From b9a6c990322d11a3aca83a19105d37d41ac5da52 Mon Sep 17 00:00:00 2001
From: Umherirrender <umherirrender_de.wp@web.de>
Date: Wed, 29 Sep 2021 14:43:22 +0200
Subject: [PATCH] Use WrappedString to build strings in MWDebug

This gives a small performance benefit on developer wikis when the html
page is build.

Change-Id: Ic90bde09500776ae24952d627e582fbce688e36c
---
 includes/OutputPage.php    |  6 ++---
 includes/debug/MWDebug.php | 48 +++++++++++++++++++++-----------------
 2 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/includes/OutputPage.php b/includes/OutputPage.php
index 1df9b2c50c6..3812d951c7f 100644
--- a/includes/OutputPage.php
+++ b/includes/OutputPage.php
@@ -4262,9 +4262,9 @@ class OutputPage extends ContextSource {
 			MWDebug::getDebugHTML( $skin ),
 			$this->getBottomScripts( $extraHtml ),
 			wfReportTime( $this->getCSP()->getNonce() ),
-			MWDebug::getHTMLDebugLog()
-			. Html::closeElement( 'body' )
-			. Html::closeElement( 'html' )
+			MWDebug::getHTMLDebugLog(),
+			Html::closeElement( 'body' ),
+			Html::closeElement( 'html' ),
 		];
 
 		return WrappedStringList::join( "\n", $tail );
diff --git a/includes/debug/MWDebug.php b/includes/debug/MWDebug.php
index 9e88aab139e..e76e76c1e84 100644
--- a/includes/debug/MWDebug.php
+++ b/includes/debug/MWDebug.php
@@ -21,6 +21,8 @@
  */
 
 use MediaWiki\Logger\LegacyLogger;
+use Wikimedia\WrappedString;
+use Wikimedia\WrappedStringList;
 
 /**
  * New debugger system that outputs a toolbar on page view.
@@ -604,12 +606,12 @@ class MWDebug {
 	 *
 	 * @since 1.19
 	 * @param IContextSource $context
-	 * @return string
+	 * @return WrappedStringList
 	 */
 	public static function getDebugHTML( IContextSource $context ) {
 		global $wgDebugComments;
 
-		$html = '';
+		$html = [];
 
 		if ( self::$enabled ) {
 			self::log( 'MWDebug output complete' );
@@ -617,19 +619,21 @@ class MWDebug {
 
 			// Cannot use OutputPage::addJsConfigVars because those are already outputted
 			// by the time this method is called.
-			$html = ResourceLoader::makeInlineScript(
+			$html[] = ResourceLoader::makeInlineScript(
 				ResourceLoader::makeConfigSetScript( [ 'debugInfo' => $debugInfo ] ),
 				$context->getOutput()->getCSP()->getNonce()
 			);
 		}
 
 		if ( $wgDebugComments ) {
-			$html .= "<!-- Debug output:\n" .
-				htmlspecialchars( implode( "\n", self::$debug ), ENT_NOQUOTES ) .
-				"\n\n-->";
+			$html[] = '<!-- Debug output:';
+			foreach ( self::$debug as $line ) {
+				$html[] = htmlspecialchars( $line, ENT_NOQUOTES );
+			}
+			$html[] = '-->';
 		}
 
-		return $html;
+		return WrappedString::join( "\n", $html );
 	}
 
 	/**
@@ -638,26 +642,26 @@ class MWDebug {
 	 * If $wgShowDebug is false, an empty string is always returned.
 	 *
 	 * @since 1.20
-	 * @return string HTML fragment
+	 * @return WrappedStringList HTML fragment
 	 */
 	public static function getHTMLDebugLog() {
 		global $wgShowDebug;
 
-		if ( !$wgShowDebug ) {
-			return '';
+		$html = [];
+		if ( $wgShowDebug ) {
+			$html[] = Html::openElement( 'div', [ 'id' => 'mw-html-debug-log' ] );
+			$html[] = "<hr />\n<strong>Debug data:</strong><ul id=\"mw-debug-html\">";
+
+			foreach ( self::$debug as $line ) {
+				$display = nl2br( htmlspecialchars( trim( $line ) ) );
+
+				$html[] = "<li><code>$display</code></li>";
+			}
+
+			$html[] = '</ul>';
+			$html[] = '</div>';
 		}
-
-		$ret = "\n<hr />\n<strong>Debug data:</strong><ul id=\"mw-debug-html\">\n";
-
-		foreach ( self::$debug as $line ) {
-			$display = nl2br( htmlspecialchars( trim( $line ) ) );
-
-			$ret .= "<li><code>$display</code></li>\n";
-		}
-
-		$ret .= '</ul>' . "\n";
-
-		return Html::rawElement( 'div', [ 'id' => 'mw-html-debug-log' ], $ret );
+		return WrappedString::join( "\n", $html );
 	}
 
 	/**