Add a new type of database to the installer from extension

Decouple Installer services
Implement injection class Autoloader and i18n messages from extension.json
Implement extension selector by type
Add i18n message key `version-database`
Extensions for testing:
- https://github.com/MWStake/PerconaDB - real Percona extension
- https://github.com/killev/mediawiki-dbext2 - fake extension for test

Bug: T226857, T255151
Change-Id: I9ec8a18ad19283f6be67ac000110ac370afc0815

RELEASE-NOTES-1.35

@@ -237,6 +237,8 @@ For notes on 1.34.x and older releases, see HISTORY.
   Doing so using that hook is now soft deprecated.
 * A new BlockPermissionChecker service was introduced for checking
   block-related permissions.
+* The support of 'database' type of extensions has been added to allow 3d party
+  databases like Percona be used as storage. See T226857, T253248.
 * …
 
 === External library changes in 1.35 ===
@@ -1243,6 +1245,8 @@ because of Phabricator reports.
   instead.
 * Using Skin::addToBodyAttributes() method to add body attributes has been
   deprecated. Use OutputPageBodyAttributes hook instead.
+* Installer::getDBTypes has been hard deprecated in favor of
+  InstallerDBSupport::getDatabases
 * …
 
 === Other changes in 1.35 ===

includes/cache/localisation/LocalisationCache.php

@@ -820,6 +820,29 @@ class LocalisationCache {
 		return $used;
 	}
 
+	/**
+	 * @var string[]
+	 */
+	private $messagesDirs = [];
+
+	/**
+	 * @var string[]
+	 */
+	private $additionalMessagesDirs = [];
+
+	/**
+	 * Add additional path for looking for i18n localization messages
+	 *
+	 * @internal for Installer with DbType extensions
+	 * @since 1.35
+	 *
+	 * @param string $name
+	 * @param string $path
+	 */
+	public function addMessagesDir( string $name, string $path ) : void {
+		$this->additionalMessagesDirs[$name] = $path;
+	}
+
 	/**
 	 * Gets the combined list of messages dirs from
 	 * core and extensions
@@ -837,7 +860,7 @@ class LocalisationCache {
 			'rest' => "$IP/includes/Rest/i18n",
 			'oojs-ui' => "$IP/resources/lib/ooui/i18n",
 			'paramvalidator' => "$IP/includes/libs/ParamValidator/i18n",
-		] + $this->options->get( 'MessagesDirs' );
+		] + $this->options->get( 'MessagesDirs' ) + $this->additionalMessagesDirs;
 	}
 
 	/**

includes/installer/DatabaseUpdater.php

@@ -20,6 +20,7 @@
  * @file
  * @ingroup Installer
  */
+use MediaWiki\Installer\Services\InstallerDBSupport;
 use MediaWiki\MediaWikiServices;
 use Wikimedia\Rdbms\IDatabase;
 use Wikimedia\Rdbms\IMaintainableDatabase;
@@ -195,8 +196,8 @@ abstract class DatabaseUpdater {
 		Maintenance $maintenance = null
 	) {
 		$type = $db->getType();
-		if ( in_array( $type, Installer::getDBTypes() ) ) {
+		if ( InstallerDBSupport::getInstance()->hasDatabase( $type ) ) {
-			$class = ucfirst( $type ) . 'Updater';
+			$class = InstallerDBSupport::getInstance()->getDBUpdaterClass( $type );
 
 			return new $class( $db, $shared, $maintenance );
 		} else {

includes/installer/Installer.php

@@ -24,6 +24,7 @@
  * @ingroup Installer
  */
 
+use MediaWiki\Installer\Services\InstallerDBSupport;
 use MediaWiki\Interwiki\NullInterwikiLookup;
 use MediaWiki\MediaWikiServices;
 use MediaWiki\Shell\Shell;
@@ -100,19 +101,9 @@ abstract class Installer {
 	protected $parserOptions;
 
 	/**
-	 * Known database types. These correspond to the class names <type>Installer,
+	 * @var InstallerDBSupport
-	 * and are also MediaWiki database types valid for $wgDBtype.
-	 *
-	 * To add a new type, create a <type>Installer class and a Database<type>
-	 * class, and add a config-type-<type> message to MessagesEn.php.
-	 *
-	 * @var array
 	 */
-	protected static $dbTypes = [
+	protected $installerDbSupport;
-		'mysql',
-		'postgres',
-		'sqlite',
-	];
 
