Support redirects in JavaScriptContent

When a JavaScript page is moved, a "redirect" in the form of
mw.loader.load(...) will be left behind, so any other
JavaScript loading the page that way will still work, albeit
with an extra HTTP request.

This also implements Content::getRedirectTarget(), so redirects
are marked properly in the database, and users viewing them
are redirected properly. A magic "/* #REDIRECT */" comment
must be in front of the mw.loader.load call. This is done so
that pages which currently are just one mw.loader.load call
aren't turned into redirects.

Bug: 71200
Bug: 33973
Change-Id: I10fdff087a901da56fad64531f0e382f90ebcf37

includes/MediaWiki.php

@@ -363,9 +363,8 @@ class MediaWiki {
 			$this->context->setWikiPage( $article->getPage() );
 		}
 
-		// NS_MEDIAWIKI has no redirects.
-		// It is also used for CSS/JS, so performance matters here...
-		if ( $title->getNamespace() == NS_MEDIAWIKI ) {
+		// Skip some unnecessary code if the content model doesn't support redirects
+		if ( !ContentHandler::getForTitle( $title )->supportsRedirects() ) {
 			return $article;
 		}
 

includes/content/JavaScriptContent.php

@@ -32,6 +32,11 @@
  */
 class JavaScriptContent extends TextContent {
 
+	/**
+	 * @var bool|Title|null
+	 */
+	private $redirectTarget = false;
+
 	/**
 	 * @param string $text JavaScript code.
 	 * @param string $modelId the content model name
@@ -73,4 +78,46 @@ class JavaScriptContent extends TextContent {
 		return $html;
 	}
 
+	/**
+	 * If this page is a redirect, return the content
+	 * if it should redirect to $target instead
+	 *
+	 * @param Title $target
+	 * @return JavaScriptContent
+	 */
+	public function updateRedirect( Title $target ) {
+		if ( !$this->isRedirect() ) {
+			return $this;
+		}
+
+		return $this->getContentHandler()->makeRedirectContent( $target );
+	}
+
+	/**
+	 * @return Title|null
+	 */
+	public function getRedirectTarget() {
+		if ( $this->redirectTarget !== false ) {
+			return $this->redirectTarget;
+		}
+		$this->redirectTarget = null;
+		$text = $this->getNativeData();
+		if ( strpos( $text, '/* #REDIRECT */' ) === 0 ) {
+			// Extract the title from the url
+			preg_match( '/title=(.*?)\\\\u0026action=raw/', $text, $matches );
+			if ( isset( $matches[1] ) ) {
+				$title = Title::newFromText( $matches[1] );
+				if ( $title ) {
+					// Have a title, check that the current content equals what
+					// the redirect content should be
+					if ( $this->equals( $this->getContentHandler()->makeRedirectContent( $title ) ) ) {
+						$this->redirectTarget = $title;
+					}
+				}
+			}
+		}
+
+		return $this->redirectTarget;
+	}
+
 }

includes/content/JavaScriptContentHandler.php

@@ -41,4 +41,22 @@ class JavaScriptContentHandler extends CodeContentHandler {
 	protected function getContentClass() {
 		return 'JavaScriptContent';
 	}
+
+	public function supportsRedirects() {
+		return true;
+	}
+
+	/**
+	 * Create a redirect that is also valid JavaScript
+	 *
+	 * @param Title $destination
+	 * @param string $text ignored
+	 * @return JavaScriptContent
+	 */
+	public function makeRedirectContent( Title $destination, $text = '' ) {
+		// The parameters are passed as a string so the / is not url-encoded by wfArrayToCgi
+		$url = $destination->getFullURL( 'action=raw&ctype=text/javascript', false, PROTO_RELATIVE );
+		$class = $this->getContentClass();
+		return new $class( '/* #REDIRECT */' . Xml::encodeJsCall( 'mw.loader.load', array( $url ) ) );
+	}
 }

includes/resourceloader/ResourceLoaderWikiModule.php

@@ -149,7 +149,7 @@ class ResourceLoaderWikiModule extends ResourceLoaderModule {
 	 */
 	protected function getContent( $titleText ) {
 		$title = Title::newFromText( $titleText );
-		if ( !$title || $title->isRedirect() ) {
+		if ( !$title ) {
 			return null;
 		}
 

tests/phpunit/includes/content/CssContentTest.php

@@ -4,6 +4,8 @@
  * @group ContentHandler
  * @group Database
  *        ^--- needed, because we do need the database to test link updates
+ *
+ * @FIXME this should not extend JavaScriptContentTest.
  */
 class CssContentTest extends JavaScriptContentTest {
 
@@ -68,7 +70,28 @@ class CssContentTest extends JavaScriptContentTest {
 		$this->assertEquals( CONTENT_MODEL_CSS, $content->getContentHandler()->getModelID() );
 	}
 
