findMissingActors.php

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<?php
use MediaWiki\Exception\CannotCreateActorException;
use MediaWiki\Maintenance\Maintenance;
use MediaWiki\User\ActorNormalization;
use MediaWiki\User\UserFactory;
use MediaWiki\User\UserNameUtils;
 
// @codeCoverageIgnoreStart
require_once __DIR__ . '/Maintenance.php';
// @codeCoverageIgnoreEnd
 
class FindMissingActors extends Maintenance {
 
    private UserFactory $userFactory;
    private UserNameUtils $userNameUtils;
    private ActorNormalization $actorNormalization;
 
    public function __construct() {
        parent::__construct();
 
        $this->addDescription( 'Find and fix invalid actor IDs.' );
        $this->addOption( 'field', 'The name of a database field to process',
            true, true );
        $this->addOption( 'type', 'Which type of invalid actors to find or fix, '
            . 'missing or broken (with empty actor_name which can\'t be associated '
            . 'with an existing user).',
            false, true );
        $this->addOption( 'skip', 'A comma-separated list of actor IDs to skip.',
            false, true );
        $this->addOption( 'overwrite-with', 'Replace invalid actors with this user. '
            . 'Typically, this would be "Unknown user", but it could be any reserved '
            . 'system user (per $wgReservedUsernames) or locally registered user. '
            . 'If not given, invalid actors will only be listed, not fixed. '
            . 'You will be prompted for confirmation before data is written. ',
            false, true );
 
        $this->setBatchSize( 1000 );
    }
 
    private function getTables() {
        return [
            'ar_actor' => [ 'archive', 'ar_actor', 'ar_id' ],
            'img_actor' => [ 'image', 'img_actor', 'img_name' ],
            'oi_actor' => [ 'oldimage', 'oi_actor', 'oi_archive_name' ], // no index on oi_archive_name!
            'fa_actor' => [ 'filearchive', 'fa_actor', 'fa_id' ],
            'fr_actor' => [ 'filerevision', 'fr_actor', 'fr_id' ],
            'rc_actor' => [ 'recentchanges', 'rc_actor', 'rc_id' ],
            'log_actor' => [ 'logging', 'log_actor', 'log_id' ],
            'rev_actor' => [ 'revision', 'rev_actor', 'rev_id' ],
            'bl_by_actor' => [ 'block', 'bl_by_actor', 'bl_id' ], // no index on bl_by_actor!
        ];
    }
 
    private function getTableInfo( $field ) {
        $tables = $this->getTables();
        return $tables[$field] ?? null;
    }
 
    private function getNewActorId() {
        $name = $this->getOption( 'overwrite-with' );
 
        if ( $name === null ) {
            return null;
        }
 
        $user = $this->userFactory->newFromName( $name );
 
        if ( !$user ) {
            $this->fatalError( "Not a valid user name: '$name'" );
        }
 
        if ( $user->isRegistered() ) {
            $this->output( "Using existing user: '$user'\n" );
        } elseif ( !$this->userNameUtils->isUsable( $user->getName() ) ) {
            $this->output( "Using system user: '{$user->getName()}'\n" );
        } else {
            $this->fatalError( "Unknown user: '{$user->getName()}'" );
        }
 
        $dbw = $this->getPrimaryDB();
 
        try {
            $actorId = $this->actorNormalization->acquireActorId( $user, $dbw );
        } catch ( CannotCreateActorException ) {
            $this->fatalError( "Failed to acquire an actor ID for user '$user'" );
        }
 
        $this->output( "Replacement actor ID is $actorId.\n" );
        return $actorId;
    }
 
    public function execute() {
        $services = $this->getServiceContainer();
        $this->userFactory = $services->getUserFactory();
        $this->userNameUtils = $services->getUserNameUtils();
        $this->actorNormalization = $services->getActorNormalization();
 
        $field = $this->getOption( 'field' );
        if ( !$this->getTableInfo( $field ) ) {
            $this->fatalError( "Unknown field: $field.\n" );
        }
 