 	/**
 	 * A list of environment check methods called by doEnvironmentChecks().
@@ -406,7 +397,6 @@ abstract class Installer {
 	 */
 	public function __construct() {
 		global $wgMemc, $wgUser, $wgObjectCaches;
-
 		$defaultConfig = new GlobalVarConfig(); // all the stuff from DefaultSettings.php
 		$installerConfig = self::getInstallerConfig( $defaultConfig );
 
@@ -458,7 +448,9 @@ abstract class Installer {
 		$this->doEnvironmentPreps();
 
 		$this->compiledDBs = [];
-		foreach ( self::getDBTypes() as $type ) {
+		$this->installerDbSupport = InstallerDBSupport::getInstance();
+
+		foreach ( $this->installerDbSupport->getDatabases() as $type ) {
 			$installer = $this->getDBInstaller( $type );
 
 			if ( !$installer->isCompiled() ) {
@@ -475,11 +467,13 @@ abstract class Installer {
 
 	/**
 	 * Get a list of known DB types.
+	 * @deprecated since 1.35 use InstallerDBSupport::getDatabases instead
 	 *
 	 * @return array
 	 */
 	public static function getDBTypes() {
-		return self::$dbTypes;
+		wfDeprecated( __METHOD__, '1.35' );
+		return InstallerDBSupport::getInstance()->getDatabases();
 	}
 
 	/**
@@ -561,13 +555,16 @@ abstract class Installer {
 
 	/**
 	 * Get the DatabaseInstaller class name for this type
+	 * @deprecated since 1.35 use InstallerDBSupport instead
 	 *
 	 * @param string $type database type ($wgDBtype)
 	 * @return string Class name
 	 * @since 1.30
 	 */
 	public static function getDBInstallerClass( $type ) {
-		return ucfirst( $type ) . 'Installer';
+		wfDeprecated( __METHOD__, '1.35' );
+
+		return InstallerDBSupport::getInstance()->getDBInstallerClass( $type );
 	}
 
 	/**
@@ -582,10 +579,8 @@ abstract class Installer {
 			$type = $this->getVar( 'wgDBtype' );
 		}
 
-		$type = strtolower( $type );
-
 		if ( !isset( $this->dbInstallers[$type] ) ) {
-			$class = self::getDBInstallerClass( $type );
+			$class = $this->installerDbSupport->getDBInstallerClass( $type );
 			$this->dbInstallers[$type] = new $class( $this );
 		}
 
@@ -769,7 +764,7 @@ abstract class Installer {
 		$allNames = [];
 
 		// Messages: config-type-mysql, config-type-postgres, config-type-sqlite
-		foreach ( self::getDBTypes() as $name ) {
+		foreach ( $this->installerDbSupport->getDatabases() as $name ) {
 			$allNames[] = wfMessage( "config-type-$name" )->text();
 		}
 

