DeletePage.php

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<?php
 
namespace MediaWiki\Page;
 
use BadMethodCallException;
use BagOStuff;
use ChangeTags;
use CommentStore;
use Content;
use DeferrableUpdate;
use DeferredUpdates;
use DeletePageJob;
use Exception;
use JobQueueGroup;
use LinksDeletionUpdate;
use LinksUpdate;
use LogicException;
use ManualLogEntry;
use MediaWiki\Cache\BacklinkCacheFactory;
use MediaWiki\Config\ServiceOptions;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\Permissions\Authority;
use MediaWiki\Permissions\PermissionStatus;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Revision\RevisionStore;
use MediaWiki\Revision\SlotRecord;
use MediaWiki\User\UserFactory;
use Message;
use RawMessage;
use ResourceLoaderWikiModule;
use SearchUpdate;
use SiteStatsUpdate;
use Status;
use StatusValue;
use Wikimedia\IPUtils;
use Wikimedia\Rdbms\ILoadBalancer;
use Wikimedia\Rdbms\LBFactory;
use WikiPage;
 
class DeletePage {
    public const CONSTRUCTOR_OPTIONS = [
        'DeleteRevisionsBatchSize',
        'ActorTableSchemaMigrationStage',
        'DeleteRevisionsLimit',
    ];
 
    private $hookRunner;
    private $revisionStore;
    private $lbFactory;
    private $loadBalancer;
    private $jobQueueGroup;
    private $commentStore;
    private $options;
    private $recentDeletesCache;
    private $localWikiID;
    private $webRequestID;
    private $userFactory;
    private $backlinkCacheFactory;
 
    private $isDeletePageUnitTest = false;
 
    private $page;
    private $deleter;
 
    private $suppress = false;
    private $tags = [];
    private $logSubtype = 'delete';
    private $forceImmediate = false;
 
    private $legacyHookErrors = '';
    private $mergeLegacyHookErrors = true;
 
    private $successfulDeletionsIDs;
    private $wasScheduled;
    private $attemptedDeletion = false;
 
    public function __construct(
        HookContainer $hookContainer,
        RevisionStore $revisionStore,
        LBFactory $lbFactory,
        JobQueueGroup $jobQueueGroup,
        CommentStore $commentStore,
        ServiceOptions $serviceOptions,
        BagOStuff $recentDeletesCache,
        string $localWikiID,
        string $webRequestID,
        WikiPageFactory $wikiPageFactory,
        UserFactory $userFactory,
        ProperPageIdentity $page,
        Authority $deleter,
        BacklinkCacheFactory $backlinkCacheFactory
    ) {
        $this->hookRunner = new HookRunner( $hookContainer );
        $this->revisionStore = $revisionStore;
        $this->lbFactory = $lbFactory;
        $this->loadBalancer = $this->lbFactory->getMainLB();
        $this->jobQueueGroup = $jobQueueGroup;
        $this->commentStore = $commentStore;
        $serviceOptions->assertRequiredOptions( self::CONSTRUCTOR_OPTIONS );
        $this->options = $serviceOptions;
        $this->recentDeletesCache = $recentDeletesCache;
        $this->localWikiID = $localWikiID;
        $this->webRequestID = $webRequestID;
        $this->userFactory = $userFactory;
 
        $this->page = $wikiPageFactory->newFromTitle( $page );
        $this->deleter = $deleter;
        $this->backlinkCacheFactory = $backlinkCacheFactory;
    }
 
    public function getLegacyHookErrors() {
        return $this->legacyHookErrors;
    }
 
    public function keepLegacyHookErrorsSeparate(): self {
        $this->mergeLegacyHookErrors = false;
        return $this;
    }
 
    public function setSuppress( bool $suppress ): self {
        $this->suppress = $suppress;
        return $this;
    }
 
    public function setTags( array $tags ): self {
        $this->tags = $tags;
        return $this;
    }
 
    public function setLogSubtype( string $logSubtype ): self {
        $this->logSubtype = $logSubtype;
        return $this;
    }
 
    public function forceImmediate( bool $forceImmediate ): self {
        $this->forceImmediate = $forceImmediate;
        return $this;
    }
 
    public function setIsDeletePageUnitTest( bool $test ): void {
        if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
            throw new BadMethodCallException( __METHOD__ . ' can only be used in tests!' );
        }
        $this->isDeletePageUnitTest = $test;
    }
 
    private function setDeletionAttempted(): void {
        $this->attemptedDeletion = true;
        $this->successfulDeletionsIDs = [];
        $this->wasScheduled = false;
    }
 
