RevisionStore.php

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<?php
namespace MediaWiki\Revision;
 
use ActorMigration;
use CommentStore;
use CommentStoreComment;
use Content;
use ContentHandler;
use DBAccessObjectUtils;
use IDBAccessObject;
use InvalidArgumentException;
use MediaWiki\Content\IContentHandlerFactory;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\Linker\LinkTarget;
use MediaWiki\Storage\BlobAccessException;
use MediaWiki\Storage\BlobStore;
use MediaWiki\Storage\NameTableStore;
use MediaWiki\Storage\SqlBlobStore;
use MediaWiki\User\UserIdentity;
use MediaWiki\User\UserIdentityValue;
use Message;
use MWException;
use MWTimestamp;
use MWUnknownContentModelException;
use Psr\Log\LoggerAwareInterface;
use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;
use RecentChange;
use Revision;
use RuntimeException;
use StatusValue;
use Title;
use Traversable;
use User;
use WANObjectCache;
use Wikimedia\Assert\Assert;
use Wikimedia\IPUtils;
use Wikimedia\Rdbms\Database;
use Wikimedia\Rdbms\DBConnRef;
use Wikimedia\Rdbms\IDatabase;
use Wikimedia\Rdbms\ILoadBalancer;
use Wikimedia\Rdbms\IResultWrapper;
 
class RevisionStore
    implements IDBAccessObject, RevisionFactory, RevisionLookup, LoggerAwareInterface {
 
    public const ROW_CACHE_KEY = 'revision-row-1.29';
 
    public const ORDER_OLDEST_TO_NEWEST = 'ASC';
    public const ORDER_NEWEST_TO_OLDEST = 'DESC';
 
    private $blobStore;
 
    private $dbDomain;
 
    private $loadBalancer;
 
    private $cache;
 
    private $commentStore;
 
    private $actorMigration;
 
    private $logger;
 
    private $contentModelStore;
 
    private $slotRoleStore;
 
    private $slotRoleRegistry;
 
    private $contentHandlerFactory;
 
    private $hookContainer;
 
    private $hookRunner;
 
    public function __construct(
        ILoadBalancer $loadBalancer,
        SqlBlobStore $blobStore,
        WANObjectCache $cache,
        CommentStore $commentStore,
        NameTableStore $contentModelStore,
        NameTableStore $slotRoleStore,
        SlotRoleRegistry $slotRoleRegistry,
        ActorMigration $actorMigration,
        IContentHandlerFactory $contentHandlerFactory,
        HookContainer $hookContainer,
        $dbDomain = false
    ) {
        Assert::parameterType( 'string|boolean', $dbDomain, '$dbDomain' );
 
        $this->loadBalancer = $loadBalancer;
        $this->blobStore = $blobStore;
        $this->cache = $cache;
        $this->commentStore = $commentStore;
        $this->contentModelStore = $contentModelStore;
        $this->slotRoleStore = $slotRoleStore;
        $this->slotRoleRegistry = $slotRoleRegistry;
        $this->actorMigration = $actorMigration;
        $this->dbDomain = $dbDomain;
        $this->logger = new NullLogger();
        $this->contentHandlerFactory = $contentHandlerFactory;
        $this->hookContainer = $hookContainer;
        $this->hookRunner = new HookRunner( $hookContainer );
    }
 
    public function setLogger( LoggerInterface $logger ) {
        $this->logger = $logger;
    }
 
    public function isReadOnly() {
        return $this->blobStore->isReadOnly();
    }
 
    private function getDBLoadBalancer() {
        return $this->loadBalancer;
    }
 
    private function getDBConnectionRefForQueryFlags( $queryFlags ) {
        list( $mode, ) = DBAccessObjectUtils::getDBOptions( $queryFlags );
        return $this->getDBConnectionRef( $mode );
    }
 
    private function getDBConnectionRef( $mode, $groups = [] ) {
        $lb = $this->getDBLoadBalancer();
        return $lb->getConnectionRef( $mode, $groups, $this->dbDomain );
    }
 
    public function getTitle( $pageId, $revId, $queryFlags = self::READ_NORMAL ) {
        if ( !$pageId && !$revId ) {
            throw new InvalidArgumentException( '$pageId and $revId cannot both be 0 or null' );
        }
 
        // This method recalls itself with READ_LATEST if READ_NORMAL doesn't get us a Title
        // So ignore READ_LATEST_IMMUTABLE flags and handle the fallback logic in this method
        if ( DBAccessObjectUtils::hasFlags( $queryFlags, self::READ_LATEST_IMMUTABLE ) ) {
            $queryFlags = self::READ_NORMAL;
        }
 
        $canUseTitleNewFromId = ( $pageId !== null && $pageId > 0 && $this->dbDomain === false );
        list( $dbMode, $dbOptions ) = DBAccessObjectUtils::getDBOptions( $queryFlags );
 
        // Loading by ID is best, but Title::newFromID does not support that for foreign IDs.
        if ( $canUseTitleNewFromId ) {
            $titleFlags = ( $dbMode == DB_MASTER ? Title::READ_LATEST : 0 );
            // TODO: better foreign title handling (introduce TitleFactory)
            $title = Title::newFromID( $pageId, $titleFlags );
            if ( $title ) {
                return $title;
            }
        }
 
        // rev_id is defined as NOT NULL, but this revision may not yet have been inserted.
        $canUseRevId = ( $revId !== null && $revId > 0 );
 
        if ( $canUseRevId ) {
            $dbr = $this->getDBConnectionRef( $dbMode );
            // @todo: Title::getSelectFields(), or Title::getQueryInfo(), or something like that
            $row = $dbr->selectRow(
                [ 'revision', 'page' ],
                [
                    'page_namespace',
                    'page_title',
                    'page_id',
                    'page_latest',
                    'page_is_redirect',
                    'page_len',
                ],
                [ 'rev_id' => $revId ],
                __METHOD__,
                $dbOptions,
                [ 'page' => [ 'JOIN', 'page_id=rev_page' ] ]
            );
            if ( $row ) {
                // TODO: better foreign title handling (introduce TitleFactory)
                return Title::newFromRow( $row );
            }
        }
 
        // If we still don't have a title, fallback to master if that wasn't already happening.
        if ( $dbMode !== DB_MASTER ) {
            $title = $this->getTitle( $pageId, $revId, self::READ_LATEST );
            if ( $title ) {
                $this->logger->info(
                    __METHOD__ . ' fell back to READ_LATEST and got a Title.',
                    [ 'trace' => wfBacktrace() ]
                );
                return $title;
            }
        }
 
        throw new RevisionAccessException(
            "Could not determine title for page ID $pageId and revision ID $revId"
        );
    }
 
    private function failOnNull( $value, $name ) {
        if ( $value === null ) {
            throw new IncompleteRevisionException(
                "$name must not be " . var_export( $value, true ) . "!"
            );
        }
 
        return $value;
    }
 
    private function failOnEmpty( $value, $name ) {
        if ( $value === null || $value === 0 || $value === '' ) {
            throw new IncompleteRevisionException(
                "$name must not be " . var_export( $value, true ) . "!"
            );
        }
 
        return $value;
    }
 
    public function insertRevisionOn( RevisionRecord $rev, IDatabase $dbw ) {
        // TODO: pass in a DBTransactionContext instead of a database connection.
        $this->checkDatabaseDomain( $dbw );
 
        $slotRoles = $rev->getSlotRoles();
 
        // Make sure the main slot is always provided throughout migration
        if ( !in_array( SlotRecord::MAIN, $slotRoles ) ) {
            throw new IncompleteRevisionException(
                'main slot must be provided'
            );
        }
 
        // Checks
        $this->failOnNull( $rev->getSize(), 'size field' );
        $this->failOnEmpty( $rev->getSha1(), 'sha1 field' );
        $this->failOnEmpty( $rev->getTimestamp(), 'timestamp field' );
        $comment = $this->failOnNull( $rev->getComment( RevisionRecord::RAW ), 'comment' );
        $user = $this->failOnNull( $rev->getUser( RevisionRecord::RAW ), 'user' );
        $this->failOnNull( $user->getId(), 'user field' );
        $this->failOnEmpty( $user->getName(), 'user_text field' );
 
        if ( !$rev->isReadyForInsertion() ) {
            // This is here for future-proofing. At the time this check being added, it
            // was redundant to the individual checks above.
            throw new IncompleteRevisionException( 'Revision is incomplete' );
        }
 
        if ( $slotRoles == [ SlotRecord::MAIN ] ) {
            // T239717: If the main slot is the only slot, make sure the revision's nominal size
            // and hash match the main slot's nominal size and hash.
            $mainSlot = $rev->getSlot( SlotRecord::MAIN, RevisionRecord::RAW );
            Assert::precondition(
                $mainSlot->getSize() === $rev->getSize(),
                'The revisions\'s size must match the main slot\'s size (see T239717)'
            );
            Assert::precondition(
                $mainSlot->getSha1() === $rev->getSha1(),
                'The revisions\'s SHA1 hash must match the main slot\'s SHA1 hash (see T239717)'
            );
        }
 
        // TODO: we shouldn't need an actual Title here.
        $title = Title::newFromLinkTarget( $rev->getPageAsLinkTarget() );
        $pageId = $this->failOnEmpty( $rev->getPageId(), 'rev_page field' ); // check this early
 
        $parentId = $rev->getParentId() === null
            ? $this->getPreviousRevisionId( $dbw, $rev )
            : $rev->getParentId();
 
        $rev = $dbw->doAtomicSection(
            __METHOD__,
            function ( IDatabase $dbw, $fname ) use (
                $rev,
                $user,
                $comment,
                $title,
                $pageId,
                $parentId
            ) {
                return $this->insertRevisionInternal(
                    $rev,
                    $dbw,
                    $user,
                    $comment,
                    $title,
                    $pageId,
                    $parentId
                );
            }
        );
 
        // sanity checks
        Assert::postcondition( $rev->getId() > 0, 'revision must have an ID' );
        Assert::postcondition( $rev->getPageId() > 0, 'revision must have a page ID' );
        Assert::postcondition(
            $rev->getComment( RevisionRecord::RAW ) !== null,
            'revision must have a comment'
        );
        Assert::postcondition(
            $rev->getUser( RevisionRecord::RAW ) !== null,
            'revision must have a user'
        );
 
