From 52e6121447a2215e6a867548a726d4c17790f6c0 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Tue, 9 Dec 2014 17:34:48 -0800
Subject: [PATCH] Cleaned up LoadBalancer::getConnection

* It will also no longer call getReaderIndex( false, ... ) twice
* Removed various related ampersands

Change-Id: Ia79e2007dbf84e7437f9439aa6371333aa3e1b23
---
 includes/GlobalFunctions.php |  4 ++--
 includes/db/LBFactory.php    |  2 +-
 includes/db/LoadBalancer.php | 20 ++++++++++----------
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/includes/GlobalFunctions.php b/includes/GlobalFunctions.php
index 14326ec29e..9cbf8157cd 100644
--- a/includes/GlobalFunctions.php
+++ b/includes/GlobalFunctions.php
@@ -3551,7 +3551,7 @@ function wfSplitWikiID( $wiki ) {
  *
  * @return DatabaseBase
  */
-function &wfGetDB( $db, $groups = array(), $wiki = false ) {
+function wfGetDB( $db, $groups = array(), $wiki = false ) {
 	return wfGetLB( $wiki )->getConnection( $db, $groups, $wiki );
 }
 
@@ -3570,7 +3570,7 @@ function wfGetLB( $wiki = false ) {
  *
  * @return LBFactory
  */
-function &wfGetLBFactory() {
+function wfGetLBFactory() {
 	return LBFactory::singleton();
 }
 
diff --git a/includes/db/LBFactory.php b/includes/db/LBFactory.php
index 0e89a5b064..4551e2d760 100644
--- a/includes/db/LBFactory.php
+++ b/includes/db/LBFactory.php
@@ -43,7 +43,7 @@ abstract class LBFactory {
 	 *
 	 * @return LBFactory
 	 */
-	public static function &singleton() {
+	public static function singleton() {
 		global $wgLBFactoryConf;
 
 		if ( is_null( self::$instance ) ) {
diff --git a/includes/db/LoadBalancer.php b/includes/db/LoadBalancer.php
index 07645bdd85..90e8867aeb 100644
--- a/includes/db/LoadBalancer.php
+++ b/includes/db/LoadBalancer.php
@@ -438,7 +438,7 @@ class LoadBalancer {
 	 * @throws MWException
 	 * @return DatabaseBase
 	 */
-	public function &getConnection( $i, $groups = array(), $wiki = false ) {
+	public function getConnection( $i, $groups = array(), $wiki = false ) {
 		wfProfileIn( __METHOD__ );
 
 		if ( $i === null || $i === false ) {
@@ -451,17 +451,14 @@ class LoadBalancer {
 			$wiki = false;
 		}
 
-		# Query groups
+		$groups = ( $groups === false || $groups === array() )
+			? array( false ) // check one "group": the generic pool
+			: (array)$groups;
+
 		if ( $i == DB_MASTER ) {
 			$i = $this->getWriterIndex();
-		} elseif ( !is_array( $groups ) ) {
-			$groupIndex = $this->getReaderIndex( $groups, $wiki );
-			if ( $groupIndex !== false ) {
-				$serverName = $this->getServerName( $groupIndex );
-				wfDebug( __METHOD__ . ": using server $serverName for group $groups\n" );
-				$i = $groupIndex;
-			}
 		} else {
+			# Try to find an available server in any the query groups (in order)
 			foreach ( $groups as $group ) {
 				$groupIndex = $this->getReaderIndex( $group, $wiki );
 				if ( $groupIndex !== false ) {
@@ -476,7 +473,10 @@ class LoadBalancer {
 		# Operation-based index
 		if ( $i == DB_SLAVE ) {
 			$this->mLastError = 'Unknown error'; // reset error string
-			$i = $this->getReaderIndex( false, $wiki );
+			# Try the general server pool if $groups are unavailable.
+			$i = in_array( false, $groups, true )
+				? false // don't bother with this if that is what was tried above
+				: $this->getReaderIndex( false, $wiki );
 			# Couldn't find a working server in getReaderIndex()?
 			if ( $i === false ) {
 				$this->mLastError = 'No working slave server: ' . $this->mLastError;
-- 
2.20.1