        $type = $this->getOption( 'type', 'missing' );
        if ( $type !== 'missing' && $type !== 'broken' ) {
            $this->fatalError( "Unknown type: $type.\n" );
        }
 
        $skip = $this->parseIntList( $this->getOption( 'skip', '' ) );
        $overwrite = $this->getNewActorId();
 
        $bad = $this->findBadActors( $field, $type, $skip );
 
        if ( $bad && $overwrite ) {
            $this->output( "\n" );
            $this->output( "Do you want to OVERWRITE the listed actor IDs?\n" );
            $this->output( "Information about the invalid IDs will be lost!\n" );
            $this->output( "\n" );
            $confirm = static::readconsole( 'Type "yes" to continue: ' );
 
            if ( $confirm === 'yes' ) {
                $this->overwriteActorIDs( $field, array_keys( $bad ), $overwrite );
            } else {
                $this->fatalError( 'Aborted.' );
            }
        }
 
        $this->output( "Done.\n" );
    }
 
    private function findBadActors( $field, $type, $skip ) {
        [ $table, $actorField, $idField ] = $this->getTableInfo( $field );
        $this->output( "Finding invalid actor IDs in $table.$actorField...\n" );
 
        $dbr = $this->getServiceContainer()->getDBLoadBalancer()->getConnection( DB_REPLICA, 'vslow' );
 
        /*
        We are building an SQL query like this one here, performing a left join
        to detect rows in $table that lack a matching row in the actor table.
 
        In this example, $field is 'log_actor', so $table is 'logging',
        $actorField is 'log_actor', and $idField is 'log_id'.
        Further, $skip is [ 1, 2, 3, 4 ] and the batch size is 1000.
 
        SELECT log_id
        FROM logging
        LEFT JOIN actor ON log_actor = actor_id
        WHERE actor_id IS NULL
        AND log_actor NOT IN (1, 2, 3, 4)
        LIMIT 1000;
        */
 
        $queryBuilder = $dbr->newSelectQueryBuilder()
            ->select( [ $actorField, $idField ] )
            ->from( $table )
            ->leftJoin( 'actor', null, [ "$actorField = actor_id" ] )
            ->where( $type == 'missing' ? [ 'actor_id' => null ] : [ 'actor_name' => '' ] )
            ->limit( $this->getBatchSize() );
 
        if ( $skip ) {
            $queryBuilder->andWhere( $dbr->expr( $actorField, '!=', $skip ) );
        }
 
        $res = $queryBuilder->caller( __METHOD__ )->fetchResultSet();
        $count = $res->numRows();
 
        $bad = [];
 
        if ( $count ) {
            $this->output( "\t\tID\tACTOR\n" );
        }
 
        foreach ( $res as $row ) {
            $id = $row->$idField;
            $actor = (int)( $row->$actorField );
 
            $bad[$id] = $actor;
            $this->output( "\t\t$id\t$actor\n" );
        }
 
        $this->output( "\tFound $count invalid actor IDs.\n" );
 
        if ( $count >= $this->getBatchSize() ) {
            $this->output( "\tBatch size reached, run again after fixing the current batch.\n" );
        }
 
        return $bad;
    }
 
    private function overwriteActorIDs( $field, array $ids, int $overwrite ) {
        [ $table, $actorField, $idField ] = $this->getTableInfo( $field );
 
        $count = count( $ids );
        $this->output( "OVERWRITING $count actor IDs in $table.$actorField with $overwrite...\n" );
 
        $dbw = $this->getPrimaryDB();
 
        $dbw->newUpdateQueryBuilder()
            ->update( $table )
            ->set( [ $actorField => $overwrite ] )
            ->where( [ $idField => $ids ] )
            ->caller( __METHOD__ )->execute();
 
        $count = $dbw->affectedRows();
 
        $this->waitForReplication();
        $this->output( "\tUpdated $count rows.\n" );
 
        return $count;
    }
 
}
 
// @codeCoverageIgnoreStart
$maintClass = FindMissingActors::class;
require_once RUN_MAINTENANCE_IF_MAIN;
// @codeCoverageIgnoreEnd