wikimedia/mediawiki-core

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includes/page/WikiPage.php

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<?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
 */

use MediaWiki\Category\Category;
use MediaWiki\CommentStore\CommentStoreComment;
use MediaWiki\DAO\WikiAwareEntityTrait;
use MediaWiki\Deferred\DeferredUpdates;
use MediaWiki\Edit\PreparedEdit;
use MediaWiki\HookContainer\ProtectedHookAccessorTrait;
use MediaWiki\Linker\LinkTarget;
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Page\DeletePage;
use MediaWiki\Page\ExistingPageRecord;
use MediaWiki\Page\PageIdentity;
use MediaWiki\Page\PageRecord;
use MediaWiki\Page\PageReference;
use MediaWiki\Page\PageStoreRecord;
use MediaWiki\Page\ParserOutputAccess;
use MediaWiki\Parser\ParserOutput;
use MediaWiki\Permissions\Authority;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Revision\RevisionStore;
use MediaWiki\Revision\SlotRecord;
use MediaWiki\Status\Status;
use MediaWiki\Storage\DerivedPageDataUpdater;
use MediaWiki\Storage\EditResult;
use MediaWiki\Storage\PageUpdater;
use MediaWiki\Storage\PageUpdaterFactory;
use MediaWiki\Storage\PageUpdateStatus;
use MediaWiki\Storage\PreparedUpdate;
use MediaWiki\Storage\RevisionSlotsUpdate;
use MediaWiki\Title\Title;
use MediaWiki\Title\TitleArrayFromResult;
use MediaWiki\User\ActorMigration;
use MediaWiki\User\User;
use MediaWiki\User\UserArrayFromResult;
use MediaWiki\User\UserIdentity;
use MediaWiki\Utils\MWTimestamp;
use MediaWiki\WikiMap\WikiMap;
use Wikimedia\Assert\Assert;
use Wikimedia\Assert\PreconditionException;
use Wikimedia\NonSerializable\NonSerializableTrait;
use Wikimedia\Rdbms\FakeResultWrapper;
use Wikimedia\Rdbms\IDatabase;
use Wikimedia\Rdbms\ILoadBalancer;
use Wikimedia\Rdbms\IReadableDatabase;

/**
 * @defgroup Page Page
 */

/**
 * Base representation for an editable wiki page.
 *
 * Some fields are public only for backwards-compatibility. Use accessor methods.
 * In the past, this class was part of Article.php and everything was public.
 *
 * @ingroup Page
 */
class WikiPage implements Page, PageRecord {
    use NonSerializableTrait;
    use ProtectedHookAccessorTrait;
    use WikiAwareEntityTrait;

    // Constants for $mDataLoadedFrom and related

    /**
     * @var Title
     * @note for access by subclasses only
     */
    protected $mTitle;

    /**
     * @var bool
     * @note for access by subclasses only
     */
    protected $mDataLoaded = false;

    /**
     * A cache of the page_is_redirect field, loaded with page data
     * @var bool
     */
    private $mPageIsRedirectField = false;

    /**
     * The cache of the redirect target
     *
     * @var Title|null
     */
    protected $mRedirectTarget = null;

    /**
     * @var bool
     */
    private $mIsNew = false;

    /**
     * @var int|false False means "not loaded"
     * @note for access by subclasses only
     */
    protected $mLatest = false;

    /**
     * @var PreparedEdit|false Map of cache fields (text, parser output, ect) for a proposed/new edit
     * @note for access by subclasses only
     */
    protected $mPreparedEdit = false;

    /**
     * @var int|null
     */
    protected $mId = null;

    /**
     * @var int One of the READ_* constants
     */
    protected $mDataLoadedFrom = IDBAccessObject::READ_NONE;

    /**
     * @var RevisionRecord|null
     */
    private $mLastRevision = null;

    /**
     * @var string Timestamp of the current revision or empty string if not loaded
     */
    protected $mTimestamp = '';

    /**
     * @var string
     */
    protected $mTouched = '19700101000000';

    /**
     * @var string|null
     */
    protected $mLanguage = null;

    /**
     * @var string
     */
    protected $mLinksUpdated = '19700101000000';

    /**
     * @var DerivedPageDataUpdater|null
     */
    private $derivedDataUpdater = null;

    /**
     * @param PageIdentity $pageIdentity
     */
    public function __construct( PageIdentity $pageIdentity ) {
        $pageIdentity->assertWiki( PageIdentity::LOCAL );

        // TODO: remove the need for casting to Title.
        $title = Title::newFromPageIdentity( $pageIdentity );
        if ( !$title->canExist() ) {
            throw new InvalidArgumentException( "WikiPage constructed on a Title that cannot exist as a page: $title" );
        }

        $this->mTitle = $title;
    }

    /**
     * Makes sure that the mTitle object is cloned
     * to the newly cloned WikiPage.
     */
    public function __clone() {
        $this->mTitle = clone $this->mTitle;
    }

    /**
     * Convert 'fromdb', 'fromdbmaster' and 'forupdate' to READ_* constants.
     *
     * @param stdClass|string|int $type
     * @return mixed
     */
    public static function convertSelectType( $type ) {
        switch ( $type ) {
            case 'fromdb':
                return IDBAccessObject::READ_NORMAL;
            case 'fromdbmaster':
                return IDBAccessObject::READ_LATEST;
            case 'forupdate':
                return IDBAccessObject::READ_LOCKING;
            default:
                // It may already be an integer or whatever else
                return $type;
        }
    }

    /**
     * @return PageUpdaterFactory
     */
    private function getPageUpdaterFactory(): PageUpdaterFactory {
        return MediaWikiServices::getInstance()->getPageUpdaterFactory();
    }

    /**
     * @return RevisionStore
     */
    private function getRevisionStore() {
        return MediaWikiServices::getInstance()->getRevisionStore();
    }

    /**
     * @return ILoadBalancer
     */
    private function getDBLoadBalancer() {
        return MediaWikiServices::getInstance()->getDBLoadBalancer();
    }

    /**
     * @todo Move this UI stuff somewhere else
     *
     * @see ContentHandler::getActionOverrides
     * @return array
     */
    public function getActionOverrides() {
        return $this->getContentHandler()->getActionOverrides();
    }

    /**
     * Returns the ContentHandler instance to be used to deal with the content of this WikiPage.
     *
     * Shorthand for ContentHandler::getForModelID( $this->getContentModel() );
     *
     * @return ContentHandler
     *
     * @since 1.21
     */
    public function getContentHandler() {
        $factory = MediaWikiServices::getInstance()->getContentHandlerFactory();
        return $factory->getContentHandler( $this->getContentModel() );
    }

    /**
     * Get the title object of the article
     * @return Title Title object of this page
     */
    public function getTitle(): Title {
        return $this->mTitle;
    }

    /**
     * Clear the object
     * @return void
     */
    public function clear() {
        $this->mDataLoaded = false;
        $this->mDataLoadedFrom = IDBAccessObject::READ_NONE;

        $this->clearCacheFields();
    }

    /**
     * Clear the object cache fields
     * @return void
     */
    protected function clearCacheFields() {
        $this->mId = null;
        $this->mRedirectTarget = null; // Title object if set
        $this->mPageIsRedirectField = false;
        $this->mLastRevision = null; // Latest revision
        $this->mTouched = '19700101000000';
        $this->mLanguage = null;
        $this->mLinksUpdated = '19700101000000';
        $this->mTimestamp = '';
        $this->mIsNew = false;
        $this->mLatest = false;
        // T59026: do not clear $this->derivedDataUpdater since getDerivedDataUpdater() already
        // checks the requested rev ID and content against the cached one. For most
        // content types, the output should not change during the lifetime of this cache.
        // Clearing it can cause extra parses on edit for no reason.
    }

    /**
     * Clear the mPreparedEdit cache field, as may be needed by mutable content types
     * @return void
     * @since 1.23
     */
    public function clearPreparedEdit() {
        $this->mPreparedEdit = false;
    }

    /**
     * Return the tables, fields, and join conditions to be selected to create
     * a new page object.
     * @since 1.31
     * @return array[] With three keys:
     *   - tables: (string[]) to include in the `$table` to `IReadableDatabase->select()` or
     *     `SelectQueryBuilder::tables`
     *   - fields: (string[]) to include in the `$vars` to `IReadableDatabase->select()` or
     *     `SelectQueryBuilder::fields`
     *   - joins: (array) to include in the `$join_conds` to `IReadableDatabase->select()` or
     *     `SelectQueryBuilder::joinConds`
     * @phan-return array{tables:string[],fields:string[],joins:array}
     */
    public static function getQueryInfo() {
        $pageLanguageUseDB = MediaWikiServices::getInstance()->getMainConfig()->get(
            MainConfigNames::PageLanguageUseDB );

        $ret = [
            'tables' => [ 'page' ],
            'fields' => [
                'page_id',
                'page_namespace',
                'page_title',
                'page_is_redirect',
                'page_is_new',
                'page_random',
                'page_touched',
                'page_links_updated',
                'page_latest',
                'page_len',
                'page_content_model',
            ],
            'joins' => [],
        ];

        if ( $pageLanguageUseDB ) {
            $ret['fields'][] = 'page_lang';
        }

        return $ret;
    }

    /**
     * Fetch a page record with the given conditions
     * @param IReadableDatabase $dbr
     * @param array $conditions
     * @param array $options
     * @return stdClass|false Database result resource, or false on failure
     */
    protected function pageData( $dbr, $conditions, $options = [] ) {
        $pageQuery = self::getQueryInfo();

        $this->getHookRunner()->onArticlePageDataBefore(
            $this, $pageQuery['fields'], $pageQuery['tables'], $pageQuery['joins'] );

        $row = $dbr->selectRow(
            $pageQuery['tables'],
            $pageQuery['fields'],
            $conditions,
            __METHOD__,
            $options,
            $pageQuery['joins']
        );

        $this->getHookRunner()->onArticlePageDataAfter( $this, $row );

        return $row;
    }

    /**
     * Fetch a page record matching the Title object's namespace and title
     * using a sanitized title string
     *
     * @param IReadableDatabase $dbr
     * @param Title $title
     * @param array $options
     * @return stdClass|false Database result resource, or false on failure
     */
    public function pageDataFromTitle( $dbr, $title, $options = [] ) {
        if ( !$title->canExist() ) {
            return false;
        }

        return $this->pageData( $dbr, [
            'page_namespace' => $title->getNamespace(),
            'page_title' => $title->getDBkey() ], $options );
    }

    /**
     * Fetch a page record matching the requested ID
     *
     * @param IReadableDatabase $dbr
     * @param int $id
     * @param array $options
     * @return stdClass|false Database result resource, or false on failure
     */
    public function pageDataFromId( $dbr, $id, $options = [] ) {
        return $this->pageData( $dbr, [ 'page_id' => $id ], $options );
    }

    /**
     * Load the object from a given source by title
     *
     * @param stdClass|string|int $from One of the following:
     *   - A DB query result object.
     *   - "fromdb" or IDBAccessObject::READ_NORMAL to get from a replica DB.
     *   - "fromdbmaster" or IDBAccessObject::READ_LATEST to get from the primary DB.
     *   - "forupdate"  or IDBAccessObject::READ_LOCKING to get from the primary DB
     *     using SELECT FOR UPDATE.
     *
     * @return void
     */
    public function loadPageData( $from = 'fromdb' ) {
        $from = self::convertSelectType( $from );
        if ( is_int( $from ) && $from <= $this->mDataLoadedFrom ) {
            // We already have the data from the correct location, no need to load it twice.
            return;
        }

        if ( is_int( $from ) ) {
            [ $index, $opts ] = DBAccessObjectUtils::getDBOptions( $from );
            $loadBalancer = $this->getDBLoadBalancer();
            $db = $loadBalancer->getConnectionRef( $index );
            $data = $this->pageDataFromTitle( $db, $this->mTitle, $opts );

            if ( !$data
                && $index == DB_REPLICA
                && $loadBalancer->hasReplicaServers()
                && $loadBalancer->hasOrMadeRecentPrimaryChanges()
            ) {
                $from = IDBAccessObject::READ_LATEST;
                [ $index, $opts ] = DBAccessObjectUtils::getDBOptions( $from );
                $db = $loadBalancer->getConnectionRef( $index );
                $data = $this->pageDataFromTitle( $db, $this->mTitle, $opts );
            }
        } else {
            // No idea from where the caller got this data, assume replica DB.
            $data = $from;
            $from = IDBAccessObject::READ_NORMAL;
        }

        $this->loadFromRow( $data, $from );
    }

    /**
     * Checks whether the page data was loaded using the given database access mode (or better).
     *
     * @since 1.32
     *
     * @param string|int $from One of the following:
     *   - "fromdb" or IDBAccessObject::READ_NORMAL to get from a replica DB.
     *   - "fromdbmaster" or IDBAccessObject::READ_LATEST to get from the primary DB.
     *   - "forupdate"  or IDBAccessObject::READ_LOCKING to get from the primary DB
     *     using SELECT FOR UPDATE.
     *
     * @return bool
     */
    public function wasLoadedFrom( $from ) {
        $from = self::convertSelectType( $from );

        if ( !is_int( $from ) ) {
            // No idea from where the caller got this data, assume replica DB.
            $from = IDBAccessObject::READ_NORMAL;
        }

        if ( $from <= $this->mDataLoadedFrom ) {
            return true;
        }

        return false;
    }

    /**
     * Load the object from a database row
     *
     * @since 1.20
     * @param stdClass|false $data DB row containing fields returned by getQueryInfo() or false
     * @param string|int $from One of the following:
     *        - "fromdb" or IDBAccessObject::READ_NORMAL if the data comes from a replica DB
     *        - "fromdbmaster" or IDBAccessObject::READ_LATEST if the data comes from the primary DB
     *        - "forupdate"  or IDBAccessObject::READ_LOCKING if the data comes from
     *          the primary DB using SELECT FOR UPDATE
     */
    public function loadFromRow( $data, $from ) {
        $lc = MediaWikiServices::getInstance()->getLinkCache();
        $lc->clearLink( $this->mTitle );

        if ( $data ) {
            $lc->addGoodLinkObjFromRow( $this->mTitle, $data );