        // Trigger exception if the main slot is missing.
        // Technically, this could go away after MCR migration: while
        // calling code may require a main slot to exist, RevisionStore
        // really should not know or care about that requirement.
        $rev->getSlot( SlotRecord::MAIN, RevisionRecord::RAW );
 
        foreach ( $slotRoles as $role ) {
            $slot = $rev->getSlot( $role, RevisionRecord::RAW );
            Assert::postcondition(
                $slot->getContent() !== null,
                $role . ' slot must have content'
            );
            Assert::postcondition(
                $slot->hasRevision(),
                $role . ' slot must have a revision associated'
            );
        }
 
        $this->hookRunner->onRevisionRecordInserted( $rev );
 
        // Soft deprecated in 1.31, hard deprecated in 1.35
        if ( $this->hookContainer->isRegistered( 'RevisionInsertComplete' ) ) {
            // Only create the Revision object if its needed
            $legacyRevision = new Revision( $rev );
            $this->hookRunner->onRevisionInsertComplete( $legacyRevision, null, null );
        }
 
        return $rev;
    }
 
    private function insertRevisionInternal(
        RevisionRecord $rev,
        IDatabase $dbw,
        User $user,
        CommentStoreComment $comment,
        Title $title,
        $pageId,
        $parentId
    ) {
        $slotRoles = $rev->getSlotRoles();
 
        $revisionRow = $this->insertRevisionRowOn(
            $dbw,
            $rev,
            $title,
            $parentId
        );
 
        $revisionId = $revisionRow['rev_id'];
 
        $blobHints = [
            BlobStore::PAGE_HINT => $pageId,
            BlobStore::REVISION_HINT => $revisionId,
            BlobStore::PARENT_HINT => $parentId,
        ];
 
        $newSlots = [];
        foreach ( $slotRoles as $role ) {
            $slot = $rev->getSlot( $role, RevisionRecord::RAW );
 
            // If the SlotRecord already has a revision ID set, this means it already exists
            // in the database, and should already belong to the current revision.
            // However, a slot may already have a revision, but no content ID, if the slot
            // is emulated based on the archive table, because we are in SCHEMA_COMPAT_READ_OLD
            // mode, and the respective archive row was not yet migrated to the new schema.
            // In that case, a new slot row (and content row) must be inserted even during
            // undeletion.
            if ( $slot->hasRevision() && $slot->hasContentId() ) {
                // TODO: properly abort transaction if the assertion fails!
                Assert::parameter(
                    $slot->getRevision() === $revisionId,
                    'slot role ' . $slot->getRole(),
                    'Existing slot should belong to revision '
                    . $revisionId . ', but belongs to revision ' . $slot->getRevision() . '!'
                );
 
                // Slot exists, nothing to do, move along.
                // This happens when restoring archived revisions.
 
                $newSlots[$role] = $slot;
            } else {
                $newSlots[$role] = $this->insertSlotOn( $dbw, $revisionId, $slot, $title, $blobHints );
            }
        }
 
        $this->insertIpChangesRow( $dbw, $user, $rev, $revisionId );
 
        $rev = new RevisionStoreRecord(
            $title,
            $user,
            $comment,
            (object)$revisionRow,
            new RevisionSlots( $newSlots ),
            $this->dbDomain
        );
 
        return $rev;
    }
 
    private function insertSlotOn(
        IDatabase $dbw,
        $revisionId,
        SlotRecord $protoSlot,
        Title $title,
        array $blobHints = []
    ) {
        if ( $protoSlot->hasAddress() ) {
            $blobAddress = $protoSlot->getAddress();
        } else {
            $blobAddress = $this->storeContentBlob( $protoSlot, $title, $blobHints );
        }
 
        $contentId = null;
 
        if ( $protoSlot->hasContentId() ) {
            $contentId = $protoSlot->getContentId();
        } else {
            $contentId = $this->insertContentRowOn( $protoSlot, $dbw, $blobAddress );
        }
 
        $this->insertSlotRowOn( $protoSlot, $dbw, $revisionId, $contentId );
 
        $savedSlot = SlotRecord::newSaved(
            $revisionId,
            $contentId,
            $blobAddress,
            $protoSlot
        );
 
        return $savedSlot;
    }
 
    private function insertIpChangesRow(
        IDatabase $dbw,
        User $user,
        RevisionRecord $rev,
        $revisionId
    ) {
        if ( $user->getId() === 0 && IPUtils::isValid( $user->getName() ) ) {
            $ipcRow = [
                'ipc_rev_id'        => $revisionId,
                'ipc_rev_timestamp' => $dbw->timestamp( $rev->getTimestamp() ),
                'ipc_hex'           => IPUtils::toHex( $user->getName() ),
            ];
            $dbw->insert( 'ip_changes', $ipcRow, __METHOD__ );
        }
    }
 
    private function insertRevisionRowOn(
        IDatabase $dbw,
        RevisionRecord $rev,
        Title $title,
        $parentId
    ) {
        $revisionRow = $this->getBaseRevisionRow( $dbw, $rev, $title, $parentId );
 
        list( $commentFields, $commentCallback ) =
            $this->commentStore->insertWithTempTable(
                $dbw,
                'rev_comment',
                $rev->getComment( RevisionRecord::RAW )
            );
        $revisionRow += $commentFields;
 
        list( $actorFields, $actorCallback ) =
            $this->actorMigration->getInsertValuesWithTempTable(
                $dbw,
                'rev_user',
                $rev->getUser( RevisionRecord::RAW )
            );
        $revisionRow += $actorFields;
 
        $dbw->insert( 'revision', $revisionRow, __METHOD__ );
 
        if ( !isset( $revisionRow['rev_id'] ) ) {
            // only if auto-increment was used
            $revisionRow['rev_id'] = intval( $dbw->insertId() );
 
            if ( $dbw->getType() === 'mysql' ) {
                // (T202032) MySQL until 8.0 and MariaDB until some version after 10.1.34 don't save the
                // auto-increment value to disk, so on server restart it might reuse IDs from deleted
                // revisions. We can fix that with an insert with an explicit rev_id value, if necessary.
 
                $maxRevId = intval( $dbw->selectField( 'archive', 'MAX(ar_rev_id)', '', __METHOD__ ) );
                $table = 'archive';
                $maxRevId2 = intval( $dbw->selectField( 'slots', 'MAX(slot_revision_id)', '', __METHOD__ ) );
                if ( $maxRevId2 >= $maxRevId ) {
                    $maxRevId = $maxRevId2;
                    $table = 'slots';
                }
 
                if ( $maxRevId >= $revisionRow['rev_id'] ) {
                    $this->logger->debug(
                        '__METHOD__: Inserted revision {revid} but {table} has revisions up to {maxrevid}.'
                            . ' Trying to fix it.',
                        [
                            'revid' => $revisionRow['rev_id'],
                            'table' => $table,
                            'maxrevid' => $maxRevId,
                        ]
                    );
 
                    if ( !$dbw->lock( 'fix-for-T202032', __METHOD__ ) ) {
                        throw new MWException( 'Failed to get database lock for T202032' );
                    }
                    $fname = __METHOD__;
                    $dbw->onTransactionResolution(
                        function ( $trigger, IDatabase $dbw ) use ( $fname ) {
                            $dbw->unlock( 'fix-for-T202032', $fname );
                        },
                        __METHOD__
                    );
 
                    $dbw->delete( 'revision', [ 'rev_id' => $revisionRow['rev_id'] ], __METHOD__ );
 
                    // The locking here is mostly to make MySQL bypass the REPEATABLE-READ transaction
                    // isolation (weird MySQL "feature"). It does seem to block concurrent auto-incrementing
                    // inserts too, though, at least on MariaDB 10.1.29.
                    //
                    // Don't try to lock `revision` in this way, it'll deadlock if there are concurrent
                    // transactions in this code path thanks to the row lock from the original ->insert() above.
                    //
                    // And we have to use raw SQL to bypass the "aggregation used with a locking SELECT" warning
                    // that's for non-MySQL DBs.
                    $row1 = $dbw->query(
                        $dbw->selectSQLText( 'archive', [ 'v' => "MAX(ar_rev_id)" ], '', __METHOD__ ) . ' FOR UPDATE',
                        __METHOD__
                    )->fetchObject();
 
                    $row2 = $dbw->query(
                        $dbw->selectSQLText( 'slots', [ 'v' => "MAX(slot_revision_id)" ], '', __METHOD__ )
                            . ' FOR UPDATE',
                        __METHOD__
                    )->fetchObject();
 
                    $maxRevId = max(
                        $maxRevId,
                        $row1 ? intval( $row1->v ) : 0,
                        $row2 ? intval( $row2->v ) : 0
                    );
 
                    // If we don't have SCHEMA_COMPAT_WRITE_NEW, all except the first of any concurrent
                    // transactions will throw a duplicate key error here. It doesn't seem worth trying
                    // to avoid that.
                    $revisionRow['rev_id'] = $maxRevId + 1;
                    $dbw->insert( 'revision', $revisionRow, __METHOD__ );
                }
            }
        }
 
        $commentCallback( $revisionRow['rev_id'] );
        $actorCallback( $revisionRow['rev_id'], $revisionRow );
 
        return $revisionRow;
    }
 
    private function getBaseRevisionRow(
        IDatabase $dbw,
        RevisionRecord $rev,
        Title $title,
        $parentId
    ) {
        // Record the edit in revisions
        $revisionRow = [
            'rev_page'       => $rev->getPageId(),
            'rev_parent_id'  => $parentId,
            'rev_minor_edit' => $rev->isMinor() ? 1 : 0,
            'rev_timestamp'  => $dbw->timestamp( $rev->getTimestamp() ),
            'rev_deleted'    => $rev->getVisibility(),
            'rev_len'        => $rev->getSize(),
            'rev_sha1'       => $rev->getSha1(),
        ];
 
        if ( $rev->getId() !== null ) {
            // Needed to restore revisions with their original ID
            $revisionRow['rev_id'] = $rev->getId();
        }
 
        return $revisionRow;
    }
 
    private function storeContentBlob(
        SlotRecord $slot,
        Title $title,
        array $blobHints = []
    ) {
        $content = $slot->getContent();
        $format = $content->getDefaultFormat();
        $model = $content->getModel();
 
