Forward-compat for merging CacheTime and ParserOutput mOptions

CacheTime::mUsedOptions and ParserOutput::mAccessedOptions
do exactly the same thing and has to be merged into a single property.
This patch adds forward-compatibility and needs to be deployed
at least one train before the patch which actually merges the properties.

Change-Id: Ic9d71a443994e2545ebf2a826b9155c82961cb88

autoload.php

@@ -1886,6 +1886,7 @@ $wgAutoloadLocalClasses = [
 	'Wikimedia\\Rdbms\\TimestampType' => __DIR__ . '/includes/libs/rdbms/database/TimestampType.php',
 	'Wikimedia\\Rdbms\\TinyIntType' => __DIR__ . '/includes/libs/rdbms/database/TinyIntType.php',
 	'Wikimedia\\Rdbms\\TransactionProfiler' => __DIR__ . '/includes/libs/rdbms/TransactionProfiler.php',
+	'Wikimedia\\Reflection\\GhostFieldAccessTrait' => __DIR__ . '/includes/libs/GhostFieldAccessTrait.php',
 	'WikitextContent' => __DIR__ . '/includes/content/WikitextContent.php',
 	'WikitextContentHandler' => __DIR__ . '/includes/content/WikitextContentHandler.php',
 	'WikitextLogFormatter' => __DIR__ . '/includes/logging/WikitextLogFormatter.php',

includes/libs/GhostFieldAccessTrait.php

@@ -0,0 +1,69 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+namespace Wikimedia\Reflection;
+
+/**
+ * Trait for accessing "ghost fields".
+ *
+ * Ghost fields are fields that have been created in an object instance
+ * by PHP's unserialize() mechanism, though they no longer exist
+ * in the current version of the corresponding class.
+ *
+ * Accessing non-public ghost fields offers some challenges due to
+ * how they are handled by PHP internally.
+ *
+ * @see https://www.php.net/manual/en/language.types.array.php#language.types.array.casting
+ * @since 1.36
+ */
+trait GhostFieldAccessTrait {
+
+	/**
+	 * Get the value of the ghost field named $name,
+	 * or null if the field does not exist.
+	 *
+	 * @param string $name
+	 * @return mixed|null
+	 */
+	private function getGhostFieldValue( string $name ) {
+		if ( isset( $this->$name ) ) {
+			return $this->$name;
+		}
+
+		$data = (array)$this;
+
+		// Protected variables have a '*' prepended to the variable name.
+		// These prepended values have null bytes on either side.
+		$protectedName = "\x00*\x00{$name}";
+		if ( isset( $data[$protectedName] ) ) {
+			return $data[$protectedName];
+		}
+
+		// Private variables have the class name prepended to the variable name.
+		// These prepended values have null bytes on either side.
+		$thisClass = get_class( $this );
+		$privateName = "\x00{$thisClass}\x00{$name}";
+		if ( isset( $data[$privateName] ) ) {
+			return $data[$privateName];
+		}
+
+		return null;
+	}
+}

includes/parser/CacheTime.php

@@ -22,6 +22,7 @@
  */
 
 use MediaWiki\Parser\ParserCacheMetadata;
+use Wikimedia\Reflection\GhostFieldAccessTrait;
 
 /**
  * Parser cache specific expiry check.
@@ -29,6 +30,7 @@ use MediaWiki\Parser\ParserCacheMetadata;
  * @ingroup Parser
  */
 class CacheTime implements ParserCacheMetadata, JsonSerializable {
+	use GhostFieldAccessTrait;
 
 	/**
 	 * @var string[] ParserOptions which have been taken into account to produce output.
@@ -264,10 +266,22 @@ class CacheTime implements ParserCacheMetadata, JsonSerializable {
 	 * @param array $jsonData
 	 */
 	protected function initFromJson( array $jsonData ) {
-		$this->mUsedOptions = $jsonData['UsedOptions'];
+		if ( array_key_exists( 'ParseUsedOptions', $jsonData ) ) {
+			// Forward compatibility
+			$this->mUsedOptions = array_keys( $jsonData['ParseUsedOptions'] ?: [] );
+		} else {
+			$this->mUsedOptions = $jsonData['UsedOptions'];
+		}
 		$this->mCacheExpiry = $jsonData['CacheExpiry'];
 		$this->mCacheTime = $jsonData['CacheTime'];
 		$this->mCacheRevisionId = $jsonData['CacheRevisionId'];
 		$this->mVersion = $jsonData['Version']; // XXX: we can probably remove this
 	}
+
+	public function __wakeup() {
+		$forwardCompatOptions = $this->getGhostFieldValue( 'mParseUsedOptions' );
+		if ( $forwardCompatOptions ) {
+			$this->mUsedOptions = array_keys( $forwardCompatOptions );
+		}
+	}
 }

includes/parser/ParserOutput.php

@@ -1,6 +1,7 @@
 <?php
 
 use MediaWiki\Logger\LoggerFactory;
+use Wikimedia\Reflection\GhostFieldAccessTrait;
 
