From 9e82828825536bfd60600af46ed5c33ffbc95303 Mon Sep 17 00:00:00 2001
From: Tim Starling <tstarling@users.mediawiki.org>
Date: Wed, 19 Mar 2008 11:19:00 +0000
Subject: [PATCH] Fixed no-op update query in common code path

---
 includes/Article.php  | 38 +++++++++++++++++++++-----------------
 includes/Database.php |  3 +--
 2 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/includes/Article.php b/includes/Article.php
index 33e21ec5ec..25157081d1 100644
--- a/includes/Article.php
+++ b/includes/Article.php
@@ -3372,31 +3372,35 @@ class Article {
 		$insertCats = array_merge( $added, $deleted );
 		$insertRows = array();
 		foreach( $insertCats as $cat ) {
-			$insertRows []= array( 'cat_title' => $cat );
+			$insertRows[] = array( 'cat_title' => $cat );
 		}
 		$dbw->insert( 'category', $insertRows, __METHOD__, 'IGNORE' );
 
 		$addFields    = array( 'cat_pages = cat_pages + 1' );
 		$removeFields = array( 'cat_pages = cat_pages - 1' );
 		if( $ns == NS_CATEGORY ) {
-			$addFields    []= 'cat_subcats = cat_subcats + 1';
-			$removeFields []= 'cat_subcats = cat_subcats - 1';
+			$addFields[]    = 'cat_subcats = cat_subcats + 1';
+			$removeFields[] = 'cat_subcats = cat_subcats - 1';
 		} elseif( $ns == NS_IMAGE ) {
-			$addFields    []= 'cat_files = cat_files + 1';
-			$removeFields []= 'cat_files = cat_files - 1';
+			$addFields[]    = 'cat_files = cat_files + 1';
+			$removeFields[] = 'cat_files = cat_files - 1';
 		}
 
-		$dbw->update(
-			'category',
-			$addFields,
-			array( 'cat_title' => $added ),
-			__METHOD__
-		);
-		$dbw->update(
-			'category',
-			$removeFields,
-			array( 'cat_title' => $deleted ),
-			__METHOD__
-		);
+		if ( $added ) {
+			$dbw->update(
+				'category',
+				$addFields,
+				array( 'cat_title' => $added ),
+				__METHOD__
+			);
+		}
+		if ( $deleted ) {
+			$dbw->update(
+				'category',
+				$removeFields,
+				array( 'cat_title' => $deleted ),
+				__METHOD__
+			);
+		}
 	}
 }
diff --git a/includes/Database.php b/includes/Database.php
index 5863750331..e9db0a38d2 100644
--- a/includes/Database.php
+++ b/includes/Database.php
@@ -1569,8 +1569,7 @@ class Database {
 				$list .= "$value";
 			} elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
 				if( count( $value ) == 0 ) {
-					// Empty input... or should this throw an error?
-					$list .= '0';
+					throw new MWException( __METHOD__.': empty input' );
 				} elseif( count( $value ) == 1 ) {
 					// Special-case single values, as IN isn't terribly efficient
 					$list .= $field." = ".$this->addQuotes( $value[0] );
-- 
2.20.1