From: Aaron Schulz <aschulz@wikimedia.org>
Date: Thu, 20 Jun 2019 22:17:22 +0000 (+0100)
Subject: rdbms: make implement IResultWrapper directly instead of via inheritence
X-Git-Tag: 1.34.0-rc.0~1175^2
X-Git-Url: http://git.cyclocoop.org/%22%20.%20generer_url_ecrire%28%22brouteur%22%2C%28%24id_rubrique%20?a=commitdiff_plain;h=a830c14d0b5c572709817ae7155a0d0ae5939436;p=lhc%2Fweb%2Fwiklou.git

rdbms: make implement IResultWrapper directly instead of via inheritence

Change-Id: If1b15c0c21d0ee336025fb99f47fc19ddf1d5435
---

diff --git a/includes/db/DatabaseOracle.php b/includes/db/DatabaseOracle.php
index c716e4d047..a123d00f27 100644
--- a/includes/db/DatabaseOracle.php
+++ b/includes/db/DatabaseOracle.php
@@ -253,11 +253,7 @@ class DatabaseOracle extends Database {
 	 * @param IResultWrapper|ORAResult $res
 	 */
 	function freeResult( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		$res->free();
+		ResultWrapper::unwrap( $res )->free();
 	}
 
 	/**
@@ -265,11 +261,7 @@ class DatabaseOracle extends Database {
 	 * @return stdClass|bool
 	 */
 	function fetchObject( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return $res->fetchObject();
+		return ResultWrapper::unwrap( $res )->fetchObject();
 	}
 
 	/**
@@ -277,11 +269,7 @@ class DatabaseOracle extends Database {
 	 * @return stdClass|bool
 	 */
 	function fetchRow( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return $res->fetchRow();
+		return ResultWrapper::unwrap( $res )->fetchRow();
 	}
 
 	/**
@@ -289,11 +277,7 @@ class DatabaseOracle extends Database {
 	 * @return int
 	 */
 	function numRows( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return $res->numRows();
+		return ResultWrapper::unwrap( $res )->numRows();
 	}
 
 	/**
@@ -301,11 +285,7 @@ class DatabaseOracle extends Database {
 	 * @return int
 	 */
 	function numFields( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return $res->numFields();
+		return ResultWrapper::unwrap( $res )->numFields();
 	}
 
 	function fieldName( $stmt, $n ) {
@@ -326,7 +306,7 @@ class DatabaseOracle extends Database {
 		if ( $res instanceof ORAResult ) {
 			$res->seek( $row );
 		} else {
-			$res->result->seek( $row );
+			ResultWrapper::unwrap( $res )->seek( $row );
 		}
 	}
 
diff --git a/includes/libs/rdbms/database/Database.php b/includes/libs/rdbms/database/Database.php
index dfad922b29..9233e13c9d 100644
--- a/includes/libs/rdbms/database/Database.php
+++ b/includes/libs/rdbms/database/Database.php
@@ -994,8 +994,8 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 	 * For SELECT queries, this returns either:
 	 *   - a) A driver-specific value/resource, only on success. This can be iterated
 	 *        over by calling fetchObject()/fetchRow() until there are no more rows.
-	 *        Alternatively, the result can be passed to resultObject() to obtain a
-	 *        ResultWrapper instance which can then be iterated over via "foreach".
+	 *        Alternatively, the result can be passed to resultObject() to obtain an
+	 *        IResultWrapper instance which can then be iterated over via "foreach".
 	 *   - b) False, on any query failure
 	 *
 	 * For non-SELECT queries, this returns either:
@@ -4185,9 +4185,8 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 	abstract protected function fetchAffectedRowCount();
 
