Merge pull request #21964 from Drenmi/enhancement/update-deprecation-message

Better deprecation warning for `ActiveRecord::Relation#update`

activerecord/CHANGELOG.md

+*   Give `AcriveRecord::Relation#update` its own deprecation warning when
+    passed an `ActiveRecord::Base` instance.
+
+    Fixes #21945.
+
+    *Ted Johansson*
+
 *   Make it possible to pass `:to_table` when adding a foreign key through
     `add_reference`.
 

activerecord/lib/active_record/relation.rb

@@ -417,6 +417,13 @@ def update(id = :all, attributes)
       elsif id == :all
         to_a.each { |record| record.update(attributes) }
       else
+        if ActiveRecord::Base === id
+          id = id.id
+          ActiveSupport::Deprecation.warn(<<-MSG.squish)
+            You are passing an instance of ActiveRecord::Base to `update`.
+            Please pass the id of the object by calling `.id`
+          MSG
+        end
         object = find(id)
         object.update(attributes)
         object

activerecord/test/cases/relations_test.rb

@@ -1541,6 +1541,13 @@ def test_update_on_relation
     assert_equal 'David', topic2.reload.author_name
   end
 
+  def test_update_on_relation_passing_active_record_object_is_deprecated
+    topic = Topic.create!(title: 'Foo', author_name: nil)
+    assert_deprecated(/update/) do
+      Topic.where(id: topic.id).update(topic, title: 'Bar')
+    end
+  end
+
   def test_distinct
     tag1 = Tag.create(:name => 'Foo')
     tag2 = Tag.create(:name => 'Foo')