includes/installer/Services/InstallerDBSupport.php

@@ -0,0 +1,336 @@
+<?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
+ * @ingroup Installer
+ *
+ * @author Art Baltai
+ */
+
+declare( strict_types = 1 );
+namespace MediaWiki\Installer\Services;
+
+use DatabaseInstaller;
+use DatabaseUpdater;
+use InvalidArgumentException;
+use MediaWiki\Logger\LoggerFactory;
+use MediaWiki\MediaWikiServices;
+use MysqlInstaller;
+use MysqlUpdater;
+use PostgresInstaller;
+use PostgresUpdater;
+use Psr\Log\LoggerInterface;
+use SqliteInstaller;
+use SqliteUpdater;
+use Wikimedia\Rdbms\Database;
+use Wikimedia\Rdbms\DatabaseMysqli;
+use Wikimedia\Rdbms\DatabasePostgres;
+use Wikimedia\Rdbms\DatabaseSqlite;
+
+/**
+ * @since 1.35
+ */
+class InstallerDBSupport {
+	public const EXTENSION_TYPE_DATABASE = 'database';
+
+	/**
+	 * @var InstallerDBSupport $instance
+	 */
+	private static $instance;
+
+	/**
+	 * Known database types. These correspond to the class names <type>Installer,
+	 * and are also MediaWiki database types valid for $wgDBtype.
+	 *
+	 * To add a new type, create a <type>Installer class and a Database<type>
+	 * class, and add a config-type-<type> message to MessagesEn.php.
+	 *
+	 * @var array<string, array>
+	 */
+	private $databaseInfo = [
+		'mysql' => [
+			'installer' => MysqlInstaller::class,
+			'updater' => MysqlUpdater::class,
+			'driver' => DatabaseMysqli::class,
+			'extension' => 'core'
+		],
+		'postgres' => [
+			'installer' => PostgresInstaller::class,
+			'updater' => PostgresUpdater::class,
+			'driver' => DatabasePostgres::class,
+			'extension' => 'core'
+		],
+		'sqlite' => [
+			'installer' => SqliteInstaller::class,
+			'updater' => SqliteUpdater::class,
+			'driver' => DatabaseSqlite::class,
+			'extension' => 'core'
+		]
+	];
+
+	/**
+	 * @var InstallerExtensionRegistration
+	 */
+	private $extensionRegistration;
+
+	/**
+	 * @var LoggerInterface
+	 */
+	private $logger;
+
+	public static function getInstance(): self {
+		global $IP, $wgExtensionDirectory;
+		if ( !isset( self::$instance ) ) {
+			$extensionDir = $wgExtensionDirectory ?: "$IP/extensions";
+			$installerRegistration = new InstallerExtensionRegistration(
+				$extensionDir,
+				MediaWikiServices::getInstance()->getLocalisationCache()
+			);
+			self::$instance = new InstallerDBSupport(
+				$installerRegistration,
+				LoggerFactory::getInstance( 'Installer' )
+			);
+			self::$instance->registerDbExtensions(
+				( new InstallerExtensionSelector( $extensionDir ) )
+					->getExtOptionsByType( self::EXTENSION_TYPE_DATABASE )
+			);
+		}
+
+		return self::$instance;
+	}
+
+	private function __construct(
+		InstallerExtensionRegistration $extensionRegistration,
+		LoggerInterface $logger
+	) {
+		$this->extensionRegistration = $extensionRegistration;
+		$this->logger = $logger;
+	}
+
+	private function registerDbExtensions( iterable $extDbOptionsByType ): bool {
+		$registered = false;
+		foreach ( $extDbOptionsByType as $extensionName => $extDbOptions ) {
+			$result = $this->registerDbExtension(
+				$extensionName,
+				$extDbOptions
+			);
+			$registered = $result || $registered;
+		}
+
+		return $registered;
+	}
+
+	private function registerDbExtension(
+		string $extensionName,
+		array $extJsonOptions
+	): bool {
+		if ( !isset( $extJsonOptions['Providers']['Databases'] ) ) {
+			return false;
+		}
+		$newDatabases = $extJsonOptions['Providers']['Databases'];
+		$isRegistred = false;
+		foreach ( $newDatabases as $database => $options ) {
+			if ( is_numeric( $database ) ) {
+				continue;
+			}
+			if ( $isRegistred === false ) {
+				$this->extensionRegistration->register(
+					$extensionName,
+					$extJsonOptions
+				);
+				$isRegistred = true;
+			}
+
+			$this->registerDatabase(
+				$database,
+				$options['Installer'] ?? $this->getInstallerClassAuto( $database ),
+				$options['Updater'] ?? $this->getUpdaterClassAuto( $database ),
+				$options['Driver'] ?? $this->getDriverClassAuto( $database ),
+				$extensionName
+			);
+		}
+
+		return $isRegistred;
+	}
+
+	private function isDatabaseInfoValid(
+		string $dbInstaller,
+		string $dbUpdater,
+		string $dbDriver
+	): bool {
+		$isValid = true;
+		if ( !is_subclass_of( $dbInstaller, DatabaseInstaller::class ) ) {
+			$this->logger->warning( 'Database `Installer` should be a subclass of '
+				. DatabaseInstaller::class );
+			$isValid = false;
+		}
+
+		if ( !is_subclass_of( $dbUpdater, DatabaseUpdater::class ) ) {
