Merge "objectcache: tweak SqlBagOStuff purging to happen on write only"

diff --combined includes/libs/objectcache/BagOStuff.php
index d7137d5,1dd46f7..00bf57d
--- 1/includes/libs/objectcache/BagOStuff.php
--- 2/includes/libs/objectcache/BagOStuff.php
+++ b/includes/libs/objectcache/BagOStuff.php
@@@ -61,7 -61,7 +61,7 @@@ use Wikimedia\WaitConditionLoop
   *
   * @ingroup Cache
   */
 -abstract class BagOStuff implements IExpiringStore, LoggerAwareInterface {
 +abstract class BagOStuff implements IExpiringStore, IStoreKeyEncoder, LoggerAwareInterface {
        /** @var array[] Lock tracking */
        protected $locks = [];
        /** @var int ERR_* class constant */
@@@ -655,11 -655,12 +655,12 @@@
         * @param string $date The reference date in MW format
         * @param callable|bool $progressCallback Optional, a function which will be called
         *     regularly during long-running operations with the percentage progress
-        *     as the first parameter.
+        *     as the first parameter. [optional]
+        * @param int $limit Maximum number of keys to delete [default: INF]
         *
         * @return bool Success, false if unimplemented
         */
-       public function deleteObjectsExpiringBefore( $date, $progressCallback = false ) {
+       public function deleteObjectsExpiringBefore( $date, $progressCallback = false, $limit = INF ) {
                // stub
                return false;
        }