wikimedia/mediawiki-core

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includes/installer/DatabaseUpdater.php

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<?php
/**
 * DBMS-specific updater helper.
 *
 * 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
 */

namespace MediaWiki\Installer;

use AddRFCandPMIDInterwiki;
use AutoLoader;
use CleanupEmptyCategories;
use DeleteDefaultMessages;
use ExtensionRegistry;
use FakeMaintenance;
use FixDefaultJsonContentPages;
use LogicException;
use Maintenance;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\HookContainer\StaticHookRegistry;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\ResourceLoader\MessageBlobStore;
use MediaWiki\SiteStats\SiteStatsInit;
use MigrateLinksTable;
use PopulateBacklinkNamespace;
use PopulateFilearchiveSha1;
use PopulateImageSha1;
use PopulateIpChanges;
use PopulatePPSortKey;
use PopulateRevisionLength;
use PopulateRevisionSha1;
use RebuildLocalisationCache;
use RefreshImageMetadata;
use RuntimeException;
use UnexpectedValueException;
use UpdateCollation;
use Wikimedia\Rdbms\IDatabase;
use Wikimedia\Rdbms\IMaintainableDatabase;
use Wikimedia\Rdbms\Platform\ISQLPlatform;

require_once __DIR__ . '/../../maintenance/Maintenance.php';

/**
 * Class for handling database updates.
 *
 * @ingroup Installer
 * @since 1.17
 */
abstract class DatabaseUpdater {
    public const REPLICATION_WAIT_TIMEOUT = 300;

    /**
     * Array of updates to perform on the database
     *
     * @var array
     */
    protected $updates = [];

    /**
     * Array of updates that were skipped
     *
     * @var array
     */
    protected $updatesSkipped = [];

    /**
     * List of extension-provided database updates
     * @var array
     */
    protected $extensionUpdates = [];

    /**
     * List of extension-provided database updates on virtual domain dbs
     * @var array
     */
    protected $extensionUpdatesWithVirtualDomains = [];

    /**
     * Handle to the database subclass
     *
     * @var IMaintainableDatabase
     */
    protected $db;

    /**
     * @var Maintenance
     */
    protected $maintenance;

    protected $shared = false;

    /** @var HookContainer|null */
    protected $autoExtensionHookContainer;

    /**
     * @var string[] Scripts to run after database update
     * Should be a subclass of LoggedUpdateMaintenance
     */
    protected $postDatabaseUpdateMaintenance = [
        DeleteDefaultMessages::class,
        PopulateRevisionLength::class,
        PopulateRevisionSha1::class,
        PopulateImageSha1::class,
        PopulateFilearchiveSha1::class,
        PopulateBacklinkNamespace::class,
        FixDefaultJsonContentPages::class,
        CleanupEmptyCategories::class,
        AddRFCandPMIDInterwiki::class,
        PopulatePPSortKey::class,
        PopulateIpChanges::class,
    ];

    /**
     * File handle for SQL output.
     *
     * @var resource|null
     */
    protected $fileHandle = null;

    /**
     * Flag specifying whether to skip schema (e.g., SQL-only) updates.
     *
     * @var bool
     */
    protected $skipSchema = false;

    /**
     * @param IMaintainableDatabase &$db To perform updates on
     * @param bool $shared Whether to perform updates on shared tables
     * @param Maintenance|null $maintenance Maintenance object which created us
     */
    protected function __construct(
        IMaintainableDatabase &$db,
        $shared,
        Maintenance $maintenance = null
    ) {
        $this->db = $db;
        $this->db->setFlag( DBO_DDLMODE );
        $this->shared = $shared;
        if ( $maintenance ) {
            $this->maintenance = $maintenance;
            $this->fileHandle = $maintenance->fileHandle;
        } else {
            $this->maintenance = new FakeMaintenance;
        }
        $this->maintenance->setDB( $db );
    }

    /**
     * Cause extensions to register any updates they need to perform.
     */
    private function loadExtensionSchemaUpdates() {
        $hookContainer = $this->loadExtensions();
        ( new HookRunner( $hookContainer ) )->onLoadExtensionSchemaUpdates( $this );
    }

    /**
     * Loads LocalSettings.php, if needed, and initialises everything needed for
     * LoadExtensionSchemaUpdates hook.
     *
     * @return HookContainer
     */
    private function loadExtensions() {
        if ( $this->autoExtensionHookContainer ) {
            // Already injected by installer
            return $this->autoExtensionHookContainer;
        }
        if ( defined( 'MW_EXTENSIONS_LOADED' ) ) {
            throw new LogicException( __METHOD__ .
                ' apparently called from installer but no hook container was injected' );
        }
        if ( !defined( 'MEDIAWIKI_INSTALL' ) ) {
            // Running under update.php: use the global locator
            return MediaWikiServices::getInstance()->getHookContainer();
        }
        $vars = Installer::getExistingLocalSettings();

        $registry = ExtensionRegistry::getInstance();
        $queue = $registry->getQueue();
        // Don't accidentally load extensions in the future
        $registry->clearQueue();

        // Read extension.json files
        $extInfo = $registry->readFromQueue( $queue );