        $this->checkContent( $content, $title, $slot->getRole() );
 
        return $this->blobStore->storeBlob(
            $content->serialize( $format ),
            // These hints "leak" some information from the higher abstraction layer to
            // low level storage to allow for optimization.
            array_merge(
                $blobHints,
                [
                    BlobStore::DESIGNATION_HINT => 'page-content',
                    BlobStore::ROLE_HINT => $slot->getRole(),
                    BlobStore::SHA1_HINT => $slot->getSha1(),
                    BlobStore::MODEL_HINT => $model,
                    BlobStore::FORMAT_HINT => $format,
                ]
            )
        );
    }
 
    private function insertSlotRowOn( SlotRecord $slot, IDatabase $dbw, $revisionId, $contentId ) {
        $slotRow = [
            'slot_revision_id' => $revisionId,
            'slot_role_id' => $this->slotRoleStore->acquireId( $slot->getRole() ),
            'slot_content_id' => $contentId,
            // If the slot has a specific origin use that ID, otherwise use the ID of the revision
            // that we just inserted.
            'slot_origin' => $slot->hasOrigin() ? $slot->getOrigin() : $revisionId,
        ];
        $dbw->insert( 'slots', $slotRow, __METHOD__ );
    }
 
    private function insertContentRowOn( SlotRecord $slot, IDatabase $dbw, $blobAddress ) {
        $contentRow = [
            'content_size' => $slot->getSize(),
            'content_sha1' => $slot->getSha1(),
            'content_model' => $this->contentModelStore->acquireId( $slot->getModel() ),
            'content_address' => $blobAddress,
        ];
        $dbw->insert( 'content', $contentRow, __METHOD__ );
        return intval( $dbw->insertId() );
    }
 
    private function checkContent( Content $content, Title $title, $role ) {
        // Note: may return null for revisions that have not yet been inserted
 
        $model = $content->getModel();
        $format = $content->getDefaultFormat();
        $handler = $content->getContentHandler();
 
        $name = "$title";
 
        if ( !$handler->isSupportedFormat( $format ) ) {
            throw new MWException( "Can't use format $format with content model $model on $name" );
        }
 
        if ( !$content->isValid() ) {
            throw new MWException(
                "New content for $name is not valid! Content model is $model"
            );
        }
    }
 
    public function newNullRevision(
        IDatabase $dbw,
        Title $title,
        CommentStoreComment $comment,
        $minor,
        User $user
    ) {
        $this->checkDatabaseDomain( $dbw );
 
        $pageId = $title->getArticleID();
 
        // T51581: Lock the page table row to ensure no other process
        // is adding a revision to the page at the same time.
        // Avoid locking extra tables, compare T191892.
        $pageLatest = $dbw->selectField(
            'page',
            'page_latest',
            [ 'page_id' => $pageId ],
            __METHOD__,
            [ 'FOR UPDATE' ]
        );
 
        if ( !$pageLatest ) {
            return null;
        }
 
        // Fetch the actual revision row from master, without locking all extra tables.
        $oldRevision = $this->loadRevisionFromConds(
            $dbw,
            [ 'rev_id' => intval( $pageLatest ) ],
            self::READ_LATEST,
            $title
        );
 
        if ( !$oldRevision ) {
            $msg = "Failed to load latest revision ID $pageLatest of page ID $pageId.";
            $this->logger->error(
                $msg,
                [ 'exception' => new RuntimeException( $msg ) ]
            );
            return null;
        }
 
        // Construct the new revision
        $timestamp = MWTimestamp::now( TS_MW );
        $newRevision = MutableRevisionRecord::newFromParentRevision( $oldRevision );
 
        $newRevision->setComment( $comment );
        $newRevision->setUser( $user );
        $newRevision->setTimestamp( $timestamp );
        $newRevision->setMinorEdit( $minor );
 
        return $newRevision;
    }
 
    public function getRcIdIfUnpatrolled( RevisionRecord $rev ) {
        $rc = $this->getRecentChange( $rev );
        if ( $rc && $rc->getAttribute( 'rc_patrolled' ) == RecentChange::PRC_UNPATROLLED ) {
            return $rc->getAttribute( 'rc_id' );
        } else {
            return 0;
        }
    }
 
    public function getRecentChange( RevisionRecord $rev, $flags = 0 ) {
        list( $dbType, ) = DBAccessObjectUtils::getDBOptions( $flags );
 
        $rc = RecentChange::newFromConds(
            [ 'rc_this_oldid' => $rev->getId() ],
            __METHOD__,
            $dbType
        );
 
        // XXX: cache this locally? Glue it to the RevisionRecord?
        return $rc;
    }
 
    private function loadSlotContent(
        SlotRecord $slot,
        $blobData = null,
        $blobFlags = null,
        $blobFormat = null,
        $queryFlags = 0
    ) {
        if ( $blobData !== null ) {
            Assert::parameterType( 'string', $blobData, '$blobData' );
            Assert::parameterType( 'string|null', $blobFlags, '$blobFlags' );
 
            $cacheKey = $slot->hasAddress() ? $slot->getAddress() : null;
 
            if ( $blobFlags === null ) {
                // No blob flags, so use the blob verbatim.
                $data = $blobData;
            } else {
                $data = $this->blobStore->expandBlob( $blobData, $blobFlags, $cacheKey );
                if ( $data === false ) {
                    throw new RevisionAccessException(
                        "Failed to expand blob data using flags $blobFlags (key: $cacheKey)"
                    );
                }
            }
 
        } else {
            $address = $slot->getAddress();
            try {
                $data = $this->blobStore->getBlob( $address, $queryFlags );
            } catch ( BlobAccessException $e ) {
                throw new RevisionAccessException(
                    "Failed to load data blob from $address: " . $e->getMessage(), 0, $e
                );
            }
        }
 
        return $this->contentHandlerFactory
            ->getContentHandler( $slot->getModel() )
            ->unserializeContent( $data, $blobFormat );
    }
 
    public function getRevisionById( $id, $flags = 0 ) {
        return $this->newRevisionFromConds( [ 'rev_id' => intval( $id ) ], $flags );
    }
 
    public function getRevisionByTitle( LinkTarget $linkTarget, $revId = 0, $flags = 0 ) {
        $conds = [
            'page_namespace' => $linkTarget->getNamespace(),
            'page_title' => $linkTarget->getDBkey()
        ];
 
        // Only resolve to a Title when operating in the context of the local wiki (T248756)
        // TODO should not require Title in future (T206498)
        $title = $this->dbDomain === false ? Title::newFromLinkTarget( $linkTarget ) : null;
 
        if ( $revId ) {
            // Use the specified revision ID.
            // Note that we use newRevisionFromConds here because we want to retry
            // and fall back to master if the page is not found on a replica.
            // Since the caller supplied a revision ID, we are pretty sure the revision is
            // supposed to exist, so we should try hard to find it.
            $conds['rev_id'] = $revId;
            return $this->newRevisionFromConds( $conds, $flags, $title );
        } else {
            // Use a join to get the latest revision.
            // Note that we don't use newRevisionFromConds here because we don't want to retry
            // and fall back to master. The assumption is that we only want to force the fallback
            // if we are quite sure the revision exists because the caller supplied a revision ID.
            // If the page isn't found at all on a replica, it probably simply does not exist.
            $db = $this->getDBConnectionRefForQueryFlags( $flags );
 
            $conds[] = 'rev_id=page_latest';
            $rev = $this->loadRevisionFromConds( $db, $conds, $flags, $title );
 
            return $rev;
        }
    }
 
    public function getRevisionByPageId( $pageId, $revId = 0, $flags = 0 ) {
        $conds = [ 'page_id' => $pageId ];
        if ( $revId ) {
            // Use the specified revision ID.
            // Note that we use newRevisionFromConds here because we want to retry
            // and fall back to master if the page is not found on a replica.
            // Since the caller supplied a revision ID, we are pretty sure the revision is
            // supposed to exist, so we should try hard to find it.
            $conds['rev_id'] = $revId;
            return $this->newRevisionFromConds( $conds, $flags );
        } else {
            // Use a join to get the latest revision.
            // Note that we don't use newRevisionFromConds here because we don't want to retry
            // and fall back to master. The assumption is that we only want to force the fallback
            // if we are quite sure the revision exists because the caller supplied a revision ID.
            // If the page isn't found at all on a replica, it probably simply does not exist.
            $db = $this->getDBConnectionRefForQueryFlags( $flags );
 
            $conds[] = 'rev_id=page_latest';
            $rev = $this->loadRevisionFromConds( $db, $conds, $flags );
 
            return $rev;
        }
    }
 
    public function getRevisionByTimestamp(
        LinkTarget $title,
        string $timestamp,
        int $flags = IDBAccessObject::READ_NORMAL
    ): ?RevisionRecord {
        $db = $this->getDBConnectionRefForQueryFlags( $flags );
        return $this->newRevisionFromConds(
            [
                'rev_timestamp' => $db->timestamp( $timestamp ),
                'page_namespace' => $title->getNamespace(),
                'page_title' => $title->getDBkey()
            ],
            $flags,
            Title::newFromLinkTarget( $title )
        );
    }
 
    private function loadSlotRecords( $revId, $queryFlags, Title $title ) {
        $revQuery = self::getSlotsQueryInfo( [ 'content' ] );
 
        list( $dbMode, $dbOptions ) = DBAccessObjectUtils::getDBOptions( $queryFlags );
        $db = $this->getDBConnectionRef( $dbMode );
 