 	/**
-	 * Take the result from a query, and wrap it in a ResultWrapper if
-	 * necessary. Boolean values are passed through as is, to indicate success
-	 * of write queries or failure.
+	 * Take a query result and wrap it in an iterable result wrapper if necessary.
+	 * Booleans are passed through as-is to indicate success/failure of write queries.
 	 *
 	 * Once upon a time, Database::query() returned a bare MySQL result
 	 * resource, and it was necessary to call this function to convert it to
@@ -4199,12 +4198,11 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 	 */
 	protected function resultObject( $result ) {
 		if ( !$result ) {
-			return false;
-		} elseif ( $result instanceof ResultWrapper ) {
+			return false; // failed query
+		} elseif ( $result instanceof IResultWrapper ) {
 			return $result;
 		} elseif ( $result === true ) {
-			// Successful write query
-			return $result;
+			return $result; // succesful write query
 		} else {
 			return new ResultWrapper( $this, $result );
 		}
diff --git a/includes/libs/rdbms/database/DatabaseMssql.php b/includes/libs/rdbms/database/DatabaseMssql.php
index 50aaff28d4..69174f96fa 100644
--- a/includes/libs/rdbms/database/DatabaseMssql.php
+++ b/includes/libs/rdbms/database/DatabaseMssql.php
@@ -229,11 +229,7 @@ class DatabaseMssql extends Database {
 	}
 
 	public function freeResult( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		sqlsrv_free_stmt( $res );
+		sqlsrv_free_stmt( ResultWrapper::unwrap( $res ) );
 	}
 
 	/**
@@ -258,12 +254,9 @@ class DatabaseMssql extends Database {
 	 * @return int
 	 */
 	public function numRows( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
+		$res = ResultWrapper::unwrap( $res );
 
 		$ret = sqlsrv_num_rows( $res );
-
 		if ( $ret === false ) {
 			// we cannot get an amount of rows from this cursor type
 			// has_rows returns bool true/false if the result has rows
@@ -278,11 +271,7 @@ class DatabaseMssql extends Database {
 	 * @return int
 	 */
 	public function numFields( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return sqlsrv_num_fields( $res );
+		return sqlsrv_num_fields( ResultWrapper::unwrap( $res ) );
 	}
 
 	/**
@@ -291,11 +280,7 @@ class DatabaseMssql extends Database {
 	 * @return int
 	 */
 	public function fieldName( $res, $n ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return sqlsrv_field_metadata( $res )[$n]['Name'];
+		return sqlsrv_field_metadata( ResultWrapper::unwrap( $res ) )[$n]['Name'];
 	}
 
 	/**
@@ -730,7 +715,7 @@ class DatabaseMssql extends Database {
 			}
 			$this->scrollableCursor = true;
 
-			if ( $ret instanceof ResultWrapper && !is_null( $identity ) ) {
+			if ( $ret instanceof IResultWrapper && !is_null( $identity ) ) {
 				// Then we want to get the identity column value we were assigned and save it off
 				$row = $ret->fetchObject();
 				if ( is_object( $row ) ) {
diff --git a/includes/libs/rdbms/database/DatabaseMysqlBase.php b/includes/libs/rdbms/database/DatabaseMysqlBase.php
index b3af8ad454..417b464b42 100644
--- a/includes/libs/rdbms/database/DatabaseMysqlBase.php
+++ b/includes/libs/rdbms/database/DatabaseMysqlBase.php
@@ -241,11 +241,8 @@ abstract class DatabaseMysqlBase extends Database {
 	 * @throws DBUnexpectedError
 	 */
 	public function freeResult( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
 		Wikimedia\suppressWarnings();
-		$ok = $this->mysqlFreeResult( $res );
+		$ok = $this->mysqlFreeResult( ResultWrapper::unwrap( $res ) );
 		Wikimedia\restoreWarnings();
 		if ( !$ok ) {
 			throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
@@ -266,11 +263,8 @@ abstract class DatabaseMysqlBase extends Database {
 	 * @throws DBUnexpectedError
 	 */
 	public function fetchObject( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
 		Wikimedia\suppressWarnings();
-		$row = $this->mysqlFetchObject( $res );
+		$row = $this->mysqlFetchObject( ResultWrapper::unwrap( $res ) );
 		Wikimedia\restoreWarnings();
 
 		$errno = $this->lastErrno();
@@ -302,11 +296,8 @@ abstract class DatabaseMysqlBase extends Database {
 	 * @throws DBUnexpectedError
 	 */
 	public function fetchRow( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
 		Wikimedia\suppressWarnings();
-		$row = $this->mysqlFetchArray( $res );
+		$row = $this->mysqlFetchArray( ResultWrapper::unwrap( $res ) );
 		Wikimedia\restoreWarnings();
 
