QueryCache will just dup an AR::Result, AR::Result can deep copy

2 files changed, 21 insertions, 9 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
index 52f09efd53..6ba64bb88f 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
@@ -65,18 +65,24 @@ module ActiveRecord
       end
 
       private
-        def cache_sql(sql, binds)
-          result =
-            if @query_cache[sql].key?(binds)
-              ActiveSupport::Notifications.instrument("sql.active_record",
-                :sql => sql, :binds => binds, :name => "CACHE", :connection_id => object_id)
-              @query_cache[sql][binds]
-            else
-              @query_cache[sql][binds] = yield
-            end
+      def cache_sql(sql, binds)
+        result =
+          if @query_cache[sql].key?(binds)
+            ActiveSupport::Notifications.instrument("sql.active_record",
+              :sql => sql, :binds => binds, :name => "CACHE", :connection_id => object_id)
+            @query_cache[sql][binds]
+          else
+            @query_cache[sql][binds] = yield
+          end
 
+        # FIXME: we should guarantee that all cached items are Result
+        # objects.  Then we can avoid this conditional
+        if ActiveRecord::Result === result
+          result.dup
+        else
           result.collect { |row| row.dup }
         end
+      end
     end
   end
 end
diff --git a/activerecord/lib/active_record/result.rb b/activerecord/lib/active_record/result.rb
index 68389a21fb..60a2e90e23 100644
--- a/activerecord/lib/active_record/result.rb
+++ b/activerecord/lib/active_record/result.rb
@@ -43,6 +43,12 @@ module ActiveRecord
       hash_rows.last
     end
 
+    def initialize_copy(other)
+      @columns   = columns.dup
+      @rows      = rows.dup
+      @hash_rows = nil
+    end
+
     private
     def hash_rows
       @hash_rows ||= @rows.map { |row|