wikimedia/mediawiki-core

<?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 Maintenance
 */

// @codeCoverageIgnoreStart
require_once __DIR__ . '/Maintenance.php';
// @codeCoverageIgnoreEnd

use MediaWiki\Title\Title;

/**
 * Maintenance script that clears rows of pages corrupted by MergeHistory, those
 * pages 'exist' but have no visible revision.
 *
 * These pages are completely inaccessible via the UI due to revision/title mismatch
 * exceptions in RevisionStore and elsewhere.
 *
 * These are rows in page_table that have 'page_latest' entry with corresponding
 * 'rev_id' but no associated 'rev_page' entry in revision table. Such rows create
 * ghost pages because their 'page_latest' is actually living on different pages
 * (which possess the associated 'rev_page' on revision table now).
 *
 * @see https://phabricator.wikimedia.org/T263340
 * @see https://phabricator.wikimedia.org/T259022
 */
class FixMergeHistoryCorruption extends Maintenance {

    public function __construct() {
        parent::__construct();
        $this->addDescription( 'Delete pages corrupted by MergeHistory' );
        $this->addOption( 'ns', 'Namespace to restrict the query', false, true );
        $this->addOption( 'dry-run', 'Run in dry-mode' );
        $this->addOption( 'delete', 'Actually delete the found rows' );
    }

    public function execute() {
        $dbr = $this->getReplicaDB();
        $dbw = $this->getPrimaryDB();

        $dryRun = true;
        if ( $this->hasOption( 'dry-run' ) && $this->hasOption( 'delete' ) ) {
            $this->fatalError( 'Cannot do both --dry-run and --delete.' );
        } elseif ( $this->hasOption( 'delete' ) ) {
            $dryRun = false;
        } elseif ( !$this->hasOption( 'dry-run' ) ) {
            $this->fatalError( 'Either --dry-run or --delete must be specified.' );
        }

        $conds = [ 'page_id<>rev_page' ];
        if ( $this->hasOption( 'ns' ) ) {
            $conds['page_namespace'] = (int)$this->getOption( 'ns' );
        }

        $res = $dbr->newSelectQueryBuilder()
            ->from( 'page' )
            ->join( 'revision', null, 'page_latest=rev_id' )
            ->fields( [ 'page_namespace', 'page_title', 'page_id' ] )
            ->where( $conds )
            ->caller( __METHOD__ )
            ->fetchResultSet();

        $count = $res->numRows();

        if ( !$count ) {
            $this->output( "Nothing was found, no page matches the criteria.\n" );
            return;
        }

        $numDeleted = 0;
        $numUpdated = 0;

        foreach ( $res as $row ) {
            $title = Title::makeTitleSafe( $row->page_namespace, $row->page_title );
            if ( !$title ) {
                $this->output( "Skipping invalid title with page_id: $row->page_id\n" );
                continue;
            }
            $titleText = $title->getPrefixedDBkey();

            // Check if there are any revisions that have this $row->page_id as their
            // rev_page and select the largest which should be the newest revision.
            $revId = $dbr->newSelectQueryBuilder()
                ->select( 'MAX(rev_id)' )
                ->from( 'revision' )
                ->where( [ 'rev_page' => $row->page_id ] )
                ->caller( __METHOD__ )->fetchField();

            if ( !$revId ) {
                if ( $dryRun ) {
                    $this->output( "Would delete $titleText with page_id: $row->page_id\n" );
                } else {
                    $this->output( "Deleting $titleText with page_id: $row->page_id\n" );
                    $dbw->newDeleteQueryBuilder()
                        ->deleteFrom( 'page' )
                        ->where( [ 'page_id' => $row->page_id ] )
                        ->caller( __METHOD__ )->execute();
                }
                $numDeleted++;
            } else {
                if ( $dryRun ) {
                    $this->output( "Would update page_id $row->page_id to page_latest $revId\n" );
                } else {
                    $this->output( "Updating page_id $row->page_id to page_latest $revId\n" );
                    $dbw->newUpdateQueryBuilder()
                        ->update( 'page' )
                        ->set( [ 'page_latest' => $revId ] )
                        ->where( [ 'page_id' => $row->page_id ] )
                        ->caller( __METHOD__ )->execute();
                }
                $numUpdated++;
            }
        }

        if ( !$dryRun ) {
            $this->output( "Updated $numUpdated row(s), deleted $numDeleted row(s)\n" );
        }
    }
}

// @codeCoverageIgnoreStart
$maintClass = FixMergeHistoryCorruption::class;
require_once RUN_MAINTENANCE_IF_MAIN;
// @codeCoverageIgnoreEnd