    private function assertDeletionAttempted(): void {
        if ( !$this->attemptedDeletion ) {
            throw new BadMethodCallException( 'No deletion was attempted' );
        }
    }
 
    public function getSuccessfulDeletionsIDs(): array {
        $this->assertDeletionAttempted();
        return $this->successfulDeletionsIDs;
    }
 
    public function deletionWasScheduled(): bool {
        $this->assertDeletionAttempted();
        return $this->wasScheduled;
    }
 
    public function deleteIfAllowed( string $reason ): StatusValue {
        $this->setDeletionAttempted();
        $status = $this->authorizeDeletion();
        if ( !$status->isGood() ) {
            return $status;
        }
 
        return $this->deleteUnsafe( $reason );
    }
 
    private function authorizeDeletion(): PermissionStatus {
        $status = PermissionStatus::newEmpty();
        $this->deleter->authorizeWrite( 'delete', $this->page, $status );
        if (
            !$this->deleter->authorizeWrite( 'bigdelete', $this->page ) &&
            $this->isBigDeletion()
        ) {
            $status->fatal( 'delete-toobig', Message::numParam( $this->options->get( 'DeleteRevisionsLimit' ) ) );
        }
        if ( $this->tags ) {
            $status->merge( ChangeTags::canAddTagsAccompanyingChange( $this->tags, $this->deleter ) );
        }
        return $status;
    }
 
    private function isBigDeletion(): bool {
        $revLimit = $this->options->get( 'DeleteRevisionsLimit' );
        if ( !$revLimit ) {
            return false;
        }
 
        $revCount = $this->revisionStore->countRevisionsByPageId(
            $this->loadBalancer->getConnectionRef( DB_REPLICA ),
            $this->page->getId()
        );
 
        return $revCount > $revLimit;
    }
 
    public function isBatchedDelete( int $safetyMargin = 0 ): bool {
        $revCount = $this->revisionStore->countRevisionsByPageId(
            $this->loadBalancer->getConnectionRef( DB_REPLICA ),
            $this->page->getId()
        );
        $revCount += $safetyMargin;
 
        return $revCount >= $this->options->get( 'DeleteRevisionsBatchSize' );
    }
 
    public function deleteUnsafe( string $reason ): Status {
        $this->setDeletionAttempted();
        $status = Status::newGood();
 
        $legacyDeleter = $this->userFactory->newFromAuthority( $this->deleter );
        if ( !$this->hookRunner->onArticleDelete(
            $this->page, $legacyDeleter, $reason, $this->legacyHookErrors, $status, $this->suppress )
        ) {
            if ( $this->mergeLegacyHookErrors && $this->legacyHookErrors !== '' ) {
                if ( is_string( $this->legacyHookErrors ) ) {
                    $this->legacyHookErrors = [ $this->legacyHookErrors ];
                }
                foreach ( $this->legacyHookErrors as $legacyError ) {
                    $status->fatal( new RawMessage( $legacyError ) );
                }
            }
            if ( $status->isOK() ) {
                // Hook aborted but didn't set a fatal status
                $status->fatal( 'delete-hook-aborted' );
            }
            return $status;
        }
 
        // Use a new Status in case a hook handler put something here without aborting.
        $status = Status::newGood();
        $hookRes = $this->hookRunner->onPageDelete( $this->page, $this->deleter, $reason, $status, $this->suppress );
        if ( !$hookRes && !$status->isGood() ) {
            // Note: as per the PageDeleteHook documentation, `return false` is ignored if $status is good.
            return $status;
        }
 
        return $this->deleteInternal( $reason );
    }
 
    public function deleteInternal( string $reason, ?string $webRequestId = null ): Status {
        // The following is necessary for direct calls from the outside
        $this->setDeletionAttempted();
 
        $title = $this->page->getTitle();
        $status = Status::newGood();
 
        $dbw = $this->loadBalancer->getConnectionRef( DB_PRIMARY );
        $dbw->startAtomic( __METHOD__ );
 
        $this->page->loadPageData( WikiPage::READ_LATEST );
        $id = $this->page->getId();
        // T98706: lock the page from various other updates but avoid using
        // WikiPage::READ_LOCKING as that will carry over the FOR UPDATE to
        // the revisions queries (which also JOIN on user). Only lock the page
        // row and CAS check on page_latest to see if the trx snapshot matches.
        $lockedLatest = $this->page->lockAndGetLatest();
        if ( $id === 0 || $this->page->getLatest() !== $lockedLatest ) {
            $dbw->endAtomic( __METHOD__ );
            // Page not there or trx snapshot is stale
            $status->error( 'cannotdelete', wfEscapeWikiText( $title->getPrefixedText() ) );
            return $status;
        }
 
        // At this point we are now committed to returning an OK
        // status unless some DB query error or other exception comes up.
        // This way callers don't have to call rollback() if $status is bad
        // unless they actually try to catch exceptions (which is rare).
 