        // Merge extension attribute hooks with hooks defined by a .php
        // registration file included from LocalSettings.php
        $legacySchemaHooks = $extInfo['globals']['wgHooks']['LoadExtensionSchemaUpdates'] ?? [];
        if ( $vars && isset( $vars['wgHooks']['LoadExtensionSchemaUpdates'] ) ) {
            $legacySchemaHooks = array_merge( $legacySchemaHooks, $vars['wgHooks']['LoadExtensionSchemaUpdates'] );
        }

        // Register classes defined by extensions that are loaded by including of a file that
        // updates global variables, rather than having an extension.json manifest.
        if ( $vars && isset( $vars['wgAutoloadClasses'] ) ) {
            AutoLoader::registerClasses( $vars['wgAutoloadClasses'] );
        }

        // Register class definitions from extension.json files
        if ( !isset( $extInfo['autoloaderPaths'] )
            || !isset( $extInfo['autoloaderClasses'] )
            || !isset( $extInfo['autoloaderNS'] )
        ) {
            // NOTE: protect against changes to the structure of $extInfo.
            // It's volatile, and this usage is easy to miss.
            throw new LogicException( 'Missing autoloader keys from extracted extension info' );
        }
        AutoLoader::loadFiles( $extInfo['autoloaderPaths'] );
        AutoLoader::registerClasses( $extInfo['autoloaderClasses'] );
        AutoLoader::registerNamespaces( $extInfo['autoloaderNS'] );

        return new HookContainer(
            new StaticHookRegistry(
                [ 'LoadExtensionSchemaUpdates' => $legacySchemaHooks ],
                $extInfo['attributes']['Hooks'] ?? [],
                $extInfo['attributes']['DeprecatedHooks'] ?? []
            ),
            MediaWikiServices::getInstance()->getObjectFactory()
        );
    }

    /**
     * @param IMaintainableDatabase $db
     * @param bool $shared
     * @param Maintenance|null $maintenance
     * @return DatabaseUpdater
     */
    public static function newForDB(
        IMaintainableDatabase $db,
        $shared = false,
        Maintenance $maintenance = null
    ) {
        $type = $db->getType();
        if ( in_array( $type, Installer::getDBTypes() ) ) {
            $class = '\\MediaWiki\\Installer\\' . ucfirst( $type ) . 'Updater';

            return new $class( $db, $shared, $maintenance );
        }

        throw new UnexpectedValueException( __METHOD__ . ' called for unsupported DB type' );
    }

    /**
     * Set the HookContainer to use for loading extension schema updates.
     *
     * @internal For use by DatabaseInstaller
     * @since 1.36
     * @param HookContainer $hookContainer
     */
    public function setAutoExtensionHookContainer( HookContainer $hookContainer ) {
        $this->autoExtensionHookContainer = $hookContainer;
    }

    /**
     * Get a database connection to run updates
     *
     * @return IMaintainableDatabase
     */
    public function getDB() {
        return $this->db;
    }

    /**
     * Output some text. If we're running via the web, escape the text first.
     *
     * @param string $str Text to output
     * @param-taint $str escapes_html
     */
    public function output( $str ) {
        if ( $this->maintenance->isQuiet() ) {
            return;
        }
        if ( MW_ENTRY_POINT !== 'cli' ) {
            $str = htmlspecialchars( $str );
        }
        echo $str;
        flush();
    }

    /**
     * Add a new update coming from an extension.
     * Intended for use in LoadExtensionSchemaUpdates hook handlers.
     *
     * @since 1.17
     *
     * @param array $update The update to run. Format is [ $callback, $params... ]
     *   $callback is the method to call; either a DatabaseUpdater method name or a callable.
     *   Must be serializable (i.e., no anonymous functions allowed). The rest of the parameters
     *   (if any) will be passed to the callback. The first parameter passed to the callback
     *   is always this object.
     */
    public function addExtensionUpdate( array $update ) {
        $this->extensionUpdates[] = $update;
    }

    /**
     * Add a new update coming from an extension on virtual domain databases.
     * Intended for use in LoadExtensionSchemaUpdates hook handlers.
     *
     * @since 1.42
     *
     * @param array $update The update to run. The format is [ $virtualDomain, $callback, $params... ]
     *   similarly to addExtensionUpdate()
     */
    public function addExtensionUpdateOnVirtualDomain( array $update ) {
        $this->extensionUpdatesWithVirtualDomains[] = $update;
    }

    /**
     * Convenience wrapper for addExtensionUpdate() when adding a new table (which
     * is the most common usage of updaters in an extension)
     * Intended for use in LoadExtensionSchemaUpdates hook handlers.
     *
     * @since 1.18
     *
     * @param string $tableName Name of table to create
     * @param string $sqlPath Full path to the schema file
     */
    public function addExtensionTable( $tableName, $sqlPath ) {
        $this->extensionUpdates[] = [ 'addTable', $tableName, $sqlPath, true ];
    }

    /**
     * Add an index to an existing extension table.
     * Intended for use in LoadExtensionSchemaUpdates hook handlers.
     *
     * @since 1.19
     *
     * @param string $tableName
     * @param string $indexName
     * @param string $sqlPath
     */
    public function addExtensionIndex( $tableName, $indexName, $sqlPath ) {
        $this->extensionUpdates[] = [ 'addIndex', $tableName, $indexName, $sqlPath, true ];
    }

    /**
     * Add a field to an existing extension table.
     * Intended for use in LoadExtensionSchemaUpdates hook handlers.
     *
     * @since 1.19
     *
     * @param string $tableName
     * @param string $columnName
     * @param string $sqlPath
     */
    public function addExtensionField( $tableName, $columnName, $sqlPath ) {
        $this->extensionUpdates[] = [ 'addField', $tableName, $columnName, $sqlPath, true ];
    }

