Merge "docs: Fix typo"

[mediawiki.git] / includes / page / WikiPage.php

<?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\Content\Content;
use MediaWiki\Content\ContentHandler;
use MediaWiki\Context\IContextSource;
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\ParserOptions;
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\User;
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\IDBAccessObject;
use Wikimedia\Rdbms\ILoadBalancer;
use Wikimedia\Rdbms\IReadableDatabase;
use Wikimedia\Rdbms\RawSQLValue;
use Wikimedia\Rdbms\SelectQueryBuilder;

/**
 * @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 Stringable, 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;

        /**
         * @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;

        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;
                }
        }

        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->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->newSelectQueryBuilder()
                        ->queryInfo( $pageQuery )
                        ->where( $conditions )
                        ->caller( __METHOD__ )
                        ->options( $options )
                        ->fetchRow();

                $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 int $recency
         * @return stdClass|false Database result resource, or false on failure
         */
        public function pageDataFromTitle( $dbr, $title, $recency = IDBAccessObject::READ_NORMAL ) {
                if ( !$title->canExist() ) {
                        return false;
                }
                $options = [];
                if ( ( $recency & IDBAccessObject::READ_EXCLUSIVE ) == IDBAccessObject::READ_EXCLUSIVE ) {
                        $options[] = 'FOR UPDATE';
                } elseif ( ( $recency & IDBAccessObject::READ_LOCKING ) == IDBAccessObject::READ_LOCKING ) {
                        $options[] = 'LOCK IN SHARE MODE';
                }

                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 ) ) {
                        $loadBalancer = $this->getDBLoadBalancer();
                        if ( ( $from & IDBAccessObject::READ_LATEST ) == IDBAccessObject::READ_LATEST ) {
                                $index = DB_PRIMARY;
                        } else {
                                $index = DB_REPLICA;
                        }
                        $db = $loadBalancer->getConnection( $index );
                        $data = $this->pageDataFromTitle( $db, $this->mTitle, $from );

                        if ( !$data
                                && $index == DB_REPLICA
                                && $loadBalancer->hasReplicaServers()
                                && $loadBalancer->hasOrMadeRecentPrimaryChanges()
                        ) {
                                $from = IDBAccessObject::READ_LATEST;
                                $db = $loadBalancer->getConnection( DB_PRIMARY );
                                $data = $this->pageDataFromTitle( $db, $this->mTitle, $from );
                        }
                } 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() {
                $this->loadPageData();
                if ( $this->mPageIsRedirectField ) {
                        return MediaWikiServices::getInstance()->getRedirectLookup()
                                        ->getRedirectTarget( $this->getTitle() ) !== null;
                }

                return false;
        }

        /**
         * 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
         */
        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 ) {
                                $hasLinks = $editInfo->output->hasLinks();
                        } 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() {
                $target = MediaWikiServices::getInstance()->getRedirectLookup()->getRedirectTarget( $this );
                return Title::castFromLinkTarget( $target );
        }

        /**
         * Insert or update the redirect table entry for this page to indicate it redirects to $rt
         * @deprecated since 1.43; use {@link RedirectStore::updateRedirectTarget()} instead.
         * @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 ) {
                return MediaWikiServices::getInstance()->getRedirectStore()
                        ->updateRedirectTarget( $this, $rt );
        }

        /**
         * 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 UserArray
         */
        public function getContributors() {
                // @todo: This is expensive; cache this info somewhere.

                $services = MediaWikiServices::getInstance();
                $dbr = $services->getConnectionProvider()->getReplicaDatabase();
                $actorNormalization = $services->getActorNormalization();
                $userIdentityLookup = $services->getUserIdentityLookup();

                $user = $this->getUser()
                        ? User::newFromId( $this->getUser() )
                        : User::newFromName( $this->getUserText(), false );

                $res = $dbr->newSelectQueryBuilder()
                        ->select( [
                                'user_id' => 'actor_user',
                                'user_name' => 'actor_name',
                                'actor_id' => 'MIN(rev_actor)',
                                'user_real_name' => 'MIN(user_real_name)',
                                'timestamp' => 'MAX(rev_timestamp)',
                        ] )
                        ->from( 'revision' )
                        ->join( 'actor', null, 'rev_actor = actor_id' )
                        ->leftJoin( 'user', null, 'actor_user = user_id' )
                        ->where( [
                                '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.
                                $dbr->expr( 'rev_actor', '!=', $actorNormalization->findActorId( $user, $dbr ) ),
                                // Username hidden?
                                $dbr->bitAnd( 'rev_deleted', RevisionRecord::DELETED_USER ) . ' = 0',
                        ] )
                        ->groupBy( [ 'actor_user', 'actor_name' ] )
                        ->orderBy( 'timestamp', SelectQueryBuilder::SORT_DESC )
                        ->caller( __METHOD__ )
                        ->fetchResultSet();
                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->getMainContentModel();