        // we need to remember the old content so we can use it to generate all deletion updates.
        $revisionRecord = $this->page->getRevisionRecord();
        if ( !$revisionRecord ) {
            throw new LogicException( "No revisions for $this->page?" );
        }
        try {
            $content = $this->page->getContent( RevisionRecord::RAW );
        } catch ( Exception $ex ) {
            wfLogWarning( __METHOD__ . ': failed to load content during deletion! '
                . $ex->getMessage() );
 
            $content = null;
        }
 
        // Archive revisions.  In immediate mode, archive all revisions.  Otherwise, archive
        // one batch of revisions and defer archival of any others to the job queue.
        $explictTrxLogged = false;
        while ( true ) {
            $done = $this->archiveRevisions( $id );
            if ( $done || !$this->forceImmediate ) {
                break;
            }
            $dbw->endAtomic( __METHOD__ );
            if ( $dbw->explicitTrxActive() ) {
                // Explict transactions may never happen here in practice.  Log to be sure.
                if ( !$explictTrxLogged ) {
                    $explictTrxLogged = true;
                    LoggerFactory::getInstance( 'wfDebug' )->debug(
                        'explicit transaction active in ' . __METHOD__ . ' while deleting {title}', [
                        'title' => $title->getText(),
                    ] );
                }
                continue;
            }
            if ( $dbw->trxLevel() ) {
                $dbw->commit( __METHOD__ );
            }
            $this->lbFactory->waitForReplication();
            $dbw->startAtomic( __METHOD__ );
        }
 
        if ( !$done ) {
            $dbw->endAtomic( __METHOD__ );
 
            $jobParams = [
                'namespace' => $title->getNamespace(),
                'title' => $title->getDBkey(),
                'wikiPageId' => $id,
                'requestId' => $webRequestId ?? $this->webRequestID,
                'reason' => $reason,
                'suppress' => $this->suppress,
                'userId' => $this->deleter->getUser()->getId(),
                'tags' => json_encode( $this->tags ),
                'logsubtype' => $this->logSubtype,
            ];
 
            $job = new DeletePageJob( $jobParams );
            $this->jobQueueGroup->push( $job );
            $this->wasScheduled = true;
            return $status;
        }
 
        // Get archivedRevisionCount by db query, because there's no better alternative.
        // Jobs cannot pass a count of archived revisions to the next job, because additional
        // deletion operations can be started while the first is running.  Jobs from each
        // gracefully interleave, but would not know about each other's count.  Deduplication
        // in the job queue to avoid simultaneous deletion operations would add overhead.
        // Number of archived revisions cannot be known beforehand, because edits can be made
        // while deletion operations are being processed, changing the number of archivals.
        $archivedRevisionCount = $dbw->selectRowCount(
            'archive',
            '*',
            [
                'ar_namespace' => $title->getNamespace(),
                'ar_title' => $title->getDBkey(),
                'ar_page_id' => $id
            ], __METHOD__
        );
 
        // Clone the title and wikiPage, so we have the information we need when
        // we log and run the ArticleDeleteComplete hook.
        $logTitle = clone $title;
        $wikiPageBeforeDelete = clone $this->page;
 
        // Now that it's safely backed up, delete it
        $dbw->delete( 'page', [ 'page_id' => $id ], __METHOD__ );
 
        // Log the deletion, if the page was suppressed, put it in the suppression log instead
        $logtype = $this->suppress ? 'suppress' : 'delete';
 
        $logEntry = new ManualLogEntry( $logtype, $this->logSubtype );
        $logEntry->setPerformer( $this->deleter->getUser() );
        $logEntry->setTarget( $logTitle );
        $logEntry->setComment( $reason );
        $logEntry->addTags( $this->tags );
        if ( !$this->isDeletePageUnitTest ) {
            // TODO: Remove conditional once ManualLogEntry is servicified (T253717)
            $logid = $logEntry->insert();
 
            $dbw->onTransactionPreCommitOrIdle(
                static function () use ( $logEntry, $logid ) {
                    // T58776: avoid deadlocks (especially from FileDeleteForm)
                    $logEntry->publish( $logid );
                },
                __METHOD__
            );
        } else {
            $logid = 42;
        }
 