    /**
     * Drop a field from an extension table.
     * Intended for use in LoadExtensionSchemaUpdates hook handlers.
     *
     * @since 1.20
     *
     * @param string $tableName
     * @param string $columnName
     * @param string $sqlPath
     */
    public function dropExtensionField( $tableName, $columnName, $sqlPath ) {
        $this->extensionUpdates[] = [ 'dropField', $tableName, $columnName, $sqlPath, true ];
    }

    /**
     * Drop an index from an extension table
     * Intended for use in LoadExtensionSchemaUpdates hook handlers.
     *
     * @since 1.21
     *
     * @param string $tableName
     * @param string $indexName
     * @param string $sqlPath The path to the SQL change path
     */
    public function dropExtensionIndex( $tableName, $indexName, $sqlPath ) {
        $this->extensionUpdates[] = [ 'dropIndex', $tableName, $indexName, $sqlPath, true ];
    }

    /**
     * Drop an extension table.
     * Intended for use in LoadExtensionSchemaUpdates hook handlers.
     *
     * @since 1.20
     *
     * @param string $tableName
     * @param string|bool $sqlPath
     */
    public function dropExtensionTable( $tableName, $sqlPath = false ) {
        $this->extensionUpdates[] = [ 'dropTable', $tableName, $sqlPath, true ];
    }

    /**
     * Rename an index on an extension table
     * Intended for use in LoadExtensionSchemaUpdates hook handlers.
     *
     * @since 1.21
     *
     * @param string $tableName
     * @param string $oldIndexName
     * @param string $newIndexName
     * @param string $sqlPath The path to the SQL change file
     * @param bool $skipBothIndexExistWarning Whether to warn if both the old
     * and the new indexes exist. [facultative; by default, false]
     */
    public function renameExtensionIndex( $tableName, $oldIndexName, $newIndexName,
        $sqlPath, $skipBothIndexExistWarning = false
    ) {
        $this->extensionUpdates[] = [
            'renameIndex',
            $tableName,
            $oldIndexName,
            $newIndexName,
            $skipBothIndexExistWarning,
            $sqlPath,
            true
        ];
    }

    /**
     * Modify an existing field in an extension table.
     * Intended for use in LoadExtensionSchemaUpdates hook handlers.
     *
     * @since 1.21
     *
     * @param string $tableName
     * @param string $fieldName The field to be modified
     * @param string $sqlPath The path to the SQL patch
     */
    public function modifyExtensionField( $tableName, $fieldName, $sqlPath ) {
        $this->extensionUpdates[] = [ 'modifyField', $tableName, $fieldName, $sqlPath, true ];
    }

    /**
     * Modify an existing extension table.
     * Intended for use in LoadExtensionSchemaUpdates hook handlers.
     *
     * @since 1.31
     *
     * @param string $tableName
     * @param string $sqlPath The path to the SQL patch
     */
    public function modifyExtensionTable( $tableName, $sqlPath ) {
        $this->extensionUpdates[] = [ 'modifyTable', $tableName, $sqlPath, true ];
    }

    /**
     * @since 1.20
     *
     * @param string $tableName
     * @return bool
     */
    public function tableExists( $tableName ) {
        return ( $this->db->tableExists( $tableName, __METHOD__ ) );
    }

    /**
     * @since 1.40
     *
     * @param string $tableName
     * @param string $fieldName
     * @return bool
     */
    public function fieldExists( $tableName, $fieldName ) {
        return ( $this->db->fieldExists( $tableName, $fieldName, __METHOD__ ) );
    }

    /**
     * Add a maintenance script to be run after the database updates are complete.
     *
     * Script should subclass LoggedUpdateMaintenance
     *
     * @since 1.19
     *
     * @param string $class Name of a Maintenance subclass
     */
    public function addPostDatabaseUpdateMaintenance( $class ) {
        $this->postDatabaseUpdateMaintenance[] = $class;
    }

    /**
     * Get the list of extension-defined updates
     *
     * @return array
     */
    protected function getExtensionUpdates() {
        return $this->extensionUpdates;
    }

    /**
     * @since 1.17
     *
     * @return string[]
     */
    public function getPostDatabaseUpdateMaintenance() {
        return $this->postDatabaseUpdateMaintenance;
    }

    /**
     * @since 1.21
     *
     * Writes the schema updates desired to a file for the DB Admin to run.
     */
    private function writeSchemaUpdateFile() {
        $updates = $this->updatesSkipped;
        $this->updatesSkipped = [];

        foreach ( $updates as [ $func, $args, $origParams ] ) {
            // @phan-suppress-next-line PhanUndeclaredInvokeInCallable
            $func( ...$args );
            flush();
            $this->updatesSkipped[] = $origParams;
        }
    }

    /**
     * Get appropriate schema variables in the current database connection.
     *
     * This should be called after any request data has been imported, but before
     * any write operations to the database. The result should be passed to the DB
     * setSchemaVars() method.
     *
     * @return array
     * @since 1.28
     */
    public function getSchemaVars() {
        return []; // DB-type specific
    }

    /**
     * Do all the updates
     *
     * @param array $what What updates to perform
     */
    public function doUpdates( array $what = [ 'core', 'extensions', 'stats' ] ) {
        $this->db->setSchemaVars( $this->getSchemaVars() );