            $this->mTitle->loadFromRow( $data );
            $this->mId = intval( $data->page_id );
            $this->mTouched = MWTimestamp::convert( TS_MW, $data->page_touched );
            $this->mLanguage = $data->page_lang ?? null;
            $this->mLinksUpdated = $data->page_links_updated === null
                ? null
                : MWTimestamp::convert( TS_MW, $data->page_links_updated );
            $this->mPageIsRedirectField = (bool)$data->page_is_redirect;
            $this->mIsNew = (bool)( $data->page_is_new ?? 0 );
            $this->mLatest = intval( $data->page_latest );
            // T39225: $latest may no longer match the cached latest RevisionRecord object.
            // Double-check the ID of any cached latest RevisionRecord object for consistency.
            if ( $this->mLastRevision && $this->mLastRevision->getId() != $this->mLatest ) {
                $this->mLastRevision = null;
                $this->mTimestamp = '';
            }
        } else {
            $lc->addBadLinkObj( $this->mTitle );

            $this->mTitle->loadFromRow( false );

            $this->clearCacheFields();

            $this->mId = 0;
        }

        $this->mDataLoaded = true;
        $this->mDataLoadedFrom = self::convertSelectType( $from );
    }

    /**
     * @param string|false $wikiId
     *
     * @return int Page ID
     */
    public function getId( $wikiId = self::LOCAL ): int {
        $this->assertWiki( $wikiId );

        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        return $this->mId;
    }

    /**
     * @return bool Whether or not the page exists in the database
     */
    public function exists(): bool {
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        return $this->mId > 0;
    }

    /**
     * Check if this page is something we're going to be showing
     * some sort of sensible content for. If we return false, page
     * views (plain action=view) will return an HTTP 404 response,
     * so spiders and robots can know they're following a bad link.
     *
     * @return bool
     */
    public function hasViewableContent() {
        return $this->mTitle->isKnown();
    }

    /**
     * Is the page a redirect, according to secondary tracking tables?
     * If this is true, getRedirectTarget() will return a Title.
     *
     * @return bool
     */
    public function isRedirect() {
        return $this->getRedirectTarget() !== null;
    }

    /**
     * Tests if the page is new (only has one revision).
     * May produce false negatives for some old pages.
     *
     * @since 1.36
     *
     * @return bool
     */
    public function isNew() {
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }

        return $this->mIsNew;
    }

    /**
     * Returns the page's content model id (see the CONTENT_MODEL_XXX constants).
     *
     * Will use the revisions actual content model if the page exists,
     * and the page's default if the page doesn't exist yet.
     *
     * @return string
     *
     * @since 1.21
     */
    public function getContentModel() {
        if ( $this->exists() ) {
            $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();

            return $cache->getWithSetCallback(
                $cache->makeKey( 'page-content-model', $this->getLatest() ),
                $cache::TTL_MONTH,
                function () {
                    $rev = $this->getRevisionRecord();
                    if ( $rev ) {
                        // Look at the revision's actual content model
                        $slot = $rev->getSlot(
                            SlotRecord::MAIN,
                            RevisionRecord::RAW
                        );
                        return $slot->getModel();
                    } else {
                        LoggerFactory::getInstance( 'wikipage' )->warning(
                            'Page exists but has no (visible) revisions!',
                            [
                                'page-title' => $this->mTitle->getPrefixedDBkey(),
                                'page-id' => $this->getId(),
                            ]
                        );
                        return $this->mTitle->getContentModel();
                    }
                },
                [ 'pcTTL' => $cache::TTL_PROC_LONG ]
            );
        }

        // use the default model for this page
        return $this->mTitle->getContentModel();
    }

    /**
     * Loads page_touched and returns a value indicating if it should be used
     * @return bool True if this page exists and is not a redirect
     */
    public function checkTouched() {
        return ( $this->exists() && !$this->isRedirect() );
    }

    /**
     * Get the page_touched field
     * @return string Timestamp in TS_MW format
     */
    public function getTouched() {
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        return $this->mTouched;
    }

    /**
     * @return ?string language code for the page
     */
    public function getLanguage() {
        if ( !$this->mDataLoaded ) {
            $this->loadLastEdit();
        }

        return $this->mLanguage;
    }

    /**
     * Get the page_links_updated field
     * @return string|null Timestamp in TS_MW format
     */
    public function getLinksTimestamp() {
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        return $this->mLinksUpdated;
    }

    /**
     * Get the page_latest field
     * @param string|false $wikiId
     * @return int The rev_id of current revision
     */
    public function getLatest( $wikiId = self::LOCAL ) {
        $this->assertWiki( $wikiId );

        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        return (int)$this->mLatest;
    }

    /**
     * Loads everything except the text
     * This isn't necessary for all uses, so it's only done if needed.
     */
    protected function loadLastEdit() {
        if ( $this->mLastRevision !== null ) {
            return; // already loaded
        }

        $latest = $this->getLatest();
        if ( !$latest ) {
            return; // page doesn't exist or is missing page_latest info
        }

        if ( $this->mDataLoadedFrom == IDBAccessObject::READ_LOCKING ) {
            // T39225: if session S1 loads the page row FOR UPDATE, the result always
            // includes the latest changes committed. This is true even within REPEATABLE-READ
            // transactions, where S1 normally only sees changes committed before the first S1
            // SELECT. Thus we need S1 to also gets the revision row FOR UPDATE; otherwise, it
            // may not find it since a page row UPDATE and revision row INSERT by S2 may have
            // happened after the first S1 SELECT.
            // https://dev.mysql.com/doc/refman/5.7/en/set-transaction.html#isolevel_repeatable-read
            $revision = $this->getRevisionStore()
                ->getRevisionByPageId( $this->getId(), $latest, IDBAccessObject::READ_LOCKING );
        } elseif ( $this->mDataLoadedFrom == IDBAccessObject::READ_LATEST ) {
            // Bug T93976: if page_latest was loaded from the primary DB, fetch the
            // revision from there as well, as it may not exist yet on a replica DB.
            // Also, this keeps the queries in the same REPEATABLE-READ snapshot.
            $revision = $this->getRevisionStore()
                ->getRevisionByPageId( $this->getId(), $latest, IDBAccessObject::READ_LATEST );
        } else {
            $revision = $this->getRevisionStore()->getKnownCurrentRevision( $this->getTitle(), $latest );
        }

        if ( $revision ) {
            $this->setLastEdit( $revision );
        }
    }

    /**
     * Set the latest revision
     * @param RevisionRecord $revRecord
     */
    private function setLastEdit( RevisionRecord $revRecord ) {
        $this->mLastRevision = $revRecord;
        $this->mLatest = $revRecord->getId();
        $this->mTimestamp = $revRecord->getTimestamp();
        $this->mTouched = max( $this->mTouched, $revRecord->getTimestamp() );
    }

    /**
     * Get the latest revision
     * @since 1.32
     * @return RevisionRecord|null
     */
    public function getRevisionRecord() {
        $this->loadLastEdit();
        return $this->mLastRevision;
    }

    /**
     * Get the content of the current revision. No side-effects...
     *
     * @param int $audience One of:
     *   RevisionRecord::FOR_PUBLIC       to be displayed to all users
     *   RevisionRecord::FOR_THIS_USER    to be displayed to the given user
     *   RevisionRecord::RAW              get the text regardless of permissions
     * @param Authority|null $performer object to check for, only if FOR_THIS_USER is passed
     *   to the $audience parameter
     * @return Content|null The content of the current revision
     *
     * @since 1.21
     */
    public function getContent( $audience = RevisionRecord::FOR_PUBLIC, Authority $performer = null ) {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            return $this->mLastRevision->getContent( SlotRecord::MAIN, $audience, $performer );
        }
        return null;
    }

    /**
     * @return string MW timestamp of last article revision
     */
    public function getTimestamp() {
        // Check if the field has been filled by WikiPage::setTimestamp()
        if ( !$this->mTimestamp ) {
            $this->loadLastEdit();
        }

        return MWTimestamp::convert( TS_MW, $this->mTimestamp );
    }

    /**
     * Set the page timestamp (use only to avoid DB queries)
     * @param string $ts MW timestamp of last article revision
     * @return void
     */
    public function setTimestamp( $ts ) {
        $this->mTimestamp = MWTimestamp::convert( TS_MW, $ts );
    }

    /**
     * @param int $audience One of:
     *   RevisionRecord::FOR_PUBLIC       to be displayed to all users
     *   RevisionRecord::FOR_THIS_USER    to be displayed to the given user
     *   RevisionRecord::RAW              get the text regardless of permissions
     * @param Authority|null $performer object to check for, only if FOR_THIS_USER is passed
     *   to the $audience parameter (since 1.36, if using FOR_THIS_USER and not specifying
     *   a user no fallback is provided and the RevisionRecord method will throw an error)
     * @return int User ID for the user that made the last article revision
     */
    public function getUser( $audience = RevisionRecord::FOR_PUBLIC, Authority $performer = null ) {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            $revUser = $this->mLastRevision->getUser( $audience, $performer );
            return $revUser ? $revUser->getId() : 0;
        } else {
            return -1;
        }
    }

    /**
     * Get the User object of the user who created the page
     * @param int $audience One of:
     *   RevisionRecord::FOR_PUBLIC       to be displayed to all users
     *   RevisionRecord::FOR_THIS_USER    to be displayed to the given user
     *   RevisionRecord::RAW              get the text regardless of permissions
     * @param Authority|null $performer object to check for, only if FOR_THIS_USER is passed
     *   to the $audience parameter (since 1.36, if using FOR_THIS_USER and not specifying
     *   a user no fallback is provided and the RevisionRecord method will throw an error)
     * @return UserIdentity|null
     */
    public function getCreator( $audience = RevisionRecord::FOR_PUBLIC, Authority $performer = null ) {
        $revRecord = $this->getRevisionStore()->getFirstRevision( $this->getTitle() );
        if ( $revRecord ) {
            return $revRecord->getUser( $audience, $performer );
        } else {
            return null;
        }
    }

    /**
     * @param int $audience One of:
     *   RevisionRecord::FOR_PUBLIC       to be displayed to all users
     *   RevisionRecord::FOR_THIS_USER    to be displayed to the given user
     *   RevisionRecord::RAW              get the text regardless of permissions
     * @param Authority|null $performer object to check for, only if FOR_THIS_USER is passed
     *   to the $audience parameter (since 1.36, if using FOR_THIS_USER and not specifying
     *   a user no fallback is provided and the RevisionRecord method will throw an error)
     * @return string Username of the user that made the last article revision
     */
    public function getUserText( $audience = RevisionRecord::FOR_PUBLIC, Authority $performer = null ) {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            $revUser = $this->mLastRevision->getUser( $audience, $performer );
            return $revUser ? $revUser->getName() : '';
        } else {
            return '';
        }
    }

    /**
     * @param int $audience One of:
     *   RevisionRecord::FOR_PUBLIC       to be displayed to all users
     *   RevisionRecord::FOR_THIS_USER    to be displayed to the given user
     *   RevisionRecord::RAW              get the text regardless of permissions
     * @param Authority|null $performer object to check for, only if FOR_THIS_USER is passed
     *   to the $audience parameter (since 1.36, if using FOR_THIS_USER and not specifying
     *   a user no fallback is provided and the RevisionRecord method will throw an error)
     * @return string|null Comment stored for the last article revision, or null if the specified
     *  audience does not have access to the comment.
     */
    public function getComment( $audience = RevisionRecord::FOR_PUBLIC, Authority $performer = null ) {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            $revComment = $this->mLastRevision->getComment( $audience, $performer );
            return $revComment ? $revComment->text : '';
        } else {
            return '';
        }
    }

    /**
     * Returns true if last revision was marked as "minor edit"
     *
     * @return bool Minor edit indicator for the last article revision.
     */
    public function getMinorEdit() {
        $this->loadLastEdit();
        if ( $this->mLastRevision ) {
            return $this->mLastRevision->isMinor();
        } else {
            return false;
        }
    }

    /**
     * Determine whether a page would be suitable for being counted as an
     * article in the site_stats table based on the title & its content
     *
     * @param PreparedEdit|PreparedUpdate|false $editInfo (false):
     *   An object returned by prepareTextForEdit() or getCurrentUpdate() respectively;
     *   If false is given, the current database state will be used.
     *
     * @return bool
     */
    public function isCountable( $editInfo = false ) {
        $mwServices = MediaWikiServices::getInstance();
        $articleCountMethod = $mwServices->getMainConfig()->get( MainConfigNames::ArticleCountMethod );

        // NOTE: Keep in sync with DerivedPageDataUpdater::isCountable.

        if ( !$this->mTitle->isContentPage() ) {
            return false;
        }

        if ( $editInfo instanceof PreparedEdit ) {
            // NOTE: only the main slot can make a page a redirect
            $content = $editInfo->pstContent;
        } elseif ( $editInfo instanceof PreparedUpdate ) {
            // NOTE: only the main slot can make a page a redirect
            $content = $editInfo->getRawContent( SlotRecord::MAIN );
        } else {
            $content = $this->getContent();
        }

        if ( !$content || $content->isRedirect() ) {
            return false;
        }

        $hasLinks = null;

        if ( $articleCountMethod === 'link' ) {
            // nasty special case to avoid re-parsing to detect links

            if ( $editInfo ) {
                // ParserOutput::getLinks() is a 2D array of page links, so
                // to be really correct we would need to recurse in the array
                // but the main array should only have items in it if there are
                // links.
                $hasLinks = (bool)count( $editInfo->output->getLinks() );
            } else {
                // NOTE: keep in sync with RevisionRenderer::getLinkCount
                // NOTE: keep in sync with DerivedPageDataUpdater::isCountable
                $dbr = $mwServices->getConnectionProvider()->getReplicaDatabase();
                $hasLinks = (bool)$dbr->newSelectQueryBuilder()
                    ->select( '1' )
                    ->from( 'pagelinks' )
                    ->where( [ 'pl_from' => $this->getId() ] )
                    ->caller( __METHOD__ )->fetchField();
            }
        }

