Merge pull request #405 from SemanticMediaWiki/hotfix-linksupdate

MW 1.23+ / Hotfix for empty ParserOutput caused by RefreshLinksJob

includes/src/MediaWiki/Hooks/LinksUpdateConstructed.php

@@ -3,15 +3,16 @@
 namespace SMW\MediaWiki\Hooks;
 
 use SMW\Application;
+use SMW\ContentParser;
+use SMW\SemanticData;
+
 use LinksUpdate;
 
 /**
- * LinksUpdateConstructed hook is called at the end of LinksUpdate() is contruction
+ * LinksUpdateConstructed hook is called at the end of LinksUpdate()
  *
  * @see http://www.mediawiki.org/wiki/Manual:Hooks/LinksUpdateConstructed
  *
- * @ingroup FunctionHook
- *
  * @license GNU GPL v2+
  * @since 1.9
  *
@@ -24,6 +25,11 @@ class LinksUpdateConstructed {
 	 */
 	protected $linksUpdate = null;
 
+	/**
+	 * @var Application
+	 */
+	private $application = null;
+
 	/**
 	 * @since  1.9
 	 *
@@ -40,17 +46,49 @@ public function __construct( LinksUpdate $linksUpdate ) {
 	 */
 	public function process() {
 
+		$this->application = Application::getInstance();
+
 		/**
 		 * @var ParserData $parserData
 		 */
-		$parserData = Application::getInstance()->newParserData(
-			$this->linksUpdate->getTitle(),
-			$this->linksUpdate->getParserOutput()
-		);
+		$parserData = $this->application
+			->newParserData( $this->linksUpdate->getTitle(), $this->linksUpdate->getParserOutput() );
+
+		if ( $parserData->getSemanticData()->isEmpty() &&
+			( $semanticData = $this->refetchSemanticData() ) instanceOf SemanticData ) {
+			$parserData->setSemanticData( $semanticData );
+		}
 
 		$parserData->updateStore();
 
 		return true;
 	}
 
+	/**
+	 * #347 showed that an external process (e.g. RefreshLinksJob) can inject a
+	 * ParserOutput without SemanticData which forces the Store updater to create
+	 * an empty container and clear all existing data. To ensure that for a Title
+	 * and its current revision are really "empty" (e.g. delete action initiated
+	 * by a human) content is re-parsed
+	 *
+	 * @note Parsing is expensive but it is more expensive to loose data or to
+	 * expect that MW adheres the object contract
+	 */
+	private function refetchSemanticData() {
+		wfDebug( __METHOD__ . ' Empty SemanticData / re-parsing: ' . $this->linksUpdate->getTitle()->getPrefixedDBkey() . "\n" );
+
+		$contentParser = $this->application->newContentParser( $this->linksUpdate->getTitle() );
+		$parserOutput = $contentParser->parse()->getOutput();
+
+		if ( $parserOutput === null ) {
+			return null;
+		}
+
+		if ( method_exists( $parserOutput, 'getExtensionData' ) ) {
+			return $parserOutput->getExtensionData( 'smwdata' );
+		}
+
+		return $parserOutput->mSMWData;
+	}
+
 }

tests/phpunit/Integration/MediaWiki/LinksUpdateEmptyParserOutputDBIntegrationTest.php

@@ -0,0 +1,64 @@
+<?php
+
+namespace SMW\Tests\Integration\MediaWiki;
+
+use SMW\Tests\Util\SemanticDataValidator;
+use SMW\Tests\Util\ParserFactory;
+use SMW\Tests\Util\PageCreator;
+use SMW\Tests\MwDBaseUnitTestCase;
+
+use SMW\ContentParser;
+use SMW\ParserData;
+use SMW\DIWikiPage;
+
+use Title;
+use LinksUpdate;
+use ParserOutput;
+
+/**
+ * @ingroup Test
+ *
+ * @group SMW
+ * @group SMWExtension
+ * @group semantic-mediawiki-integration
+ * @group mediawiki-databaseless
+ * @group medium
+ *
+ * @license GNU GPL v2+
+ * @since   2.0
+ *
+ * @author mwjames
+ */
+class LinksUpdateEmptyParserOutputDBIntegrationTest extends MwDBaseUnitTestCase {
+
+	public function testDoUpdate() {
+
+		$title   = Title::newFromText( __METHOD__ );
+		$subject = DIWikiPage::newFromTitle( $title );
+
+		$pageCreator = new PageCreator();
+
+		$pageCreator
+			->createPage( $title )
+			->doEdit( '[[Has some property::LinksUpdateConstructedOnEmptyParserOutput]]' );
+
+		$propertiesCountBeforeUpdate = count( $this->getStore()->getSemanticData( $subject )->getProperties() );
+
+		/**
+		 * See #347 and LinksUpdateConstructed
+		 */
+		$linksUpdate = new LinksUpdate( $title, new ParserOutput() );
+		$linksUpdate->doUpdate();
+
+		/**
+		 * Asserts that before and after the update, the SemanticData container
+		 * holds the same amount of properties despite the fact that the ParserOutput
+		 * was invoked empty
+		 */
+		$this->assertCount(
+			$propertiesCountBeforeUpdate,
+			$this->getStore()->getSemanticData( $subject )->getProperties()
+		);
+	}
+
+}

tests/phpunit/Integration/MediaWiki/LinksUpdateSQLStoreDBIntegrationTest.php

@@ -231,7 +231,7 @@ public function propertyCountProvider() {
 					'msg'     => 'Asserts property Aa, Fuyu, _SKEY, and _MDAT from the previous state as no update has been made yet'
 				),
 				'poAfter'    => array(
-					'count'  => 1,
+					'count'  => 0,
 					'msg'    => 'Asserts property _MDAT exists after the update'
 				),
 				'storeAfter' => array(