Define id_was to get the previous value of the primary key

Currently when we call id_was and we have a custom primary key name
Active Record will return the current value of the primary key. This
make impossible to correctly do an update operation if you change the
id.

Fixes #16413

1 files changed, 10 insertions, 0 deletions

diff --git a/activerecord/test/cases/primary_keys_test.rb b/activerecord/test/cases/primary_keys_test.rb
index b04df7ce43..f19a6ea5e3 100644
--- a/activerecord/test/cases/primary_keys_test.rb
+++ b/activerecord/test/cases/primary_keys_test.rb
@@ -5,6 +5,7 @@ require 'models/subscriber'
 require 'models/movie'
 require 'models/keyboard'
 require 'models/mixed_case_monkey'
+require 'models/dashboard'
 
 class PrimaryKeysTest < ActiveRecord::TestCase
   fixtures :topics, :subscribers, :movies, :mixed_case_monkeys
@@ -164,6 +165,15 @@ class PrimaryKeysTest < ActiveRecord::TestCase
     MixedCaseMonkey.reset_primary_key
     assert_equal "monkeyID", MixedCaseMonkey.primary_key
   end
+
+  def test_primary_key_update_with_custom_key_name
+    dashboard = Dashboard.create!(dashboard_id: '1')
+    dashboard.id = '2'
+    dashboard.save!
+
+    dashboard = Dashboard.first
+    assert_equal '2', dashboard.id
+  end
 end
 
 class PrimaryKeyWithNoConnectionTest < ActiveRecord::TestCase