Make use of the list() feature where it makes sense

This code is functionally identical, but less error prone (not so easy
to forget or mix these numerical indexes).

This patch happens to touch the Parser, which might be a bit scary. We
can remove this file from this patch if you prefer.

Change-Id: I8cbe3a9a6725d1c42b86e67678c1af15fbc5961a

includes/Linker.php

@@ -1710,12 +1710,8 @@ class Linker {
 	static function splitTrail( $trail ) {
 		$regex = MediaWikiServices::getInstance()->getContentLanguage()->linkTrail();
 		$inside = '';
-		if ( $trail !== '' ) {
-			$m = [];
-			if ( preg_match( $regex, $trail, $m ) ) {
-				$inside = $m[1];
-				$trail = $m[2];
-			}
+		if ( $trail !== '' && preg_match( $regex, $trail, $m ) ) {
+			list( , $inside, $trail ) = $m;
 		}
 		return [ $inside, $trail ];
 	}

includes/cache/localisation/LCStoreStaticArray.php

@@ -101,8 +101,7 @@ class LCStoreStaticArray implements LCStore {
 			return $encoded;
 		}
 
-		$type = $encoded[0];
-		$data = $encoded[1];
+		list( $type, $data ) = $encoded;
 
 		switch ( $type ) {
 			case 'a':

includes/diff/DiffEngine.php

@@ -456,9 +456,7 @@ class DiffEngine {
 
 		// need to store these so we don't lose them when they're
 		// overwritten by the recursion
-		$len = $snake[2];
-		$startx = $snake[0];
-		$starty = $snake[1];
+		list( $startx, $starty, $len ) = $snake;
 
 		// the middle snake is part of the LCS, store it
 		for ( $i = 0; $i < $len; ++$i ) {

includes/gallery/TraditionalImageGallery.php

@@ -72,11 +72,9 @@ class TraditionalImageGallery extends ImageGalleryBase {
 		$lang = $this->getRenderLang();
 		# Output each image...
 		foreach ( $this->mImages as $pair ) {
+			// "text" means "caption" here
 			/** @var Title $nt */
-			$nt = $pair[0];
-			$text = $pair[1]; # "text" means "caption" here
-			$alt = $pair[2];
-			$link = $pair[3];
+			list( $nt, $text, $alt, $link ) = $pair;
 
 			$descQuery = false;
 			if ( $nt->getNamespace() === NS_FILE ) {

includes/installer/DatabaseUpdater.php

@@ -410,9 +410,7 @@ abstract class DatabaseUpdater {
 		$this->updatesSkipped = [];
 
 		foreach ( $updates as $funcList ) {
-			$func = $funcList[0];
-			$args = $funcList[1];
-			$origParams = $funcList[2];
+			list( $func, $args, $origParams ) = $funcList;
 			$func( ...$args );
 			flush();
 			$this->updatesSkipped[] = $origParams;

includes/libs/rdbms/database/DatabaseMysqli.php

@@ -78,9 +78,7 @@ class DatabaseMysqli extends DatabaseMysqlBase {
 		} elseif ( substr_count( $realServer, ':' ) == 1 ) {
 			// If we have a colon and something that's not a port number
 			// inside the hostname, assume it's the socket location
-			$hostAndSocket = explode( ':', $realServer, 2 );
-			$realServer = $hostAndSocket[0];
-			$socket = $hostAndSocket[1];
+			list( $realServer, $socket ) = explode( ':', $realServer, 2 );
 		}
 
 		$mysqli = mysqli_init();

includes/page/ImagePage.php

@@ -321,9 +321,7 @@ class ImagePage extends Article {
 		$dirmark = $lang->getDirMarkEntity();
 		$request = $this->getContext()->getRequest();
 
-		$max = $this->getImageLimitsFromOption( $user, 'imagesize' );
-		$maxWidth = $max[0];
-		$maxHeight = $max[1];
+		list( $maxWidth, $maxHeight ) = $this->getImageLimitsFromOption( $user, 'imagesize' );
 
 		if ( $this->displayImg->exists() ) {
 			# image
@@ -1029,7 +1027,7 @@ EOT
 	 *
 	 * @param User $user
 	 * @param string $optionName Name of a option to check, typically imagesize or thumbsize
-	 * @return array
+	 * @return int[]
 	 * @since 1.21
 	 */
 	public function getImageLimitsFromOption( $user, $optionName ) {

includes/parser/LinkHolderArray.php

@@ -632,8 +632,7 @@ class LinkHolderArray {
 	 * @private
 	 */
 	public function replaceTextCallback( $matches ) {
-		$type = $matches[1];
-		$key = $matches[2];
+		list( , $type, $key ) = $matches;
 		if ( $type == 'LINK' ) {
 			list( $ns, $index ) = explode( ':', $key, 2 );
 			if ( isset( $this->internals[$ns][$index]['text'] ) ) {

includes/parser/Parser.php

@@ -1045,10 +1045,7 @@ class Parser {
 				$inside = $p[5];
 			} else {
 				# tag
-				$element = $p[1];
-				$attributes = $p[2];
-				$close = $p[3];
-				$inside = $p[4];
+				list( , $element, $attributes, $close, $inside ) = $p;
 			}
 
 			$marker = self::MARKER_PREFIX . "-$element-" . sprintf( '%08X', $n++ ) . self::MARKER_SUFFIX;
@@ -1072,8 +1069,7 @@ class Parser {
 					$tail = '';
 					$text = '';
 				} else {
-					$tail = $q[1];
-					$text = $q[2];
+					list( , $tail, $text ) = $q;
 				}
 			}
 