        $dbw->endAtomic( __METHOD__ );
 
        $this->doDeleteUpdates( $revisionRecord );
 
        $legacyDeleter = $this->userFactory->newFromAuthority( $this->deleter );
        $this->hookRunner->onArticleDeleteComplete(
            $wikiPageBeforeDelete,
            $legacyDeleter,
            $reason,
            $id,
            $content,
            $logEntry,
            $archivedRevisionCount
        );
        $this->hookRunner->onPageDeleteComplete(
            $wikiPageBeforeDelete,
            $this->deleter,
            $reason,
            $id,
            $revisionRecord,
            $logEntry,
            $archivedRevisionCount
        );
        $this->successfulDeletionsIDs[] = $logid;
 
        // Show log excerpt on 404 pages rather than just a link
        $key = $this->recentDeletesCache->makeKey( 'page-recent-delete', md5( $logTitle->getPrefixedText() ) );
        $this->recentDeletesCache->set( $key, 1, BagOStuff::TTL_DAY );
 
        return $status;
    }
 
    private function archiveRevisions( int $id ): bool {
        // Given the lock above, we can be confident in the title and page ID values
        $namespace = $this->page->getTitle()->getNamespace();
        $dbKey = $this->page->getTitle()->getDBkey();
 
        $dbw = $this->loadBalancer->getConnectionRef( DB_PRIMARY );
 
        $revQuery = $this->revisionStore->getQueryInfo();
        $bitfield = false;
 
        // Bitfields to further suppress the content
        if ( $this->suppress ) {
            $bitfield = RevisionRecord::SUPPRESSED_ALL;
            $revQuery['fields'] = array_diff( $revQuery['fields'], [ 'rev_deleted' ] );
        }
 
        // For now, shunt the revision data into the archive table.
        // Text is *not* removed from the text table; bulk storage
        // is left intact to avoid breaking block-compression or
        // immutable storage schemes.
        // In the future, we may keep revisions and mark them with
        // the rev_deleted field, which is reserved for this purpose.
 
        // Lock rows in `revision` and its temp tables, but not any others.
        // Note array_intersect() preserves keys from the first arg, and we're
        // assuming $revQuery has `revision` primary and isn't using subtables
        // for anything we care about.
        $dbw->lockForUpdate(
            array_intersect(
                $revQuery['tables'],
                [ 'revision', 'revision_comment_temp', 'revision_actor_temp' ]
            ),
            [ 'rev_page' => $id ],
            __METHOD__,
            [],
            $revQuery['joins']
        );
 
        $deleteBatchSize = $this->options->get( 'DeleteRevisionsBatchSize' );
        // Get as many of the page revisions as we are allowed to.  The +1 lets us recognize the
        // unusual case where there were exactly $deleteBatchSize revisions remaining.
        $res = $dbw->select(
            $revQuery['tables'],
            $revQuery['fields'],
            [ 'rev_page' => $id ],
            __METHOD__,
            [ 'ORDER BY' => 'rev_timestamp ASC, rev_id ASC', 'LIMIT' => $deleteBatchSize + 1 ],
            $revQuery['joins']
        );
 
        // Build their equivalent archive rows
        $rowsInsert = [];
        $revids = [];
 
        $ipRevIds = [];
 
        $done = true;
        foreach ( $res as $row ) {
            if ( count( $revids ) >= $deleteBatchSize ) {
                $done = false;
                break;
            }
 
            $comment = $this->commentStore->getComment( 'rev_comment', $row );
            $rowInsert = [
                    'ar_namespace'  => $namespace,
                    'ar_title'      => $dbKey,
                    'ar_actor'      => $row->rev_actor,
                    'ar_timestamp'  => $row->rev_timestamp,
                    'ar_minor_edit' => $row->rev_minor_edit,
                    'ar_rev_id'     => $row->rev_id,
                    'ar_parent_id'  => $row->rev_parent_id,
                    'ar_len'        => $row->rev_len,
                    'ar_page_id'    => $id,
                    'ar_deleted'    => $this->suppress ? $bitfield : $row->rev_deleted,
                    'ar_sha1'       => $row->rev_sha1,
                ] + $this->commentStore->insert( $dbw, 'ar_comment', $comment );
 
            $rowsInsert[] = $rowInsert;
            $revids[] = $row->rev_id;
 
            // Keep track of IP edits, so that the corresponding rows can
            // be deleted in the ip_changes table.
            if ( (int)$row->rev_user === 0 && IPUtils::isValid( $row->rev_user_text ) ) {
                $ipRevIds[] = $row->rev_id;
            }
        }
 
