wikimedia / mediawiki

		list( $index, $options, $fallbackIndex, $fallbackOptions ) =

			DBAccessObjectUtils::getDBOptions( $flags );

		if ( !$row ) {

			// Text data is immutable; check replica DBs first.

			$row = wfGetDB( $index )->selectRow(

				'text',

				[ 'old_text', 'old_flags' ],

				[ 'old_id' => $textId ],

				__METHOD__,

				$options

			);

		}

		// Fallback to DB_MASTER in some cases if the row was not found

		if ( !$row && $fallbackIndex !== null ) {

		}

		// Fallback to DB_MASTER in some cases if the row was not found

		if ( !$row && $fallbackIndex !== null ) {

			// Use FOR UPDATE if it was used to fetch this revision. This avoids missing the row

			// due to REPEATABLE-READ. Also fallback to the master if READ_LATEST is provided.

			$row = wfGetDB( $fallbackIndex )->selectRow(

				'text',

				[ 'old_text', 'old_flags' ],

				[ 'old_id' => $textId ],

				__METHOD__,

				$fallbackOptions

			);

		}

		if ( !$row ) {

			wfDebugLog( 'Revision', "No text row with ID '$textId' (revision {$this->getId()})." );