-	public static function dataEquals() {
+	/**
+	 * Redirects aren't supported
+	 */
+	public static function provideUpdateRedirect() {
+		return array(
+			array(
+				'#REDIRECT [[Someplace]]',
+				'#REDIRECT [[Someplace]]',
+			),
+		);
+	}
+
+	/**
+	 * Override this since CssContent does not support redirects yet
+	 */
+	public static function provideGetRedirectTarget() {
+		return array(
+			array( null, '' ),
+		);
+	}
+
+		public static function dataEquals() {
 		return array(
 			array( new CssContent( 'hallo' ), null, false ),
 			array( new CssContent( 'hallo' ), new CssContent( 'hallo' ), true ),

tests/phpunit/includes/content/JavaScriptContentHandlerTest.php

@@ -0,0 +1,30 @@
+<?php
+
+class JavaScriptContentHandlerTest extends MediaWikiTestCase {
+
+	/**
+	 * @dataProvider provideMakeRedirectContent
+	 * @covers JavaScriptContentHandler::makeRedirectContent
+	 */
+	public function testMakeRedirectContent( $title, $expected ) {
+		$this->setMwGlobals( array(
+			'wgServer' => '//example.org',
+			'wgScript' => '/w/index.php',
+		) );
+		$ch = new JavaScriptContentHandler();
+		$content = $ch->makeRedirectContent( Title::newFromText( $title ) );
+		$this->assertInstanceOf( 'JavaScriptContent', $content );
+		$this->assertEquals( $expected, $content->serialize( CONTENT_FORMAT_JAVASCRIPT ) );
+	}
+
+	/**
+	 * Keep this in sync with JavaScriptContentTest::provideGetRedirectTarget()
+	 */
+	public static function provideMakeRedirectContent() {
+		return array(
+			array( 'MediaWiki:MonoBook.js', '/* #REDIRECT */mw.loader.load("//example.org/w/index.php?title=MediaWiki:MonoBook.js\u0026action=raw\u0026ctype=text/javascript");' ),
+			array( 'User:FooBar/common.js', '/* #REDIRECT */mw.loader.load("//example.org/w/index.php?title=User:FooBar/common.js\u0026action=raw\u0026ctype=text/javascript");' ),
+			array( 'Gadget:FooBaz.js', '/* #REDIRECT */mw.loader.load("//example.org/w/index.php?title=Gadget:FooBaz.js\u0026action=raw\u0026ctype=text/javascript");' ),
+		);
+	}
+}

tests/phpunit/includes/content/JavaScriptContentTest.php

@@ -251,16 +251,31 @@ class JavaScriptContentTest extends TextContentTest {
 
 	/**
 	 * @covers JavaScriptContent::updateRedirect
+	 * @dataProvider provideUpdateRedirect
 	 */
-	public function testUpdateRedirect() {
+	public function testUpdateRedirect( $oldText, $expectedText) {
+		$this->setMwGlobals( array(
+			'wgServer' => '//example.org',
+			'wgScriptPath' => '/w/index.php',
+		) );
 		$target = Title::newFromText( "testUpdateRedirect_target" );
 
-		$content = $this->newContent( "#REDIRECT [[Someplace]]" );
+		$content = new JavaScriptContent( $oldText );
 		$newContent = $content->updateRedirect( $target );
 
-		$this->assertTrue(
-			$content->equals( $newContent ),
-			"content should be unchanged since it's not wikitext"
+		$this->assertEquals( $expectedText, $newContent->getNativeData() );
+	}
+
+	public static function provideUpdateRedirect() {
+		return array(
+			array(
+				'#REDIRECT [[Someplace]]',
+				'#REDIRECT [[Someplace]]',
+			),
+			array(
+				'/* #REDIRECT */mw.loader.load("//example.org/w/index.php?title=MediaWiki:MonoBook.js\u0026action=raw\u0026ctype=text/javascript");',
+				'/* #REDIRECT */mw.loader.load("//example.org/w/index.php?title=TestUpdateRedirect_target\u0026action=raw\u0026ctype=text/javascript");'
+			)
 		);
 	}
 
@@ -290,4 +305,32 @@ class JavaScriptContentTest extends TextContentTest {
 			array( new JavaScriptContent( "hallo" ), new JavaScriptContent( "HALLO" ), false ),
 		);
 	}
+
+	/**
+	 * @dataProvider provideGetRedirectTarget
+	 */
+	public function testGetRedirectTarget( $title, $text ) {
+		$this->setMwGlobals( array(
+			'wgServer' => '//example.org',
+			'wgScriptPath' => '/w/index.php',
+		) );
+		$content = new JavaScriptContent( $text );
+		$target = $content->getRedirectTarget();
+		$this->assertEquals( $title, $target ? $target->getPrefixedText() : null );
+	}
+
+	/**
+	 * Keep this in sync with JavaScriptContentHandlerTest::provideMakeRedirectContent()
+	 */
+	public static function provideGetRedirectTarget() {
+		return array(
+			array( 'MediaWiki:MonoBook.js', '/* #REDIRECT */mw.loader.load("//example.org/w/index.php?title=MediaWiki:MonoBook.js\u0026action=raw\u0026ctype=text/javascript");' ),
+			array( 'User:FooBar/common.js', '/* #REDIRECT */mw.loader.load("//example.org/w/index.php?title=User:FooBar/common.js\u0026action=raw\u0026ctype=text/javascript");' ),
+			array( 'Gadget:FooBaz.js', '/* #REDIRECT */mw.loader.load("//example.org/w/index.php?title=Gadget:FooBaz.js\u0026action=raw\u0026ctype=text/javascript");' ),
+			// No #REDIRECT comment
+			array( null, 'mw.loader.load("//example.org/w/index.php?title=MediaWiki:NoRedirect.js\u0026action=raw\u0026ctype=text/javascript");' ),
+			// Different domain
+			array( null, '/* #REDIRECT */mw.loader.load("//example.com/w/index.php?title=MediaWiki:OtherWiki.js\u0026action=raw\u0026ctype=text/javascript");' ),
+		);
+	}
 }