Merge pull request #9105 from bemurphy/cache_key_updated_on

cache_key consults updated_on timestamp if present

Conflicts:
	activerecord/CHANGELOG.md

2 files changed, 7 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb
index 32d35f0ec1..48c73d7781 100644
--- a/activerecord/lib/active_record/integration.rb
+++ b/activerecord/lib/active_record/integration.rb
@@ -49,7 +49,7 @@ module ActiveRecord
       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 8ded6d4a86..ae99cff35e 100644
--- a/activerecord/lib/active_record/timestamp.rb
+++ b/activerecord/lib/active_record/timestamp.rb
@@ -98,6 +98,12 @@ module ActiveRecord
       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