        $what = array_fill_keys( $what, true );
        $this->skipSchema = isset( $what['noschema'] ) || $this->fileHandle !== null;
        if ( isset( $what['core'] ) ) {
            $this->doCollationUpdate();
            $this->runUpdates( $this->getCoreUpdateList(), false );
        }
        if ( isset( $what['extensions'] ) ) {
            $this->loadExtensionSchemaUpdates();
            $this->runUpdates( $this->getExtensionUpdates(), true );
            $this->runUpdates( $this->extensionUpdatesWithVirtualDomains, true, true );
        }

        if ( isset( $what['stats'] ) ) {
            $this->checkStats();
        }

        if ( $this->fileHandle ) {
            $this->skipSchema = false;
            $this->writeSchemaUpdateFile();
        }
    }

    /**
     * Helper function for doUpdates()
     *
     * @param array $updates Array of updates to run
     * @param bool $passSelf Whether to pass this object when calling external functions
     * @param bool $hasVirtualDomain Whether the updates' array include virtual domains
     */
    private function runUpdates( array $updates, $passSelf, $hasVirtualDomain = false ) {
        $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
        $updatesDone = [];
        $updatesSkipped = [];
        foreach ( $updates as $params ) {
            $origParams = $params;
            $oldDb = null;
            $virtualDomain = null;
            if ( $hasVirtualDomain === true ) {
                $virtualDomain = array_shift( $params );
                $oldDb = $this->db;
                $this->db = $lbFactory->getPrimaryDatabase( $virtualDomain );
                '@phan-var IMaintainableDatabase $this->db';
            }
            $func = array_shift( $params );
            if ( !is_array( $func ) && method_exists( $this, $func ) ) {
                $func = [ $this, $func ];
            } elseif ( $passSelf ) {
                array_unshift( $params, $this );
            }
            $ret = $func( ...$params );
            if ( $hasVirtualDomain === true && $oldDb ) {
                $this->db = $oldDb;
            }

            flush();
            if ( $ret !== false ) {
                $updatesDone[] = $origParams;
                $lbFactory->waitForReplication( [ 'timeout' => self::REPLICATION_WAIT_TIMEOUT ] );
            } else {
                if ( $hasVirtualDomain === true ) {
                    $params = $origParams;
                    $func = array_shift( $params );
                }
                $updatesSkipped[] = [ $func, $params, $origParams ];
            }
        }
        $this->updatesSkipped = array_merge( $this->updatesSkipped, $updatesSkipped );
        $this->updates = array_merge( $this->updates, $updatesDone );
    }

    /**
     * Helper function: check if the given key is present in the updatelog table.
     *
     * @param string $key Name of the key to check for
     * @return bool
     */
    public function updateRowExists( $key ) {
        $row = $this->db->newSelectQueryBuilder()
            ->select( '1 AS X' ) // T67813
            ->from( 'updatelog' )
            ->where( [ 'ul_key' => $key ] )
            ->caller( __METHOD__ )->fetchRow();

        return (bool)$row;
    }

    /**
     * Helper function: Add a key to the updatelog table
     *
     * @note Extensions must only use this from within callbacks registered with
     * addExtensionUpdate(). In particular, this method must not be called directly
     * from a LoadExtensionSchemaUpdates handler.
     *
     * @param string $key Name of the key to insert
     * @param string|null $val [optional] Value to insert along with the key
     */
    public function insertUpdateRow( $key, $val = null ) {
        $this->db->clearFlag( DBO_DDLMODE );
        $values = [ 'ul_key' => $key ];
        if ( $val ) {
            $values['ul_value'] = $val;
        }
        $this->db->newInsertQueryBuilder()
            ->insertInto( 'updatelog' )
            ->ignore()
            ->row( $values )
            ->caller( __METHOD__ )->execute();
        $this->db->setFlag( DBO_DDLMODE );
    }

    /**
     * Returns whether updates should be executed on the database table $name.
     * Updates will be prevented if the table is a shared table, and it is not
     * specified to run updates on shared tables.
     *
     * @param string $name Table name
     * @return bool
     */
    protected function doTable( $name ) {
        global $wgSharedDB, $wgSharedTables;

        // Don't bother to check $wgSharedTables if there isn't a shared database
        // or the user actually also wants to do updates on the shared database.
        if ( $wgSharedDB === null || $this->shared ) {
            return true;
        }

        if ( in_array( $name, $wgSharedTables ) ) {
            $this->output( "...skipping update to shared table $name.\n" );
            return false;
        }

        return true;
    }

    /**
     * Get an array of updates to perform on the database. Should return a
     * multidimensional array. The main key is the MediaWiki version (1.12,
     * 1.13...) with the values being arrays of updates.
     *
     * @return array[]
     */
    abstract protected function getCoreUpdateList();

    /**
     * Append an SQL fragment to the open file handle.
     *
     * @note protected since 1.35
     *
     * @param string $filename File name to open
     */
    protected function copyFile( $filename ) {
        $this->db->sourceFile(
            $filename,
            null,
            null,
            __METHOD__,
            function ( $line ) {
                return $this->appendLine( $line );
            }
        );
    }