        // This conditional is just a sanity check
        if ( count( $revids ) > 0 ) {
            // Copy them into the archive table
            $dbw->insert( 'archive', $rowsInsert, __METHOD__ );
 
            $dbw->delete( 'revision', [ 'rev_id' => $revids ], __METHOD__ );
            $dbw->delete( 'revision_comment_temp', [ 'revcomment_rev' => $revids ], __METHOD__ );
            if ( $this->options->get( 'ActorTableSchemaMigrationStage' ) & SCHEMA_COMPAT_WRITE_TEMP ) {
                $dbw->delete( 'revision_actor_temp', [ 'revactor_rev' => $revids ], __METHOD__ );
            }
 
            // Also delete records from ip_changes as applicable.
            if ( count( $ipRevIds ) > 0 ) {
                $dbw->delete( 'ip_changes', [ 'ipc_rev_id' => $ipRevIds ], __METHOD__ );
            }
        }
 
        return $done;
    }
 
    public function doDeleteUpdates( RevisionRecord $revRecord ): void {
        try {
            $countable = $this->page->isCountable();
        } catch ( Exception $ex ) {
            // fallback for deleting broken pages for which we cannot load the content for
            // some reason. Note that doDeleteArticleReal() already logged this problem.
            $countable = false;
        }
 
        // Update site status
        if ( !$this->isDeletePageUnitTest ) {
            // TODO Remove conditional once DeferredUpdates is servicified (T265749)
            DeferredUpdates::addUpdate( SiteStatsUpdate::factory(
                [ 'edits' => 1, 'articles' => -$countable, 'pages' => -1 ]
            ) );
 
            // Delete pagelinks, update secondary indexes, etc
            $updates = $this->getDeletionUpdates( $revRecord );
            foreach ( $updates as $update ) {
                DeferredUpdates::addUpdate( $update );
            }
        }
 
        // Reparse any pages transcluding this page
        LinksUpdate::queueRecursiveJobsForTable(
            $this->page->getTitle(),
            'templatelinks',
            'delete-page',
            $this->deleter->getUser()->getName(),
            $this->backlinkCacheFactory->getBacklinkCache( $this->page->getTitle() )
        );
        // Reparse any pages including this image
        if ( $this->page->getTitle()->getNamespace() === NS_FILE ) {
            LinksUpdate::queueRecursiveJobsForTable(
                $this->page->getTitle(),
                'imagelinks',
                'delete-page',
                $this->deleter->getUser()->getName(),
                $this->backlinkCacheFactory->getBacklinkCache( $this->page->getTitle() )
            );
        }
 
        if ( !$this->isDeletePageUnitTest ) {
            // TODO Remove conditional once WikiPage::onArticleDelete is moved to a proper service
            // Clear caches
            WikiPage::onArticleDelete( $this->page->getTitle() );
        }
 
        ResourceLoaderWikiModule::invalidateModuleCache(
            $this->page->getTitle(),
            $revRecord,
            null,
            $this->localWikiID
        );
 
        // Reset the page object and the Title object
        $this->page->loadFromRow( false, WikiPage::READ_LATEST );
 
        if ( !$this->isDeletePageUnitTest ) {
            // TODO Remove conditional once DeferredUpdates is servicified (T265749)
            // Search engine
            DeferredUpdates::addUpdate( new SearchUpdate( $this->page->getId(), $this->page->getTitle() ) );
        }
    }
 
    public function getDeletionUpdates( RevisionRecord $rev ): array {
        $slotContent = array_map( static function ( SlotRecord $slot ) {
            return $slot->getContent();
        }, $rev->getSlots()->getSlots() );
 
        $allUpdates = [ new LinksDeletionUpdate( $this->page ) ];
 
        // NOTE: once Content::getDeletionUpdates() is removed, we only need the content
        // model here, not the content object!
        // TODO: consolidate with similar logic in DerivedPageDataUpdater::getSecondaryDataUpdates()
        $content = null; // in case $slotContent is zero-length
        foreach ( $slotContent as $role => $content ) {
            $handler = $content->getContentHandler();
 
            $updates = $handler->getDeletionUpdates(
                $this->page->getTitle(),
                $role
            );
 
            $allUpdates = array_merge( $allUpdates, $updates );
        }
 
        $this->hookRunner->onPageDeletionDataUpdates(
            $this->page->getTitle(), $rev, $allUpdates );
 
        // TODO: hard deprecate old hook in 1.33
        $this->hookRunner->onWikiPageDeletionUpdates( $this->page, $content, $allUpdates );
        return $allUpdates;
    }
}