        // TODO: MCR: determine $hasLinks for each slot, and use that info
        // with that slot's Content's isCountable method. That requires per-
        // slot ParserOutput in the ParserCache, or per-slot info in the
        // pagelinks table.
        return $content->isCountable( $hasLinks );
    }

    /**
     * If this page is a redirect, get its target
     *
     * The target will be fetched from the redirect table if possible.
     *
     * @deprecated since 1.38 Use RedirectLookup::getRedirectTarget() instead.
     *
     * @return Title|null Title object, or null if this page is not a redirect
     */
    public function getRedirectTarget() {
        if ( $this->mRedirectTarget !== null ) {
            return $this->mRedirectTarget;
        }
        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }
        if ( !$this->mPageIsRedirectField ) {
            return null;
        }

        // Query the redirect table
        $dbr = MediaWikiServices::getInstance()->getConnectionProvider()->getReplicaDatabase();
        $row = $dbr->newSelectQueryBuilder()
            ->select( [ 'rd_namespace', 'rd_title', 'rd_fragment', 'rd_interwiki' ] )
            ->from( 'redirect' )
            ->where( [ 'rd_from' => $this->getId() ] )
            ->caller( __METHOD__ )->fetchRow();

        if ( !$row ) {
            LoggerFactory::getInstance( 'wikipage' )->info(
                'WikiPage found inconsistent redirect status; probably the page was deleted after it was loaded'
            );
            return null;
        }

        $this->mRedirectTarget = self::createRedirectTarget(
            $row->rd_namespace, $row->rd_title,
            $row->rd_fragment, $row->rd_interwiki
        );
        return $this->mRedirectTarget;
    }

    /**
     * Truncate link fragment to maximum storable value
     *
     * @param string $fragment The link fragment (after the "#")
     * @return string
     */
    private static function truncateFragment( $fragment ) {
        return mb_strcut( $fragment, 0, 255 );
    }

    /**
     * Create a Title object appropriate for WikiPage::$mRedirectTarget
     *
     * @param int $namespace The namespace of the article
     * @param string $title Database key form
     * @param string $fragment The link fragment (after the "#")
     * @param string $interwiki Interwiki prefix
     * @return Title|null Title object, or null if this is not a valid redirect
     */
    private static function createRedirectTarget( $namespace, $title, $fragment, $interwiki ): ?Title {
        // (T203942) We can't redirect to Media namespace because it's virtual.
        // We don't want to modify Title objects farther down the
        // line. So, let's fix this here by changing to File namespace.
        if ( $namespace == NS_MEDIA ) {
            $namespace = NS_FILE;
        }

        // mimic behaviour of self::insertRedirectEntry for fragments that didn't
        // come from the redirect table
        $fragment = self::truncateFragment( $fragment );

        // T261347: be defensive when fetching data from the redirect table.
        // Use Title::makeTitleSafe(), and if that returns null, ignore the
        // row. In an ideal world, the DB would be cleaned up after a
        // namespace change, but nobody could be bothered to do that.
        $title = Title::makeTitleSafe( $namespace, $title, $fragment, $interwiki );
        if ( $title !== null && $title->isValidRedirectTarget() ) {
            return $title;
        }
        return null;
    }

    /**
     * Insert or update the redirect table entry for this page to indicate it redirects to $rt
     * @param LinkTarget $rt Redirect target
     * @param int|null $oldLatest Prior page_latest for check and set
     * @return bool Success
     */
    public function insertRedirectEntry( LinkTarget $rt, $oldLatest = null ) {
        $rt = Title::newFromLinkTarget( $rt );
        if ( !$rt->isValidRedirectTarget() ) {
            // Don't put a bad redirect into the database (T278367)
            return false;
        }

        $dbw = MediaWikiServices::getInstance()->getConnectionProvider()->getPrimaryDatabase();
        $dbw->startAtomic( __METHOD__ );

        if ( !$oldLatest || $oldLatest == $this->lockAndGetLatest() ) {
            $truncatedFragment = self::truncateFragment( $rt->getFragment() );
            $dbw->newInsertQueryBuilder()
                ->insertInto( 'redirect' )
                ->row( [
                    'rd_from' => $this->getId(),
                    'rd_namespace' => $rt->getNamespace(),
                    'rd_title' => $rt->getDBkey(),
                    'rd_fragment' => $truncatedFragment,
                    'rd_interwiki' => $rt->getInterwiki(),
                ] )
                ->onDuplicateKeyUpdate()
                ->uniqueIndexFields( [ 'rd_from' ] )
                ->set( [
                    'rd_namespace' => $rt->getNamespace(),
                    'rd_title' => $rt->getDBkey(),
                    'rd_fragment' => $truncatedFragment,
                    'rd_interwiki' => $rt->getInterwiki(),
                ] )
                ->caller( __METHOD__ )->execute();
            $success = true;
        } else {
            $success = false;
        }

        $dbw->endAtomic( __METHOD__ );

        return $success;
    }

    /**
     * Get the Title object or URL this page redirects to
     *
     * @return bool|Title|string False, Title of in-wiki target, or string with URL
     */
    public function followRedirect() {
        return $this->getRedirectURL( $this->getRedirectTarget() );
    }

    /**
     * Get the Title object or URL to use for a redirect. We use Title
     * objects for same-wiki, non-special redirects and URLs for everything
     * else.
     * @param Title $rt Redirect target
     * @return Title|string|false False, Title object of local target, or string with URL
     */
    public function getRedirectURL( $rt ) {
        if ( !$rt ) {
            return false;
        }

        if ( $rt->isExternal() ) {
            if ( $rt->isLocal() ) {
                // Offsite wikis need an HTTP redirect.
                // This can be hard to reverse and may produce loops,
                // so they may be disabled in the site configuration.
                $source = $this->mTitle->getFullURL( 'redirect=no' );
                return $rt->getFullURL( [ 'rdfrom' => $source ] );
            } else {
                // External pages without "local" bit set are not valid
                // redirect targets
                return false;
            }
        }

        if ( $rt->isSpecialPage() ) {
            // Gotta handle redirects to special pages differently:
            // Fill the HTTP response "Location" header and ignore the rest of the page we're on.
            // Some pages are not valid targets.
            if ( $rt->isValidRedirectTarget() ) {
                return $rt->getFullURL();
            } else {
                return false;
            }
        } elseif ( !$rt->isValidRedirectTarget() ) {
            // We somehow got a bad redirect target into the database (T278367)
            return false;
        }

        return $rt;
    }

    /**
     * Get a list of users who have edited this article, not including the user who made
     * the most recent revision, which you can get from $article->getUser() if you want it
     * @return UserArrayFromResult
     */
    public function getContributors() {
        // @todo: This is expensive; cache this info somewhere.

        $dbr = MediaWikiServices::getInstance()->getConnectionProvider()->getReplicaDatabase();

        $actorMigration = ActorMigration::newMigration();
        $actorQuery = $actorMigration->getJoin( 'rev_user' );

        $tables = array_merge( [ 'revision' ], $actorQuery['tables'], [ 'user' ] );

        $revactor_actor = $actorQuery['fields']['rev_actor'];
        $fields = [
            'user_id' => $actorQuery['fields']['rev_user'],
            'user_name' => $actorQuery['fields']['rev_user_text'],
            'actor_id' => "MIN($revactor_actor)",
            'user_real_name' => 'MIN(user_real_name)',
            'timestamp' => 'MAX(rev_timestamp)',
        ];

        $conds = [ 'rev_page' => $this->getId() ];

        // The user who made the top revision gets credited as "this page was last edited by
        // John, based on contributions by Tom, Dick and Harry", so don't include them twice.
        $user = $this->getUser()
            ? User::newFromId( $this->getUser() )
            : User::newFromName( $this->getUserText(), false );
        $conds[] = 'NOT(' . $actorMigration->getWhere( $dbr, 'rev_user', $user )['conds'] . ')';

        // Username hidden?
        $conds[] = "{$dbr->bitAnd( 'rev_deleted', RevisionRecord::DELETED_USER )} = 0";

        $jconds = [
            'user' => [ 'LEFT JOIN', $actorQuery['fields']['rev_user'] . ' = user_id' ],
        ] + $actorQuery['joins'];

        $options = [
            'GROUP BY' => [ $fields['user_id'], $fields['user_name'] ],
            'ORDER BY' => 'timestamp DESC',
        ];

        $res = $dbr->select( $tables, $fields, $conds, __METHOD__, $options, $jconds );
        return new UserArrayFromResult( $res );
    }

    /**
     * Should the parser cache be used?
     *
     * @param ParserOptions $parserOptions ParserOptions to check
     * @param int $oldId
     * @return bool
     */
    public function shouldCheckParserCache( ParserOptions $parserOptions, $oldId ) {
        // NOTE: Keep in sync with ParserOutputAccess::shouldUseCache().
        // TODO: Once ParserOutputAccess is stable, deprecated this method.
        return $this->exists()
            && ( $oldId === null || $oldId === 0 || $oldId === $this->getLatest() )
            && $this->getContentHandler()->isParserCacheSupported();
    }

    /**
     * Get a ParserOutput for the given ParserOptions and revision ID.
     *
     * The parser cache will be used if possible. Cache misses that result
     * in parser runs are debounced with PoolCounter.
     *
     * XXX merge this with updateParserCache()?
     *
     * @since 1.19
     * @param ParserOptions|null $parserOptions ParserOptions to use for the parse operation
     * @param null|int $oldid Revision ID to get the text from, passing null or 0 will
     *   get the current revision (default value)
     * @param bool $noCache Do not read from or write to caches.
     * @return ParserOutput|false ParserOutput or false if the revision was not found or is not public
     */
    public function getParserOutput(
        ?ParserOptions $parserOptions = null, $oldid = null, $noCache = false
    ) {
        if ( $oldid ) {
            $revision = $this->getRevisionStore()->getRevisionByTitle( $this->getTitle(), $oldid );

            if ( !$revision ) {
                return false;
            }
        } else {
            $revision = $this->getRevisionRecord();
        }

        if ( !$parserOptions ) {
            $parserOptions = ParserOptions::newFromAnon();
        }

        $options = $noCache ? ParserOutputAccess::OPT_NO_CACHE : 0;

        $status = MediaWikiServices::getInstance()->getParserOutputAccess()->getParserOutput(
            $this, $parserOptions, $revision, $options
        );
        return $status->isOK() ? $status->getValue() : false; // convert null to false
    }

    /**
     * Do standard deferred updates after page view (existing or missing page)
     * @param Authority $performer The viewing user
     * @param int $oldid Revision id being viewed; if not given or 0, latest revision is assumed
     * @param RevisionRecord|null $oldRev The RevisionRecord associated with $oldid.
     */
    public function doViewUpdates(
        Authority $performer,
        $oldid = 0,
        RevisionRecord $oldRev = null
    ) {
        if ( MediaWikiServices::getInstance()->getReadOnlyMode()->isReadOnly() ) {
            return;
        }

        DeferredUpdates::addCallableUpdate(
            function () use ( $performer ) {
                // In practice, these hook handlers simply debounce into a post-send
                // to do their work since none of the use cases for this hook require
                // a blocking pre-send callback.
                //
                // TODO: Move this hook to post-send.
                //
                // For now, it is unofficially possible for an extension to use
                // onPageViewUpdates to try to insert JavaScript via global $wgOut.
                // This isn't supported (the hook doesn't pass OutputPage), and
                // can't be since OutputPage may be disabled or replaced on some
                // pages that we do support page view updates for. We also run
                // this hook after HTMLFileCache, which also naturally can't
                // support modifying OutputPage. Handlers that modify the page
                // may use onBeforePageDisplay instead, which runs behind
                // HTMLFileCache and won't run on non-OutputPage responses.
                $legacyUser = MediaWikiServices::getInstance()
                    ->getUserFactory()
                    ->newFromAuthority( $performer );
                $this->getHookRunner()->onPageViewUpdates( $this, $legacyUser );
            },
            DeferredUpdates::PRESEND
        );

        // Update newtalk and watchlist notification status
        MediaWikiServices::getInstance()
            ->getWatchlistManager()
            ->clearTitleUserNotifications( $performer, $this, $oldid, $oldRev );
    }

    /**
     * Perform the actions of a page purging
     * @return bool
     * @note In 1.28 (and only 1.28), this took a $flags parameter that
     *  controlled how much purging was done.
     */
    public function doPurge() {
        if ( !$this->getHookRunner()->onArticlePurge( $this ) ) {
            return false;
        }

        $this->mTitle->invalidateCache();

        // Clear file cache and send purge after above page_touched update was committed
        $hcu = MediaWikiServices::getInstance()->getHtmlCacheUpdater();
        $hcu->purgeTitleUrls( $this->mTitle, $hcu::PURGE_PRESEND );

        if ( $this->mTitle->getNamespace() === NS_MEDIAWIKI ) {
            MediaWikiServices::getInstance()->getMessageCache()
                ->updateMessageOverride( $this->mTitle, $this->getContent() );
        }
        InfoAction::invalidateCache( $this->mTitle, $this->getLatest() );

        return true;
    }

    /**
     * Insert a new empty page record for this article.
     * This *must* be followed up by creating a revision
     * and running $this->updateRevisionOn( ... );
     * or else the record will be left in a funky state.
     * Best if all done inside a transaction.
     *
     * @todo Factor out into a PageStore service, to be used by PageUpdater.
     *
     * @param IDatabase $dbw
     * @param int|null $pageId Custom page ID that will be used for the insert statement
     *
     * @return int|false The newly created page_id key; false if the row was not
     *   inserted, e.g. because the title already existed or because the specified
     *   page ID is already in use.
     */
    public function insertOn( $dbw, $pageId = null ) {
        $pageIdForInsert = $pageId ? [ 'page_id' => $pageId ] : [];
        $dbw->newInsertQueryBuilder()
            ->insertInto( 'page' )
            ->ignore()
            ->row( [
                'page_namespace'    => $this->mTitle->getNamespace(),
                'page_title'        => $this->mTitle->getDBkey(),
                'page_is_redirect'  => 0, // Will set this shortly...
                'page_is_new'       => 1,
                'page_random'       => wfRandom(),
                'page_touched'      => $dbw->timestamp(),
                'page_latest'       => 0, // Fill this in shortly...
                'page_len'          => 0, // Fill this in shortly...
            ] + $pageIdForInsert )
            ->caller( __METHOD__ )->execute();

        if ( $dbw->affectedRows() > 0 ) {
            $newid = $pageId ? (int)$pageId : $dbw->insertId();
            $this->mId = $newid;
            $this->mTitle->resetArticleID( $newid );

            return $newid;
        } else {
            return false; // nothing changed
        }
    }

    /**
     * Update the page record to point to a newly saved revision.
     *
     * @todo Factor out into a PageStore service, or move into PageUpdater.
     *
     * @param IDatabase $dbw
     * @param RevisionRecord $revision For ID number, and text used to set
     *   length and redirect status fields.
     * @param int|null $lastRevision If given, will not overwrite the page field
     *   when different from the currently set value.
     *   Giving 0 indicates the new page flag should be set on.
     * @param bool|null $lastRevIsRedirect If given, will optimize adding and
     *   removing rows in redirect table.
     * @return bool Success; false if the page row was missing or page_latest changed
     */
    public function updateRevisionOn(
        $dbw,
        RevisionRecord $revision,
        $lastRevision = null,
        $lastRevIsRedirect = null
    ) {
        // TODO: move into PageUpdater or PageStore
        // NOTE: when doing that, make sure cached fields get reset in doUserEditContent,
        // and in the compat stub!