    /**
     * Append a line to the open file handle. The line is assumed to
     * be a complete SQL statement.
     *
     * This is used as a callback for sourceLine().
     *
     * @note protected since 1.35
     *
     * @param string $line Text to append to the file
     * @return bool False to skip actually executing the file
     */
    protected function appendLine( $line ) {
        $line = rtrim( $line ) . ";\n";
        if ( fwrite( $this->fileHandle, $line ) === false ) {
            throw new RuntimeException( "trouble writing file" );
        }

        return false;
    }

    /**
     * Applies a SQL patch
     *
     * @note Do not use this in a LoadExtensionSchemaUpdates handler,
     *       use addExtensionUpdate instead!
     *
     * @param string $path Path to the patch file
     * @param bool $isFullPath Whether to treat $path as a relative or not
     * @param string|null $msg Description of the patch
     * @return bool False if the patch was skipped.
     */
    protected function applyPatch( $path, $isFullPath = false, $msg = null ) {
        $msg ??= "Applying $path patch";
        if ( $this->skipSchema ) {
            $this->output( "...skipping schema change ($msg).\n" );

            return false;
        }

        $this->output( "{$msg}..." );

        if ( !$isFullPath ) {
            $path = $this->patchPath( $this->db, $path );
        }
        if ( $this->fileHandle !== null ) {
            $this->copyFile( $path );
        } else {
            $this->db->sourceFile( $path );
        }
        $this->output( "done.\n" );

        return true;
    }

    /**
     * Get the full path of a patch file. Keep in mind this always returns a patch, as
     * it fails back to MySQL if no DB-specific patch can be found
     *
     * @param IDatabase $db
     * @param string $patch The name of the patch, like patch-something.sql
     * @return string Full path to patch file
     */
    public function patchPath( IDatabase $db, $patch ) {
        $baseDir = MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::BaseDirectory );

        $dbType = $db->getType();
        if ( file_exists( "$baseDir/maintenance/$dbType/archives/$patch" ) ) {
            return "$baseDir/maintenance/$dbType/archives/$patch";
        }

        return "$baseDir/maintenance/archives/$patch";
    }

    /**
     * Add a new table to the database
     *
     * @note Code in a LoadExtensionSchemaUpdates handler should
     *       use addExtensionTable instead!
     *
     * @param string $name Name of the new table
     * @param string $patch Path to the patch file
     * @param bool $fullpath Whether to treat $patch path as a relative or not
     * @return bool False if this was skipped because schema changes are skipped
     */
    protected function addTable( $name, $patch, $fullpath = false ) {
        if ( !$this->doTable( $name ) ) {
            return true;
        }

        if ( $this->db->tableExists( $name, __METHOD__ ) ) {
            $this->output( "...$name table already exists.\n" );
            return true;
        }

        return $this->applyPatch( $patch, $fullpath, "Creating $name table" );
    }

    /**
     * Add a new field to an existing table
     *
     * @note Code in a LoadExtensionSchemaUpdates handler should
     *       use addExtensionField instead!
     *
     * @param string $table Name of the table to modify
     * @param string $field Name of the new field
     * @param string $patch Path to the patch file
     * @param bool $fullpath Whether to treat $patch path as a relative or not
     * @return bool False if this was skipped because schema changes are skipped
     */
    protected function addField( $table, $field, $patch, $fullpath = false ) {
        if ( !$this->doTable( $table ) ) {
            return true;
        }

        if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
            $this->output( "...$table table does not exist, skipping new field patch.\n" );
        } elseif ( $this->db->fieldExists( $table, $field, __METHOD__ ) ) {
            $this->output( "...have $field field in $table table.\n" );
        } else {
            return $this->applyPatch( $patch, $fullpath, "Adding $field field to table $table" );
        }

        return true;
    }

    /**
     * Add a new index to an existing table
     *
     * @note Code in a LoadExtensionSchemaUpdates handler should
     *       use addExtensionIndex instead!
     *
     * @param string $table Name of the table to modify
     * @param string $index Name of the new index
     * @param string $patch Path to the patch file
     * @param bool $fullpath Whether to treat $patch path as a relative or not
     * @return bool False if this was skipped because schema changes are skipped
     */
    protected function addIndex( $table, $index, $patch, $fullpath = false ) {
        if ( !$this->doTable( $table ) ) {
            return true;
        }

        if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
            $this->output( "...skipping: '$table' table doesn't exist yet.\n" );
        } elseif ( $this->db->indexExists( $table, $index, __METHOD__ ) ) {
            $this->output( "...index $index already set on $table table.\n" );
        } else {
            return $this->applyPatch( $patch, $fullpath, "Adding index $index to table $table" );
        }

        return true;
    }

    /**
     * Drop a field from an existing table
     *
     * @note Code in a LoadExtensionSchemaUpdates handler should
     *       use dropExtensionField instead!
     *
     * @param string $table Name of the table to modify
     * @param string $field Name of the old field
     * @param string $patch Path to the patch file
     * @param bool $fullpath Whether to treat $patch path as a relative or not
     * @return bool False if this was skipped because schema changes are skipped
     */
    protected function dropField( $table, $field, $patch, $fullpath = false ) {
        if ( !$this->doTable( $table ) ) {
            return true;
        }

        if ( $this->db->fieldExists( $table, $field, __METHOD__ ) ) {
            return $this->applyPatch( $patch, $fullpath, "Table $table contains $field field. Dropping" );
        }

        $this->output( "...$table table does not contain $field field.\n" );
        return true;
    }