 		$errno = $this->lastErrno();
@@ -338,12 +329,13 @@ abstract class DatabaseMysqlBase extends Database {
 	 * @return int
 	 */
 	function numRows( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
+		if ( is_bool( $res ) ) {
+			$n = 0;
+		} else {
+			Wikimedia\suppressWarnings();
+			$n = $this->mysqlNumRows( ResultWrapper::unwrap( $res ) );
+			Wikimedia\restoreWarnings();
 		}
-		Wikimedia\suppressWarnings();
-		$n = !is_bool( $res ) ? $this->mysqlNumRows( $res ) : 0;
-		Wikimedia\restoreWarnings();
 
 		// Unfortunately, mysql_num_rows does not reset the last errno.
 		// We are not checking for any errors here, since
@@ -366,11 +358,7 @@ abstract class DatabaseMysqlBase extends Database {
 	 * @return int
 	 */
 	public function numFields( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return $this->mysqlNumFields( $res );
+		return $this->mysqlNumFields( ResultWrapper::unwrap( $res ) );
 	}
 
 	/**
@@ -387,11 +375,7 @@ abstract class DatabaseMysqlBase extends Database {
 	 * @return string
 	 */
 	public function fieldName( $res, $n ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return $this->mysqlFieldName( $res, $n );
+		return $this->mysqlFieldName( ResultWrapper::unwrap( $res ), $n );
 	}
 
 	/**
@@ -410,11 +394,7 @@ abstract class DatabaseMysqlBase extends Database {
 	 * @return string
 	 */
 	public function fieldType( $res, $n ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return $this->mysqlFieldType( $res, $n );
+		return $this->mysqlFieldType( ResultWrapper::unwrap( $res ), $n );
 	}
 
 	/**
@@ -432,11 +412,7 @@ abstract class DatabaseMysqlBase extends Database {
 	 * @return bool
 	 */
 	public function dataSeek( $res, $row ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return $this->mysqlDataSeek( $res, $row );
+		return $this->mysqlDataSeek( ResultWrapper::unwrap( $res ), $row );
 	}
 
 	/**
@@ -606,9 +582,9 @@ abstract class DatabaseMysqlBase extends Database {
 		if ( !$res ) {
 			return false;
 		}
-		$n = $this->mysqlNumFields( $res->result );
+		$n = $this->mysqlNumFields( ResultWrapper::unwrap( $res ) );
 		for ( $i = 0; $i < $n; $i++ ) {
-			$meta = $this->mysqlFetchField( $res->result, $i );
+			$meta = $this->mysqlFetchField( ResultWrapper::unwrap( $res ), $i );
 			if ( $field == $meta->name ) {
 				return new MySQLField( $meta );
 			}
diff --git a/includes/libs/rdbms/database/DatabasePostgres.php b/includes/libs/rdbms/database/DatabasePostgres.php
index 92eac90a16..08987d98dd 100644
--- a/includes/libs/rdbms/database/DatabasePostgres.php
+++ b/includes/libs/rdbms/database/DatabasePostgres.php
@@ -274,11 +274,8 @@ class DatabasePostgres extends Database {
 	}
 
 	public function freeResult( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
 		Wikimedia\suppressWarnings();
-		$ok = pg_free_result( $res );
+		$ok = pg_free_result( ResultWrapper::unwrap( $res ) );
 		Wikimedia\restoreWarnings();
 		if ( !$ok ) {
 			throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
@@ -286,11 +283,8 @@ class DatabasePostgres extends Database {
 	}
 
 	public function fetchObject( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
 		Wikimedia\suppressWarnings();
-		$row = pg_fetch_object( $res );
+		$row = pg_fetch_object( ResultWrapper::unwrap( $res ) );
 		Wikimedia\restoreWarnings();
 		# @todo FIXME: HACK HACK HACK HACK debug
 
@@ -308,11 +302,8 @@ class DatabasePostgres extends Database {
 	}
 
 	public function fetchRow( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
 		Wikimedia\suppressWarnings();
-		$row = pg_fetch_array( $res );
+		$row = pg_fetch_array( ResultWrapper::unwrap( $res ) );
 		Wikimedia\restoreWarnings();
 
 		$conn = $this->getBindingHandle();
@@ -331,11 +322,8 @@ class DatabasePostgres extends Database {
 			return 0;
 		}
 
