From 1dc98c143c4bf84ccfb55b30c7d41b29b62d50cf Mon Sep 17 00:00:00 2001
From: Brendon Murphy <xternal1+github@gmail.com>
Date: Wed, 23 Jan 2013 01:47:23 -0800
Subject: [PATCH] cache_key consults updated_on timestamp if present

- Extract max timestamp retrieval for cache_key
- Update changelog for cache_key changes
---
 activerecord/CHANGELOG.md                     | 10 +++++++++
 activerecord/lib/active_record/integration.rb |  2 +-
 activerecord/lib/active_record/timestamp.rb   |  6 +++++
 activerecord/test/cases/base_test.rb          | 22 +++++++++++++++++--
 activerecord/test/schema/schema.rb            |  2 ++
 5 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index a135b3c91f7aa..d494d41aac114 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,13 @@
+*   Expand `#cache_key` to consult all relevant updated timestamps.
+
+    Previously only `updated_at` column was checked, now it will
+    consult other columns that received updated timestamps on save,
+    such as `updated_on`.  When multiple columns are present it will
+    use the most recent timestamp.
+    Fixes #9033.
+
+    *Brendon Murphy*
+
 ## Rails 4.0.0.beta1 (February 25, 2013) ##
 
 *   Fix overriding of attributes by default_scope on `ActiveRecord::Base#dup`.
diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb
index 32d35f0ec1097..48c73d77817ed 100644
--- a/activerecord/lib/active_record/integration.rb
+++ b/activerecord/lib/active_record/integration.rb
@@ -49,7 +49,7 @@ def cache_key
       case
       when new_record?
         "#{self.class.model_name.cache_key}/new"
-      when timestamp = self[:updated_at]
+      when timestamp = max_updated_column_timestamp
         timestamp = timestamp.utc.to_s(cache_timestamp_format)
         "#{self.class.model_name.cache_key}/#{id}-#{timestamp}"
       else
diff --git a/activerecord/lib/active_record/timestamp.rb b/activerecord/lib/active_record/timestamp.rb
index 8ded6d4a8661d..ae99cff35e211 100644
--- a/activerecord/lib/active_record/timestamp.rb
+++ b/activerecord/lib/active_record/timestamp.rb
@@ -98,6 +98,12 @@ def all_timestamp_attributes
       timestamp_attributes_for_create + timestamp_attributes_for_update
     end
 
+    def max_updated_column_timestamp
+      if (timestamps = timestamp_attributes_for_update.map { |attr| self[attr] }.compact).present?
+        timestamps.map { |ts| ts.to_time }.max
+      end
+    end
+
     def current_time_from_proper_timezone
       self.class.default_timezone == :utc ? Time.now.utc : Time.now
     end
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index af1845c937986..5d558d5093658 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -1441,12 +1441,30 @@ def test_cache_key_changes_when_child_touched
     assert_not_equal key, car.cache_key
   end
 
-  def test_cache_key_format_for_existing_record_with_nil_updated_at
+  def test_cache_key_format_for_existing_record_with_nil_updated_timestamps
     dev = Developer.first
-    dev.update_columns(updated_at: nil)
+    dev.update_columns(updated_at: nil, updated_on: nil)
     assert_match(/\/#{dev.id}$/, dev.cache_key)
   end
 
+  def test_cache_key_for_updated_on
+    dev = Developer.first
+    dev.updated_at = nil
+    assert_equal "developers/#{dev.id}-#{dev.updated_on.utc.to_s(:nsec)}", dev.cache_key
+  end
+
+  def test_cache_key_for_newer_updated_at
+    dev = Developer.first
+    dev.updated_at += 3600
+    assert_equal "developers/#{dev.id}-#{dev.updated_at.utc.to_s(:nsec)}", dev.cache_key
+  end
+
+  def test_cache_key_for_newer_updated_on
+    dev = Developer.first
+    dev.updated_on += 3600
+    assert_equal "developers/#{dev.id}-#{dev.updated_on.utc.to_s(:nsec)}", 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
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index d789b6cb7a8c9..a323b1e7225e5 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -219,6 +219,8 @@ def create_table(*args, &block)
     t.integer  :salary, :default => 70000
     t.datetime :created_at
     t.datetime :updated_at
+    t.datetime :created_on
+    t.datetime :updated_on
   end
 
   create_table :developers_projects, :force => true, :id => false do |t|