+			$this->logger->warning( 'Database `Updater` should be a subclass of '
+				. DatabaseUpdater::class );
+			$isValid = false;
+		}
+
+		if ( !is_subclass_of( $dbDriver, Database::class ) ) {
+			$this->logger->warning( 'Database `Driver` should be a subclass of ' . Database::class );
+			$isValid = false;
+		}
+		return $isValid;
+	}
+
+	/**
+	 * @param string $database
+	 * @param string $dbInstaller
+	 * @param string $dbUpdater
+	 * @param string $dbDriver
+	 * @param string $extensionName
+	 */
+	private function registerDatabase(
+		string $database,
+		string $dbInstaller,
+		string $dbUpdater,
+		string $dbDriver,
+		string $extensionName
+	): void {
+		if ( !$this->isDatabaseInfoValid( $dbInstaller, $dbUpdater, $dbDriver ) ) {
+			return;
+		}
+
+		$this->databaseInfo[ strtolower( $database ) ] = [
+			'installer' => $dbInstaller,
+			'updater' => $dbUpdater,
+			'driver' => $dbDriver,
+			'extension' => $extensionName,
+		];
+	}
+
+	/**
+	 * Get a list of known DB types.
+	 *
+	 * @return string[]
+	 */
+	public function getDatabases(): array {
+		return array_keys( $this->databaseInfo );
+	}
+
+	/**
+	 * Checks wheather given database type is registered
+	 * @param string $database
+	 *
+	 * @return bool
+	 */
+	public function hasDatabase( string $database ): bool {
+		return array_key_exists( $database, $this->databaseInfo );
+	}
+
+	/**
+	 * Get the database installer class for given database type, throws an
+	 * InvalidArgumentException if no given database registerred
+	 *
+	 * @param string $database
+	 * @return string Class name
+	 * @throws InvalidArgumentException
+	 */
+	public function getDBInstallerClass( string $database ): string {
+		if ( !isset( $this->databaseInfo[strtolower( $database )] ) ) {
+			throw new InvalidArgumentException( __METHOD__ .
+				" no registered database found for type '$database'" );
+		}
+		return $this->databaseInfo[strtolower( $database )]['installer'];
+	}
+
+	/**
+	 * Get the database updater class for given database type, throws an
+	 * InvalidArgumentException if no given database registerred
+	 *
+	 * @param string $database
+	 * @return string class name
+	 * @throws InvalidArgumentException
+	 */
+	public function getDBUpdaterClass( string $database ): string {
+		if ( !isset( $this->databaseInfo[strtolower( $database )] ) ) {
+			throw new InvalidArgumentException( __METHOD__ .
+				" no registered database found for type '$database'" );
+		}
+		return $this->databaseInfo[strtolower( $database )]['updater'];
+	}
+
+	/**
+	 * Get the database driver class for given database type, throws an
+	 * InvalidArgumentException if no given database registerred
+	 *
+	 * @param string $database
+	 * @return string class name
+	 * @throws InvalidArgumentException
+	 */
+	public function getDBDriverClass( string $database ): string {
+		if ( !isset( $this->databaseInfo[strtolower( $database )] ) ) {
+			throw new InvalidArgumentException( __METHOD__ .
+				" no registered database found for type '$database'" );
+		}
+		return $this->databaseInfo[strtolower( $database )]['driver'];
+	}
+
+	/**
+	 * Gets extension name that implements classes for given database type, throws an
+	 * InvalidArgumentException if no given database registerred
+	 *
+	 * @param string $database
+	 * @return string|null
+	 * @throws InvalidArgumentException
+	 */
+	public function getExtensionNameForDatabase(
+		string $database
+	): string {
+		if ( !isset( $this->databaseInfo[strtolower( $database )] ) ) {
+			throw new InvalidArgumentException( __METHOD__ .
+				" no registered database found for type '$database'" );
+		}
+		return $this->databaseInfo[strtolower( $database )]['extension'];
+	}
+
+	/**
+	 * Generate default name for database Installer
+	 *
+	 * @param string $type database type ($wgDBtype)
+	 * @return string Class name
+	 */
+	private function getInstallerClassAuto( string $type ): string {
+		return ucfirst( $type ) . 'Installer';
+	}
+
+	/**
+	 * Generate default name for database Updater
+	 *
+	 * @param string $type database type ($wgDBtype)
+	 * @return string Class name
+	 */
+	private function getUpdaterClassAuto( string $type ): string {
+		return ucfirst( $type ) . 'Updater';
+	}
+
+	/**
+	 * Generate default name for database Driver
+	 *
+	 * @param string $type database type ($wgDBtype)
+	 * @return string Class name
+	 */
+	private function getDriverClassAuto( string $type ): string {
+		return 'Database' . ucfirst( $type );
+	}
+}