        $revId = $revision->getId();
        Assert::parameter( $revId > 0, '$revision->getId()', 'must be > 0' );

        $content = $revision->getContent( SlotRecord::MAIN );
        $len = $content ? $content->getSize() : 0;
        $rt = $content ? $content->getRedirectTarget() : null;
        $isNew = $lastRevision === 0;
        $isRedirect = $rt !== null;

        $conditions = [ 'page_id' => $this->getId() ];

        if ( $lastRevision !== null ) {
            // An extra check against threads stepping on each other
            $conditions['page_latest'] = $lastRevision;
        }

        $model = $revision->getSlot( SlotRecord::MAIN, RevisionRecord::RAW )->getModel();

        $row = [ /* SET */
            'page_latest'        => $revId,
            'page_touched'       => $dbw->timestamp( $revision->getTimestamp() ),
            'page_is_new'        => $isNew ? 1 : 0,
            'page_is_redirect'   => $isRedirect ? 1 : 0,
            'page_len'           => $len,
            'page_content_model' => $model,
        ];

        $dbw->newUpdateQueryBuilder()
            ->update( 'page' )
            ->set( $row )
            ->where( $conditions )
            ->caller( __METHOD__ )->execute();

        $result = $dbw->affectedRows() > 0;
        if ( $result ) {
            $insertedRow = $this->pageData( $dbw, [ 'page_id' => $this->getId() ] );

            if ( !$insertedRow ) {
                throw new RuntimeException( 'Failed to load freshly inserted row' );
            }

            $this->mTitle->loadFromRow( $insertedRow );
            $this->updateRedirectOn( $dbw, $rt, $lastRevIsRedirect );
            $this->setLastEdit( $revision );
            $this->mRedirectTarget = $rt == null ? null : self::createRedirectTarget(
                $rt->getNamespace(), $rt->getDBkey(), $rt->getFragment(), $rt->getInterwiki() );
            $this->mPageIsRedirectField = (bool)$rt;
            $this->mIsNew = $isNew;

            // Update the LinkCache.
            $linkCache = MediaWikiServices::getInstance()->getLinkCache();
            $linkCache->addGoodLinkObjFromRow(
                $this->mTitle,
                $insertedRow
            );
        }

        return $result;
    }

    /**
     * Add row to the redirect table if this is a redirect, remove otherwise.
     *
     * @param IDatabase $dbw
     * @param Title|null $redirectTitle Title object pointing to the redirect target,
     *   or NULL if this is not a redirect
     * @param null|bool $lastRevIsRedirect If given, will optimize adding and
     *   removing rows in redirect table.
     * @return bool True on success, false on failure
     */
    private function updateRedirectOn( $dbw, $redirectTitle, $lastRevIsRedirect = null ) {
        // Always update redirects (target link might have changed)
        // Update/Insert if we don't know if the last revision was a redirect or not
        // Delete if changing from redirect to non-redirect
        $isRedirect = $redirectTitle !== null;

        if ( !$isRedirect && $lastRevIsRedirect === false ) {
            return true;
        }

        if ( $isRedirect ) {
            $success = $this->insertRedirectEntry( $redirectTitle );
        } else {
            // This is not a redirect, remove row from redirect table
            $dbw->newDeleteQueryBuilder()
                ->deleteFrom( 'redirect' )
                ->where( [ 'rd_from' => $this->getId() ] )
                ->caller( __METHOD__ )->execute();
            $success = true;
        }

        if ( $this->getTitle()->getNamespace() === NS_FILE ) {
            MediaWikiServices::getInstance()->getRepoGroup()->getLocalRepo()
                ->invalidateImageRedirect( $this->getTitle() );
        }

        return $success;
    }

    /**
     * Helper method for checking whether two revisions have differences that go
     * beyond the main slot.
     *
     * MCR migration note: this method should go away!
     *
     * @deprecated Use only as a stop-gap before refactoring to support MCR.
     *
     * @param RevisionRecord $a
     * @param RevisionRecord $b
     * @return bool
     */
    public static function hasDifferencesOutsideMainSlot( RevisionRecord $a, RevisionRecord $b ) {
        $aSlots = $a->getSlots();
        $bSlots = $b->getSlots();
        $changedRoles = $aSlots->getRolesWithDifferentContent( $bSlots );

        return ( $changedRoles !== [ SlotRecord::MAIN ] && $changedRoles !== [] );
    }

    /**
     * Returns true if this page's content model supports sections.
     *
     * @return bool
     *
     * @todo The skin should check this and not offer section functionality if
     *   sections are not supported.
     * @todo The EditPage should check this and not offer section functionality
     *   if sections are not supported.
     */
    public function supportsSections() {
        return $this->getContentHandler()->supportsSections();
    }

    /**
     * @param string|int|null|false $sectionId Section identifier as a number or string
     * (e.g. 0, 1 or 'T-1'), null/false or an empty string for the whole page
     * or 'new' for a new section.
     * @param Content $sectionContent New content of the section.
     * @param string $sectionTitle New section's subject, only if $section is "new".
     * @param string $edittime Revision timestamp or null to use the current revision.
     *
     * @return Content|null New complete article content, or null if error.
     *
     * @since 1.21
     * @deprecated since 1.24, use replaceSectionAtRev instead
     */
    public function replaceSectionContent(
        $sectionId, Content $sectionContent, $sectionTitle = '', $edittime = null
    ) {
        $baseRevId = null;
        if ( $edittime && $sectionId !== 'new' ) {
            $lb = $this->getDBLoadBalancer();
            $rev = $this->getRevisionStore()->getRevisionByTimestamp( $this->mTitle, $edittime );
            // Try the primary database if this thread may have just added it.
            // The logic to fallback to the primary database if the replica is missing
            // the revision could be generalized into RevisionStore, but we don't want
            // to encourage loading of revisions by timestamp.
            if ( !$rev
                && $lb->hasReplicaServers()
                && $lb->hasOrMadeRecentPrimaryChanges()
            ) {
                $rev = $this->getRevisionStore()->getRevisionByTimestamp(
                    $this->mTitle, $edittime, IDBAccessObject::READ_LATEST );
            }
            if ( $rev ) {
                $baseRevId = $rev->getId();
            }
        }

        return $this->replaceSectionAtRev( $sectionId, $sectionContent, $sectionTitle, $baseRevId );
    }

    /**
     * @param string|int|null|false $sectionId Section identifier as a number or string
     * (e.g. 0, 1 or 'T-1'), null/false or an empty string for the whole page
     * or 'new' for a new section.
     * @param Content $sectionContent New content of the section.
     * @param string $sectionTitle New section's subject, only if $section is "new".
     * @param int|null $baseRevId
     *
     * @return Content|null New complete article content, or null if error.
     *
     * @since 1.24
     */
    public function replaceSectionAtRev( $sectionId, Content $sectionContent,
        $sectionTitle = '', $baseRevId = null
    ) {
        if ( strval( $sectionId ) === '' ) {
            // Whole-page edit; let the whole text through
            $newContent = $sectionContent;
        } else {
            if ( !$this->supportsSections() ) {
                throw new BadMethodCallException( "sections not supported for content model " .
                    $this->getContentHandler()->getModelID() );
            }

            // T32711: always use current version when adding a new section
            if ( $baseRevId === null || $sectionId === 'new' ) {
                $oldContent = $this->getContent();
            } else {
                $revRecord = $this->getRevisionStore()->getRevisionById( $baseRevId );
                if ( !$revRecord ) {
                    wfDebug( __METHOD__ . " asked for bogus section (page: " .
                        $this->getId() . "; section: $sectionId)" );
                    return null;
                }

                $oldContent = $revRecord->getContent( SlotRecord::MAIN );
            }

            if ( !$oldContent ) {
                wfDebug( __METHOD__ . ": no page text" );
                return null;
            }

            $newContent = $oldContent->replaceSection( $sectionId, $sectionContent, $sectionTitle );
        }

        return $newContent;
    }

    /**
     * Check flags and add EDIT_NEW or EDIT_UPDATE to them as needed.
     *
     * @deprecated since 1.32, use exists() instead, or simply omit the EDIT_UPDATE
     * and EDIT_NEW flags. To protect against race conditions, use PageUpdater::grabParentRevision.
     *
     * @param int $flags
     * @return int Updated $flags
     */
    public function checkFlags( $flags ) {
        if ( !( $flags & EDIT_NEW ) && !( $flags & EDIT_UPDATE ) ) {
            if ( $this->exists() ) {
                $flags |= EDIT_UPDATE;
            } else {
                $flags |= EDIT_NEW;
            }
        }

        return $flags;
    }

    /**
     * Returns a DerivedPageDataUpdater for use with the given target revision or new content.
     * This method attempts to re-use the same DerivedPageDataUpdater instance for subsequent calls.
     * The parameters passed to this method are used to ensure that the DerivedPageDataUpdater
     * returned matches that caller's expectations, allowing an existing instance to be re-used
     * if the given parameters match that instance's internal state according to
     * DerivedPageDataUpdater::isReusableFor(), and creating a new instance of the parameters do not
     * match the existing one.
     *
     * If neither $forRevision nor $forUpdate is given, a new DerivedPageDataUpdater is always
     * created, replacing any DerivedPageDataUpdater currently cached.
     *
     * MCR migration note: this replaces WikiPage::prepareContentForEdit.
     *
     * @since 1.32
     *
     * @param UserIdentity|null $forUser The user that will be used for, or was used for, PST.
     * @param RevisionRecord|null $forRevision The revision created by the edit for which
     *        to perform updates, if the edit was already saved.
     * @param RevisionSlotsUpdate|null $forUpdate The new content to be saved by the edit (pre PST),
     *        if the edit was not yet saved.
     * @param bool $forEdit Only re-use if the cached DerivedPageDataUpdater has the current
     *       revision as the edit's parent revision. This ensures that the same
     *       DerivedPageDataUpdater cannot be re-used for two consecutive edits.
     *
     * @return DerivedPageDataUpdater
     */
    private function getDerivedDataUpdater(
        UserIdentity $forUser = null,
        RevisionRecord $forRevision = null,
        RevisionSlotsUpdate $forUpdate = null,
        $forEdit = false
    ) {
        if ( !$forRevision && !$forUpdate ) {
            // NOTE: can't re-use an existing derivedDataUpdater if we don't know what the caller is
            // going to use it with.
            $this->derivedDataUpdater = null;
        }

        if ( $this->derivedDataUpdater && !$this->derivedDataUpdater->isContentPrepared() ) {
            // NOTE: can't re-use an existing derivedDataUpdater if other code that has a reference
            // to it did not yet initialize it, because we don't know what data it will be
            // initialized with.
            $this->derivedDataUpdater = null;
        }

        // XXX: It would be nice to have an LRU cache instead of trying to re-use a single instance.
        // However, there is no good way to construct a cache key. We'd need to check against all
        // cached instances.

        if ( $this->derivedDataUpdater
            && !$this->derivedDataUpdater->isReusableFor(
                $forUser,
                $forRevision,
                $forUpdate,
                $forEdit ? $this->getLatest() : null
            )
        ) {
            $this->derivedDataUpdater = null;
        }

        if ( !$this->derivedDataUpdater ) {
            $this->derivedDataUpdater =
                $this->getPageUpdaterFactory()->newDerivedPageDataUpdater( $this );
        }

        return $this->derivedDataUpdater;
    }

    /**
     * Returns a PageUpdater for creating new revisions on this page (or creating the page).
     *
     * The PageUpdater can also be used to detect the need for edit conflict resolution,
     * and to protected such conflict resolution from concurrent edits using a check-and-set
     * mechanism.
     *
     * @since 1.32
     *
     * @note Once extensions no longer rely on WikiPage to get access to the state of an ongoing
     * edit via prepareContentForEdit() and WikiPage::getCurrentUpdate(),
     * this method should be deprecated and callers should be migrated to using
     * PageUpdaterFactory::newPageUpdater() instead.
     *
     * @param Authority|UserIdentity $performer
     * @param RevisionSlotsUpdate|null $forUpdate If given, allows any cached ParserOutput
     *        that may already have been returned via getDerivedDataUpdater to be re-used.
     *
     * @return PageUpdater
     */
    public function newPageUpdater( $performer, RevisionSlotsUpdate $forUpdate = null ) {
        if ( $performer instanceof Authority ) {
            // TODO: Deprecate this. But better get rid of this method entirely.
            $performer = $performer->getUser();
        }