        $res = $db->select(
            $revQuery['tables'],
            $revQuery['fields'],
            [
                'slot_revision_id' => $revId,
            ],
            __METHOD__,
            $dbOptions,
            $revQuery['joins']
        );
 
        if ( !$res->numRows() && !( $queryFlags & self::READ_LATEST ) ) {
            // If we found no slots, try looking on the master database (T212428, T252156)
            $this->logger->info(
                __METHOD__ . ' falling back to READ_LATEST.',
                [
                    'revid' => $revId,
                    'trace' => wfBacktrace( true )
                ]
            );
            return $this->loadSlotRecords(
                $revId,
                $queryFlags | self::READ_LATEST,
                $title
            );
        }
 
        $slots = $this->constructSlotRecords( $revId, $res, $queryFlags, $title );
 
        return $slots;
    }
 
    private function constructSlotRecords(
        $revId,
        $slotRows,
        $queryFlags,
        Title $title,
        $slotContents = null
    ) {
        $slots = [];
 
        foreach ( $slotRows as $row ) {
            // Resolve role names and model names from in-memory cache, if they were not joined in.
            if ( !isset( $row->role_name ) ) {
                $row->role_name = $this->slotRoleStore->getName( (int)$row->slot_role_id );
            }
 
            if ( !isset( $row->model_name ) ) {
                if ( isset( $row->content_model ) ) {
                    $row->model_name = $this->contentModelStore->getName( (int)$row->content_model );
                } else {
                    // We may get here if $row->model_name is set but null, perhaps because it
                    // came from rev_content_model, which is NULL for the default model.
                    $slotRoleHandler = $this->slotRoleRegistry->getRoleHandler( $row->role_name );
                    $row->model_name = $slotRoleHandler->getDefaultModel( $title );
                }
            }
 
            // We may have a fake blob_data field from getSlotRowsForBatch(), use it!
            if ( isset( $row->blob_data ) ) {
                $slotContents[$row->content_address] = $row->blob_data;
            }
 
            $contentCallback = function ( SlotRecord $slot ) use ( $slotContents, $queryFlags ) {
                $blob = null;
                if ( isset( $slotContents[$slot->getAddress()] ) ) {
                    $blob = $slotContents[$slot->getAddress()];
                    if ( $blob instanceof Content ) {
                        return $blob;
                    }
                }
                return $this->loadSlotContent( $slot, $blob, null, null, $queryFlags );
            };
 
            $slots[$row->role_name] = new SlotRecord( $row, $contentCallback );
        }
 
        if ( !isset( $slots[SlotRecord::MAIN] ) ) {
            $this->logger->error(
                __METHOD__ . ': Main slot of revision not found in database. See T212428.',
                [
                    'revid' => $revId,
                    'queryFlags' => $queryFlags,
                    'trace' => wfBacktrace( true )
                ]
            );
 
            throw new RevisionAccessException(
                'Main slot of revision not found in database. See T212428.'
            );
        }
 
        return $slots;
    }
 
    private function newRevisionSlots(
        $revId,
        $revisionRow,
        $slotRows,
        $queryFlags,
        Title $title
    ) {
        if ( $slotRows ) {
            $slots = new RevisionSlots(
                $this->constructSlotRecords( $revId, $slotRows, $queryFlags, $title )
            );
        } else {
            // XXX: do we need the same kind of caching here
            // that getKnownCurrentRevision uses (if $revId == page_latest?)
 
            $slots = new RevisionSlots( function () use( $revId, $queryFlags, $title ) {
                return $this->loadSlotRecords( $revId, $queryFlags, $title );
            } );
        }
 
        return $slots;
    }
 
    public function newRevisionFromArchiveRow(
        $row,
        $queryFlags = 0,
        Title $title = null,
        array $overrides = []
    ) {
        return $this->newRevisionFromArchiveRowAndSlots( $row, null, $queryFlags, $title, $overrides );
    }
 
    public function newRevisionFromRow(
        $row,
        $queryFlags = 0,
        Title $title = null,
        $fromCache = false
    ) {
        return $this->newRevisionFromRowAndSlots( $row, null, $queryFlags, $title, $fromCache );
    }
 
    public function newRevisionFromArchiveRowAndSlots(
        $row,
        $slots,
        $queryFlags = 0,
        Title $title = null,
        array $overrides = []
    ) {
        Assert::parameterType( \stdClass::class, $row, '$row' );
 
        // check second argument, since Revision::newFromArchiveRow had $overrides in that spot.
        Assert::parameterType( 'integer', $queryFlags, '$queryFlags' );
 
        if ( !$title && isset( $overrides['title'] ) ) {
            if ( !( $overrides['title'] instanceof Title ) ) {
                throw new MWException( 'title field override must contain a Title object.' );
            }
 
            $title = $overrides['title'];
        }
 
        if ( !isset( $title ) ) {
            if ( isset( $row->ar_namespace ) && isset( $row->ar_title ) ) {
                $title = Title::makeTitle( $row->ar_namespace, $row->ar_title );
            } else {
                throw new InvalidArgumentException(
                    'A Title or ar_namespace and ar_title must be given'
                );
            }
        }
 
        foreach ( $overrides as $key => $value ) {
            $field = "ar_$key";
            $row->$field = $value;
        }
 
        try {
            $user = User::newFromAnyId(
                $row->ar_user ?? null,
                $row->ar_user_text ?? null,
                $row->ar_actor ?? null,
                $this->dbDomain
            );
        } catch ( InvalidArgumentException $ex ) {
            wfWarn( __METHOD__ . ': ' . $title->getPrefixedDBkey() . ': ' . $ex->getMessage() );
            $user = new UserIdentityValue( 0, 'Unknown user', 0 );
        }
 
        if ( $user->getName() === '' ) {
            // T236624: If the user name is empty, force 'Unknown user',
            // even if the actor table has an entry for the empty user name.
            $user = new UserIdentityValue( 0, 'Unknown user', 0 );
        }
 
        $db = $this->getDBConnectionRefForQueryFlags( $queryFlags );
        // Legacy because $row may have come from self::selectFields()
        $comment = $this->commentStore->getCommentLegacy( $db, 'ar_comment', $row, true );
 
        if ( !( $slots instanceof RevisionSlots ) ) {
            $slots = $this->newRevisionSlots( $row->ar_rev_id, $row, $slots, $queryFlags, $title );
        }
 
        return new RevisionArchiveRecord( $title, $user, $comment, $row, $slots, $this->dbDomain );
    }
 
    public function newRevisionFromRowAndSlots(
        $row,
        $slots,
        $queryFlags = 0,
        Title $title = null,
        $fromCache = false
    ) {
        Assert::parameterType( \stdClass::class, $row, '$row' );
 
        if ( !$title ) {
            $pageId = (int)( $row->rev_page ?? 0 ); // XXX: fall back to page_id?
            $revId = (int)( $row->rev_id ?? 0 );
 
            $title = $this->getTitle( $pageId, $revId, $queryFlags );
        } else {
            $this->ensureRevisionRowMatchesTitle( $row, $title );
        }
 
        if ( !isset( $row->page_latest ) ) {
            $row->page_latest = $title->getLatestRevID();
            if ( $row->page_latest === 0 && $title->exists() ) {
                wfWarn( 'Encountered title object in limbo: ID ' . $title->getArticleID() );
            }
        }
 
        try {
            $user = User::newFromAnyId(
                $row->rev_user ?? null,
                $row->rev_user_text ?? null,
                $row->rev_actor ?? null,
                $this->dbDomain
            );
        } catch ( InvalidArgumentException $ex ) {
            wfWarn( __METHOD__ . ': ' . $title->getPrefixedDBkey() . ': ' . $ex->getMessage() );
            $user = new UserIdentityValue( 0, 'Unknown user', 0 );
        }
 
        $db = $this->getDBConnectionRefForQueryFlags( $queryFlags );
        // Legacy because $row may have come from self::selectFields()
        $comment = $this->commentStore->getCommentLegacy( $db, 'rev_comment', $row, true );
 
        if ( !( $slots instanceof RevisionSlots ) ) {
            $slots = $this->newRevisionSlots( $row->rev_id, $row, $slots, $queryFlags, $title );
        }
 
        // If this is a cached row, instantiate a cache-aware revision class to avoid stale data.
        if ( $fromCache ) {
            $rev = new RevisionStoreCacheRecord(
                function ( $revId ) use ( $queryFlags ) {
                    $db = $this->getDBConnectionRefForQueryFlags( $queryFlags );
                    return $this->fetchRevisionRowFromConds(
                        $db,
                        [ 'rev_id' => intval( $revId ) ]
                    );
                },
                $title, $user, $comment, $row, $slots, $this->dbDomain
            );
        } else {
            $rev = new RevisionStoreRecord(
                $title, $user, $comment, $row, $slots, $this->dbDomain );
        }
        return $rev;
    }
 
    private function ensureRevisionRowMatchesTitle( $row, Title $title, $context = [] ) {
        $revId = (int)( $row->rev_id ?? 0 );
        $revPageId = (int)( $row->rev_page ?? 0 ); // XXX: also check $row->page_id?
        $titlePageId = $title->getArticleID();
 
        // Avoid fatal error when the Title's ID changed, T246720
        if ( $revPageId && $titlePageId && $revPageId !== $titlePageId ) {
            $masterPageId = $title->getArticleID( Title::READ_LATEST );
            $masterLatest = $title->getLatestRevID( Title::READ_LATEST );
 
            if ( $revPageId === $masterPageId ) {
                $this->logger->warning(
                    "Encountered stale Title object",
                    [
                        'page_id_stale' => $titlePageId,
                        'page_id_reloaded' => $masterPageId,
                        'page_latest' => $masterLatest,
                        'rev_id' => $revId,
                        'trace' => wfBacktrace()
                    ] + $context
                );
            } else {
                throw new InvalidArgumentException(
                    "Revision $revId belongs to page ID $revPageId, "
                    . "the provided Title object belongs to page ID $masterPageId"
                );
            }
        }
    }
 
    public function newRevisionsFromBatch(
        $rows,
        array $options = [],
        $queryFlags = 0,
        Title $title = null
    ) {
        $result = new StatusValue();
        $archiveMode = $options['archive'] ?? false;
 
        if ( $archiveMode ) {
            $revIdField = 'ar_rev_id';
        } else {
            $revIdField = 'rev_id';
        }
 