includes/installer/Services/InstallerExtensionRegistration.php

@@ -0,0 +1,110 @@
+<?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
+ * @ingroup Installer
+ *
+ * @author Art Baltai
+ */
+
+declare( strict_types = 1 );
+namespace MediaWiki\Installer\Services;
+
+use ExtensionRegistry;
+use LocalisationCache;
+
+/**
+ * @since 1.35
+ */
+class InstallerExtensionRegistration {
+
+	/** @var string */
+	private $extensionDir;
+
+	/** @var LocalisationCache */
+	private $localisationCache;
+
+	public function __construct( string $extensionDir, LocalisationCache $localisationCache ) {
+		$this->extensionDir = $extensionDir;
+		$this->localisationCache = $localisationCache;
+	}
+
+	/**
+	 * Register class autoloader, i18n messages
+	 * @param string $extensionName
+	 * @param array $extJsonOptions
+	 */
+	public function register(
+		string $extensionName,
+		array $extJsonOptions
+	): void {
+		$this->registerClassAutoloader( $extensionName, $extJsonOptions );
+		$this->registerMessagesDirs( $extensionName, $extJsonOptions );
+	}
+
+	public function registerClassAutoloader(
+		string $extensionName,
+		array $extJsonOptions
+	): void {
+		global $wgAutoloadLocalClasses;
+
+		$extPath = $this->getExtensionPath( $extensionName );
+		ExtensionRegistry::exportAutoloadClassesAndNamespaces(
+			$extPath,
+			$extJsonOptions
+		);
+		// important for upgrade (mw-config/?page=ExistingWiki) with existing LocalSettings.php
+		if (
+			!empty( $extJsonOptions['AutoloadClasses'] )
+			&& is_array( $extJsonOptions['AutoloadClasses'] )
+		) {
+			foreach ( $extJsonOptions['AutoloadClasses'] as $extensionName => $path ) {
+				$wgAutoloadLocalClasses[$extensionName] = "$extPath/$path";
+			}
+		}
+	}
+
+	public function registerMessagesDirs(
+		string $extensionName,
+		array $extJsonOptions
+	): void {
+		if ( !is_array( $extJsonOptions['MessagesDirs'] ?? null ) ) {
+			return;
+		}
+
+		foreach ( $extJsonOptions['MessagesDirs'] as $messageType => $messagesDirs ) {
+			$messagesDirs = (array)$messagesDirs;
+			foreach ( $messagesDirs as $key => $messageDir ) {
+				$i18nDir = $this->getExtensionPath( $extensionName ) . "/$messageDir";
+				if ( !is_dir( $i18nDir ) ) {
+					continue;
+				}
+				$this->localisationCache->addMessagesDir(
+					count( $messagesDirs ) === 1
+						? $messageType
+						: "{$messageType}_{$key}",
+					$i18nDir
+				);
+			}
+		}
+	}
+
+	private function getExtensionPath( string $extensionName ) : string {
+		return "{$this->extensionDir}/{$extensionName}";
+	}
+}