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
 		Wikimedia\suppressWarnings();
-		$n = pg_num_rows( $res );
+		$n = pg_num_rows( ResultWrapper::unwrap( $res ) );
 		Wikimedia\restoreWarnings();
 
 		$conn = $this->getBindingHandle();
@@ -350,19 +338,11 @@ class DatabasePostgres extends Database {
 	}
 
 	public function numFields( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return pg_num_fields( $res );
+		return pg_num_fields( ResultWrapper::unwrap( $res ) );
 	}
 
 	public function fieldName( $res, $n ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return pg_field_name( $res, $n );
+		return pg_field_name( ResultWrapper::unwrap( $res ), $n );
 	}
 
 	public function insertId() {
@@ -372,11 +352,7 @@ class DatabasePostgres extends Database {
 	}
 
 	public function dataSeek( $res, $row ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return pg_result_seek( $res, $row );
+		return pg_result_seek( ResultWrapper::unwrap( $res ), $row );
 	}
 
 	public function lastError() {
@@ -1307,11 +1283,7 @@ SQL;
 	 * @return string
 	 */
 	public function fieldType( $res, $index ) {
-		if ( $res instanceof ResultWrapper ) {
-			$res = $res->result;
-		}
-
-		return pg_field_type( $res, $index );
+		return pg_field_type( ResultWrapper::unwrap( $res ), $index );
 	}
 
 	public function encodeBlob( $b ) {
diff --git a/includes/libs/rdbms/database/DatabaseSqlite.php b/includes/libs/rdbms/database/DatabaseSqlite.php
index c1a3ab5829..c875e56684 100644
--- a/includes/libs/rdbms/database/DatabaseSqlite.php
+++ b/includes/libs/rdbms/database/DatabaseSqlite.php
@@ -355,9 +355,9 @@ class DatabaseSqlite extends Database {
 			return false;
 		}
 
-		$r = $res instanceof ResultWrapper ? $res->result : $res;
-		$this->lastAffectedRowCount = $r->rowCount();
-		$res = new ResultWrapper( $this, $r->fetchAll() );
+		$resource = ResultWrapper::unwrap( $res );
+		$this->lastAffectedRowCount = $resource->rowCount();
+		$res = new ResultWrapper( $this, $resource->fetchAll() );
 
 		return $res;
 	}
@@ -367,9 +367,7 @@ class DatabaseSqlite extends Database {
 	 */
 	function freeResult( $res ) {
 		if ( $res instanceof ResultWrapper ) {
-			$res->result = null;
-		} else {
-			$res = null;
+			$res->free();
 		}
 	}
 
@@ -378,15 +376,11 @@ class DatabaseSqlite extends Database {
 	 * @return stdClass|bool
 	 */
 	function fetchObject( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$r =& $res->result;
-		} else {
-			$r =& $res;
-		}
+		$resource =& ResultWrapper::unwrap( $res );
 
-		$cur = current( $r );
+		$cur = current( $resource );
 		if ( is_array( $cur ) ) {
-			next( $r );
+			next( $resource );
 			$obj = new stdClass;
 			foreach ( $cur as $k => $v ) {
 				if ( !is_numeric( $k ) ) {
@@ -405,14 +399,10 @@ class DatabaseSqlite extends Database {
 	 * @return array|bool
 	 */
 	function fetchRow( $res ) {
-		if ( $res instanceof ResultWrapper ) {
-			$r =& $res->result;
-		} else {
-			$r =& $res;
-		}
-		$cur = current( $r );
+		$resource =& ResultWrapper::unwrap( $res );
+		$cur = current( $resource );
 		if ( is_array( $cur ) ) {
-			next( $r );
+			next( $resource );
 
 			return $cur;
 		}
@@ -428,9 +418,9 @@ class DatabaseSqlite extends Database {
 	 */
 	function numRows( $res ) {
 		// false does not implement Countable
-		$r = $res instanceof ResultWrapper ? $res->result : $res;
+		$resource = ResultWrapper::unwrap( $res );
 
-		return is_array( $r ) ? count( $r ) : 0;
+		return is_array( $resource ) ? count( $resource ) : 0;
 	}
 
