        if yield(key, attribute)
+          hash[key] = attribute
+        end
+      end
+    end
+
     protected
 
     attr_reader :types, :values, :additional_types, :delegate_hash
diff --git a/activerecord/test/cases/attribute_set_test.rb b/activerecord/test/cases/attribute_set_test.rb
index 8025c7c4d2..112cd2fb14 100644
--- a/activerecord/test/cases/attribute_set_test.rb
+++ b/activerecord/test/cases/attribute_set_test.rb
@@ -65,6 +65,16 @@ module ActiveRecord
       assert_equal({ foo: 1, bar: 2.2 }, attributes.to_h)
     end
 
+    test "to_hash maintains order" do
+      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+      attributes = builder.build_from_database(foo: '2.2', bar: '3.3')
+
+      attributes[:bar]
+      hash = attributes.to_h
+
+      assert_equal [[:foo, 2], [:bar, 3.3]], hash.to_a
+    end
+
     test "values_before_type_cast" do
       builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Integer.new)
       attributes = builder.build_from_database(foo: '1.1', bar: '2.2')