objectcache: make BagOStuff::getMulti() preserve order and omit keys with missing...

A key missing segments should count as non-existing, meaning that it should
not appear in the return value at all

Change-Id: I0f08b3dba77e0d335ebb2d75061927ebd36570d2

diff --git a/includes/libs/objectcache/BagOStuff.php b/includes/libs/objectcache/BagOStuff.php
index c47f6ee..dce49c4 100644 (file)
--- a/includes/libs/objectcache/BagOStuff.php
+++ b/includes/libs/objectcache/BagOStuff.php
@@ -682,25 +682,33 @@ abstract class BagOStuff implements IExpiringStore, IStoreKeyEncoder, LoggerAwar
 
        /**
         * Get an associative array containing the item for each of the keys that have items.
-        * @param string[] $keys List of keys
+        * @param string[] $keys List of keys; can be a map of (unused => key) for convenience
         * @param int $flags Bitfield; supports READ_LATEST [optional]
-        * @return array Map of (key => value) for existing keys
+        * @return mixed[] Map of (key => value) for existing keys; preserves the order of $keys
         */
        public function getMulti( array $keys, $flags = 0 ) {
-               $valuesBykey = $this->doGetMulti( $keys, $flags );
-               foreach ( $valuesBykey as $key => $value ) {
+               $foundByKey = $this->doGetMulti( $keys, $flags );
+
+               $res = [];
+               foreach ( $keys as $key ) {
                        // Resolve one blob at a time (avoids too much I/O at once)
-                       $valuesBykey[$key] = $this->resolveSegments( $key, $value );
+                       if ( array_key_exists( $key, $foundByKey ) ) {
+                               // A value should not appear in the key if a segment is missing
+                               $value = $this->resolveSegments( $key, $foundByKey[$key] );
+                               if ( $value !== false ) {
+                                       $res[$key] = $value;
+                               }
+                       }
                }
 
-               return $valuesBykey;
+               return $res;
        }
 
        /**
         * Get an associative array containing the item for each of the keys that have items.
         * @param string[] $keys List of keys
         * @param int $flags Bitfield; supports READ_LATEST [optional]
-        * @return array Map of (key => value) for existing keys
+        * @return mixed[] Map of (key => value) for existing keys
         */
        protected function doGetMulti( array $keys, $flags = 0 ) {
                $res = [];