 	/**
@@ -438,10 +428,10 @@ class DatabaseSqlite extends Database {
 	 * @return int
 	 */
 	function numFields( $res ) {
-		$r = $res instanceof ResultWrapper ? $res->result : $res;
-		if ( is_array( $r ) && count( $r ) > 0 ) {
+		$resource = ResultWrapper::unwrap( $res );
+		if ( is_array( $resource ) && count( $resource ) > 0 ) {
 			// The size of the result array is twice the number of fields. (T67578)
-			return count( $r[0] ) / 2;
+			return count( $resource[0] ) / 2;
 		} else {
 			// If the result is empty return 0
 			return 0;
@@ -454,9 +444,9 @@ class DatabaseSqlite extends Database {
 	 * @return bool
 	 */
 	function fieldName( $res, $n ) {
-		$r = $res instanceof ResultWrapper ? $res->result : $res;
-		if ( is_array( $r ) ) {
-			$keys = array_keys( $r[0] );
+		$resource = ResultWrapper::unwrap( $res );
+		if ( is_array( $resource ) ) {
+			$keys = array_keys( $resource[0] );
 
 			return $keys[$n];
 		}
@@ -495,15 +485,11 @@ class DatabaseSqlite extends Database {
 	 * @param int $row
 	 */
 	function dataSeek( $res, $row ) {
-		if ( $res instanceof ResultWrapper ) {
-			$r =& $res->result;
-		} else {
-			$r =& $res;
-		}
-		reset( $r );
+		$resource =& ResultWrapper::unwrap( $res );
+		reset( $resource );
 		if ( $row > 0 ) {
 			for ( $i = 0; $i < $row; $i++ ) {
-				next( $r );
+				next( $resource );
 			}
 		}
 	}
diff --git a/includes/libs/rdbms/database/resultwrapper/FakeResultWrapper.php b/includes/libs/rdbms/database/resultwrapper/FakeResultWrapper.php
index 2ca3d7d51b..1094fafc96 100644
--- a/includes/libs/rdbms/database/resultwrapper/FakeResultWrapper.php
+++ b/includes/libs/rdbms/database/resultwrapper/FakeResultWrapper.php
@@ -8,21 +8,29 @@ use stdClass;
  * Overloads the relevant methods of the real ResultsWrapper so it
  * doesn't go anywhere near an actual database.
  */
-class FakeResultWrapper extends ResultWrapper {
-	/** @var stdClass[]|array[] $result */
+class FakeResultWrapper implements IResultWrapper {
+	/** @var stdClass[]|array[] */
+	protected $result;
+
+	/** @var int */
+	protected $pos = 0;
 
 	/**
-	 * @param stdClass[]|array[] $rows
+	 * @param stdClass[]|array[]|FakeResultWrapper $result
 	 */
-	function __construct( array $rows ) {
-		parent::__construct( null, $rows );
+	public function __construct( $result ) {
+		if ( $result instanceof self ) {
+			$this->result = $result->result;
+		} else {
+			$this->result = $result;
+		}
 	}
 
-	function numRows() {
+	public function numRows() {
 		return count( $this->result );
 	}
 
-	function fetchObject() {
+	public function fetchObject() {
 		$current = $this->current();
 
 		$this->next();
@@ -30,7 +38,7 @@ class FakeResultWrapper extends ResultWrapper {
 		return $current;
 	}
 
-	function fetchRow() {
+	public function fetchRow() {
 		$row = $this->valid() ? $this->result[$this->pos] : false;
 
 		$this->next();
@@ -38,35 +46,35 @@ class FakeResultWrapper extends ResultWrapper {
 		return is_object( $row ) ? get_object_vars( $row ) : $row;
 	}
 
-	function seek( $pos ) {
+	public function seek( $pos ) {
 		$this->pos = $pos;
 	}
 