    /**
     * Drop an index from an existing table
     *
     * @note Code in a LoadExtensionSchemaUpdates handler should
     *       use dropExtensionIndex instead!
     *
     * @param string $table Name of the table to modify
     * @param string $index Name of the index
     * @param string $patch Path to the patch file
     * @param bool $fullpath Whether to treat $patch path as a relative or not
     * @return bool False if this was skipped because schema changes are skipped
     */
    protected function dropIndex( $table, $index, $patch, $fullpath = false ) {
        if ( !$this->doTable( $table ) ) {
            return true;
        }

        if ( $this->db->indexExists( $table, $index, __METHOD__ ) ) {
            return $this->applyPatch( $patch, $fullpath, "Dropping $index index from table $table" );
        }

        $this->output( "...$index key doesn't exist.\n" );
        return true;
    }

    /**
     * Rename an index from an existing table
     *
     * @note Code in a LoadExtensionSchemaUpdates handler should
     *       use renameExtensionIndex instead!
     *
     * @param string $table Name of the table to modify
     * @param string $oldIndex Old name of the index
     * @param string $newIndex New name of the index
     * @param bool $skipBothIndexExistWarning Whether to warn if both the old and new indexes exist.
     * @param string $patch Path to the patch file
     * @param bool $fullpath Whether to treat $patch path as a relative or not
     * @return bool False if this was skipped because schema changes are skipped
     */
    protected function renameIndex( $table, $oldIndex, $newIndex,
        $skipBothIndexExistWarning, $patch, $fullpath = false
    ) {
        if ( !$this->doTable( $table ) ) {
            return true;
        }

        // First requirement: the table must exist
        if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
            $this->output( "...skipping: '$table' table doesn't exist yet.\n" );

            return true;
        }

        // Second requirement: the new index must be missing
        if ( $this->db->indexExists( $table, $newIndex, __METHOD__ ) ) {
            $this->output( "...index $newIndex already set on $table table.\n" );
            if ( !$skipBothIndexExistWarning &&
                $this->db->indexExists( $table, $oldIndex, __METHOD__ )
            ) {
                $this->output( "...WARNING: $oldIndex still exists, despite it has " .
                    "been renamed into $newIndex (which also exists).\n" .
                    "            $oldIndex should be manually removed if not needed anymore.\n" );
            }

            return true;
        }

        // Third requirement: the old index must exist
        if ( !$this->db->indexExists( $table, $oldIndex, __METHOD__ ) ) {
            $this->output( "...skipping: index $oldIndex doesn't exist.\n" );

            return true;
        }

        // Requirements have been satisfied, the patch can be applied
        return $this->applyPatch(
            $patch,
            $fullpath,
            "Renaming index $oldIndex into $newIndex to table $table"
        );
    }

    /**
     * If the specified table exists, drop it, or execute the
     * patch if one is provided.
     *
     * @note Code in a LoadExtensionSchemaUpdates handler should
     *       use dropExtensionTable instead!
     *
     * @note protected since 1.35
     *
     * @param string $table Table to drop.
     * @param string|false $patch String of patch file that will drop the table. Default: false.
     * @param bool $fullpath Whether $patch is a full path. Default: false.
     * @return bool False if this was skipped because schema changes are skipped
     */
    protected function dropTable( $table, $patch = false, $fullpath = false ) {
        if ( !$this->doTable( $table ) ) {
            return true;
        }

        if ( $this->db->tableExists( $table, __METHOD__ ) ) {
            $msg = "Dropping table $table";

            if ( $patch === false ) {
                $this->output( "$msg ..." );
                $this->db->dropTable( $table, __METHOD__ );
                $this->output( "done.\n" );
            } else {
                return $this->applyPatch( $patch, $fullpath, $msg );
            }
        } else {
            $this->output( "...$table doesn't exist.\n" );
        }

        return true;
    }

    /**
     * Modify an existing field
     *
     * @note Code in a LoadExtensionSchemaUpdates handler should
     *       use modifyExtensionField instead!
     *
     * @note protected since 1.35
     *
     * @param string $table Name of the table to which the field belongs
     * @param string $field Name of the field to modify
     * @param string $patch Path to the patch file
     * @param bool $fullpath Whether to treat $patch path as a relative or not
     * @return bool False if this was skipped because schema changes are skipped
     */
    protected function modifyField( $table, $field, $patch, $fullpath = false ) {
        if ( !$this->doTable( $table ) ) {
            return true;
        }

        $updateKey = "$table-$field-$patch";
        if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
            $this->output( "...$table table does not exist, skipping modify field patch.\n" );
        } elseif ( !$this->db->fieldExists( $table, $field, __METHOD__ ) ) {
            $this->output( "...$field field does not exist in $table table, " .
                "skipping modify field patch.\n" );
        } elseif ( $this->updateRowExists( $updateKey ) ) {
            $this->output( "...$field in table $table already modified by patch $patch.\n" );
        } else {
            $apply = $this->applyPatch( $patch, $fullpath, "Modifying $field field of table $table" );
            if ( $apply ) {
                $this->insertUpdateRow( $updateKey );
            }
            return $apply;
        }
        return true;
    }