        $pageUpdater = $this->getPageUpdaterFactory()->newPageUpdaterForDerivedPageDataUpdater(
            $this,
            $performer,
            $this->getDerivedDataUpdater( $performer, null, $forUpdate, true )
        );

        return $pageUpdater;
    }

    /**
     * Change an existing article or create a new article. Updates RC and all necessary caches,
     * optionally via the deferred update array.
     *
     * @deprecated since 1.36, use PageUpdater::saveRevision instead. Note that the new method
     * expects callers to take care of checking EDIT_MINOR against the minoredit right, and to
     * apply the autopatrol right as appropriate.
     *
     * @param Content $content New content
     * @param Authority $performer doing the edit
     * @param string|CommentStoreComment $summary Edit summary
     * @param int $flags Bitfield:
     *      EDIT_NEW
     *          Article is known or assumed to be non-existent, create a new one
     *      EDIT_UPDATE
     *          Article is known or assumed to be pre-existing, update it
     *      EDIT_MINOR
     *          Mark this edit minor, if the user is allowed to do so
     *      EDIT_SUPPRESS_RC
     *          Do not log the change in recentchanges
     *      EDIT_FORCE_BOT
     *          Mark the edit a "bot" edit regardless of user rights
     *      EDIT_AUTOSUMMARY
     *          Fill in blank summaries with generated text where possible
     *      EDIT_INTERNAL
     *          Signal that the page retrieve/save cycle happened entirely in this request.
     *
     * If neither EDIT_NEW nor EDIT_UPDATE is specified, the status of the
     * article will be detected. If EDIT_UPDATE is specified and the article
     * doesn't exist, the function will return an edit-gone-missing error. If
     * EDIT_NEW is specified and the article does exist, an edit-already-exists
     * error will be returned. These two conditions are also possible with
     * auto-detection due to MediaWiki's performance-optimised locking strategy.
     *
     * @param int|false $originalRevId: The ID of an original revision that the edit
     * restores or repeats. The new revision is expected to have the exact same content as
     * the given original revision. This is used with rollbacks and with dummy "null" revisions
     * which are created to record things like page moves. Default is false, meaning we are not
     * making a rollback edit.
     * @param array|null $tags Change tags to apply to this edit
     * Callers are responsible for permission checks
     * (with ChangeTags::canAddTagsAccompanyingChange)
     * @param int $undidRevId Id of revision that was undone or 0
     *
     * @return PageUpdateStatus Possible errors:
     *     edit-hook-aborted: The ArticleSave hook aborted the edit but didn't
     *       set the fatal flag of $status.
     *     edit-gone-missing: In update mode, but the article didn't exist.
     *     edit-conflict: In update mode, the article changed unexpectedly.
     *     edit-no-change: Warning that the text was the same as before.
     *     edit-already-exists: In creation mode, but the article already exists.
     *
     *  Extensions may define additional errors.
     *
     *  $return->value will contain an associative array with members as follows:
     *     new: Boolean indicating if the function attempted to create a new article.
     *     revision-record: The revision record object for the inserted revision, or null.
     *
     * @since 1.36
     */
    public function doUserEditContent(
        Content $content,
        Authority $performer,
        $summary,
        $flags = 0,
        $originalRevId = false,
        $tags = [],
        $undidRevId = 0
    ): PageUpdateStatus {
        $useNPPatrol = MediaWikiServices::getInstance()->getMainConfig()->get(
            MainConfigNames::UseNPPatrol );
        $useRCPatrol = MediaWikiServices::getInstance()->getMainConfig()->get(
            MainConfigNames::UseRCPatrol );
        if ( !( $summary instanceof CommentStoreComment ) ) {
            $summary = CommentStoreComment::newUnsavedComment( trim( $summary ) );
        }

        // TODO: this check is here for backwards-compatibility with 1.31 behavior.
        // Checking the minoredit right should be done in the same place the 'bot' right is
        // checked for the EDIT_FORCE_BOT flag, which is currently in EditPage::attemptSave.
        if ( ( $flags & EDIT_MINOR ) && !$performer->isAllowed( 'minoredit' ) ) {
            $flags &= ~EDIT_MINOR;
        }

        $slotsUpdate = new RevisionSlotsUpdate();
        $slotsUpdate->modifyContent( SlotRecord::MAIN, $content );

        // NOTE: while doUserEditContent() executes, callbacks to getDerivedDataUpdater and
        // prepareContentForEdit will generally use the DerivedPageDataUpdater that is also
        // used by this PageUpdater. However, there is no guarantee for this.
        $updater = $this->newPageUpdater( $performer, $slotsUpdate )
                ->setContent( SlotRecord::MAIN, $content )
            ->setOriginalRevisionId( $originalRevId );
        if ( $undidRevId ) {
            $updater->markAsRevert(
                EditResult::REVERT_UNDO,
                $undidRevId,
                $originalRevId ?: null
            );
        }

        $needsPatrol = $useRCPatrol || ( $useNPPatrol && !$this->exists() );

        // TODO: this logic should not be in the storage layer, it's here for compatibility
        // with 1.31 behavior. Applying the 'autopatrol' right should be done in the same
        // place the 'bot' right is handled, which is currently in EditPage::attemptSave.

        if ( $needsPatrol && $performer->authorizeWrite( 'autopatrol', $this->getTitle() ) ) {
            $updater->setRcPatrolStatus( RecentChange::PRC_AUTOPATROLLED );
        }

        $updater->addTags( $tags );

        $revRec = $updater->saveRevision(
            $summary,
            $flags
        );

        // $revRec will be null if the edit failed, or if no new revision was created because
        // the content did not change.
        if ( $revRec ) {
            // update cached fields
            // TODO: this is currently redundant to what is done in updateRevisionOn.
            // But updateRevisionOn() should move into PageStore, and then this will be needed.
            $this->setLastEdit( $revRec );
        }

        return $updater->getStatus();
    }

    /**
     * Get parser options suitable for rendering the primary article wikitext
     *
     * @see ParserOptions::newCanonical
     *
     * @param IContextSource|UserIdentity|string $context One of the following:
     *        - IContextSource: Use the User and the Language of the provided
     *          context
     *        - UserIdentity: Use the provided UserIdentity object and $wgLang
     *          for the language, so use an IContextSource object if possible.
     *        - 'canonical': Canonical options (anonymous user with default
     *          preferences and content language).
     * @return ParserOptions
     */
    public function makeParserOptions( $context ) {
        return self::makeParserOptionsFromTitleAndModel(
            $this->getTitle(), $this->getContentModel(), $context
        );
    }

    /**
     * Create canonical parser options for a given title and content model.
     * @internal
     * @param PageReference $pageRef
     * @param string $contentModel
     * @param IContextSource|UserIdentity|string $context See ::makeParserOptions
     * @return ParserOptions
     */
    public static function makeParserOptionsFromTitleAndModel(
        PageReference $pageRef, string $contentModel, $context
    ) {
        $options = ParserOptions::newCanonical( $context );

        $title = Title::newFromPageReference( $pageRef );
        if ( $title->isConversionTable() ) {
            // @todo ConversionTable should become a separate content model, so
            // we don't need special cases like this one, but see T313455.
            $options->disableContentConversion();
        }

        return $options;
    }

    /**
     * Prepare content which is about to be saved.
     *
     * Prior to 1.30, this returned a stdClass.
     *
     * @deprecated since 1.32, use newPageUpdater() or getCurrentUpdate() instead.
     * @note Calling without a UserIdentity was separately deprecated from 1.37 to 1.39, since
     * 1.39 the UserIdentity has been required.
     *
     * @param Content $content
     * @param RevisionRecord|null $revision
     *        Used with vary-revision or vary-revision-id.
     * @param UserIdentity $user
     * @param string|null $serialFormat IGNORED
     * @param bool $useStash Use prepared edit stash
     *
     * @return PreparedEdit
     *
     * @since 1.21
     */
    public function prepareContentForEdit(
        Content $content,
        ?RevisionRecord $revision,
        UserIdentity $user,
        $serialFormat = null,
        $useStash = true
    ) {
        $slots = RevisionSlotsUpdate::newFromContent( [ SlotRecord::MAIN => $content ] );
        $updater = $this->getDerivedDataUpdater( $user, $revision, $slots );

        if ( !$updater->isUpdatePrepared() ) {
            $updater->prepareContent( $user, $slots, $useStash );

            if ( $revision ) {
                $updater->prepareUpdate(
                    $revision,
                    [
                        'causeAction' => 'prepare-edit',
                        'causeAgent' => $user->getName(),
                    ]
                );
            }
        }

        return $updater->getPreparedEdit();
    }

    /**
     * Do standard deferred updates after page edit.
     * Update links tables, site stats, search index and message cache.
     * Purges pages that include this page if the text was changed here.
     * Every 100th edit, prune the recent changes table.
     *
     * @deprecated since 1.32 (soft), use DerivedPageDataUpdater::doUpdates instead.
     *
     * @param RevisionRecord $revisionRecord (Switched from the old Revision class to
     *    RevisionRecord since 1.35)
     * @param UserIdentity $user User object that did the revision
     * @param array $options Array of options, following indexes are used:
     * - changed: bool, whether the revision changed the content (default true)
     * - created: bool, whether the revision created the page (default false)
     * - moved: bool, whether the page was moved (default false)
     * - restored: bool, whether the page was undeleted (default false)
     * - oldrevision: RevisionRecord object for the pre-update revision (default null)
     * - oldcountable: bool, null, or string 'no-change' (default null):
     *   - bool: whether the page was counted as an article before that
     *     revision, only used in changed is true and created is false
     *   - null: if created is false, don't update the article count; if created
     *     is true, do update the article count
     *   - 'no-change': don't update the article count, ever
     *  - causeAction: an arbitrary string identifying the reason for the update.
     *    See DataUpdate::getCauseAction(). (default 'edit-page')
     *  - causeAgent: name of the user who caused the update. See DataUpdate::getCauseAgent().
     *    (string, defaults to the passed user)
     */
    public function doEditUpdates(
        RevisionRecord $revisionRecord,
        UserIdentity $user,
        array $options = []
    ) {
        $options += [
            'causeAction' => 'edit-page',
            'causeAgent' => $user->getName(),
        ];

        $updater = $this->getDerivedDataUpdater( $user, $revisionRecord );

        $updater->prepareUpdate( $revisionRecord, $options );

        $updater->doUpdates();
    }

    /**
     * Update the parser cache.
     *
     * @note This does not update links tables. Use doSecondaryDataUpdates() for that.
     *
     * @param array $options
     *   - causeAction: an arbitrary string identifying the reason for the update.
     *     See DataUpdate::getCauseAction(). (default 'edit-page')
     *   - causeAgent: name of the user who caused the update (string, defaults to the
     *     user who created the revision)
     * @since 1.32
     */
    public function updateParserCache( array $options = [] ) {
        $revision = $this->getRevisionRecord();
        if ( !$revision || !$revision->getId() ) {
            LoggerFactory::getInstance( 'wikipage' )->info(
                __METHOD__ . ' called with ' . ( $revision ? 'unsaved' : 'no' ) . ' revision'
            );
            return;
        }
        $userIdentity = $revision->getUser( RevisionRecord::RAW );

        $updater = $this->getDerivedDataUpdater( $userIdentity, $revision );
        $updater->prepareUpdate( $revision, $options );
        $updater->doParserCacheUpdate();
    }

    /**
     * Do secondary data updates (such as updating link tables).
     * Secondary data updates are only a small part of the updates needed after saving
     * a new revision; normally PageUpdater::doUpdates should be used instead (which includes
     * secondary data updates). This method is provided for partial purges.
     *
     * @note This does not update the parser cache. Use updateParserCache() for that.
     *
     * @param array $options
     *   - recursive (bool, default true): whether to do a recursive update (update pages that
     *     depend on this page, e.g. transclude it). This will set the $recursive parameter of
     *     Content::getSecondaryDataUpdates. Typically this should be true unless the update
     *     was something that did not really change the page, such as a null edit.
     *   - triggeringUser: The user triggering the update (UserIdentity, defaults to the
     *     user who created the revision)
     *   - causeAction: an arbitrary string identifying the reason for the update.
     *     See DataUpdate::getCauseAction(). (default 'unknown')
     *   - causeAgent: name of the user who caused the update (string, default 'unknown')
     *   - defer: one of the DeferredUpdates constants, or false to run immediately (default: false).
     *     Note that even when this is set to false, some updates might still get deferred (as
     *     some update might directly add child updates to DeferredUpdates).
     *   - known-revision-output: a combined canonical ParserOutput for the revision, perhaps
     *     from some cache. The caller is responsible for ensuring that the ParserOutput indeed
     *     matched the $rev and $options. This mechanism is intended as a temporary stop-gap,
     *     for the time until caches have been changed to store RenderedRevision states instead
     *     of ParserOutput objects. (default: null) (since 1.33)
     * @since 1.32
     */
    public function doSecondaryDataUpdates( array $options = [] ) {
        $options['recursive'] ??= true;
        $revision = $this->getRevisionRecord();
        if ( !$revision || !$revision->getId() ) {
            LoggerFactory::getInstance( 'wikipage' )->info(
                __METHOD__ . ' called with ' . ( $revision ? 'unsaved' : 'no' ) . ' revision'
            );
            return;
        }
        $userIdentity = $revision->getUser( RevisionRecord::RAW );

        $updater = $this->getDerivedDataUpdater( $userIdentity, $revision );
        $updater->prepareUpdate( $revision, $options );
        $updater->doSecondaryDataUpdates( $options );
    }

    /**
     * Update the article's restriction field, and leave a log entry.
     * This works for protection both existing and non-existing pages.
     *
     * @param array $limit Set of restriction keys
     * @param array $expiry Per restriction type expiration
     * @param bool &$cascade Set to false if cascading protection isn't allowed.
     * @param string $reason
     * @param UserIdentity $user The user updating the restrictions
     * @param string[] $tags Change tags to add to the pages and protection log entries
     *   ($user should be able to add the specified tags before this is called)
     * @return Status Status object; if action is taken, $status->value is the log_id of the
     *   protection log entry.
     */
    public function doUpdateRestrictions( array $limit, array $expiry,
        &$cascade, $reason, UserIdentity $user, $tags = []
    ) {
        $services = MediaWikiServices::getInstance();
        $readOnlyMode = $services->getReadOnlyMode();
        if ( $readOnlyMode->isReadOnly() ) {
            return Status::newFatal( wfMessage( 'readonlytext', $readOnlyMode->getReason() ) );
        }