@@ -2240,8 +2236,7 @@ class Parser {
 
 			if ( $useLinkPrefixExtension ) {
 				if ( preg_match( $e2, $s, $m ) ) {
-					$prefix = $m[2];
-					$s = $m[1];
+					list( , $s, $prefix ) = $m;
 				} else {
 					$prefix = '';
 				}

includes/utils/UIDGenerator.php

@@ -137,8 +137,7 @@ class UIDGenerator {
 			$time = $info['time'];
 			$counter = $info['offsetCounter'];
 		} else {
-			$time = $info[0];
-			$counter = $info[1];
+			list( $time, $counter ) = $info;
 		}
 		// Take the 46 LSBs of "milliseconds since epoch"
 		$id_bin = $this->millisecondsSinceEpochBinary( $time );
@@ -192,9 +191,7 @@ class UIDGenerator {
 			$counter = $info['offsetCounter'];
 			$clkSeq = $info['clkSeq'];
 		} else {
-			$time = $info[0];
-			$counter = $info[1];
-			$clkSeq = $info[2];
+			list( $time, $counter, $clkSeq ) = $info;
 		}
 		// Take the 46 LSBs of "milliseconds since epoch"
 		$id_bin = $this->millisecondsSinceEpochBinary( $time );

languages/classes/LanguageKk_cyrl.php

@@ -63,9 +63,7 @@ class LanguageKk_cyrl extends Language {
 		$secondPerson = [ "з" ]; // 1st plural, 2nd formal
 		$thirdPerson = [ "ы", "і" ]; // 3rd
 
-		$lastLetter = $this->lastLetter( $word, $allVowels );
-		$wordEnding =& $lastLetter[0];
-		$wordLastVowel =& $lastLetter[1];
+		list( $wordEnding, $wordLastVowel ) = $this->lastLetter( $word, $allVowels );
 
 		// Now convert the word
 		switch ( $case ) {
@@ -297,9 +295,7 @@ class LanguageKk_cyrl extends Language {
 		$secondPerson = [ "z" ]; // 1st plural, 2nd formal
 		$thirdPerson = [ "ı", "i" ]; // 3rd
 
-		$lastLetter = $this->lastLetter( $word, $allVowels );
-		$wordEnding =& $lastLetter[0];
-		$wordLastVowel =& $lastLetter[1];
+		list( $wordEnding, $wordLastVowel ) = $this->lastLetter( $word, $allVowels );
 
 		// Now convert the word
 		switch ( $case ) {
@@ -531,9 +527,7 @@ class LanguageKk_cyrl extends Language {
 		$secondPerson = [ "ز" ]; // 1st plural, 2nd formal
 		$thirdPerson = [ "ى", "ٸ" ]; // 3rd
 
-		$lastLetter = $this->lastLetter( $word, $allVowels );
-		$wordEnding = $lastLetter[0];
-		$wordLastVowel = $lastLetter[1];
+		list( $wordEnding, $wordLastVowel ) = $this->lastLetter( $word, $allVowels );
 
 		// Now convert the word
 		switch ( $case ) {
@@ -737,7 +731,7 @@ class LanguageKk_cyrl extends Language {
 
 	/**
 	 * @param string $word
-	 * @param array $allVowels
+	 * @param string[] $allVowels
 	 * @return array
 	 */
 	function lastLetter( $word, $allVowels ) {

maintenance/cleanupInvalidDbKeys.php

@@ -121,8 +121,7 @@ TEXT
 	 * @param array $tableParams A child array of self::$tables
 	 */
 	protected function cleanupTable( $tableParams ) {
-		$table = $tableParams[0];
-		$prefix = $tableParams[1];
+		list( $table, $prefix ) = $tableParams;
 		$idField = $tableParams['idField'] ?? "{$prefix}_id";
 		$nsField = $tableParams['nsField'] ?? "{$prefix}_namespace";
 		$titleField = $tableParams['titleField'] ?? "{$prefix}_title";

maintenance/includes/BackupDumper.php

@@ -163,8 +163,7 @@ abstract class BackupDumper extends Maintenance {
 
 		$options = $this->orderedOptions;
 		foreach ( $options as $arg ) {
-			$opt = $arg[0];
-			$param = $arg[1];
+			list( $opt, $param ) = $arg;
 
 			switch ( $opt ) {
 				case 'plugin':

maintenance/mysql.php

@@ -137,9 +137,7 @@ class MysqlMaintenance extends Maintenance {
 		} elseif ( substr_count( $realServer, ':' ) == 1 ) {
 			// If we have a colon and something that's not a port number
 			// inside the hostname, assume it's the socket location
-			$hostAndSocket = explode( ':', $realServer, 2 );
-			$realServer = $hostAndSocket[0];
-			$socket = $hostAndSocket[1];
+			list( $realServer, $socket ) = explode( ':', $realServer, 2 );
 		}
 
 		if ( $dbName === false ) {

tests/phpunit/includes/specials/QueryAllSpecialPagesTest.php

@@ -42,8 +42,7 @@ class QueryAllSpecialPagesTest extends MediaWikiTestCase {
 		parent::__construct();
 
 		foreach ( QueryPage::getPages() as $page ) {
-			$class = $page[0];
-			$name = $page[1];
+			list( $class, $name ) = $page;
 			if ( !in_array( $class, $this->manualTest ) ) {
 				$this->queryPages[$class] =
 					MediaWikiServices::getInstance()->getSpecialPageFactory()->getPage( $name );