 /**
  * Output of the PHP parser.
@@ -25,6 +26,8 @@ use MediaWiki\Logger\LoggerFactory;
  */
 
 class ParserOutput extends CacheTime {
+	use GhostFieldAccessTrait;
+
 	/**
 	 * Feature flags to indicate to extensions that MediaWiki core supports and
 	 * uses getText() stateless transforms.
@@ -1785,6 +1788,7 @@ class ParserOutput extends CacheTime {
 	 */
 	protected function initFromJson( array $jsonData ) {
 		parent::initFromJson( $jsonData );
+		$this->mUsedOptions = null;
 
 		$this->mText = $jsonData['Text'];
 		$this->mLanguageLinks = $jsonData['LanguageLinks'];
@@ -1814,7 +1818,12 @@ class ParserOutput extends CacheTime {
 		$this->mTimestamp = $jsonData['Timestamp'];
 		$this->mEnableOOUI = $jsonData['EnableOOUI'];
 		$this->mIndexPolicy = $jsonData['IndexPolicy'];
-		$this->mAccessedOptions = $jsonData['AccessedOptions'];
+		if ( array_key_exists( 'ParseUsedOptions', $jsonData ) ) {
+			// Forward compatibility
+			$this->mAccessedOptions = $jsonData['ParseUsedOptions'];
+		} else {
+			$this->mAccessedOptions = $jsonData['AccessedOptions'];
+		}
 		$this->mExtensionData = $jsonData['ExtensionData'];
 		$this->mLimitReportData = $jsonData['LimitReportData'];
 		$this->mLimitReportJSData = $jsonData['LimitReportJSData'];
@@ -1876,4 +1885,12 @@ class ParserOutput extends CacheTime {
 
 		return $properties;
 	}
+
+	public function __wakeup() {
+		$forwardOptions = $this->getGhostFieldValue( 'mParseUsedOptions' );
+		if ( $forwardOptions ) {
+			$this->mAccessedOptions = $forwardOptions;
+			$this->mUsedOptions = null;
+		}
+	}
 }

tests/common/TestsAutoLoader.php

@@ -140,10 +140,10 @@ $wgAutoloadClasses += [
 	'ParserIntegrationTest' => "$testDir/phpunit/suites/ParserIntegrationTest.php",
 	'MediaWiki\Tests\Parser\ParserCacheSerializationTestCases' =>
 		"$testDir/phpunit/includes/parser/ParserCacheSerializationTestCases.php",
-	'MediaWiki\Tests\Parser\SerializationTestTrait' =>
-		"$testDir/phpunit/includes/parser/SerializationTestTrait.php",
-	'MediaWiki\Tests\Parser\SerializationTestUtils' =>
-		"$testDir/phpunit/includes/parser/SerializationTestUtils.php",
+	'Wikimedia\Tests\SerializationTestTrait' =>
+		"$testDir/phpunit/includes/libs/serialization/SerializationTestTrait.php",
+	'Wikimedia\Tests\SerializationTestUtils' =>
+		"$testDir/phpunit/includes/libs/serialization/SerializationTestUtils.php",
 
 	# tests/phpunit/includes/resourceloader
 	'ResourceLoaderImageModuleTest' =>
@@ -223,6 +223,7 @@ $wgAutoloadClasses += [
 
 	# tests/phpunit/unit/includes
 	'BadFileLookupTest' => "$testDir/phpunit/unit/includes/BadFileLookupTest.php",
+	'Wikimedia\\Reflection\\GhostFieldTestClass' => "$testDir/phpunit/mocks/GhostFieldTestClass.php",
 
 	# tests/phpunit/unit/includes/editpage/Constraint and tests/phpunit/integration/includes/editpage/Constraint
 	'EditConstraintTestTrait' => "$testDir/phpunit/unit/includes/editpage/Constraint/EditConstraintTestTrait.php",

tests/phpunit/data/ParserCache/1.36_fc-CacheTime-usedOptions.json

@@ -0,0 +1 @@
+{"_type_":"CacheTime","ParseUsedOptions":{"optA":true,"optX":true},"CacheExpiry":null,"CacheTime":"","CacheRevisionId":null,"Version":"1.6.4"}