        $this->loadPageData( 'fromdbmaster' );
        $restrictionStore = $services->getRestrictionStore();
        $restrictionStore->loadRestrictions( $this->mTitle, IDBAccessObject::READ_LATEST );
        $restrictionTypes = $restrictionStore->listApplicableRestrictionTypes( $this->mTitle );
        $id = $this->getId();

        if ( !$cascade ) {
            $cascade = false;
        }

        // Take this opportunity to purge out expired restrictions
        Title::purgeExpiredRestrictions();

        // @todo: Same limitations as described in ProtectionForm.php (line 37);
        // we expect a single selection, but the schema allows otherwise.
        $isProtected = false;
        $protect = false;
        $changed = false;

        $dbw = MediaWikiServices::getInstance()->getConnectionProvider()->getPrimaryDatabase();

        foreach ( $restrictionTypes as $action ) {
            if ( !isset( $expiry[$action] ) || $expiry[$action] === $dbw->getInfinity() ) {
                $expiry[$action] = 'infinity';
            }
            if ( !isset( $limit[$action] ) ) {
                $limit[$action] = '';
            } elseif ( $limit[$action] != '' ) {
                $protect = true;
            }

            // Get current restrictions on $action
            $current = implode( '', $restrictionStore->getRestrictions( $this->mTitle, $action ) );
            if ( $current != '' ) {
                $isProtected = true;
            }

            if ( $limit[$action] != $current ) {
                $changed = true;
            } elseif ( $limit[$action] != '' ) {
                // Only check expiry change if the action is actually being
                // protected, since expiry does nothing on an not-protected
                // action.
                if ( $restrictionStore->getRestrictionExpiry( $this->mTitle, $action ) != $expiry[$action] ) {
                    $changed = true;
                }
            }
        }

        if ( !$changed && $protect && $restrictionStore->areRestrictionsCascading( $this->mTitle ) != $cascade ) {
            $changed = true;
        }

        // If nothing has changed, do nothing
        if ( !$changed ) {
            return Status::newGood();
        }

        if ( !$protect ) { // No protection at all means unprotection
            $revCommentMsg = 'unprotectedarticle-comment';
            $logAction = 'unprotect';
        } elseif ( $isProtected ) {
            $revCommentMsg = 'modifiedarticleprotection-comment';
            $logAction = 'modify';
        } else {
            $revCommentMsg = 'protectedarticle-comment';
            $logAction = 'protect';
        }

        $logRelationsValues = [];
        $logRelationsField = null;
        $logParamsDetails = [];

        // Null revision (used for change tag insertion)
        $nullRevisionRecord = null;

        if ( $id ) { // Protection of existing page
            $legacyUser = $services->getUserFactory()->newFromUserIdentity( $user );
            if ( !$this->getHookRunner()->onArticleProtect( $this, $legacyUser, $limit, $reason ) ) {
                return Status::newGood();
            }

            // Only certain restrictions can cascade...
            $editrestriction = isset( $limit['edit'] )
                ? [ $limit['edit'] ]
                : $restrictionStore->getRestrictions( $this->mTitle, 'edit' );
            foreach ( array_keys( $editrestriction, 'sysop' ) as $key ) {
                $editrestriction[$key] = 'editprotected'; // backwards compatibility
            }
            foreach ( array_keys( $editrestriction, 'autoconfirmed' ) as $key ) {
                $editrestriction[$key] = 'editsemiprotected'; // backwards compatibility
            }

            $cascadingRestrictionLevels = $services->getMainConfig()
                ->get( MainConfigNames::CascadingRestrictionLevels );

            foreach ( array_keys( $cascadingRestrictionLevels, 'sysop' ) as $key ) {
                $cascadingRestrictionLevels[$key] = 'editprotected'; // backwards compatibility
            }
            foreach ( array_keys( $cascadingRestrictionLevels, 'autoconfirmed' ) as $key ) {
                $cascadingRestrictionLevels[$key] = 'editsemiprotected'; // backwards compatibility
            }

            // The schema allows multiple restrictions
            if ( !array_intersect( $editrestriction, $cascadingRestrictionLevels ) ) {
                $cascade = false;
            }

            // insert null revision to identify the page protection change as edit summary
            $latest = $this->getLatest();
            $nullRevisionRecord = $this->insertNullProtectionRevision(
                $revCommentMsg,
                $limit,
                $expiry,
                $cascade,
                $reason,
                $user
            );

            if ( $nullRevisionRecord === null ) {
                return Status::newFatal( 'no-null-revision', $this->mTitle->getPrefixedText() );
            }

            $logRelationsField = 'pr_id';

            // T214035: Avoid deadlock on MySQL.
            // Do a DELETE by primary key (pr_id) for any existing protection rows.
            // On MySQL and derivatives, unconditionally deleting by page ID (pr_page) would.
            // place a gap lock if there are no matching rows. This can deadlock when another
            // thread modifies protection settings for page IDs in the same gap.
            $existingProtectionIds = $dbw->newSelectQueryBuilder()
                ->select( 'pr_id' )
                ->from( 'page_restrictions' )
                ->where( [ 'pr_page' => $id, 'pr_type' => array_map( 'strval', array_keys( $limit ) ) ] )
                ->caller( __METHOD__ )->fetchFieldValues();

            if ( $existingProtectionIds ) {
                $dbw->newDeleteQueryBuilder()
                    ->deleteFrom( 'page_restrictions' )
                    ->where( [ 'pr_id' => $existingProtectionIds ] )
                    ->caller( __METHOD__ )->execute();
            }

            // Update restrictions table
            foreach ( $limit as $action => $restrictions ) {
                if ( $restrictions != '' ) {
                    $cascadeValue = ( $cascade && $action == 'edit' ) ? 1 : 0;
                    $dbw->newInsertQueryBuilder()
                        ->insertInto( 'page_restrictions' )
                        ->row( [
                            'pr_page' => $id,
                            'pr_type' => $action,
                            'pr_level' => $restrictions,
                            'pr_cascade' => $cascadeValue,
                            'pr_expiry' => $dbw->encodeExpiry( $expiry[$action] )
                        ] )
                        ->caller( __METHOD__ )->execute();
                    $logRelationsValues[] = $dbw->insertId();
                    $logParamsDetails[] = [
                        'type' => $action,
                        'level' => $restrictions,
                        'expiry' => $expiry[$action],
                        'cascade' => (bool)$cascadeValue,
                    ];
                }
            }

            $this->getHookRunner()->onRevisionFromEditComplete(
                $this, $nullRevisionRecord, $latest, $user, $tags );

            $this->getHookRunner()->onArticleProtectComplete( $this, $legacyUser, $limit, $reason );
        } else { // Protection of non-existing page (also known as "title protection")
            // Cascade protection is meaningless in this case
            $cascade = false;

            if ( $limit['create'] != '' ) {
                $commentFields = $services->getCommentStore()->insert( $dbw, 'pt_reason', $reason );
                $dbw->newReplaceQueryBuilder()
                    ->table( 'protected_titles' )
                    ->uniqueIndexFields( [ 'pt_namespace', 'pt_title' ] )
                    ->rows( [
                        'pt_namespace' => $this->mTitle->getNamespace(),
                        'pt_title' => $this->mTitle->getDBkey(),
                        'pt_create_perm' => $limit['create'],
                        'pt_timestamp' => $dbw->timestamp(),
                        'pt_expiry' => $dbw->encodeExpiry( $expiry['create'] ),
                        'pt_user' => $user->getId(),
                    ] + $commentFields )
                    ->caller( __METHOD__ )->execute();
                $logParamsDetails[] = [
                    'type' => 'create',
                    'level' => $limit['create'],
                    'expiry' => $expiry['create'],
                ];
            } else {
                $dbw->newDeleteQueryBuilder()
                    ->deleteFrom( 'protected_titles' )
                    ->where( [
                        'pt_namespace' => $this->mTitle->getNamespace(),
                        'pt_title' => $this->mTitle->getDBkey()
                    ] )
                    ->caller( __METHOD__ )->execute();
            }
        }

        $this->mTitle->flushRestrictions();
        InfoAction::invalidateCache( $this->mTitle );

        if ( $logAction == 'unprotect' ) {
            $params = [];
        } else {
            $protectDescriptionLog = $this->protectDescriptionLog( $limit, $expiry );
            $params = [
                '4::description' => $protectDescriptionLog, // parameter for IRC
                '5:bool:cascade' => $cascade,
                'details' => $logParamsDetails, // parameter for localize and api
            ];
        }

        // Update the protection log
        $logEntry = new ManualLogEntry( 'protect', $logAction );
        $logEntry->setTarget( $this->mTitle );
        $logEntry->setComment( $reason );
        $logEntry->setPerformer( $user );
        $logEntry->setParameters( $params );
        if ( $nullRevisionRecord !== null ) {
            $logEntry->setAssociatedRevId( $nullRevisionRecord->getId() );
        }
        $logEntry->addTags( $tags );
        if ( $logRelationsField !== null && count( $logRelationsValues ) ) {
            $logEntry->setRelations( [ $logRelationsField => $logRelationsValues ] );
        }
        $logId = $logEntry->insert();
        $logEntry->publish( $logId );

        return Status::newGood( $logId );
    }

    /**
     * Get the state of an ongoing update, shortly before or just after it is saved to the database.
     * If there is no ongoing edit tracked by this WikiPage instance, this methods throws a
     * PreconditionException.
     *
     * If possible, state is shared with subsequent calls of getPreparedUpdate(),
     * prepareContentForEdit(), and newPageUpdater().
     *
     * @note This method should generally be avoided, since it forces WikiPage to maintain state
     *       representing ongoing edits. Code that initiates an edit should use newPageUpdater()
     *       instead. Hooks that interact with the edit should have a the relevant
     *       information provided as a PageUpdater, PreparedUpdate, or RenderedRevision.
     *
     * @throws PreconditionException if there is no ongoing update. This method must only be
     *         called after newPageUpdater() had already been called, typically while executing
     *         a handler for a hook that is triggered during a page edit.
     * @return PreparedUpdate
     *
     * @since 1.38
     */
    public function getCurrentUpdate(): PreparedUpdate {
        Assert::precondition(
            $this->derivedDataUpdater !== null,
            'There is no ongoing update tracked by this instance of WikiPage!'
        );

        return $this->derivedDataUpdater;
    }

    /**
     * Insert a new null revision for this page.
     *
     * @since 1.35
     *
     * @param string $revCommentMsg Comment message key for the revision
     * @param array $limit Set of restriction keys
     * @param array $expiry Per restriction type expiration
     * @param bool $cascade Set to false if cascading protection isn't allowed.
     * @param string $reason
     * @param UserIdentity $user User to attribute to
     * @return RevisionRecord|null Null on error
     */
    public function insertNullProtectionRevision(
        string $revCommentMsg,
        array $limit,
        array $expiry,
        bool $cascade,
        string $reason,
        UserIdentity $user
    ): ?RevisionRecord {
        $dbw = MediaWikiServices::getInstance()->getConnectionProvider()->getPrimaryDatabase();

        // Prepare a null revision to be added to the history
        $editComment = wfMessage(
            $revCommentMsg,
            $this->mTitle->getPrefixedText(),
            $user->getName()
        )->inContentLanguage()->text();
        if ( $reason ) {
            $editComment .= wfMessage( 'colon-separator' )->inContentLanguage()->text() . $reason;
        }
        $protectDescription = $this->protectDescription( $limit, $expiry );
        if ( $protectDescription ) {
            $editComment .= wfMessage( 'word-separator' )->inContentLanguage()->text();
            $editComment .= wfMessage( 'parentheses' )->params( $protectDescription )
                ->inContentLanguage()->text();
        }
        if ( $cascade ) {
            $editComment .= wfMessage( 'word-separator' )->inContentLanguage()->text();
            $editComment .= wfMessage( 'brackets' )->params(
                wfMessage( 'protect-summary-cascade' )->inContentLanguage()->text()
            )->inContentLanguage()->text();
        }

        $revStore = $this->getRevisionStore();
        $comment = CommentStoreComment::newUnsavedComment( $editComment );
        $nullRevRecord = $revStore->newNullRevision(
            $dbw,
            $this->getTitle(),
            $comment,
            true,
            $user
        );

        if ( $nullRevRecord ) {
            $inserted = $revStore->insertRevisionOn( $nullRevRecord, $dbw );

            // Update page record and touch page
            $oldLatest = $inserted->getParentId();

            $this->updateRevisionOn( $dbw, $inserted, $oldLatest );

            return $inserted;
        } else {
            return null;
        }
    }

    /**
     * @param string $expiry 14-char timestamp or "infinity", or false if the input was invalid
     * @return string
     */
    protected function formatExpiry( $expiry ) {
        if ( $expiry != 'infinity' ) {
            $contLang = MediaWikiServices::getInstance()->getContentLanguage();
            return wfMessage(
                'protect-expiring',
                $contLang->timeanddate( $expiry, false, false ),
                $contLang->date( $expiry, false, false ),
                $contLang->time( $expiry, false, false )
            )->inContentLanguage()->text();
        } else {
            return wfMessage( 'protect-expiry-indefinite' )
                ->inContentLanguage()->text();
        }
    }

    /**
     * Builds the description to serve as comment for the edit.
     *
     * @param array $limit Set of restriction keys
     * @param array $expiry Per restriction type expiration
     * @return string
     */
    public function protectDescription( array $limit, array $expiry ) {
        $protectDescription = '';

        foreach ( array_filter( $limit ) as $action => $restrictions ) {
            # $action is one of $wgRestrictionTypes = [ 'create', 'edit', 'move', 'upload' ].
            # All possible message keys are listed here for easier grepping:
            # * restriction-create
            # * restriction-edit
            # * restriction-move
            # * restriction-upload
            $actionText = wfMessage( 'restriction-' . $action )->inContentLanguage()->text();
            # $restrictions is one of $wgRestrictionLevels = [ '', 'autoconfirmed', 'sysop' ],
            # with '' filtered out. All possible message keys are listed below:
            # * protect-level-autoconfirmed
            # * protect-level-sysop
            $restrictionsText = wfMessage( 'protect-level-' . $restrictions )
                ->inContentLanguage()->text();