        $rowsByRevId = [];
        $pageIdsToFetchTitles = [];
        $titlesByPageKey = [];
        foreach ( $rows as $row ) {
            if ( isset( $rowsByRevId[$row->$revIdField] ) ) {
                $result->warning(
                    'internalerror_info',
                    "Duplicate rows in newRevisionsFromBatch, $revIdField {$row->$revIdField}"
                );
            }
 
            // Attach a page key to the row, so we can find and reuse Title objects easily.
            $row->_page_key =
                $archiveMode ? $row->ar_namespace . ':' . $row->ar_title : $row->rev_page;
 
            if ( $title ) {
                if ( !$archiveMode && $row->rev_page != $title->getArticleID() ) {
                    throw new InvalidArgumentException(
                        "Revision {$row->$revIdField} doesn't belong to page "
                            . $title->getArticleID()
                    );
                }
 
                if ( $archiveMode
                    && ( $row->ar_namespace != $title->getNamespace()
                        || $row->ar_title !== $title->getDBkey() )
                ) {
                    throw new InvalidArgumentException(
                        "Revision {$row->$revIdField} doesn't belong to page "
                            . $title->getPrefixedDBkey()
                    );
                }
            } elseif ( !isset( $titlesByPageKey[ $row->_page_key ] ) ) {
                if ( isset( $row->page_namespace ) && isset( $row->page_title )
                    // This should always be true, but just in case we don't have a page_id
                    // set or it doesn't match rev_page, let's fetch the title again.
                    && isset( $row->page_id ) && isset( $row->rev_page )
                    && $row->rev_page === $row->page_id
                ) {
                    $titlesByPageKey[ $row->_page_key ] = Title::newFromRow( $row );
                } elseif ( $archiveMode ) {
                    // Can't look up deleted pages by ID, but we have namespace and title
                    $titlesByPageKey[ $row->_page_key ] =
                        Title::makeTitle( $row->ar_namespace, $row->ar_title );
                } else {
                    $pageIdsToFetchTitles[] = $row->rev_page;
                }
            }
            $rowsByRevId[$row->$revIdField] = $row;
        }
 
        if ( empty( $rowsByRevId ) ) {
            $result->setResult( true, [] );
            return $result;
        }
 
        // If the title is not supplied, batch-fetch Title objects.
        if ( $title ) {
            // same logic as for $row->_page_key above
            $pageKey = $archiveMode
                ? $title->getNamespace() . ':' . $title->getDBkey()
                : $title->getArticleID();
 
            $titlesByPageKey[$pageKey] = $title;
        } elseif ( !empty( $pageIdsToFetchTitles ) ) {
            // Note: when we fetch titles by ID, the page key is also the ID.
            // We should never get here if $archiveMode is true.
            Assert::invariant( !$archiveMode, 'Titles are not loaded by ID in archive mode.' );
 
            $pageIdsToFetchTitles = array_unique( $pageIdsToFetchTitles );
            foreach ( Title::newFromIDs( $pageIdsToFetchTitles ) as $t ) {
                $titlesByPageKey[$t->getArticleID()] = $t;
            }
        }
 
        // which method to use for creating RevisionRecords
        $newRevisionRecord = [
            $this,
            $archiveMode ? 'newRevisionFromArchiveRowAndSlots' : 'newRevisionFromRowAndSlots'
        ];
 
        if ( !isset( $options['slots'] ) ) {
            $result->setResult(
                true,
                array_map(
                    function ( $row )
                    use ( $queryFlags, $titlesByPageKey, $result, $newRevisionRecord, $revIdField ) {
                        try {
                            if ( !isset( $titlesByPageKey[$row->_page_key] ) ) {
                                $result->warning(
                                    'internalerror_info',
                                    "Couldn't find title for rev {$row->$revIdField} "
                                    . "(page key {$row->_page_key})"
                                );
                                return null;
                            }
                            return $newRevisionRecord( $row, null, $queryFlags,
                                $titlesByPageKey[ $row->_page_key ] );
                        } catch ( MWException $e ) {
                            $result->warning( 'internalerror_info', $e->getMessage() );
                            return null;
                        }
                    },
                    $rowsByRevId
                )
            );
            return $result;
        }
 
        $slotRowOptions = [
            'slots' => $options['slots'] ?? true,
            'blobs' => $options['content'] ?? false,
        ];
 
        if ( is_array( $slotRowOptions['slots'] )
            && !in_array( SlotRecord::MAIN, $slotRowOptions['slots'] )
        ) {
            // Make sure the main slot is always loaded, RevisionRecord requires this.
            $slotRowOptions['slots'][] = SlotRecord::MAIN;
        }
 
        $slotRowsStatus = $this->getSlotRowsForBatch( $rowsByRevId, $slotRowOptions, $queryFlags );
 
        $result->merge( $slotRowsStatus );
        $slotRowsByRevId = $slotRowsStatus->getValue();
 
        $result->setResult(
            true,
            array_map(
                function ( $row )
                use ( $slotRowsByRevId, $queryFlags, $titlesByPageKey, $result,
                    $revIdField, $newRevisionRecord
                ) {
                    if ( !isset( $slotRowsByRevId[$row->$revIdField] ) ) {
                        $result->warning(
                            'internalerror_info',
                            "Couldn't find slots for rev {$row->$revIdField}"
                        );
                        return null;
                    }
                    if ( !isset( $titlesByPageKey[$row->_page_key] ) ) {
                        $result->warning(
                            'internalerror_info',
                            "Couldn't find title for rev {$row->$revIdField} "
                                . "(page key {$row->_page_key})"
                        );
                        return null;
                    }
                    try {
                        return $newRevisionRecord(
                            $row,
                            new RevisionSlots(
                                $this->constructSlotRecords(
                                    $row->$revIdField,
                                    $slotRowsByRevId[$row->$revIdField],
                                    $queryFlags,
                                    $titlesByPageKey[$row->_page_key]
                                )
                            ),
                            $queryFlags,
                            $titlesByPageKey[$row->_page_key]
                        );
                    } catch ( MWException $e ) {
                        $result->warning( 'internalerror_info', $e->getMessage() );
                        return null;
                    }
                },
                $rowsByRevId
            )
        );
        return $result;
    }
 
    private function getSlotRowsForBatch(
        $rowsOrIds,
        array $options = [],
        $queryFlags = 0
    ) {
        $result = new StatusValue();
 
        $revIds = [];
        foreach ( $rowsOrIds as $row ) {
            if ( is_object( $row ) ) {
                $revIds[] = isset( $row->ar_rev_id ) ? (int)$row->ar_rev_id : (int)$row->rev_id;
            } else {
                $revIds[] = (int)$row;
            }
        }
 
        // Nothing to do.
        // Note that $rowsOrIds may not be "empty" even if $revIds is, e.g. if it's a ResultWrapper.
        if ( empty( $revIds ) ) {
            $result->setResult( true, [] );
            return $result;
        }
 
        // We need to set the `content` flag to join in content meta-data
        $slotQueryInfo = self::getSlotsQueryInfo( [ 'content' ] );
        $revIdField = $slotQueryInfo['keys']['rev_id'];
        $slotQueryConds = [ $revIdField => $revIds ];
 
        if ( isset( $options['slots'] ) && is_array( $options['slots'] ) ) {
            if ( empty( $options['slots'] ) ) {
                // Degenerate case: return no slots for each revision.
                $result->setResult( true, array_fill_keys( $revIds, [] ) );
                return $result;
            }
 
            $roleIdField = $slotQueryInfo['keys']['role_id'];
            $slotQueryConds[$roleIdField] = array_map( function ( $slot_name ) {
                return $this->slotRoleStore->getId( $slot_name );
            }, $options['slots'] );
        }
 
        $db = $this->getDBConnectionRefForQueryFlags( $queryFlags );
        $slotRows = $db->select(
            $slotQueryInfo['tables'],
            $slotQueryInfo['fields'],
            $slotQueryConds,
            __METHOD__,
            [],
            $slotQueryInfo['joins']
        );
 
        $slotContents = null;
        if ( $options['blobs'] ?? false ) {
            $blobAddresses = [];
            foreach ( $slotRows as $slotRow ) {
                $blobAddresses[] = $slotRow->content_address;
            }
            $slotContentFetchStatus = $this->blobStore
                ->getBlobBatch( $blobAddresses, $queryFlags );
            foreach ( $slotContentFetchStatus->getErrors() as $error ) {
                $result->warning( $error['message'], ...$error['params'] );
            }
            $slotContents = $slotContentFetchStatus->getValue();
        }
 
        $slotRowsByRevId = [];
        foreach ( $slotRows as $slotRow ) {
            if ( $slotContents === null ) {
                // nothing to do
            } elseif ( isset( $slotContents[$slotRow->content_address] ) ) {
                $slotRow->blob_data = $slotContents[$slotRow->content_address];
            } else {
                $result->warning(
                    'internalerror_info',
                    "Couldn't find blob data for rev {$slotRow->slot_revision_id}"
                );
                $slotRow->blob_data = null;
            }
 
            // conditional needed for SCHEMA_COMPAT_READ_OLD
            if ( !isset( $slotRow->role_name ) && isset( $slotRow->slot_role_id ) ) {
                $slotRow->role_name = $this->slotRoleStore->getName( (int)$slotRow->slot_role_id );
            }
 
            // conditional needed for SCHEMA_COMPAT_READ_OLD
            if ( !isset( $slotRow->model_name ) && isset( $slotRow->content_model ) ) {
                $slotRow->model_name = $this->contentModelStore->getName( (int)$slotRow->content_model );
            }
 
            $slotRowsByRevId[$slotRow->slot_revision_id][$slotRow->role_name] = $slotRow;
        }
 
        $result->setResult( true, $slotRowsByRevId );
        return $result;
    }
 
    public function getContentBlobsForBatch(
        $rowsOrIds,
        $slots = null,
        $queryFlags = 0
    ) {
        $result = $this->getSlotRowsForBatch(
            $rowsOrIds,
            [ 'slots' => $slots, 'blobs' => true ],
            $queryFlags
        );
 
        if ( $result->isOK() ) {
            // strip out all internal meta data that we don't want to expose
            foreach ( $result->value as $revId => $rowsByRole ) {
                foreach ( $rowsByRole as $role => $slotRow ) {
                    if ( is_array( $slots ) && !in_array( $role, $slots ) ) {
                        // In SCHEMA_COMPAT_READ_OLD mode we may get the main slot even
                        // if we didn't ask for it.
                        unset( $result->value[$revId][$role] );
                        continue;
                    }
 