includes/installer/Services/InstallerExtensionSelector.php

@@ -0,0 +1,104 @@
+<?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
+ * @ingroup Installer
+ *
+ * @author Art Baltai
+ */
+
+declare( strict_types = 1 );
+namespace MediaWiki\Installer\Services;
+
+use Generator;
+
+/**
+ * @since 1.35
+ */
+class InstallerExtensionSelector {
+
+	/**
+	 * @var string
+	 */
+	private $extensionDir;
+
+	/**
+	 * @var string[]|null
+	 */
+	private $extensionJsonPath;
+
+	public function __construct( string $extensionDir ) {
+		$this->extensionDir = $extensionDir;
+	}
+
+	private function getExtensionJsonPaths() : array {
+		if ( $this->extensionJsonPath === null ) {
+			$this->extensionJsonPath = [];
+			if ( is_dir( $this->extensionDir ) ) {
+				$dh = opendir( $this->extensionDir );
+				while ( ( $extension = readdir( $dh ) ) !== false ) {
+					if ( mb_substr( $extension, 0, 1 ) === '.' ) {
+						continue;
+					}
+					$jsonPath = "{$this->extensionDir}/{$extension}/extension.json";
+					if ( is_file( $jsonPath ) && is_readable( $jsonPath ) ) {
+						$this->extensionJsonPath[$extension] = $jsonPath;
+					}
+				}
+				closedir( $dh );
+
+				uksort( $this->extensionJsonPath, 'strnatcasecmp' );
+			} // @todo else:warning?
+		}
+
+		return $this->extensionJsonPath;
+	}
+
+	/**
+	 * Returns a Generator for interating through all exntension.json files converterd
+	 * into array. Key is string of exntension name and value is decoded exntension.json.
+	 *
+	 * @return Generator
+	 */
+	private function getExtensionJsons() : Generator {
+		foreach ( $this->getExtensionJsonPaths() as $extension => $jsonPath ) {
+			$json = file_get_contents( $jsonPath );
+			$options = json_decode( $json, true );
+			if ( !is_array( $options ) ) {
+				continue;
+			}
+
+			yield $extension => $options;
+		}
+	}
+
+	/**
+	 * Returns a Generator for interating through extension's options
+	 * filtered by certain type.
+	 *
+	 * @param string $type
+	 * @return Generator
+	 */
+	public function getExtOptionsByType( string $type ) : Generator {
+		foreach ( $this->getExtensionJsons() as $extensionName => $options ) {
+			if ( $type === ( $options['type'] ?? null ) ) {
+				yield $extensionName => $options;
+			}
+		}
+	}
+}

includes/installer/WebInstallerDBConnect.php

@@ -18,6 +18,7 @@
  * @file
  * @ingroup Installer
  */
+use MediaWiki\Installer\Services\InstallerDBSupport;
 
 class WebInstallerDBConnect extends WebInstallerPage {
 
@@ -50,7 +51,7 @@ class WebInstallerDBConnect extends WebInstallerPage {
 
 		// Messages: config-dbsupport-mysql, config-dbsupport-postgres, config-dbsupport-sqlite
 		$dbSupport = '';
-		foreach ( Installer::getDBTypes() as $type ) {
+		foreach ( InstallerDBSupport::getInstance()->getDatabases() as $type ) {
 			$dbSupport .= wfMessage( "config-dbsupport-$type" )->plain() . "\n";
 		}
 		$this->addHTML( $this->parent->getInfoBox(

includes/installer/WebInstallerExistingWiki.php

@@ -19,6 +19,8 @@
  * @ingroup Installer
  */
 
+use MediaWiki\Installer\Services\InstallerDBSupport;
+
 class WebInstallerExistingWiki extends WebInstallerPage {
 
 	/**
@@ -140,7 +142,7 @@ class WebInstallerExistingWiki extends WebInstallerPage {
 	protected function handleExistingUpgrade( $vars ) {
 		// Check $wgDBtype
 		if ( !isset( $vars['wgDBtype'] ) ||
-			!in_array( $vars['wgDBtype'], Installer::getDBTypes() )
+			!InstallerDBSupport::getInstance()->hasDatabase( $vars['wgDBtype'] )
 		) {
 			return Status::newFatal( 'config-localsettings-connection-error', '' );
 		}

includes/installer/WebInstallerOptions.php

@@ -19,6 +19,7 @@
  * @ingroup Installer
  */
 
+use MediaWiki\Installer\Services\InstallerDBSupport;
 use Wikimedia\IPUtils;
 
 class WebInstallerOptions extends WebInstallerPage {
@@ -147,7 +148,14 @@ class WebInstallerOptions extends WebInstallerPage {
 			$this->getFieldsetEnd();
 		$this->addHTML( $skinHtml );
 
-		$extensions = $this->parent->findExtensions()->value;
+		$extensions = array_filter(
+			$this->parent->findExtensions()->value,
+			function ( $extensionInfo ) {
+				return ( $extensionInfo['type'] ?? null )
+					!== InstallerDBSupport::EXTENSION_TYPE_DATABASE;
+			}
+		);
+
 		'@phan-var array[] $extensions';
 		$dependencyMap = [];
 