-	function free() {
+	public function free() {
 		$this->result = null;
 	}
 
-	function rewind() {
+	public function rewind() {
 		$this->pos = 0;
 	}
 
-	function current() {
+	public function current() {
 		$row = $this->valid() ? $this->result[$this->pos] : false;
 
 		return is_array( $row ) ? (object)$row : $row;
 	}
 
-	function key() {
+	public function key() {
 		return $this->pos;
 	}
 
-	function next() {
+	public function next() {
 		$this->pos++;
 
 		return $this->current();
 	}
 
-	function valid() {
+	public function valid() {
 		return array_key_exists( $this->pos, $this->result );
 	}
 }
diff --git a/includes/libs/rdbms/database/resultwrapper/ResultWrapper.php b/includes/libs/rdbms/database/resultwrapper/ResultWrapper.php
index b7938ad256..3e509677a3 100644
--- a/includes/libs/rdbms/database/resultwrapper/ResultWrapper.php
+++ b/includes/libs/rdbms/database/resultwrapper/ResultWrapper.php
@@ -4,29 +4,27 @@ namespace Wikimedia\Rdbms;
 
 use stdClass;
 use RuntimeException;
+use InvalidArgumentException;
 
 /**
  * Result wrapper for grabbing data queried from an IDatabase object
  *
+ * Only IDatabase-related classes should construct these. Other code may
+ * use the FakeResultWrapper class for convenience or compatibility shims.
+ *
  * Note that using the Iterator methods in combination with the non-Iterator
- * DB result iteration functions may cause rows to be skipped or repeated.
+ * IDatabase result iteration functions may cause rows to be skipped or repeated.
  *
  * By default, this will use the iteration methods of the IDatabase handle if provided.
  * Subclasses can override methods to make it solely work on the result resource instead.
- * If no database is provided, and the subclass does not override the DB iteration methods,
- * then a RuntimeException will be thrown when iteration is attempted.
- *
- * The result resource field should not be accessed from non-Database related classes.
- * It is database class specific and is stored here to associate iterators with queries.
  *
  * @ingroup Database
  */
 class ResultWrapper implements IResultWrapper {
-	/** @var resource|array|null Optional underlying result handle for subclass usage */
-	public $result;
-
-	/** @var IDatabase|null */
+	/** @var IDatabase */
 	protected $db;
+	/** @var mixed|null RDBMS driver-specific result resource */
+	protected $result;
 
 	/** @var int */
 	protected $pos = 0;
@@ -34,20 +32,39 @@ class ResultWrapper implements IResultWrapper {
 	protected $currentRow;
 
 	/**
-	 * Create a row iterator from a result resource and an optional Database object
-	 *
-	 * Only Database-related classes should construct ResultWrapper. Other code may
-	 * use the FakeResultWrapper subclass for convenience or compatibility shims, however.
-	 *
-	 * @param IDatabase|null $db Optional database handle
-	 * @param ResultWrapper|array|resource $result Optional underlying result handle
+	 * @param IDatabase $db Database handle that the result comes from
+	 * @param self|mixed $result RDBMS driver-specific result resource
 	 */
-	public function __construct( IDatabase $db = null, $result ) {
+	public function __construct( IDatabase $db, $result ) {
 		$this->db = $db;
-		if ( $result instanceof ResultWrapper ) {
+		if ( $result instanceof self ) {
 			$this->result = $result->result;
-		} else {
+		} elseif ( $result !== null ) {
 			$this->result = $result;
+		} else {
+			throw new InvalidArgumentException( "Null result resource provided" );
+		}
+	}
+
+	/**
+	 * Get the underlying RDBMS driver-specific result resource
+	 *
+	 * The result resource field should not be accessed from non-Database related classes.
+	 * It is database class specific and is stored here to associate iterators with queries.
+	 *
+	 * @param self|mixed &$res
+	 * @return mixed
+	 * @since 1.34
+	 */
+	public static function &unwrap( &$res ) {
+		if ( $res instanceof self ) {
+			if ( $res->result === null ) {
+				throw new RuntimeException( "The result resource was already freed" );
+			}
+
+			return $res->result;
+		} else {
+			return $res;
 		}
 	}
 
@@ -110,7 +127,7 @@ class ResultWrapper implements IResultWrapper {
 	 */
 	private function getDB() {
 		if ( !$this->db ) {
-			throw new RuntimeException( static::class . ' needs a DB handle for iteration.' );
+			throw new RuntimeException( "Database handle was already freed" );
 		}
 
 		return $this->db;
diff --git a/includes/specials/pagers/AllMessagesTablePager.php b/includes/specials/pagers/AllMessagesTablePager.php
index 6facda11eb..76e2ab7754 100644
--- a/includes/specials/pagers/AllMessagesTablePager.php
+++ b/includes/specials/pagers/AllMessagesTablePager.php
@@ -176,11 +176,11 @@ class AllMessagesTablePager extends TablePager {
 	 */
 	function reallyDoQuery( $offset, $limit, $order ) {
 		$asc = ( $order === self::QUERY_ASCENDING );
-		$result = new FakeResultWrapper( [] );
 
