rdmbs: Start of SQLPlatform to split out of Database

This is the first step to split parts of Database that doesn't require a
connection and are used for query parts.

Bug: T299691
Change-Id: I140aa4328865994499926f898233867ce383908c

autoload.php

@@ -1807,6 +1807,7 @@ $wgAutoloadLocalClasses = [
 	'Wikimedia\\Rdbms\\DBConnectionError' => __DIR__ . '/includes/libs/rdbms/exception/DBConnectionError.php',
 	'Wikimedia\\Rdbms\\DBError' => __DIR__ . '/includes/libs/rdbms/exception/DBError.php',
 	'Wikimedia\\Rdbms\\DBExpectedError' => __DIR__ . '/includes/libs/rdbms/exception/DBExpectedError.php',
+	'Wikimedia\\Rdbms\\DBLanguageError' => __DIR__ . '/includes/libs/rdbms/exception/DBLanguageError.php',
 	'Wikimedia\\Rdbms\\DBPrimaryPos' => __DIR__ . '/includes/libs/rdbms/database/position/DBPrimaryPos.php',
 	'Wikimedia\\Rdbms\\DBQueryDisconnectedError' => __DIR__ . '/includes/libs/rdbms/exception/DBQueryDisconnectedError.php',
 	'Wikimedia\\Rdbms\\DBQueryError' => __DIR__ . '/includes/libs/rdbms/exception/DBQueryError.php',

includes/AutoLoader.php

@@ -179,6 +179,7 @@ class AutoLoader {
 			'MediaWiki\\Widget\\' => __DIR__ . '/widget/',
 			'Wikimedia\\' => __DIR__ . '/libs/',
 			'Wikimedia\\Http\\' => __DIR__ . '/libs/http/',
+			'Wikimedia\\Rdbms\\Platform\\' => __DIR__ . '/libs/rdbms/platform/',
 			'Wikimedia\\UUID\\' => __DIR__ . '/libs/uuid/',
 		];
 	}

includes/libs/rdbms/database/DatabaseMysqlBase.php

@@ -26,6 +26,8 @@ use InvalidArgumentException;
 use RuntimeException;
 use stdClass;
 use Wikimedia\AtEase\AtEase;
+use Wikimedia\Rdbms\Platform\ISQLPlatform;
+use Wikimedia\Rdbms\Platform\MySQLPlatform;
 
 /**
  * Database abstraction object for MySQL.
@@ -81,6 +83,9 @@ abstract class DatabaseMysqlBase extends Database {
 	/** @var float Warn if lag estimates are made for transactions older than this many seconds */
 	private const LAG_STALE_WARN_THRESHOLD = 0.100;
 
+	/** @var ISQLPlatform */
+	protected $platform;
+
 	/**
 	 * Additional $params include:
 	 *   - lagDetectionMethod : set to one of (Seconds_Behind_Master,pt-heartbeat).
@@ -114,6 +119,7 @@ abstract class DatabaseMysqlBase extends Database {
 		$this->utf8Mode = !empty( $params['utf8Mode'] );
 		$this->insertSelectIsSafe = isset( $params['insertSelectIsSafe'] )
 			? (bool)$params['insertSelectIsSafe'] : null;
+		$this->platform = new MySQLPlatform();
 
 		parent::__construct( $params );
 	}
@@ -164,7 +170,7 @@ abstract class DatabaseMysqlBase extends Database {
 				if ( !is_int( $val ) && !is_float( $val ) ) {
 					$val = $this->addQuotes( $val );
 				}
-				$set[] = $this->addIdentifierQuotes( $var ) . ' = ' . $val;
+				$set[] = $this->platform->addIdentifierQuotes( $var ) . ' = ' . $val;
 			}
 
 			// @phan-suppress-next-next-line PhanRedundantCondition
@@ -205,7 +211,7 @@ abstract class DatabaseMysqlBase extends Database {
 		}
 
 		if ( $database !== $this->getDBname() ) {
-			$sql = 'USE ' . $this->addIdentifierQuotes( $database );
+			$sql = 'USE ' . $this->platform->addIdentifierQuotes( $database );
 			list( $res, $err, $errno ) =
 				$this->executeQuery( $sql, __METHOD__, self::QUERY_IGNORE_DBO_TRX );
 