    /**
     * Modify an existing table, similar to modifyField. Intended for changes that
     *  touch more than one column on a table.
     *
     * @note Code in a LoadExtensionSchemaUpdates handler should
     *       use modifyExtensionTable instead!
     *
     * @note protected since 1.35
     *
     * @param string $table Name of the table to modify
     * @param string $patch Name of the patch file to apply
     * @param string|bool $fullpath Whether to treat $patch path as relative or not, defaults to false
     * @return bool False if this was skipped because of schema changes being skipped
     */
    protected function modifyTable( $table, $patch, $fullpath = false ) {
        if ( !$this->doTable( $table ) ) {
            return true;
        }

        $updateKey = "$table-$patch";
        if ( !$this->db->tableExists( $table, __METHOD__ ) ) {
            $this->output( "...$table table does not exist, skipping modify table patch.\n" );
        } elseif ( $this->updateRowExists( $updateKey ) ) {
            $this->output( "...table $table already modified by patch $patch.\n" );
        } else {
            $apply = $this->applyPatch( $patch, $fullpath, "Modifying table $table" );
            if ( $apply ) {
                $this->insertUpdateRow( $updateKey );
            }
            return $apply;
        }
        return true;
    }

    /**
     * Run a maintenance script
     *
     * This should only be used when the maintenance script must run before
     * later updates. If later updates don't depend on the script, add it to
     * DatabaseUpdater::$postDatabaseUpdateMaintenance instead.
     *
     * The script's execute() method must return true to indicate successful
     * completion, and must return false (or throw an exception) to indicate
     * unsuccessful completion.
     *
     * @note Code in a LoadExtensionSchemaUpdates handler should
     *       use addExtensionUpdate instead!
     *
     * @note protected since 1.35
     *
     * @since 1.32
     * @param string $class Maintenance subclass
     * @param string $script Script path and filename, usually "maintenance/fooBar.php"
     */
    protected function runMaintenance( $class, $script ) {
        $this->output( "Running $script...\n" );
        $task = $this->maintenance->runChild( $class );
        $ok = $task->execute();
        if ( !$ok ) {
            throw new RuntimeException( "Execution of $script did not complete successfully." );
        }
        $this->output( "done.\n" );
    }

    /**
     * Set any .htaccess files or equivalent for storage repos
     *
     * Some zones (e.g. "temp") used to be public and may have been initialized as such
     */
    public function setFileAccess() {
        $repo = MediaWikiServices::getInstance()->getRepoGroup()->getLocalRepo();
        $zonePath = $repo->getZonePath( 'temp' );
        if ( $repo->getBackend()->directoryExists( [ 'dir' => $zonePath ] ) ) {
            // If the directory was never made, then it will have the right ACLs when it is made
            $status = $repo->getBackend()->secure( [
                'dir' => $zonePath,
                'noAccess' => true,
                'noListing' => true
            ] );
            if ( $status->isOK() ) {
                $this->output( "Set the local repo temp zone container to be private.\n" );
            } else {
                $this->output( "Failed to set the local repo temp zone container to be private.\n" );
            }
        }
    }

    /**
     * Purge various database caches
     */
    public function purgeCache() {
        global $wgLocalisationCacheConf;
        // We can't guarantee that the user will be able to use TRUNCATE,
        // but we know that DELETE is available to us
        $this->output( "Purging caches..." );

        // ObjectCache
        $this->db->newDeleteQueryBuilder()
            ->deleteFrom( 'objectcache' )
            ->where( ISQLPlatform::ALL_ROWS )
            ->caller( __METHOD__ )
            ->execute();

        // LocalisationCache
        if ( $wgLocalisationCacheConf['manualRecache'] ) {
            $this->rebuildLocalisationCache();
        }

        // ResourceLoader: Message cache
        $services = MediaWikiServices::getInstance();
        MessageBlobStore::clearGlobalCacheEntry(
            $services->getMainWANObjectCache()
        );

        // ResourceLoader: File-dependency cache
        $this->db->newDeleteQueryBuilder()
            ->deleteFrom( 'module_deps' )
            ->where( ISQLPlatform::ALL_ROWS )
            ->caller( __METHOD__ )
            ->execute();
        $this->output( "done.\n" );
    }

    /**
     * Check the site_stats table is not properly populated.
     */
    protected function checkStats() {
        $this->output( "...site_stats is populated..." );
        $row = $this->db->newSelectQueryBuilder()
            ->select( '*' )
            ->from( 'site_stats' )
            ->where( [ 'ss_row_id' => 1 ] )
            ->caller( __METHOD__ )->fetchRow();
        if ( $row === false ) {
            $this->output( "data is missing! rebuilding...\n" );
        } elseif ( isset( $row->site_stats ) && $row->ss_total_pages == -1 ) {
            $this->output( "missing ss_total_pages, rebuilding...\n" );
        } else {
            $this->output( "done.\n" );

            return;
        }
        SiteStatsInit::doAllAndCommit( $this->db );
    }

    # Common updater functions

    /**
     * Update CategoryLinks collation
     */
    protected function doCollationUpdate() {
        global $wgCategoryCollation;
        if ( $this->updateRowExists( 'UpdateCollation::' . $wgCategoryCollation ) ) {
            $this->output( "...collations up-to-date.\n" );
            return;
        }
        $this->output( "Updating category collations...\n" );
        $task = $this->maintenance->runChild( UpdateCollation::class );
        $ok = $task->execute();
        if ( $ok !== false ) {
            $this->output( "...done.\n" );
            $this->insertUpdateRow( 'UpdateCollation::' . $wgCategoryCollation );
        }
    }

    protected function doConvertDjvuMetadata() {
        if ( $this->updateRowExists( 'ConvertDjvuMetadata' ) ) {
            return;
        }
        $this->output( "Converting djvu metadata..." );
        $task = $this->maintenance->runChild( RefreshImageMetadata::class );
        '@phan-var RefreshImageMetadata $task';
        $task->loadParamsAndArgs( RefreshImageMetadata::class, [
            'force' => true,
            'mediatype' => 'OFFICE',
            'mime' => 'image/*',
            'batch-size' => 1,
            'sleep' => 1
        ] );
        $ok = $task->execute();
        if ( $ok !== false ) {
            $this->output( "...done.\n" );
            $this->insertUpdateRow( 'ConvertDjvuMetadata' );
        }
    }