 		$messageNames = $this->getAllMessages( $order );
 		$statuses = self::getCustomisedStatuses( $messageNames, $this->langcode, $this->foreign );
 
+		$rows = [];
 		$count = 0;
 		foreach ( $messageNames as $key ) {
 			$customised = isset( $statuses['pages'][$key] );
@@ -190,7 +190,7 @@ class AllMessagesTablePager extends TablePager {
 			) {
 				$actual = $this->msg( $key )->inLanguage( $this->lang )->plain();
 				$default = $this->msg( $key )->inLanguage( $this->lang )->useDatabase( false )->plain();
-				$result->result[] = [
+				$rows[] = [
 					'am_title' => $key,
 					'am_actual' => $actual,
 					'am_default' => $default,
@@ -205,7 +205,7 @@ class AllMessagesTablePager extends TablePager {
 			}
 		}
 
-		return $result;
+		return new FakeResultWrapper( $rows );
 	}
 
 	protected function getStartBody() {
diff --git a/tests/phpunit/includes/libs/rdbms/database/DBConnRefTest.php b/tests/phpunit/includes/libs/rdbms/database/DBConnRefTest.php
index 833ac2c397..fafeb4e20d 100644
--- a/tests/phpunit/includes/libs/rdbms/database/DBConnRefTest.php
+++ b/tests/phpunit/includes/libs/rdbms/database/DBConnRefTest.php
@@ -4,7 +4,7 @@ use Wikimedia\Rdbms\IDatabase;
 use Wikimedia\Rdbms\DBConnRef;
 use Wikimedia\Rdbms\FakeResultWrapper;
 use Wikimedia\Rdbms\ILoadBalancer;
-use Wikimedia\Rdbms\ResultWrapper;
+use Wikimedia\Rdbms\IResultWrapper;
 
 /**
  * @covers Wikimedia\Rdbms\DBConnRef
@@ -75,7 +75,7 @@ class DBConnRefTest extends PHPUnit\Framework\TestCase {
 		$lb = $this->getLoadBalancerMock();
 		$ref = new DBConnRef( $lb, $this->getDatabaseMock(), DB_MASTER );
 
-		$this->assertInstanceOf( ResultWrapper::class, $ref->select( 'whatever', '*' ) );
+		$this->assertInstanceOf( IResultWrapper::class, $ref->select( 'whatever', '*' ) );
 	}
 
 	public function testConstruct_params() {
@@ -96,7 +96,7 @@ class DBConnRefTest extends PHPUnit\Framework\TestCase {
 			DB_MASTER
 		);
 
-		$this->assertInstanceOf( ResultWrapper::class, $ref->select( 'whatever', '*' ) );
+		$this->assertInstanceOf( IResultWrapper::class, $ref->select( 'whatever', '*' ) );
 		$this->assertEquals( DB_MASTER, $ref->getReferenceRole() );
 
 		$ref2 = new DBConnRef(
@@ -119,7 +119,7 @@ class DBConnRefTest extends PHPUnit\Framework\TestCase {
 	private function innerMethodForTestDestruct( ILoadBalancer $lb ) {
 		$ref = $lb->getConnectionRef( DB_REPLICA );
 
-		$this->assertInstanceOf( ResultWrapper::class, $ref->select( 'whatever', '*' ) );
+		$this->assertInstanceOf( IResultWrapper::class, $ref->select( 'whatever', '*' ) );
 	}
 
 	public function testConstruct_failure() {
@@ -150,7 +150,7 @@ class DBConnRefTest extends PHPUnit\Framework\TestCase {
 	public function testSelect() {
 		// select should get passed through normally
 		$ref = $this->getDBConnRef();
-		$this->assertInstanceOf( ResultWrapper::class, $ref->select( 'whatever', '*' ) );
+		$this->assertInstanceOf( IResultWrapper::class, $ref->select( 'whatever', '*' ) );
 	}
 
 	public function testToString() {