Merge pull request #9320 from wangjohn/touch_handling_on_new_instances

Raising an ActiveRecordError when one tries to use touch on a new record object

3 files changed, 20 insertions, 0 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index b3301f70dc..c7085a0eaa 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,5 +1,16 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Fixing issue #8345. Now throwing an error when one attempts to touch a
+    new object that has not yet been persisted. For instance:
+
+      ball = Ball.new
+      ball.touch :updated_at   # => raises error
+
+    It is not until the ball object has been persisted that it can be touched.
+    This follows the behavior of update_column.
+
+    *John Wang*
+
 *   Preloading ordered `has_many :through` associations no longer applies
     invalid ordering to the `:through` association.
     Fixes #8663.
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index 066f93635a..26c11b50a2 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -368,6 +368,8 @@ module ActiveRecord
     #   # triggers @brake.car.touch and @brake.car.corporation.touch
     #   @brake.touch
     def touch(name = nil)
+      raise ActiveRecordError, "can not touch on a new record object" unless persisted?
+
       attributes = timestamp_attributes_for_update_in_model
       attributes << name if name
 
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index fbc66540d6..af1845c937 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -1447,6 +1447,13 @@ class BasicsTest < ActiveRecord::TestCase
     assert_match(/\/#{dev.id}$/, dev.cache_key)
   end
 
+  def test_touch_should_raise_error_on_a_new_object
+    company = Company.new(:rating => 1, :name => "37signals", :firm_name => "37signals")
+    assert_raises(ActiveRecord::ActiveRecordError) do
+      company.touch :updated_at
+    end
+  end
+
   def test_cache_key_format_is_precise_enough
     dev = Developer.first
     key = dev.cache_key