tests/phpunit/data/ParserCache/1.36_fc-ParserOutput-empty.json

@@ -0,0 +1 @@
+{"_type_":"ParserOutput","Text":"","LanguageLinks":[],"Categories":[],"Indicators":[],"TitleText":"","Links":[],"LinksSpecial":[],"Templates":[],"TemplateIds":[],"Images":[],"FileSearchOptions":[],"ExternalLinks":[],"InterwikiLinks":[],"NewSection":false,"HideNewSection":false,"NoGallery":false,"HeadItems":[],"Modules":[],"ModuleStyles":[],"JsConfigVars":[],"OutputHooks":[],"Warnings":[],"Sections":[],"Properties":[],"TOCHTML":"","Timestamp":null,"EnableOOUI":false,"IndexPolicy":"","ExtensionData":[],"LimitReportData":[],"LimitReportJSData":[],"ParseStartTime":[],"PreventClickjacking":false,"ExtraScriptSrcs":[],"ExtraDefaultSrcs":[],"ExtraStyleSrcs":[],"Flags":[],"SpeculativeRevId":null,"SpeculativePageIdUsed":null,"RevisionTimestampUsed":null,"RevisionUsedSha1Base36":null,"WrapperDivClasses":[],"ParseUsedOptions":null,"CacheExpiry":null,"CacheTime":"","CacheRevisionId":null,"Version":"1.6.4"}

tests/phpunit/data/ParserCache/1.36_fc-ParserOutput-usedOptions.json

@@ -0,0 +1 @@
+{"_type_":"ParserOutput","Text":"Dummy","LanguageLinks":[],"Categories":[],"Indicators":[],"TitleText":"","Links":[],"LinksSpecial":[],"Templates":[],"TemplateIds":[],"Images":[],"FileSearchOptions":[],"ExternalLinks":[],"InterwikiLinks":[],"NewSection":false,"HideNewSection":false,"NoGallery":false,"HeadItems":[],"Modules":[],"ModuleStyles":[],"JsConfigVars":[],"OutputHooks":[],"Warnings":[],"Sections":[],"Properties":[],"TOCHTML":"","Timestamp":null,"EnableOOUI":false,"IndexPolicy":"","ExtensionData":[],"LimitReportData":[],"LimitReportJSData":[],"ParseStartTime":[],"PreventClickjacking":false,"ExtraScriptSrcs":[],"ExtraDefaultSrcs":[],"ExtraStyleSrcs":[],"Flags":[],"SpeculativeRevId":null,"SpeculativePageIdUsed":null,"RevisionTimestampUsed":null,"RevisionUsedSha1Base36":null,"WrapperDivClasses":[],"ParseUsedOptions":{"optA":true,"optX":true},"CacheExpiry":null,"CacheTime":"","CacheRevisionId":null,"Version":"1.6.4"}

tests/phpunit/includes/libs/serialization/SerializationTestTrait.php

@@ -1,6 +1,6 @@
 <?php
 
-namespace MediaWiki\Tests\Parser;
+namespace Wikimedia\Tests;
 
 use Generator;
 use ReflectionClass;

tests/phpunit/includes/libs/serialization/SerializationTestUtils.php

@@ -19,9 +19,8 @@
  * @ingroup Cache Parser
  */
 
-namespace MediaWiki\Tests\Parser;
+namespace Wikimedia\Tests;
 
-use CacheTime;
 use InvalidArgumentException;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
@@ -167,7 +166,7 @@ class SerializationTestUtils {
 	 */
 	public function getSerializedInstances(): array {
 		$instances = $this->getTestInstances();
-		return array_map( function ( CacheTime $object )  {
+		return array_map( function ( $object )  {
 			return call_user_func( $this->serializer, $object );
 		}, $instances );
 	}

tests/phpunit/includes/parser/CacheTimeTest.php

@@ -5,6 +5,7 @@ namespace MediaWiki\Tests\Parser;
 use CacheTime;
 use MediaWikiIntegrationTestCase;
 use MWTimestamp;
+use Wikimedia\Tests\SerializationTestTrait;
 
 /**
  * @covers CacheTime

tests/phpunit/includes/parser/ParserCacheSerializationTestCases.php

@@ -8,6 +8,7 @@ use MediaWikiIntegrationTestCase;
 use MWTimestamp;
 use ParserOutput;
 use Title;
+use Wikimedia\Tests\SerializationTestUtils;
 
 /**
  * A collection of serialization test cases for parser cache.

tests/phpunit/includes/parser/ParserOutputTest.php

@@ -1,8 +1,8 @@
 <?php
 
 use MediaWiki\Tests\Parser\ParserCacheSerializationTestCases;
-use MediaWiki\Tests\Parser\SerializationTestTrait;
 use Wikimedia\TestingAccessWrapper;
+use Wikimedia\Tests\SerializationTestTrait;
 
