commit 9f6228794ad6faedc3550ffa69950660576013aa
Author: Reedy <reedy@wikimedia.org>
Date:   Mon Jul 18 00:44:11 2016 +0100

    Detect/use APCu properly
    
    In PHP 5.5 and above, userland APC caching moved to an extension
    
    Bug: T140587
    Change-Id: Ie0871776cd7e67838471a4fe95451cf4164079b7

diff --git a/includes/installer/Installer.php b/includes/installer/Installer.php
index 4d5aa7a..9384ca1 100644
--- a/includes/installer/Installer.php
+++ b/includes/installer/Installer.php
@@ -242,7 +242,8 @@ abstract class Installer {
 	 */
 	protected $objectCaches = [
 		'xcache' => 'xcache_get',
-		'apc' => 'apc_fetch',
+		'apc' => 'apcu_fetch',
+		'apcu' => 'apcu_fetch',
 		'wincache' => 'wincache_ucache_get'
 	];
 
diff --git a/includes/libs/MemoizedCallable.php b/includes/libs/MemoizedCallable.php
index 50e9732..c20c4ac 100644
--- a/includes/libs/MemoizedCallable.php
+++ b/includes/libs/MemoizedCallable.php
@@ -77,7 +77,9 @@ class MemoizedCallable {
 	 */
 	protected function fetchResult( $key, &$success ) {
 		$success = false;
-		if ( function_exists( 'apc_fetch' ) ) {
+		if ( function_exists( 'apcu_fetch' ) ) {
+			return apcu_fetch( $key, success );
+		} elseif ( function_exists( 'apc_fetch' ) ) {
 			return apc_fetch( $key, $success );
 		}
 		return false;
@@ -90,7 +92,9 @@ class MemoizedCallable {
 	 * @param mixed $result
 	 */
 	protected function storeResult( $key, $result ) {
-		if ( function_exists( 'apc_store' ) ) {
+		if ( function_exists( 'apcu_store' ) ) {
+			apcu_store( $key, $result, $this->ttl );
+		} elseif ( function_exists( 'apc_store' ) ) {
 			apc_store( $key, $result, $this->ttl );
 		}
 	}
diff --git a/includes/libs/objectcache/APCuBagOStuff.php b/includes/libs/objectcache/APCuBagOStuff.php
new file mode 100644
index 0000000..693e558
--- /dev/null
+++ b/includes/libs/objectcache/APCuBagOStuff.php
@@ -0,0 +1,67 @@
+<?php
+/**
+ * Object caching using PHP's APC accelerator.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup Cache
+ */
+
+/**
+ * This is a wrapper for APCu's shared memory functions
+ *
+ * @ingroup Cache
+ */
+class APCuBagOStuff extends APCBagOStuff {
+	/**
+	 * Constructor
+	 *
+	 * Available parameters are:
+	 *   - nativeSerialize:     If true, pass objects to apcu_store(), and trust it
+	 *                          to serialize them correctly. If false, serialize
+	 *                          all values in PHP.
+	 *
+	 * @param array $params
+	 */
+	public function __construct( array $params = [] ) {
+		parent::__construct( $params );
+	}
+
+	public function set( $key, $value, $exptime = 0, $flags = 0 ) {
+		if ( !$this->nativeSerialize && !$this->isInteger( $value ) ) {
+			$value = serialize( $value );
+		}
+
+		apcu_store( $key . self::KEY_SUFFIX, $value, $exptime );
+
+		return true;
+	}
+
+	public function delete( $key ) {
+		apcu_delete( $key . self::KEY_SUFFIX );
+
+		return true;
+	}
+
+	public function incr( $key, $value = 1 ) {
+		return apc_inc( $key . self::KEY_SUFFIX, $value );
+	}
+
+	public function decr( $key, $value = 1 ) {
+		return apc_dec( $key . self::KEY_SUFFIX, $value );
+	}
+}
diff --git a/includes/objectcache/ObjectCache.php b/includes/objectcache/ObjectCache.php
index e1bb2db..0891450 100644
--- a/includes/objectcache/ObjectCache.php
+++ b/includes/objectcache/ObjectCache.php
@@ -259,7 +259,9 @@ class ObjectCache {
 	 * @since 1.27
 	 */
 	public static function getLocalServerInstance( $fallback = CACHE_NONE ) {
-		if ( function_exists( 'apc_fetch' ) ) {
+		if ( function_exists( 'apcu_fetch' ) ) {
+			$id = 'apcu';
+		} elseif ( function_exists( 'apc_fetch' ) {
 			$id = 'apc';
 		} elseif ( function_exists( 'xcache_get' ) && wfIniGetBool( 'xcache.var_size' ) ) {
 			$id = 'xcache';
diff --git a/tests/phpunit/includes/libs/MemoizedCallableTest.php b/tests/phpunit/includes/libs/MemoizedCallableTest.php
index 6eb96b1..4d3a629 100644
--- a/tests/phpunit/includes/libs/MemoizedCallableTest.php
+++ b/tests/phpunit/includes/libs/MemoizedCallableTest.php
@@ -44,7 +44,7 @@ class MemoizedCallableTest extends PHPUnit_Framework_TestCase {
 	 * Consecutive calls to the memoized callable with the same arguments
 	 * should result in just one invocation of the underlying callable.
 	 *
-	 * @requires function apc_store
+	 * @requires function apcu_store/apc_store
 	 */
 	public function testCallableMemoized() {
 		$observer = $this->getMock( 'stdClass', [ 'computeSomething' ] );