                    $result->value[$revId][$role] = (object)[
                        'blob_data' => $slotRow->blob_data,
                        'model_name' => $slotRow->model_name,
                    ];
                }
            }
        }
 
        return $result;
    }
 
    public function newMutableRevisionFromArray(
        array $fields,
        $queryFlags = 0,
        Title $title = null
    ) {
        if ( !$title && isset( $fields['title'] ) ) {
            if ( !( $fields['title'] instanceof Title ) ) {
                throw new MWException( 'title field must contain a Title object.' );
            }
 
            $title = $fields['title'];
        }
 
        if ( !$title ) {
            $pageId = $fields['page'] ?? 0;
            $revId = $fields['id'] ?? 0;
 
            $title = $this->getTitle( $pageId, $revId, $queryFlags );
        }
 
        if ( !isset( $fields['page'] ) ) {
            $fields['page'] = $title->getArticleID( $queryFlags );
        }
 
        // if we have a content object, use it to set the model and type
        if ( !empty( $fields['content'] ) && !( $fields['content'] instanceof Content )
            && !is_array( $fields['content'] )
        ) {
            throw new MWException(
                'content field must contain a Content object or an array of Content objects.'
            );
        }
 
        if ( !empty( $fields['text_id'] ) ) {
            throw new MWException( 'The text_id field can not be used in MediaWiki 1.35 and later' );
        }
 
        if (
            isset( $fields['comment'] )
            && !( $fields['comment'] instanceof CommentStoreComment )
        ) {
            $commentData = $fields['comment_data'] ?? null;
 
            if ( $fields['comment'] instanceof Message ) {
                $fields['comment'] = CommentStoreComment::newUnsavedComment(
                    $fields['comment'],
                    $commentData
                );
            } else {
                $commentText = trim( strval( $fields['comment'] ) );
                $fields['comment'] = CommentStoreComment::newUnsavedComment(
                    $commentText,
                    $commentData
                );
            }
        }
 
        $revision = new MutableRevisionRecord( $title, $this->dbDomain );
 
        if ( isset( $fields['content'] ) ) {
            if ( is_array( $fields['content'] ) ) {
                $slotContent = $fields['content'];
            } else {
                $slotContent = [ SlotRecord::MAIN => $fields['content'] ];
            }
        } elseif ( isset( $fields['text'] ) ) {
            if ( isset( $fields['content_model'] ) ) {
                $model = $fields['content_model'];
            } else {
                $slotRoleHandler = $this->slotRoleRegistry->getRoleHandler( SlotRecord::MAIN );
                $model = $slotRoleHandler->getDefaultModel( $title );
            }
 
            $contentHandler = ContentHandler::getForModelID( $model );
            $content = $contentHandler->unserializeContent( $fields['text'] );
            $slotContent = [ SlotRecord::MAIN => $content ];
        } else {
            $slotContent = [];
        }
 
        foreach ( $slotContent as $role => $content ) {
            $revision->setContent( $role, $content );
        }
 
        $this->initializeMutableRevisionFromArray( $revision, $fields );
 
        return $revision;
    }
 
    private function initializeMutableRevisionFromArray(
        MutableRevisionRecord $record,
        array $fields
    ) {
        $user = null;
 
        // If a user is passed in, use it if possible. We cannot use a user from a
        // remote wiki with unsuppressed ids, due to issues described in T222212.
        if ( isset( $fields['user'] ) &&
            ( $fields['user'] instanceof UserIdentity ) &&
            ( $this->dbDomain === false ||
                ( !$fields['user']->getId() && !$fields['user']->getActorId() ) )
        ) {
            $user = $fields['user'];
        } else {
            $userID = isset( $fields['user'] ) && is_numeric( $fields['user'] ) ? $fields['user'] : null;
            try {
                $user = User::newFromAnyId(
                    $userID,
                    $fields['user_text'] ?? null,
                    $fields['actor'] ?? null,
                    $this->dbDomain
                );
            } catch ( InvalidArgumentException $ex ) {
                $user = null;
            }
        }
 
        if ( $user ) {
            $record->setUser( $user );
        }
 
        $timestamp = isset( $fields['timestamp'] )
            ? strval( $fields['timestamp'] )
            : MWTimestamp::now( TS_MW );
 
        $record->setTimestamp( $timestamp );
 
        if ( isset( $fields['page'] ) ) {
            $record->setPageId( intval( $fields['page'] ) );
        }
 
        if ( isset( $fields['id'] ) ) {
            $record->setId( intval( $fields['id'] ) );
        }
        if ( isset( $fields['parent_id'] ) ) {
            $record->setParentId( intval( $fields['parent_id'] ) );
        }
 
        if ( isset( $fields['sha1'] ) ) {
            $record->setSha1( $fields['sha1'] );
        }
 
        if ( isset( $fields['size'] ) ) {
            $record->setSize( intval( $fields['size'] ) );
        } elseif ( isset( $fields['len'] ) ) {
            $record->setSize( intval( $fields['len'] ) );
        }
 
        if ( isset( $fields['minor_edit'] ) ) {
            $record->setMinorEdit( intval( $fields['minor_edit'] ) !== 0 );
        }
        if ( isset( $fields['deleted'] ) ) {
            $record->setVisibility( intval( $fields['deleted'] ) );
        }
 
        if ( isset( $fields['comment'] ) ) {
            Assert::parameterType(
                CommentStoreComment::class,
                $fields['comment'],
                '$row[\'comment\']'
            );
            $record->setComment( $fields['comment'] );
        }
    }
 
    public function loadRevisionFromPageId( IDatabase $db, $pageid, $id = 0 ) {
        wfDeprecated( __METHOD__, '1.35' );
        $conds = [ 'rev_page' => intval( $pageid ), 'page_id' => intval( $pageid ) ];
        if ( $id ) {
            $conds['rev_id'] = intval( $id );
        } else {
            $conds[] = 'rev_id=page_latest';
        }
        return $this->loadRevisionFromConds( $db, $conds );
    }
 
    public function loadRevisionFromTitle( IDatabase $db, $title, $id = 0 ) {
        wfDeprecated( __METHOD__, '1.35' );
        if ( $id ) {
            $matchId = intval( $id );
        } else {
            $matchId = 'page_latest';
        }
 
        return $this->loadRevisionFromConds(
            $db,
            [
                "rev_id=$matchId",
                'page_namespace' => $title->getNamespace(),
                'page_title' => $title->getDBkey()
            ],
            0,
            $title
        );
    }
 
    public function loadRevisionFromTimestamp( IDatabase $db, $title, $timestamp ) {
        wfDeprecated( __METHOD__, '1.35' );
        return $this->loadRevisionFromConds( $db,
            [
                'rev_timestamp' => $db->timestamp( $timestamp ),
                'page_namespace' => $title->getNamespace(),
                'page_title' => $title->getDBkey()
            ],
            0,
            $title
        );
    }
 
    private function newRevisionFromConds(
        array $conditions,
        int $flags = IDBAccessObject::READ_NORMAL,
        Title $title = null,
        array $options = []
    ) {
        $db = $this->getDBConnectionRefForQueryFlags( $flags );
        $rev = $this->loadRevisionFromConds( $db, $conditions, $flags, $title, $options );
 
        $lb = $this->getDBLoadBalancer();
 
        // Make sure new pending/committed revision are visibile later on
        // within web requests to certain avoid bugs like T93866 and T94407.
        if ( !$rev
            && !( $flags & self::READ_LATEST )
            && $lb->hasStreamingReplicaServers()
            && $lb->hasOrMadeRecentMasterChanges()
        ) {
            $flags = self::READ_LATEST;
            $dbw = $this->getDBConnectionRef( DB_MASTER );
            $rev = $this->loadRevisionFromConds( $dbw, $conditions, $flags, $title, $options );
        }
 
        return $rev;
    }
 
    private function loadRevisionFromConds(
        IDatabase $db,
        array $conditions,
        int $flags = IDBAccessObject::READ_NORMAL,
        Title $title = null,
        array $options = []
    ) {
        $row = $this->fetchRevisionRowFromConds( $db, $conditions, $flags, $options );
        if ( $row ) {
            $rev = $this->newRevisionFromRow( $row, $flags, $title );
 
            return $rev;
        }
 
        return null;
    }
 
    private function checkDatabaseDomain( IDatabase $db ) {
        $dbDomain = $db->getDomainID();
        $storeDomain = $this->loadBalancer->resolveDomainID( $this->dbDomain );
        if ( $dbDomain === $storeDomain ) {
            return;
        }
 
        throw new MWException( "DB connection domain '$dbDomain' does not match '$storeDomain'" );
    }
 
    private function fetchRevisionRowFromConds(
        IDatabase $db,
        array $conditions,
        int $flags = IDBAccessObject::READ_NORMAL,
        array $options = []
    ) {
        $this->checkDatabaseDomain( $db );
 
        $revQuery = $this->getQueryInfo( [ 'page', 'user' ] );
        if ( ( $flags & self::READ_LOCKING ) == self::READ_LOCKING ) {
            $options[] = 'FOR UPDATE';
        }
        return $db->selectRow(
            $revQuery['tables'],
            $revQuery['fields'],
            $conditions,
            __METHOD__,
            $options,
            $revQuery['joins']
        );
    }
 
    public function getQueryInfo( $options = [] ) {
        $ret = [
            'tables' => [],
            'fields' => [],
            'joins'  => [],
        ];
 
        $ret['tables'][] = 'revision';
        $ret['fields'] = array_merge( $ret['fields'], [
            'rev_id',
            'rev_page',
            'rev_timestamp',
            'rev_minor_edit',
            'rev_deleted',
            'rev_len',
            'rev_parent_id',
            'rev_sha1',
        ] );
 