@@ -182,7 +190,7 @@ class WebInstallerOptions extends WebInstallerPage {
 						'class' => 'config-ext-input'
 					];
 					$labelAttribs = [];
-					$fullDepList = [];
+
 					if ( isset( $info['requires']['extensions'] ) ) {
 						$dependencyMap[$ext]['extensions'] = $info['requires']['extensions'];
 						$labelAttribs['class'] = 'mw-ext-with-dependencies';

includes/libs/rdbms/database/Database.php

@@ -30,6 +30,7 @@ use Exception;
 use HashBagOStuff;
 use InvalidArgumentException;
 use LogicException;
+use MediaWiki\Installer\Services\InstallerDBSupport;
 use Psr\Log\LoggerAwareInterface;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
@@ -392,7 +393,7 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 	 * @since 1.18
 	 */
 	final public static function factory( $type, $params = [], $connect = self::NEW_CONNECTED ) {
-		$class = self::getClass( $type, $params['driver'] ?? null );
+		$class = InstallerDBSupport::getInstance()->getDBDriverClass( $type );
 
 		if ( class_exists( $class ) && is_subclass_of( $class, IDatabase::class ) ) {
 			$params += [
@@ -453,64 +454,11 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 			self::ATTR_SCHEMAS_AS_TABLE_GROUPS => false
 		];
 
-		$class = self::getClass( $dbType, $driver );
+		$class = InstallerDBSupport::getInstance()->getDBDriverClass( $dbType );
 
 		return call_user_func( [ $class, 'getAttributes' ] ) + $defaults;
 	}
 
-	/**
-	 * @param string $dbType A possible DB type (sqlite, mysql, postgres,...)
-	 * @param string|null $driver Optional name of a specific DB client driver
-	 * @return string Database subclass name to use
-	 * @throws InvalidArgumentException
-	 */
-	private static function getClass( $dbType, $driver = null ) {
-		// For database types with built-in support, the below maps type to IDatabase
-		// implementations. For types with multiple driver implementations (PHP extensions),
-		// an array can be used, keyed by extension name. In case of an array, the
-		// optional 'driver' parameter can be used to force a specific driver. Otherwise,
-		// we auto-detect the first available driver. For types without built-in support,
-		// an class named "Database<Type>" us used, eg. DatabaseFoo for type 'foo'.
-		static $builtinTypes = [
-			'mysql' => [ 'mysqli' => DatabaseMysqli::class ],
-			'sqlite' => DatabaseSqlite::class,
-			'postgres' => DatabasePostgres::class,
-		];
-
-		$dbType = strtolower( $dbType );
-		$class = false;
-
-		if ( isset( $builtinTypes[$dbType] ) ) {
-			$possibleDrivers = $builtinTypes[$dbType];
-			if ( is_string( $possibleDrivers ) ) {
-				$class = $possibleDrivers;
-			} elseif ( (string)$driver !== '' ) {
-				if ( !isset( $possibleDrivers[$driver] ) ) {
-					throw new InvalidArgumentException( __METHOD__ .
-						" type '$dbType' does not support driver '{$driver}'" );
-				}
-
-				$class = $possibleDrivers[$driver];
-			} else {
-				foreach ( $possibleDrivers as $posDriver => $possibleClass ) {
-					if ( extension_loaded( $posDriver ) ) {
-						$class = $possibleClass;
-						break;
-					}
-				}
-			}
-		} else {
-			$class = 'Database' . ucfirst( $dbType );
-		}
-
-		if ( $class === false ) {
-			throw new InvalidArgumentException( __METHOD__ .
-				" no viable database extension found for type '$dbType'" );
-		}
-
-		return $class;
-	}
-
 	/**
 	 * @return array Map of (Database::ATTR_* constant => value)
 	 * @since 1.31

includes/specials/SpecialVersion.php

@@ -24,6 +24,7 @@
  */
 
 use MediaWiki\ExtensionInfo;
+use MediaWiki\Installer\Services\InstallerDBSupport;
 use MediaWiki\MediaWikiServices;
 