            $expiryText = $this->formatExpiry( $expiry[$action] );

            if ( $protectDescription !== '' ) {
                $protectDescription .= wfMessage( 'word-separator' )->inContentLanguage()->text();
            }
            $protectDescription .= wfMessage( 'protect-summary-desc' )
                ->params( $actionText, $restrictionsText, $expiryText )
                ->inContentLanguage()->text();
        }

        return $protectDescription;
    }

    /**
     * Builds the description to serve as comment for the log entry.
     *
     * Some bots may parse IRC lines, which are generated from log entries which contain plain
     * protect description text. Keep them in old format to avoid breaking compatibility.
     * TODO: Fix protection log to store structured description and format it on-the-fly.
     *
     * @param array $limit Set of restriction keys
     * @param array $expiry Per restriction type expiration
     * @return string
     */
    public function protectDescriptionLog( array $limit, array $expiry ) {
        $protectDescriptionLog = '';

        $dirMark = MediaWikiServices::getInstance()->getContentLanguage()->getDirMark();
        foreach ( array_filter( $limit ) as $action => $restrictions ) {
            $expiryText = $this->formatExpiry( $expiry[$action] );
            $protectDescriptionLog .=
                $dirMark .
                "[$action=$restrictions] ($expiryText)";
        }

        return trim( $protectDescriptionLog );
    }

    /**
     * Determines if deletion of this page would be batched (executed over time by the job queue)
     * or not (completed in the same request as the delete call).
     *
     * It is unlikely but possible that an edit from another request could push the page over the
     * batching threshold after this function is called, but before the caller acts upon the
     * return value.  Callers must decide for themselves how to deal with this.  $safetyMargin
     * is provided as an unreliable but situationally useful help for some common cases.
     *
     * @deprecated since 1.37 Use DeletePage::isBatchedDelete instead.
     *
     * @param int $safetyMargin Added to the revision count when checking for batching
     * @return bool True if deletion would be batched, false otherwise
     */
    public function isBatchedDelete( $safetyMargin = 0 ) {
        $deleteRevisionsBatchSize = MediaWikiServices::getInstance()
            ->getMainConfig()->get( MainConfigNames::DeleteRevisionsBatchSize );

        $dbr = MediaWikiServices::getInstance()->getConnectionProvider()->getReplicaDatabase();
        $revCount = $this->getRevisionStore()->countRevisionsByPageId( $dbr, $this->getId() );
        $revCount += $safetyMargin;

        return $revCount >= $deleteRevisionsBatchSize;
    }

    /**
     * Back-end article deletion
     * Deletes the article with database consistency, writes logs, purges caches
     *
     * @since 1.19
     * @since 1.35 Signature changed, user moved to second parameter to prepare for requiring
     *             a user to be passed
     * @since 1.36 User second parameter is required
     * @deprecated since 1.37 Use DeletePage instead. Calling ::deleteIfAllowed and letting DeletePage handle
     * permission checks is preferred over doing permission checks yourself and then calling ::deleteUnsafe.
     * Note that DeletePage returns a good status with false value in case of scheduled deletion, instead of
     * a status with a warning. Also, the new method doesn't have an $error parameter, since any error is
     * added to the returned Status.
     *
     * @param string $reason Delete reason for deletion log
     * @param UserIdentity $deleter The deleting user
     * @param bool $suppress Suppress all revisions and log the deletion in
     *   the suppression log instead of the deletion log
     * @param bool|null $u1 Unused
     * @param array|string &$error Array of errors to append to
     * @param mixed $u2 Unused
     * @param string[]|null $tags Tags to apply to the deletion action
     * @param string $logsubtype
     * @param bool $immediate false allows deleting over time via the job queue
     * @return Status Status object; if successful, $status->value is the log_id of the
     *   deletion log entry. If the page couldn't be deleted because it wasn't
     *   found, $status is a non-fatal 'cannotdelete' error
     */
    public function doDeleteArticleReal(
        $reason, UserIdentity $deleter, $suppress = false, $u1 = null, &$error = '', $u2 = null,
        $tags = [], $logsubtype = 'delete', $immediate = false
    ) {
        $services = MediaWikiServices::getInstance();
        $deletePage = $services->getDeletePageFactory()->newDeletePage(
            $this,
            $services->getUserFactory()->newFromUserIdentity( $deleter )
        );

        $status = $deletePage
            ->setSuppress( $suppress )
            ->setTags( $tags ?: [] )
            ->setLogSubtype( $logsubtype )
            ->forceImmediate( $immediate )
            ->keepLegacyHookErrorsSeparate()
            ->deleteUnsafe( $reason );
        $error = $deletePage->getLegacyHookErrors();
        if ( $status->isGood() ) {
            // BC with old return format
            if ( $deletePage->deletionsWereScheduled()[DeletePage::PAGE_BASE] ) {
                $status->warning( 'delete-scheduled', wfEscapeWikiText( $this->getTitle()->getPrefixedText() ) );
            } else {
                $status->value = $deletePage->getSuccessfulDeletionsIDs()[DeletePage::PAGE_BASE];
            }
        }
        return $status;
    }

    /**
     * Back-end article deletion
     *
     * Only invokes batching via the job queue if necessary per $wgDeleteRevisionsBatchSize.
     * Deletions can often be completed inline without involving the job queue.
     *
     * Potentially called many times per deletion operation for pages with many revisions.
     * @deprecated since 1.37 No external caller besides DeletePageJob should use this.
     *
     * @param string $reason
     * @param bool $suppress
     * @param UserIdentity $deleter
     * @param string[] $tags
     * @param string $logsubtype
     * @param bool $immediate
     * @param string|null $webRequestId
     * @return Status
     */
    public function doDeleteArticleBatched(
        $reason, $suppress, UserIdentity $deleter, $tags,
        $logsubtype, $immediate = false, $webRequestId = null
    ) {
        wfDeprecated( __METHOD__, '1.37' );
        $services = MediaWikiServices::getInstance();
        $deletePage = $services->getDeletePageFactory()->newDeletePage(
            $this,
            $services->getUserFactory()->newFromUserIdentity( $deleter )
        );

        $status = $deletePage
            ->setSuppress( $suppress )
            ->setTags( $tags )
            ->setLogSubtype( $logsubtype )
            ->forceImmediate( $immediate )
            ->deleteInternal( $this, DeletePage::PAGE_BASE, $reason, $webRequestId );
        if ( $status->isGood() ) {
            // BC with old return format
            if ( $deletePage->deletionsWereScheduled()[DeletePage::PAGE_BASE] ) {
                $status->warning( 'delete-scheduled', wfEscapeWikiText( $this->getTitle()->getPrefixedText() ) );
            } else {
                $status->value = $deletePage->getSuccessfulDeletionsIDs()[DeletePage::PAGE_BASE];
            }
        }
        return $status;
    }

    /**
     * Lock the page row for this title+id and return page_latest (or 0)
     *
     * @return int Returns 0 if no row was found with this title+id
     * @since 1.27
     */
    public function lockAndGetLatest() {
        $dbw = MediaWikiServices::getInstance()->getConnectionProvider()->getPrimaryDatabase();
        return (int)$dbw->newSelectQueryBuilder()
            ->select( 'page_latest' )
            ->forUpdate()
            ->from( 'page' )
            ->where( [
                'page_id' => $this->getId(),
                // Typically page_id is enough, but some code might try to do
                // updates assuming the title is the same, so verify that
                'page_namespace' => $this->getTitle()->getNamespace(),
                'page_title' => $this->getTitle()->getDBkey()
            ] )
            ->caller( __METHOD__ )->fetchField();
    }

    /**
     * The onArticle*() functions are supposed to be a kind of hooks
     * which should be called whenever any of the specified actions
     * are done.
     *
     * This is a good place to put code to clear caches, for instance.
     *
     * This is called on page move and undelete, as well as edit
     *
     * @param Title $title
     * @param bool $maybeIsRedirect True if the page may have been created as a redirect.
     *   If false, this is used as a hint to skip some unnecessary updates.
     */
    public static function onArticleCreate( Title $title, $maybeIsRedirect = true ) {
        // TODO: move this into a PageEventEmitter service

        // Update existence markers on article/talk tabs...
        $other = $title->getOtherPage();

        $services = MediaWikiServices::getInstance();
        $hcu = $services->getHtmlCacheUpdater();
        $hcu->purgeTitleUrls( [ $title, $other ], $hcu::PURGE_INTENT_TXROUND_REFLECTED );

        $title->touchLinks();
        $title->deleteTitleProtection();

        $services->getLinkCache()->invalidateTitle( $title );

        // Invalidate caches of articles which include this page
        $jobs = [];
        $jobs[] = HTMLCacheUpdateJob::newForBacklinks(
            $title,
            'templatelinks',
            [ 'causeAction' => 'create-page' ]
        );
        // Images
        if ( $maybeIsRedirect && $title->getNamespace() === NS_FILE ) {
            // Process imagelinks when the file page was created as a redirect
            $jobs[] = HTMLCacheUpdateJob::newForBacklinks(
                $title,
                'imagelinks',
                [ 'causeAction' => 'create-page' ]
            );
        }
        $services->getJobQueueGroup()->lazyPush( $jobs );

        if ( $title->getNamespace() === NS_CATEGORY ) {
            // Load the Category object, which will schedule a job to create
            // the category table row if necessary. Checking a replica DB is ok
            // here, in the worst case it'll run an unnecessary recount job on
            // a category that probably doesn't have many members.
            Category::newFromTitle( $title )->getID();
        }
    }

    /**
     * Clears caches when article is deleted
     *
     * @param Title $title
     */
    public static function onArticleDelete( Title $title ) {
        // TODO: move this into a PageEventEmitter service

        // Update existence markers on article/talk tabs...
        $other = $title->getOtherPage();

        $hcu = MediaWikiServices::getInstance()->getHtmlCacheUpdater();
        $hcu->purgeTitleUrls( [ $title, $other ], $hcu::PURGE_INTENT_TXROUND_REFLECTED );

        $title->touchLinks();

        $services = MediaWikiServices::getInstance();
        $services->getLinkCache()->invalidateTitle( $title );

        InfoAction::invalidateCache( $title );

        // Messages
        if ( $title->getNamespace() === NS_MEDIAWIKI ) {
            $services->getMessageCache()->updateMessageOverride( $title, null );
        }

        // Invalidate caches of articles which include this page
        $jobs = [];
        $jobs[] = HTMLCacheUpdateJob::newForBacklinks(
            $title,
            'templatelinks',
            [ 'causeAction' => 'delete-page' ]
        );
        // Images
        if ( $title->getNamespace() === NS_FILE ) {
            $jobs[] = HTMLCacheUpdateJob::newForBacklinks(
                $title,
                'imagelinks',
                [ 'causeAction' => 'delete-page' ]
            );
        }
        $services->getJobQueueGroup()->lazyPush( $jobs );

        // User talk pages
        if ( $title->getNamespace() === NS_USER_TALK ) {
            $user = User::newFromName( $title->getText(), false );
            if ( $user ) {
                MediaWikiServices::getInstance()
                    ->getTalkPageNotificationManager()
                    ->removeUserHasNewMessages( $user );
            }
        }

        // Image redirects
        $services->getRepoGroup()->getLocalRepo()->invalidateImageRedirect( $title );

        // Purge cross-wiki cache entities referencing this page
        self::purgeInterwikiCheckKey( $title );
    }

    /**
     * Purge caches on page update etc
     *
     * @param Title $title
     * @param RevisionRecord|null $revRecord revision that was just saved, may be null
     * @param string[]|null $slotsChanged The role names of the slots that were changed.
     *        If not given, all slots are assumed to have changed.
     * @param bool $maybeRedirectChanged True if the page's redirect target may have changed in the
     *   latest revision. If false, this is used as a hint to skip some unnecessary updates.
     */
    public static function onArticleEdit(
        Title $title,
        RevisionRecord $revRecord = null,
        $slotsChanged = null,
        $maybeRedirectChanged = true
    ) {
        // TODO: move this into a PageEventEmitter service

        $jobs = [];
        if ( $slotsChanged === null || in_array( SlotRecord::MAIN, $slotsChanged ) ) {
            // Invalidate caches of articles which include this page.
            // Only for the main slot, because only the main slot is transcluded.
            // TODO: MCR: not true for TemplateStyles! [SlotHandler]
            $jobs[] = HTMLCacheUpdateJob::newForBacklinks(
                $title,
                'templatelinks',
                [ 'causeAction' => 'edit-page' ]
            );
        }
        // Images
        if ( $maybeRedirectChanged && $title->getNamespace() === NS_FILE ) {
            // Process imagelinks in case the redirect target has changed
            $jobs[] = HTMLCacheUpdateJob::newForBacklinks(
                $title,
                'imagelinks',
                [ 'causeAction' => 'edit-page' ]
            );
        }
        // Invalidate the caches of all pages which redirect here
        $jobs[] = HTMLCacheUpdateJob::newForBacklinks(
            $title,
            'redirect',
            [ 'causeAction' => 'edit-page' ]
        );
        $services = MediaWikiServices::getInstance();
        $services->getJobQueueGroup()->lazyPush( $jobs );

        $services->getLinkCache()->invalidateTitle( $title );

        $hcu = MediaWikiServices::getInstance()->getHtmlCacheUpdater();
        $hcu->purgeTitleUrls( $title, $hcu::PURGE_INTENT_TXROUND_REFLECTED );

        // Purge ?action=info cache
        $revid = $revRecord ? $revRecord->getId() : null;
        DeferredUpdates::addCallableUpdate( static function () use ( $title, $revid ) {
            InfoAction::invalidateCache( $title, $revid );
        } );

        // Purge cross-wiki cache entities referencing this page
        self::purgeInterwikiCheckKey( $title );
    }