        $commentQuery = $this->commentStore->getJoin( 'rev_comment' );
        $ret['tables'] = array_merge( $ret['tables'], $commentQuery['tables'] );
        $ret['fields'] = array_merge( $ret['fields'], $commentQuery['fields'] );
        $ret['joins'] = array_merge( $ret['joins'], $commentQuery['joins'] );
 
        $actorQuery = $this->actorMigration->getJoin( 'rev_user' );
        $ret['tables'] = array_merge( $ret['tables'], $actorQuery['tables'] );
        $ret['fields'] = array_merge( $ret['fields'], $actorQuery['fields'] );
        $ret['joins'] = array_merge( $ret['joins'], $actorQuery['joins'] );
 
        if ( in_array( 'page', $options, true ) ) {
            $ret['tables'][] = 'page';
            $ret['fields'] = array_merge( $ret['fields'], [
                'page_namespace',
                'page_title',
                'page_id',
                'page_latest',
                'page_is_redirect',
                'page_len',
            ] );
            $ret['joins']['page'] = [ 'JOIN', [ 'page_id = rev_page' ] ];
        }
 
        if ( in_array( 'user', $options, true ) ) {
            $ret['tables'][] = 'user';
            $ret['fields'] = array_merge( $ret['fields'], [
                'user_name',
            ] );
            $u = $actorQuery['fields']['rev_user'];
            $ret['joins']['user'] = [ 'LEFT JOIN', [ "$u != 0", "user_id = $u" ] ];
        }
 
        if ( in_array( 'text', $options, true ) ) {
            throw new InvalidArgumentException(
                'The `text` option is no longer supported in MediaWiki 1.35 and later.'
            );
        }
 
        return $ret;
    }
 
    public function getSlotsQueryInfo( $options = [] ) {
        $ret = [
            'tables' => [],
            'fields' => [],
            'joins'  => [],
            'keys'  => [],
        ];
 
        $ret['keys']['rev_id'] = 'slot_revision_id';
        $ret['keys']['role_id'] = 'slot_role_id';
 
        $ret['tables'][] = 'slots';
        $ret['fields'] = array_merge( $ret['fields'], [
            'slot_revision_id',
            'slot_content_id',
            'slot_origin',
            'slot_role_id',
        ] );
 
        if ( in_array( 'role', $options, true ) ) {
            // Use left join to attach role name, so we still find the revision row even
            // if the role name is missing. This triggers a more obvious failure mode.
            $ret['tables'][] = 'slot_roles';
            $ret['joins']['slot_roles'] = [ 'LEFT JOIN', [ 'slot_role_id = role_id' ] ];
            $ret['fields'][] = 'role_name';
        }
 
        if ( in_array( 'content', $options, true ) ) {
            $ret['keys']['model_id'] = 'content_model';
 
            $ret['tables'][] = 'content';
            $ret['fields'] = array_merge( $ret['fields'], [
                'content_size',
                'content_sha1',
                'content_address',
                'content_model',
            ] );
            $ret['joins']['content'] = [ 'JOIN', [ 'slot_content_id = content_id' ] ];
 
            if ( in_array( 'model', $options, true ) ) {
                // Use left join to attach model name, so we still find the revision row even
                // if the model name is missing. This triggers a more obvious failure mode.
                $ret['tables'][] = 'content_models';
                $ret['joins']['content_models'] = [ 'LEFT JOIN', [ 'content_model = model_id' ] ];
                $ret['fields'][] = 'model_name';
            }
 
        }
 
        return $ret;
    }
 
    public function getArchiveQueryInfo() {
        $commentQuery = $this->commentStore->getJoin( 'ar_comment' );
        $actorQuery = $this->actorMigration->getJoin( 'ar_user' );
        $ret = [
            'tables' => [ 'archive' ] + $commentQuery['tables'] + $actorQuery['tables'],
            'fields' => [
                    'ar_id',
                    'ar_page_id',
                    'ar_namespace',
                    'ar_title',
                    'ar_rev_id',
                    'ar_timestamp',
                    'ar_minor_edit',
                    'ar_deleted',
                    'ar_len',
                    'ar_parent_id',
                    'ar_sha1',
                ] + $commentQuery['fields'] + $actorQuery['fields'],
            'joins' => $commentQuery['joins'] + $actorQuery['joins'],
        ];
 
        return $ret;
    }
 
    public function getRevisionSizes( array $revIds ) {
        $dbr = $this->getDBConnectionRef( DB_REPLICA );
        $revLens = [];
        if ( !$revIds ) {
            return $revLens; // empty
        }
 
        $res = $dbr->select(
            'revision',
            [ 'rev_id', 'rev_len' ],
            [ 'rev_id' => $revIds ],
            __METHOD__
        );
 
        foreach ( $res as $row ) {
            $revLens[$row->rev_id] = intval( $row->rev_len );
        }
 
        return $revLens;
    }
 
    public function listRevisionSizes( IDatabase $db, array $revIds ) {
        wfDeprecated( __METHOD__, '1.35' );
        return $this->getRevisionSizes( $revIds );
    }
 
    private function getRelativeRevision( RevisionRecord $rev, $flags, $dir ) {
        $op = $dir === 'next' ? '>' : '<';
        $sort = $dir === 'next' ? 'ASC' : 'DESC';
 
        if ( !$rev->getId() || !$rev->getPageId() ) {
            // revision is unsaved or otherwise incomplete
            return null;
        }
 
        if ( $rev instanceof RevisionArchiveRecord ) {
            // revision is deleted, so it's not part of the page history
            return null;
        }
 
        list( $dbType, ) = DBAccessObjectUtils::getDBOptions( $flags );
        $db = $this->getDBConnectionRef( $dbType, [ 'contributions' ] );
 
        $ts = $this->getTimestampFromId( $rev->getId(), $flags );
        if ( $ts === false ) {
            // XXX Should this be moved into getTimestampFromId?
            $ts = $db->selectField( 'archive', 'ar_timestamp',
                [ 'ar_rev_id' => $rev->getId() ], __METHOD__ );
            if ( $ts === false ) {
                // XXX Is this reachable? How can we have a page id but no timestamp?
                return null;
            }
        }
        $dbts = $db->addQuotes( $db->timestamp( $ts ) );
 
        $revId = $db->selectField( 'revision', 'rev_id',
            [
                'rev_page' => $rev->getPageId(),
                "rev_timestamp $op $dbts OR (rev_timestamp = $dbts AND rev_id $op {$rev->getId()})"
            ],
            __METHOD__,
            [
                'ORDER BY' => [ "rev_timestamp $sort", "rev_id $sort" ],
                'IGNORE INDEX' => 'rev_timestamp', // Probably needed for T159319
            ]
        );
 
        if ( $revId === false ) {
            return null;
        }
 
        return $this->getRevisionById( intval( $revId ) );
    }
 
    public function getPreviousRevision( RevisionRecord $rev, $flags = 0 ) {
        if ( $flags instanceof Title ) {
            // Old calling convention, we don't use Title here anymore
            wfDeprecated( __METHOD__ . ' with Title', '1.34' );
            $flags = 0;
        }
 
        return $this->getRelativeRevision( $rev, $flags, 'prev' );
    }
 
    public function getNextRevision( RevisionRecord $rev, $flags = 0 ) {
        if ( $flags instanceof Title ) {
            // Old calling convention, we don't use Title here anymore
            wfDeprecated( __METHOD__ . ' with Title', '1.34' );
            $flags = 0;
        }
 
        return $this->getRelativeRevision( $rev, $flags, 'next' );
    }
 
    private function getPreviousRevisionId( IDatabase $db, RevisionRecord $rev ) {
        $this->checkDatabaseDomain( $db );
 
        if ( $rev->getPageId() === null ) {
            return 0;
        }
        # Use page_latest if ID is not given
        if ( !$rev->getId() ) {
            $prevId = $db->selectField(
                'page', 'page_latest',
                [ 'page_id' => $rev->getPageId() ],
                __METHOD__
            );
        } else {
            $prevId = $db->selectField(
                'revision', 'rev_id',
                [ 'rev_page' => $rev->getPageId(), 'rev_id < ' . $rev->getId() ],
                __METHOD__,
                [ 'ORDER BY' => 'rev_id DESC' ]
            );
        }
        return intval( $prevId );
    }
 
    public function getTimestampFromId( $id, $flags = 0 ) {
        if ( $id instanceof Title ) {
            // Old deprecated calling convention supported for backwards compatibility
            $id = $flags;
            $flags = func_num_args() > 2 ? func_get_arg( 2 ) : 0;
        }
        $db = $this->getDBConnectionRefForQueryFlags( $flags );
 
        $timestamp =
            $db->selectField( 'revision', 'rev_timestamp', [ 'rev_id' => $id ], __METHOD__ );
 
        return ( $timestamp !== false ) ? MWTimestamp::convert( TS_MW, $timestamp ) : false;
    }
 
    public function countRevisionsByPageId( IDatabase $db, $id ) {
        $this->checkDatabaseDomain( $db );
 
        $row = $db->selectRow( 'revision',
            [ 'revCount' => 'COUNT(*)' ],
            [ 'rev_page' => $id ],
            __METHOD__
        );
        if ( $row ) {
            return intval( $row->revCount );
        }
        return 0;
    }
 
    public function countRevisionsByTitle( IDatabase $db, $title ) {
        $id = $title->getArticleID();
        if ( $id ) {
            return $this->countRevisionsByPageId( $db, $id );
        }
        return 0;
    }
 
    public function userWasLastToEdit( IDatabase $db, $pageId, $userId, $since ) {
        $this->checkDatabaseDomain( $db );
 
        if ( !$userId ) {
            return false;
        }
 
        $revQuery = $this->getQueryInfo();
        $res = $db->select(
            $revQuery['tables'],
            [
                'rev_user' => $revQuery['fields']['rev_user'],
            ],
            [
                'rev_page' => $pageId,
                'rev_timestamp > ' . $db->addQuotes( $db->timestamp( $since ) )
            ],
            __METHOD__,
            [ 'ORDER BY' => 'rev_timestamp ASC', 'LIMIT' => 50 ],
            $revQuery['joins']
        );
        foreach ( $res as $row ) {
            if ( $row->rev_user != $userId ) {
                return false;
            }
        }
        return true;
    }
 
    public function getKnownCurrentRevision( Title $title, $revId = 0 ) {
        $db = $this->getDBConnectionRef( DB_REPLICA );
 