                $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 );
                        MediaWikiServices::getInstance()->getRedirectStore()
                                ->updateRedirectTarget( $this, $rt, $lastRevIsRedirect );
                        $this->setLastEdit( $revision );
                        $this->mPageIsRedirectField = (bool)$rt;
                        $this->mIsNew = $isNew;

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

                return $result;
        }

        /**
         * Helper method for checking whether two revisions have differences that go
         * beyond the main slot.
         *
         * MCR migration note: this method should go away!
         *
         * @deprecated since 1.43; 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, use DerivedPageDataUpdater::doUpdates instead.
         *             Emitting warnings since 1.44
         *
         * @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, see DerivedPageDataUpdater::prepareUpdate.
         */
        public function doEditUpdates(
                RevisionRecord $revisionRecord,
                UserIdentity $user,
                array $options = []
        ) {
                wfDeprecated( __METHOD__, '1.32' ); // emitting warnings since 1.44

                $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 = $services->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;

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

                if ( $id ) { // Protection of existing page
                        // 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 );
                } 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->getHookRunner()->onArticleProtectComplete( $this, $legacyUser, $limit, $reason );

                $services->getRestrictionStore()->flushRestrictions( $this->mTitle );

                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;
        }

        /**
         * 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 );

                DeferredUpdates::addCallableUpdate(
                        static function () use ( $title, $maybeIsRedirect ) {
                                self::queueBacklinksJobs( $title, true, $maybeIsRedirect, 'create-page' );
                        }
                );

                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
         */
        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
                DeferredUpdates::addCallableUpdate( static function () use ( $title ) {
                        self::queueBacklinksJobs( $title, true, true, 'delete-page' );
                } );

                // 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

                DeferredUpdates::addCallableUpdate(
                        static function () use ( $title, $slotsChanged, $maybeRedirectChanged ) {
                                self::queueBacklinksJobs(
                                        $title,
                                        $slotsChanged === null || in_array( SlotRecord::MAIN, $slotsChanged ),
                                        $maybeRedirectChanged,
                                        'edit-page'
                                );
                        }
                );

                $services = MediaWikiServices::getInstance();
                $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 );
        }

        private static function queueBacklinksJobs(
                Title $title, $mainSlotChanged, $maybeRedirectChanged, $causeAction
        ) {
                $services = MediaWikiServices::getInstance();
                $backlinkCache = $services->getBacklinkCacheFactory()->getBacklinkCache( $title );

                $jobs = [];
                if ( $mainSlotChanged
                        && $backlinkCache->hasLinks( 'templatelinks' )
                ) {
                        // 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' => $causeAction ]
                        );
                }
                // Images
                if ( $maybeRedirectChanged && $title->getNamespace() === NS_FILE
                        && $backlinkCache->hasLinks( 'imagelinks' )
                ) {
                        // Process imagelinks in case the redirect target has changed
                        $jobs[] = HTMLCacheUpdateJob::newForBacklinks(
                                $title,
                                'imagelinks',
                                [ 'causeAction' => $causeAction ]
                        );
                }
                // Invalidate the caches of all pages which redirect here
                if ( $backlinkCache->hasLinks( 'redirect' ) ) {
                        $jobs[] = HTMLCacheUpdateJob::newForBacklinks(
                                $title,
                                'redirect',
                                [ 'causeAction' => $causeAction ]
                        );
                }
                if ( $jobs ) {
                        $services->getJobQueueGroup()->push( $jobs );
                }
        }

        /**
         * Purge the check key for cross-wiki cache entries referencing this page
         */
        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->getConnectionProvider()->getReplicaDatabase();
                $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();

                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' => new RawSQLValue( 'cat_pages + 1' ) ];
                $removeFields = [ 'cat_pages' => new RawSQLValue( 'cat_pages - 1' ) ];
                if ( $type !== 'page' ) {
                        $addFields["cat_{$type}s"] = new RawSQLValue( "cat_{$type}s + 1" );
                        $removeFields["cat_{$type}s"] = new RawSQLValue( "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 subpage 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.
                                $services = MediaWikiServices::getInstance()->getObjectCacheFactory();
                                $cache = $services->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
                );
        }

}