    /**
     * Purge the check key for cross-wiki cache entries referencing this page
     *
     * @param Title $title
     */
    private static function purgeInterwikiCheckKey( Title $title ) {
        $enableScaryTranscluding = MediaWikiServices::getInstance()->getMainConfig()->get(
            MainConfigNames::EnableScaryTranscluding );

        if ( !$enableScaryTranscluding ) {
            return; // @todo: perhaps this wiki is only used as a *source* for content?
        }

        DeferredUpdates::addCallableUpdate( static function () use ( $title ) {
            $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
            $cache->resetCheckKey(
                // Do not include the namespace since there can be multiple aliases to it
                // due to different namespace text definitions on different wikis. This only
                // means that some cache invalidations happen that are not strictly needed.
                $cache->makeGlobalKey(
                    'interwiki-page',
                    WikiMap::getCurrentWikiDbDomain()->getId(),
                    $title->getDBkey()
                )
            );
        } );
    }

    /**
     * Returns a list of categories this page is a member of.
     * Results will include hidden categories
     *
     * @return TitleArrayFromResult
     */
    public function getCategories() {
        $services = MediaWikiServices::getInstance();
        $id = $this->getId();
        if ( $id == 0 ) {
            return $services->getTitleFactory()->newTitleArrayFromResult( new FakeResultWrapper( [] ) );
        }

        $dbr = $services->getDBLoadBalancer()->getMaintenanceConnectionRef( DB_REPLICA );
        $res = $dbr->newSelectQueryBuilder()
            ->select( [ 'page_title' => 'cl_to', 'page_namespace' => (string)NS_CATEGORY ] )
            ->from( 'categorylinks' )
            ->where( [ 'cl_from' => $id ] )
            ->caller( __METHOD__ )->fetchResultSet();

        return $services->getTitleFactory()->newTitleArrayFromResult( $res );
    }

    /**
     * Returns a list of hidden categories this page is a member of.
     * Uses the page_props and categorylinks tables.
     *
     * @return Title[]
     */
    public function getHiddenCategories() {
        $result = [];
        $id = $this->getId();

        if ( $id == 0 ) {
            return [];
        }

        $dbr = MediaWikiServices::getInstance()->getConnectionProvider()->getReplicaDatabase();
        $res = $dbr->newSelectQueryBuilder()
            ->select( [ 'cl_to' ] )
            ->from( 'categorylinks' )
            ->join( 'page', null, 'page_title=cl_to' )
            ->join( 'page_props', null, 'pp_page=page_id' )
            ->where( [ 'cl_from' => $id, 'pp_propname' => 'hiddencat', 'page_namespace' => NS_CATEGORY ] )
            ->caller( __METHOD__ )->fetchResultSet();

        if ( $res !== false ) {
            foreach ( $res as $row ) {
                $result[] = Title::makeTitle( NS_CATEGORY, $row->cl_to );
            }
        }

        return $result;
    }

    /**
     * Auto-generates a deletion reason
     *
     * @param bool &$hasHistory Whether the page has a history
     * @return string|false String containing deletion reason or empty string, or boolean false
     *    if no revision occurred
     */
    public function getAutoDeleteReason( &$hasHistory = false ) {
        if ( func_num_args() === 1 ) {
            wfDeprecated( __METHOD__ . ': $hasHistory parameter', '1.38' );
            return $this->getContentHandler()->getAutoDeleteReason( $this->getTitle(), $hasHistory );
        }
        return $this->getContentHandler()->getAutoDeleteReason( $this->getTitle() );
    }

    /**
     * Update all the appropriate counts in the category table, given that
     * we've added the categories $added and deleted the categories $deleted.
     *
     * This should only be called from deferred updates or jobs to avoid contention.
     *
     * @param string[] $added The names of categories that were added
     * @param string[] $deleted The names of categories that were deleted
     * @param int $id Page ID (this should be the original deleted page ID)
     */
    public function updateCategoryCounts( array $added, array $deleted, $id = 0 ) {
        $id = $id ?: $this->getId();
        // Guard against data corruption T301433
        $added = array_map( 'strval', $added );
        $deleted = array_map( 'strval', $deleted );
        $type = MediaWikiServices::getInstance()->getNamespaceInfo()->
            getCategoryLinkType( $this->getTitle()->getNamespace() );

        $addFields = [ 'cat_pages = cat_pages + 1' ];
        $removeFields = [ 'cat_pages = cat_pages - 1' ];
        if ( $type !== 'page' ) {
            $addFields[] = "cat_{$type}s = cat_{$type}s + 1";
            $removeFields[] = "cat_{$type}s = cat_{$type}s - 1";
        }

        $dbw = MediaWikiServices::getInstance()->getConnectionProvider()->getPrimaryDatabase();
        $res = $dbw->newSelectQueryBuilder()
            ->select( [ 'cat_id', 'cat_title' ] )
            ->from( 'category' )
            ->where( [ 'cat_title' => array_merge( $added, $deleted ) ] )
            ->caller( __METHOD__ )
            ->fetchResultSet();
        $existingCategories = [];
        foreach ( $res as $row ) {
            $existingCategories[$row->cat_id] = $row->cat_title;
        }
        $existingAdded = array_intersect( $existingCategories, $added );
        $existingDeleted = array_intersect( $existingCategories, $deleted );
        $missingAdded = array_diff( $added, $existingAdded );

        // For category rows that already exist, do a plain
        // UPDATE instead of INSERT...ON DUPLICATE KEY UPDATE
        // to avoid creating gaps in the cat_id sequence.
        if ( $existingAdded ) {
            $dbw->newUpdateQueryBuilder()
                ->update( 'category' )
                ->set( $addFields )
                ->where( [ 'cat_id' => array_keys( $existingAdded ) ] )
                ->caller( __METHOD__ )->execute();
        }

        if ( $missingAdded ) {
            $queryBuilder = $dbw->newInsertQueryBuilder()
                ->insertInto( 'category' )
                ->onDuplicateKeyUpdate()
                ->uniqueIndexFields( [ 'cat_title' ] )
                ->set( $addFields );
            foreach ( $missingAdded as $cat ) {
                $queryBuilder->row( [
                    'cat_title'   => $cat,
                    'cat_pages'   => 1,
                    'cat_subcats' => ( $type === 'subcat' ) ? 1 : 0,
                    'cat_files'   => ( $type === 'file' ) ? 1 : 0,
                ] );
            }
            $queryBuilder->caller( __METHOD__ )->execute();
        }

        if ( $existingDeleted ) {
            $dbw->newUpdateQueryBuilder()
                ->update( 'category' )
                ->set( $removeFields )
                ->where( [ 'cat_id' => array_keys( $existingDeleted ) ] )
                ->caller( __METHOD__ )->execute();
        }

        foreach ( $added as $catName ) {
            $cat = Category::newFromName( $catName );
            $this->getHookRunner()->onCategoryAfterPageAdded( $cat, $this );
        }

        foreach ( $deleted as $catName ) {
            $cat = Category::newFromName( $catName );
            $this->getHookRunner()->onCategoryAfterPageRemoved( $cat, $this, $id );
            // Refresh counts on categories that should be empty now (after commit, T166757)
            DeferredUpdates::addCallableUpdate( static function () use ( $cat ) {
                $cat->refreshCountsIfEmpty();
            } );
        }
    }

    /**
     * Opportunistically enqueue link update jobs after a fresh parser output was generated.
     *
     * This method should only be called by PoolWorkArticleViewCurrent, after a page view
     * experienced a miss from the ParserCache, and a new ParserOutput was generated.
     * Specifically, for load reasons, this method must not get called during page views that
     * use a cached ParserOutput.
     *
     * @since 1.25
     * @internal For use by PoolWorkArticleViewCurrent
     * @param ParserOutput $parserOutput Current version page output
     */
    public function triggerOpportunisticLinksUpdate( ParserOutput $parserOutput ) {
        if ( MediaWikiServices::getInstance()->getReadOnlyMode()->isReadOnly() ) {
            return;
        }

        if ( !$this->getHookRunner()->onOpportunisticLinksUpdate( $this,
            $this->mTitle, $parserOutput )
        ) {
            return;
        }

        $config = MediaWikiServices::getInstance()->getMainConfig();

        $params = [
            'isOpportunistic' => true,
            'rootJobTimestamp' => $parserOutput->getCacheTime()
        ];

        if ( MediaWikiServices::getInstance()->getRestrictionStore()->areRestrictionsCascading( $this->mTitle ) ) {
            // In general, MediaWiki does not re-run LinkUpdate (e.g. for search index, category
            // listings, and backlinks for Whatlinkshere), unless either the page was directly
            // edited, or was re-generate following a template edit propagating to an affected
            // page. As such, during page views when there is no valid ParserCache entry,
            // we re-parse and save, but leave indexes as-is.
            //
            // We make an exception for pages that have cascading protection (perhaps for a wiki's
            // "Main Page"). When such page is re-parsed on-demand after a parser cache miss, we
            // queue a high-priority LinksUpdate job, to ensure that we really protect all
            // content that is currently transcluded onto the page. This is important, because
            // wikitext supports conditional statements based on the current time, which enables
            // transcluding of a different sub page based on which day it is, and then show that
            // information on the Main Page, without the Main Page itself being edited.
            MediaWikiServices::getInstance()->getJobQueueGroup()->lazyPush(
                RefreshLinksJob::newPrioritized( $this->mTitle, $params )
            );
        } elseif ( !$config->get( MainConfigNames::MiserMode ) &&
            $parserOutput->hasReducedExpiry()
        ) {
            // Assume the output contains "dynamic" time/random based magic words.
            // Only update pages that expired due to dynamic content and NOT due to edits
            // to referenced templates/files. When the cache expires due to dynamic content,
            // page_touched is unchanged. We want to avoid triggering redundant jobs due to
            // views of pages that were just purged via HTMLCacheUpdateJob. In that case, the
            // template/file edit already triggered recursive RefreshLinksJob jobs.
            if ( $this->getLinksTimestamp() > $this->getTouched() ) {
                // If a page is uncacheable, do not keep spamming a job for it.
                // Although it would be de-duplicated, it would still waste I/O.
                $cache = ObjectCache::getLocalClusterInstance();
                $key = $cache->makeKey( 'dynamic-linksupdate', 'last', $this->getId() );
                $ttl = max( $parserOutput->getCacheExpiry(), 3600 );
                if ( $cache->add( $key, time(), $ttl ) ) {
                    MediaWikiServices::getInstance()->getJobQueueGroup()->lazyPush(
                        RefreshLinksJob::newDynamic( $this->mTitle, $params )
                    );
                }
            }
        }
    }

    /**
     * Whether this content displayed on this page
     * comes from the local database
     *
     * @since 1.28
     * @return bool
     */
    public function isLocal() {
        return true;
    }

    /**
     * The display name for the site this content
     * come from. If a subclass overrides isLocal(),
     * this could return something other than the
     * current site name
     *
     * @since 1.28
     * @return string
     */
    public function getWikiDisplayName() {
        $sitename = MediaWikiServices::getInstance()->getMainConfig()->get(
            MainConfigNames::Sitename );
        return $sitename;
    }

    /**
     * Get the source URL for the content on this page,
     * typically the canonical URL, but may be a remote
     * link if the content comes from another site
     *
     * @since 1.28
     * @return string
     */
    public function getSourceURL() {
        return $this->getTitle()->getCanonicalURL();
    }

    /**
     * Ensure consistency when unserializing.
     * @note WikiPage objects should never be serialized in the first place.
     * But some extensions like AbuseFilter did (see T213006),
     * and we need to be able to read old data (see T187153).
     */
    public function __wakeup() {
        // Make sure we re-fetch the latest state from the database.
        // In particular, the latest revision may have changed.
        // As a side-effect, this makes sure mLastRevision doesn't
        // end up being an instance of the old Revision class (see T259181),
        // especially since that class was removed entirely in 1.37.
        $this->clear();
    }

    /**
     * @inheritDoc
     * @since 1.36
     */
    public function getNamespace(): int {
        return $this->getTitle()->getNamespace();
    }

    /**
     * @inheritDoc
     * @since 1.36
     */
    public function getDBkey(): string {
        return $this->getTitle()->getDBkey();
    }

    /**
     * @return false self::LOCAL
     * @since 1.36
     */
    public function getWikiId() {
        return $this->getTitle()->getWikiId();
    }

    /**
     * @return true
     * @since 1.36
     */
    public function canExist(): bool {
        return true;
    }

    /**
     * @inheritDoc
     * @since 1.36
     */
    public function __toString(): string {
        return $this->mTitle->__toString();
    }

    /**
     * @inheritDoc
     * @since 1.36
     */
    public function isSamePageAs( PageReference $other ): bool {
        // NOTE: keep in sync with PageReferenceValue::isSamePageAs()!
        return $this->getWikiId() === $other->getWikiId()
            && $this->getNamespace() === $other->getNamespace()
            && $this->getDBkey() === $other->getDBkey();
    }

    /**
     * Returns the page represented by this WikiPage as a PageStoreRecord.
     * The PageRecord returned by this method is guaranteed to be immutable.
     *
     * It is preferred to use this method rather than using the WikiPage as a PageIdentity directly.
     * @since 1.36
     *
     * @throws PreconditionException if the page does not exist.
     *
     * @return ExistingPageRecord
     */
    public function toPageRecord(): ExistingPageRecord {
        // TODO: replace individual member fields with a PageRecord instance that is always present

        if ( !$this->mDataLoaded ) {
            $this->loadPageData();
        }

        Assert::precondition(
            $this->exists(),
            'This WikiPage instance does not represent an existing page: ' . $this->mTitle
        );

        return new PageStoreRecord(
            (object)[
                'page_id' => $this->getId(),
                'page_namespace' => $this->mTitle->getNamespace(),
                'page_title' => $this->mTitle->getDBkey(),
                'page_latest' => $this->mLatest,
                'page_is_new' => $this->mIsNew ? 1 : 0,
                'page_is_redirect' => $this->mPageIsRedirectField ? 1 : 0,
                'page_touched' => $this->getTouched(),
                'page_lang' => $this->getLanguage()
            ],
            PageIdentity::LOCAL
        );
    }

}