 /**
@@ -416,6 +417,8 @@ class SpecialVersion extends SpecialPage {
 				'antispam' => wfMessage( 'version-antispam' )->text(),
 				'skin' => wfMessage( 'version-skins' )->text(),
 				'api' => wfMessage( 'version-api' )->text(),
+				InstallerDBSupport::EXTENSION_TYPE_DATABASE =>
+					wfMessage( 'version-database' )->text(),
 				'other' => wfMessage( 'version-other' )->text(),
 			];
 

languages/i18n/en.json

@@ -3561,6 +3561,7 @@
 	"version-variables": "Variables",
 	"version-editors": "Editors",
 	"version-antispam": "Spam prevention",
+	"version-database": "Custom database support",
 	"version-api": "API",
 	"version-other": "Other",
 	"version-mediahandlers": "Media handlers",

languages/i18n/qqq.json

@@ -3778,6 +3778,7 @@
 	"version-antispam": "Part of [[Special:Version]].\nThis message is followed by the list of SPAM prevention extensions.",
 	"version-api": "{{optional}}",
 	"version-other": "{{Identical|Other}}",
+	"version-database": "Database type",
 	"version-mediahandlers": "Used in [[Special:Version]]. It is the title of a section for media handler extensions (e.g. [[mw:Extension:OggHandler]]).\nThere are no such extensions here, so look at [[wikipedia:Special:Version]] for an example.",
 	"version-hooks": "Shown in [[Special:Version]]\n{{Identical|Hook}}",
 	"version-parser-extensiontags": "Part of [[Special:Version]].\nThis message is followed by the list of parser extension tags like <code><nowiki><charinsert></nowiki></code>, <code><nowiki><coordinates></nowiki></code>, etc.",

maintenance/update.php

@@ -27,6 +27,7 @@
 
 require_once __DIR__ . '/Maintenance.php';
 
+use MediaWiki\Installer\Services\InstallerDBSupport;
 use MediaWiki\MediaWikiServices;
 use Wikimedia\Rdbms\DatabaseSqlite;
 
@@ -141,8 +142,9 @@ class UpdateMediaWiki extends Maintenance {
 		$db = $this->getDB( DB_MASTER );
 
 		# Check to see whether the database server meets the minimum requirements
-		/** @var DatabaseInstaller $dbInstallerClass */
+		/** @var string|DatabaseInstaller $dbInstallerClass */
-		$dbInstallerClass = Installer::getDBInstallerClass( $db->getType() );
+		$dbInstallerClass = InstallerDBSupport::getInstance()
+			->getDBInstallerClass( $db->getType() );
 		$status = $dbInstallerClass::meetsMinimumRequirement( $db->getServerVersion() );
 		if ( !$status->isOK() ) {
 			// This might output some wikitext like <strong> but it should be comprehensible

tests/phpunit/includes/libs/rdbms/database/DatabaseTest.php

@@ -30,9 +30,9 @@ class DatabaseTest extends PHPUnit\Framework\TestCase {
 		$m = Database::NEW_UNCONNECTED; // no-connect mode
 		$p = [ 'host' => 'localhost', 'user' => 'me', 'password' => 'myself', 'dbname' => 'i' ];
 
-		$this->assertInstanceOf( DatabaseMysqli::class, Database::factory( 'mysqli', $p, $m ) );
+		$this->assertInstanceOf( DatabaseMysqli::class, Database::factory( 'mysql', $p, $m ) );
-		$this->assertInstanceOf( DatabaseMysqli::class, Database::factory( 'MySqli', $p, $m ) );
+		$this->assertInstanceOf( DatabaseMysqli::class, Database::factory( 'MySql', $p, $m ) );
-		$this->assertInstanceOf( DatabaseMysqli::class, Database::factory( 'MySQLi', $p, $m ) );
+		$this->assertInstanceOf( DatabaseMysqli::class, Database::factory( 'MySQL', $p, $m ) );
 		$this->assertInstanceOf( DatabasePostgres::class, Database::factory( 'postgres', $p, $m ) );
 		$this->assertInstanceOf( DatabasePostgres::class, Database::factory( 'Postgres', $p, $m ) );
 

tests/phpunit/suite.xml

@@ -21,6 +21,9 @@
 		<testsuite name="languages">
 			<directory>languages</directory>
 		</testsuite>
+		<testsuite name="rdbms">
+			<directory>includes/libs/rdbms</directory>
+		</testsuite>
 		<testsuite name="parsertests">
 			<file>suites/CoreParserTestSuite.php</file>
 			<file>suites/ExtensionsParserTestSuite.php</file>