        $revIdPassed = $revId;
        $pageId = $title->getArticleID();
 
        if ( !$pageId ) {
            return false;
        }
 
        if ( !$revId ) {
            $revId = $title->getLatestRevID();
        }
 
        if ( !$revId ) {
            wfWarn(
                'No latest revision known for page ' . $title->getPrefixedDBkey()
                . ' even though it exists with page ID ' . $pageId
            );
            return false;
        }
 
        // Load the row from cache if possible.  If not possible, populate the cache.
        // As a minor optimization, remember if this was a cache hit or miss.
        // We can sometimes avoid a database query later if this is a cache miss.
        $fromCache = true;
        $row = $this->cache->getWithSetCallback(
            // Page/rev IDs passed in from DB to reflect history merges
            $this->getRevisionRowCacheKey( $db, $pageId, $revId ),
            WANObjectCache::TTL_WEEK,
            function ( $curValue, &$ttl, array &$setOpts ) use (
                $db, $revId, &$fromCache
            ) {
                $setOpts += Database::getCacheSetOptions( $db );
                $row = $this->fetchRevisionRowFromConds( $db, [ 'rev_id' => intval( $revId ) ] );
                if ( $row ) {
                    $fromCache = false;
                }
                return $row; // don't cache negatives
            }
        );
 
        // Reflect revision deletion and user renames.
        if ( $row ) {
            $this->ensureRevisionRowMatchesTitle( $row, $title, [
                'from_cache_flag' => $fromCache,
                'page_id_initial' => $pageId,
                'rev_id_used' => $revId,
                'rev_id_requested' => $revIdPassed,
            ] );
 
            return $this->newRevisionFromRow( $row, 0, $title, $fromCache );
        } else {
            return false;
        }
    }
 
    public function getFirstRevision(
        LinkTarget $title,
        int $flags = IDBAccessObject::READ_NORMAL
    ): ?RevisionRecord {
        $titleObj = Title::newFromLinkTarget( $title ); // TODO: eventually we shouldn't need a title
        return $this->newRevisionFromConds(
            [
                'page_namespace' => $title->getNamespace(),
                'page_title' => $title->getDBkey()
            ],
            $flags,
            $titleObj,
            [
                'ORDER BY' => [ 'rev_timestamp ASC', 'rev_id ASC' ],
                'IGNORE INDEX' => [ 'revision' => 'rev_timestamp' ], // See T159319
            ]
        );
    }
 
    private function getRevisionRowCacheKey( IDatabase $db, $pageId, $revId ) {
        return $this->cache->makeGlobalKey(
            self::ROW_CACHE_KEY,
            $db->getDomainID(),
            $pageId,
            $revId
        );
    }
 
    private function assertRevisionParameter( $paramName, $pageId, RevisionRecord $rev = null ) {
        if ( $rev ) {
            if ( $rev->getId() === null ) {
                throw new InvalidArgumentException( "Unsaved {$paramName} revision passed" );
            }
            if ( $rev->getPageId() !== $pageId ) {
                throw new InvalidArgumentException(
                    "Revision {$rev->getId()} doesn't belong to page {$pageId}"
                );
            }
        }
    }
 
    private function getRevisionLimitConditions(
        IDatabase $dbr,
        RevisionRecord $old = null,
        RevisionRecord $new = null,
        $options = []
    ) {
        $options = (array)$options;
        $oldCmp = '>';
        $newCmp = '<';
        if ( in_array( 'include_old', $options ) ) {
            $oldCmp = '>=';
        }
        if ( in_array( 'include_new', $options ) ) {
            $newCmp = '<=';
        }
        if ( in_array( 'include_both', $options ) ) {
            $oldCmp = '>=';
            $newCmp = '<=';
        }
 
        $conds = [];
        if ( $old ) {
            $oldTs = $dbr->addQuotes( $dbr->timestamp( $old->getTimestamp() ) );
            $conds[] = "(rev_timestamp = {$oldTs} AND rev_id {$oldCmp} {$old->getId()}) " .
                "OR rev_timestamp > {$oldTs}";
        }
        if ( $new ) {
            $newTs = $dbr->addQuotes( $dbr->timestamp( $new->getTimestamp() ) );
            $conds[] = "(rev_timestamp = {$newTs} AND rev_id {$newCmp} {$new->getId()}) " .
                "OR rev_timestamp < {$newTs}";
        }
        return $conds;
    }
 
    public function getRevisionIdsBetween(
        int $pageId,
        RevisionRecord $old = null,
        RevisionRecord $new = null,
        ?int $max = null,
        $options = [],
        ?string $order = null,
        int $flags = IDBAccessObject::READ_NORMAL
    ) : array {
        $this->assertRevisionParameter( 'old', $pageId, $old );
        $this->assertRevisionParameter( 'new', $pageId, $new );
 
        $options = (array)$options;
        $includeOld = in_array( 'include_old', $options ) ||
            in_array( 'include_both', $options );
        $includeNew = in_array( 'include_new', $options ) ||
            in_array( 'include_both', $options );
 
        // No DB query needed if old and new are the same revision.
        // Can't check for consecutive revisions with 'getParentId' for a similar
        // optimization as edge cases exist when there are revisions between
        // a revision and it's parent. See T185167 for more details.
        if ( $old && $new && $new->getId() === $old->getId() ) {
            return $includeOld || $includeNew ? [ $new->getId() ] : [];
        }
 
        $db = $this->getDBConnectionRefForQueryFlags( $flags );
        $conds = array_merge(
            [
                'rev_page' => $pageId,
                $db->bitAnd( 'rev_deleted', RevisionRecord::DELETED_TEXT ) . ' = 0'
            ],
            $this->getRevisionLimitConditions( $db, $old, $new, $options )
        );
 
        $queryOptions = [];
        if ( $order !== null ) {
            $queryOptions['ORDER BY'] = [ "rev_timestamp $order", "rev_id $order" ];
        }
        if ( $max !== null ) {
            $queryOptions['LIMIT'] = $max + 1; // extra to detect truncation
        }
 
        $values = $db->selectFieldValues(
            'revision',
            'rev_id',
            $conds,
            __METHOD__,
            $queryOptions
        );
        return array_map( 'intval', $values );
    }
 
    public function getAuthorsBetween(
        $pageId,
        RevisionRecord $old = null,
        RevisionRecord $new = null,
        User $user = null,
        $max = null,
        $options = []
    ) {
        $this->assertRevisionParameter( 'old', $pageId, $old );
        $this->assertRevisionParameter( 'new', $pageId, $new );
        $options = (array)$options;
 
        // No DB query needed if old and new are the same revision.
        // Can't check for consecutive revisions with 'getParentId' for a similar
        // optimization as edge cases exist when there are revisions between
        //a revision and it's parent. See T185167 for more details.
        if ( $old && $new && $new->getId() === $old->getId() ) {
            if ( empty( $options ) ) {
                return [];
            } else {
                return $user ? [ $new->getUser( RevisionRecord::FOR_PUBLIC, $user ) ] : [ $new->getUser() ];
            }
        }
 
        $dbr = $this->getDBConnectionRef( DB_REPLICA );
        $conds = array_merge(
            [
                'rev_page' => $pageId,
                $dbr->bitAnd( 'rev_deleted', RevisionRecord::DELETED_USER ) . " = 0"
            ],
            $this->getRevisionLimitConditions( $dbr, $old, $new, $options )
        );
 
        $queryOpts = [ 'DISTINCT' ];
        if ( $max !== null ) {
            $queryOpts['LIMIT'] = $max + 1;
        }
 
        $actorQuery = $this->actorMigration->getJoin( 'rev_user' );
        return array_map( function ( $row ) {
            return new UserIdentityValue( (int)$row->rev_user, $row->rev_user_text, (int)$row->rev_actor );
        }, iterator_to_array( $dbr->select(
            array_merge( [ 'revision' ], $actorQuery['tables'] ),
            $actorQuery['fields'],
            $conds, __METHOD__,
            $queryOpts,
            $actorQuery['joins']
        ) ) );
    }
 
    public function countAuthorsBetween(
        $pageId,
        RevisionRecord $old = null,
        RevisionRecord $new = null,
        User $user = null,
        $max = null,
        $options = []
    ) {
        // TODO: Implement with a separate query to avoid cost of selecting unneeded fields
        // and creation of UserIdentity stuff.
        return count( $this->getAuthorsBetween( $pageId, $old, $new, $user, $max, $options ) );
    }
 
    public function countRevisionsBetween(
        $pageId,
        RevisionRecord $old = null,
        RevisionRecord $new = null,
        $max = null,
        $options = []
    ) {
        $this->assertRevisionParameter( 'old', $pageId, $old );
        $this->assertRevisionParameter( 'new', $pageId, $new );
 
        // No DB query needed if old and new are the same revision.
        // Can't check for consecutive revisions with 'getParentId' for a similar
        // optimization as edge cases exist when there are revisions between
        //a revision and it's parent. See T185167 for more details.
        if ( $old && $new && $new->getId() === $old->getId() ) {
            return 0;
        }
 
        $dbr = $this->getDBConnectionRef( DB_REPLICA );
        $conds = array_merge(
            [
                'rev_page' => $pageId,
                $dbr->bitAnd( 'rev_deleted', RevisionRecord::DELETED_TEXT ) . " = 0"
            ],
            $this->getRevisionLimitConditions( $dbr, $old, $new, $options )
        );
        if ( $max !== null ) {
            return $dbr->selectRowCount( 'revision', '1',
                $conds,
                __METHOD__,
                [ 'LIMIT' => $max + 1 ] // extra to detect truncation
            );
        } else {
            return (int)$dbr->selectField( 'revision', 'count(*)', $conds, __METHOD__ );
        }
    }
 
    // TODO: move relevant methods from Title here, e.g. getFirstRevision, isBigDeletion, etc.
}
 
class_alias( RevisionStore::class, 'MediaWiki\Storage\RevisionStore' );