    /**
     * Rebuilds the localisation cache
     */
    protected function rebuildLocalisationCache() {
        /**
         * @var RebuildLocalisationCache $cl
         */
        $cl = $this->maintenance->runChild(
            RebuildLocalisationCache::class, 'rebuildLocalisationCache.php'
        );
        '@phan-var RebuildLocalisationCache $cl';
        $this->output( "Rebuilding localisation cache...\n" );
        $cl->setForce();
        $cl->execute();
        $this->output( "done.\n" );
    }

    protected function migrateTemplatelinks() {
        if ( $this->updateRowExists( MigrateLinksTable::class . 'templatelinks' ) ) {
            $this->output( "...templatelinks table has already been migrated.\n" );
            return;
        }
        /**
         * @var MigrateLinksTable $task
         */
        $task = $this->maintenance->runChild(
            MigrateLinksTable::class, 'migrateLinksTable.php'
        );
        '@phan-var MigrateLinksTable $task';
        $task->loadParamsAndArgs( MigrateLinksTable::class, [
            'force' => true,
            'table' => 'templatelinks'
        ] );
        $this->output( "Running migrateLinksTable.php on templatelinks...\n" );
        $task->execute();
        $this->output( "done.\n" );
    }

    protected function migratePagelinks() {
        if ( $this->updateRowExists( MigrateLinksTable::class . 'pagelinks' ) ) {
            $this->output( "...pagelinks table has already been migrated.\n" );
            return;
        }
        /**
         * @var MigrateLinksTable $task
         */
        $task = $this->maintenance->runChild(
            MigrateLinksTable::class, 'migrateLinksTable.php'
        );
        '@phan-var MigrateLinksTable $task';
        $task->loadParamsAndArgs( MigrateLinksTable::class, [
            'force' => true,
            'table' => 'pagelinks'
        ] );
        $this->output( "Running migrateLinksTable.php on pagelinks...\n" );
        $task->execute();
        $this->output( "done.\n" );
    }

    /**
     * Only run a function if a table does not exist
     *
     * @since 1.35
     * @param string $table Table to check.
     *  If passed $this, it's assumed to be a call from runUpdates() with
     *  $passSelf = true: all other parameters are shifted and $this is
     *  prepended to the rest of $params.
     * @param string|array|static $func Normally this is the string naming the method on $this to
     *  call. It may also be an array style callable.
     * @param mixed ...$params Parameters for `$func`
     * @return mixed Whatever $func returns, or null when skipped.
     */
    protected function ifTableNotExists( $table, $func, ...$params ) {
        // Handle $passSelf from runUpdates().
        $passSelf = false;
        if ( $table === $this ) {
            $passSelf = true;
            $table = $func;
            $func = array_shift( $params );
        }

        if ( $this->db->tableExists( $table, __METHOD__ ) ) {
            return null;
        }

        if ( !is_array( $func ) && method_exists( $this, $func ) ) {
            $func = [ $this, $func ];
        } elseif ( $passSelf ) {
            array_unshift( $params, $this );
        }

        // @phan-suppress-next-line PhanUndeclaredInvokeInCallable Phan is confused
        return $func( ...$params );
    }

    /**
     * Only run a function if the named field exists
     *
     * @since 1.35
     * @param string $table Table to check.
     *  If passed $this, it's assumed to be a call from runUpdates() with
     *  $passSelf = true: all other parameters are shifted and $this is
     *  prepended to the rest of $params.
     * @param string $field Field to check
     * @param string|array|static $func Normally this is the string naming the method on $this to
     *  call. It may also be an array style callable.
     * @param mixed ...$params Parameters for `$func`
     * @return mixed Whatever $func returns, or null when skipped.
     */
    protected function ifFieldExists( $table, $field, $func, ...$params ) {
        // Handle $passSelf from runUpdates().
        $passSelf = false;
        if ( $table === $this ) {
            $passSelf = true;
            $table = $field;
            $field = $func;
            $func = array_shift( $params );
        }

        if ( !$this->db->tableExists( $table, __METHOD__ ) ||
            !$this->db->fieldExists( $table, $field, __METHOD__ )
        ) {
            return null;
        }

        if ( !is_array( $func ) && method_exists( $this, $func ) ) {
            $func = [ $this, $func ];
        } elseif ( $passSelf ) {
            array_unshift( $params, $this );
        }

        // @phan-suppress-next-line PhanUndeclaredInvokeInCallable Phan is confused
        return $func( ...$params );
    }

}

/** @deprecated class alias since 1.41 */
class_alias( DatabaseUpdater::class, 'DatabaseUpdater' );