 /**
  * @covers ParserOutput

tests/phpunit/includes/parser/validateParserCacheSerializationTestData.php

@@ -9,7 +9,7 @@ use ParserOutput;
 
 require_once __DIR__ . '/../../../../maintenance/Maintenance.php';
 require __DIR__ . '/ParserCacheSerializationTestCases.php';
-require __DIR__ . '/SerializationTestUtils.php';
+require __DIR__ . '/../libs/serialization/SerializationTestUtils.php';
 
 class ValidateParserCacheSerializationTestData extends Maintenance {
 
@@ -55,7 +55,7 @@ class ValidateParserCacheSerializationTestData extends Maintenance {
 	public function validateSerialization( string $className, array $testInstances ) {
 		$supportedFormats = ParserCacheSerializationTestCases::getSupportedSerializationFormats( $className );
 		foreach ( $supportedFormats as $serializationFormat ) {
-			$serializationUtils = new SerializationTestUtils(
+			$serializationUtils = new \Wikimedia\Tests\SerializationTestUtils(
 				$this->getArg( 1 ) ?: __DIR__ . '/../../data/ParserCache',
 				$testInstances,
 				$serializationFormat['ext'],

tests/phpunit/mocks/GhostFieldTestClass.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Wikimedia\Reflection;
+
+/**
+ * This class used to contain a $privateField, $protectedField and $publicField.
+ * This is used to test that unserialized instances still have the values of
+ * these ghost fields and the values can be accessed with GhostFieldAccessTrait.
+ * @package Wikimedia\Reflection
+ */
+class GhostFieldTestClass {
+	use GhostFieldAccessTrait;
+
+	public function getPrivateField() {
+		return $this->getGhostFieldValue( 'privateField' );
+	}
+
+	public function getProtectedField() {
+		return $this->getGhostFieldValue( 'protectedField' );
+	}
+
+	public function getPublicField() {
+		return $this->getGhostFieldValue( 'publicField' );
+	}
+}

tests/phpunit/unit/includes/libs/GhostFieldAccessTraitTest.php

@@ -0,0 +1,71 @@
+<?php
+
+namespace Wikimedia\Tests\Reflection;
+
+use MediaWikiUnitTestCase;
+use Wikimedia\Reflection\GhostFieldTestClass;
+use Wikimedia\Tests\SerializationTestUtils;
+
+/**
+ * @covers \Wikimedia\Reflection\GhostFieldAccessTrait
+ * @package Wikimedia\Tests\Reflection
+ */
+class GhostFieldAccessTraitTest extends MediaWikiUnitTestCase {
+
+	private $serializationTestUtils;
+
+	protected function setUp() : void {
+		parent::setUp();
+		// Not using the trait since we only need deserialization tests.
+		$this->serializationTestUtils = new SerializationTestUtils(
+			__DIR__ . '/../../data/GhostFieldAccess',
+			[],
+			'serialized',
+			'serialize',
+			'unserialize'
+		);
+	}
+
+	private function provideUnserializedInstances( string $testCaseName ) {
+		$serializationTestUtils = new SerializationTestUtils(
+			__DIR__ . '/../../data/GhostFieldAccess',
+			[],
+			'serialized',
+			'serialize',
+			'unserialize'
+		);
+		$instances = $serializationTestUtils
+			->getDeserializedInstancesForTestCase( 'GhostFieldTestClass', $testCaseName );
+		foreach ( $instances as $instance ) {
+			yield "{$instance->version}" => [ $instance->object ];
+		}
+	}
+
+	public function provideUnserializedInstancesWithValues() {
+		return $this->provideUnserializedInstances( 'withValues' );
+	}
+
+	/**
+	 * @dataProvider provideUnserializedInstancesWithValues
+	 * @param GhostFieldTestClass $instance
+	 */
+	public function testUnserializedWithValues( GhostFieldTestClass $instance ) {
+		$this->assertSame( 'private_value', $instance->getPrivateField() );
+		$this->assertSame( 'protected_value', $instance->getProtectedField() );
+		$this->assertSame( 'public_value', $instance->getPublicField() );
+	}
+
+	public function provideUnserializedInstancesWithNulls() {
+		return $this->provideUnserializedInstances( 'withNulls' );
+	}
+
+	/**
+	 * @dataProvider provideUnserializedInstancesWithNulls
+	 * @param GhostFieldTestClass $instance
+	 */
+	public function testUnserializedWithNulls( GhostFieldTestClass $instance ) {
+		$this->assertNull( $instance->getPrivateField() );
+		$this->assertNull( $instance->getProtectedField() );
+		$this->assertNull( $instance->getPublicField() );
+	}
+}