Add saved changes helpers for store accessors

2 files changed, 32 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/store.rb b/activerecord/lib/active_record/store.rb
index 03225668da..6fecb06897 100644
--- a/activerecord/lib/active_record/store.rb
+++ b/activerecord/lib/active_record/store.rb
@@ -11,7 +11,9 @@ module ActiveRecord
   # of the model. This is very helpful for easily exposing store keys to a form or elsewhere that's
   # already built around just accessing attributes on the model.
   #
-  # Every accessor comes with dirty tracking methods (+key_changed?+, +key_was+ and +key_change+).
+  # Every accessor comes with dirty tracking methods (+key_changed?+, +key_was+ and +key_change+) and
+  # methods to access the changes made during the last save (+saved_change_to_key?+, +saved_change_to_key+ and
+  # +key_before_last_save+).
   #
   # NOTE: There is no +key_will_change!+ method for accessors, use +store_will_change!+ instead.
   #
@@ -155,6 +157,24 @@ module ActiveRecord
               prev_store, _new_store = changes[store_attribute]
               prev_store&.dig(key)
             end
+
+            define_method("saved_change_to_#{accessor_key}?") do
+              return false unless saved_change_to_attribute?(store_attribute)
+              prev_store, new_store = saved_change_to_attribute(store_attribute)
+              prev_store&.dig(key) != new_store&.dig(key)
+            end
+
+            define_method("saved_change_to_#{accessor_key}") do
+              return unless saved_change_to_attribute?(store_attribute)
+              prev_store, new_store = saved_change_to_attribute(store_attribute)
+              [prev_store&.dig(key), new_store&.dig(key)]
+            end
+
+            define_method("#{accessor_key}_before_last_save") do
+              return unless saved_change_to_attribute?(store_attribute)
+              prev_store, _new_store = saved_change_to_attribute(store_attribute)
+              prev_store&.dig(key)
+            end
           end
         end
 
diff --git a/activerecord/test/cases/store_test.rb b/activerecord/test/cases/store_test.rb
index 1947868f05..91c0e959f4 100644
--- a/activerecord/test/cases/store_test.rb
+++ b/activerecord/test/cases/store_test.rb
@@ -136,6 +136,17 @@ class StoreTest < ActiveRecord::TestCase
     assert_equal ["Dallas", "Lena"], @john.partner_name_change
   end
 
+  test "saved changes tracking for accessors" do
+    @john.spouse[:name] = "Lena"
+    assert @john.partner_name_changed?
+
+    @john.save!
+    assert_not @john.partner_name_change
+    assert @john.saved_change_to_partner_name?
+    assert_equal ["Dallas", "Lena"], @john.saved_change_to_partner_name
+    assert_equal "Dallas", @john.partner_name_before_last_save
+  end
+
   test "object initialization with not nullable column" do
     assert_equal true, @john.remember_login
   end