findMissingActors.php

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<?php
use MediaWiki\MediaWikiServices;
use Wikimedia\Rdbms\LBFactory;
use Wikimedia\Rdbms\LoadBalancer;
 
require_once __DIR__ . '/Maintenance.php';
 
class FindMissingActors extends Maintenance {
 
    private $loadBalancer;
 
    private $lbFactory;
 
    private const TABLES = [
        // 'rev_actor' => [ 'revision', 'rev_actor', 'rev_id' ], // not yet used in 1.35
        'revactor_actor' => [ 'revision_actor_temp', 'revactor_actor', 'revactor_rev' ],
        'ar_actor' => [ 'archive', 'ar_actor', 'ar_id' ],
        'ipb_by_actor' => [ 'ipblocks', 'ipb_by_actor', 'ipb_id' ], // no index on ipb_by_actor!
        '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' ],
        'rc_actor' => [ 'recentchanges', 'rc_actor', 'rc_id' ],
        'log_actor' => [ 'logging', 'log_actor', 'log_id' ],
    ];
 
    public function __construct() {
        parent::__construct();
 
        $this->addDescription( 'Find and fix invalid actor IDs.' );
        $this->addOption( 'field', 'The name of a database field to process. '
            . 'Possible values: ' . implode( ', ', array_keys( self::TABLES ) ),
             true, true );
        $this->addOption( 'skip', 'A comma-separated list of actor IDs to skip.',
            false, true );
        $this->addOption( 'overwrite-with', 'Replace missing 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 );
    }
 
    public function initializeServices(
        $userFactory = null,
        $userNameUtils = null,
        ?LoadBalancer $loadBalancer = null,
        ?LBFactory $lbFactory = null
    ) {
        $services = MediaWikiServices::getInstance();
 
        $this->loadBalancer = $loadBalancer ?? $this->loadBalancer ?? $services->getDBLoadBalancer();
        $this->lbFactory = $lbFactory ?? $this->lbFactory ?? $services->getDBLoadBalancerFactory();
    }
 
    private function getNewActorId() {
        $name = $this->getOption( 'overwrite-with' );
 
        if ( $name === null ) {
            return null;
        }
 
        $user = User::newFromName( $name );
 
        if ( !$user ) {
            $this->fatalError( "Not a valid user name: '$user'" );
        }
 
        $name = User::getCanonicalName( $name );
 
        if ( $user->isRegistered() ) {
            $this->output( "Using existing user: '$user'\n" );
        } elseif ( !User::isValidUserName( $name ) ) {
            $this->fatalError( "Not a valid user name: '$name'" );
        } elseif ( !User::isUsableName( $name ) ) {
            $this->output( "Using system user: '$name'\n" );
        } else {
            $this->fatalError( "Unknown user: '$name'" );
        }
 
        // Supply write connection to assign an actor ID if needed.
        $dbw = $this->loadBalancer->getConnectionRef( DB_MASTER );
        $actorId = $user->getActorId( $dbw );
 
        if ( !$actorId ) {
            $this->fatalError( "Failed to acquire an actor ID for user '$user'" );
        }
 
        $this->output( "Replacement actor ID is $actorId.\n" );
        return $actorId;
    }
 
    public function execute() {
        $this->initializeServices();
 
        $field = $this->getOption( 'field' );
        if ( !isset( self::TABLES[$field] ) ) {
            $this->fatalError( "Unknown field: $field.\n" );
        }
 
        $skip = $this->parseIntList( $this->getOption( 'skip', '' ) );
        $overwrite = $this->getNewActorId();
 
        $bad = $this->findBadActors( $field, $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 = $this->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, $skip ) {
        [ $table, $actorField, $idField ] = self::TABLES[$field];
        $this->output( "Finding invalid actor IDs in $table.$actorField...\n" );
 
        $dbr = $this->loadBalancer->getConnectionRef(
            DB_REPLICA,
            [ 'maintenance', 'vslow', 'slow' ]
        );
 
        /*
        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
        JOIN actor ON log_actor = actor_id
        WHERE actor_id IS NULL
        AND log_actor NOT IN (1, 2, 3, 4)
        LIMIT 1000;
         */
 
        $conds = [ 'actor_id' => null ];
 
        if ( $skip ) {
            $conds[] = $actorField . ' NOT IN ( ' . $dbr->makeList( $skip ) . ' ) ';
        }
 
        $queryBuilder = $dbr->newSelectQueryBuilder();
        $queryBuilder->table( $table )
            ->fields( [ $actorField, $idField ] )
            ->conds( $conds )
            ->leftJoin( 'actor', null, [ "$actorField = actor_id" ] )
            ->limit( $this->getBatchSize() )
            ->caller( __METHOD__ );
 
        $res = $queryBuilder->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, $idField ] = self::TABLES[$field];
 
        $count = count( $ids );
        $this->output( "OVERWRITING $count actor IDs in $table.$actorField with $overwrite...\n" );
 
        $dbw = $this->loadBalancer->getConnectionRef( DB_MASTER );
 
        $dbw->update( $table, [ $actorField => $overwrite ], [ $idField => $ids ], __METHOD__ );
 
        $count = $dbw->affectedRows();
 
        $this->lbFactory->waitForReplication();
        $this->output( "\tUpdated $count rows.\n" );
 
        return $count;
    }
 
}
 
$maintClass = FindMissingActors::class;
require_once RUN_MAINTENANCE_IF_MAIN;