@@ -365,7 +371,7 @@ abstract class DatabaseMysqlBase extends Database {
 
 		// If the database has been specified (such as for shared tables), use "FROM"
 		if ( $database !== '' ) {
-			$encDatabase = $this->addIdentifierQuotes( $database );
+			$encDatabase = $this->platform->addIdentifierQuotes( $database );
 			$sql = "SHOW TABLES FROM $encDatabase LIKE '$encLike'";
 		} else {
 			$sql = "SHOW TABLES LIKE '$encLike'";
@@ -459,15 +465,15 @@ abstract class DatabaseMysqlBase extends Database {
 	abstract protected function mysqlRealEscapeString( $s );
 
 	/**
-	 * MySQL uses `backticks` for identifier quoting instead of the sql standard "double quotes".
-	 *
 	 * @param string $s
 	 * @return string
 	 */
 	public function addIdentifierQuotes( $s ) {
-		// Characters in the range \u0001-\uFFFF are valid in a quoted identifier
-		// Remove NUL bytes and escape backticks by doubling
-		return '`' . str_replace( [ "\0", '`' ], [ '', '``' ], $s ) . '`';
+		// Tests disabling constructor
+		if ( !$this->platform ) {
+			$this->platform = new MySQLPlatform();
+		}
+		return $this->platform->addIdentifierQuotes( $s );
 	}
 
 	/**

includes/libs/rdbms/database/DatabasePostgres.php

@@ -23,6 +23,8 @@
 namespace Wikimedia\Rdbms;
 
 use RuntimeException;
+use Wikimedia\Rdbms\Platform\ISQLPlatform;
+use Wikimedia\Rdbms\Platform\PostgresPlatform;
 use Wikimedia\Timestamp\ConvertibleTimestamp;
 use Wikimedia\WaitConditionLoop;
 
@@ -44,6 +46,9 @@ class DatabasePostgres extends Database {
 	/** @var resource|null */
 	private $lastResultHandle;
 
+	/** @var ISQLPlatform */
+	private $platform;
+
 	/**
 	 * @see Database::__construct()
 	 * @param array $params Additional parameters include:
@@ -63,6 +68,7 @@ class DatabasePostgres extends Database {
 		}
 
 		parent::__construct( $params );
+		$this->platform = new PostgresPlatform();
 	}
 
 	public function getType() {
@@ -129,7 +135,7 @@ class DatabasePostgres extends Database {
 			];
 			foreach ( $variables as $var => $val ) {
 				$this->query(
-					'SET ' . $this->addIdentifierQuotes( $var ) . ' = ' . $this->addQuotes( $val ),
+					'SET ' . $this->platform->addIdentifierQuotes( $var ) . ' = ' . $this->addQuotes( $val ),
 					__METHOD__,
 					self::QUERY_NO_RETRY | self::QUERY_CHANGE_TRX
 				);
@@ -456,7 +462,9 @@ __INDEXATTR__;
 							$toCheck = array_merge( $toCheck, $name );
 						} else {
 							// Quote alias names so $this->tableName() won't mangle them
-							$options['FOR UPDATE'][] = $hasAlias ? $this->addIdentifierQuotes( $alias ) : $alias;
+							$options['FOR UPDATE'][] = $hasAlias ?
+								// @phan-suppress-next-line PhanTypeMismatchArgumentNullable
+								$this->platform->addIdentifierQuotes( $alias ) : $alias;
 						}
 					}
 				}
@@ -674,8 +682,8 @@ __INDEXATTR__;
 	public function duplicateTableStructure(
 		$oldName, $newName, $temporary = false, $fname = __METHOD__
 	) {
-		$newNameE = $this->addIdentifierQuotes( $newName );
-		$oldNameE = $this->addIdentifierQuotes( $oldName );
+		$newNameE = $this->platform->addIdentifierQuotes( $newName );
+		$oldNameE = $this->platform->addIdentifierQuotes( $oldName );
 
 		$temporary = $temporary ? 'TEMPORARY' : '';
 
@@ -705,8 +713,8 @@ __INDEXATTR__;
 		if ( $row ) {
 			$field = $row->attname;
 			$newSeq = "{$newName}_{$field}_seq";
-			$fieldE = $this->addIdentifierQuotes( $field );
-			$newSeqE = $this->addIdentifierQuotes( $newSeq );
+			$fieldE = $this->platform->addIdentifierQuotes( $field );
+			$newSeqE = $this->platform->addIdentifierQuotes( $newSeq );
 			$newSeqQ = $this->addQuotes( $newSeq );
 			$this->query(
 				"CREATE $temporary SEQUENCE $newSeqE OWNED BY $newNameE.$fieldE",
@@ -921,7 +929,7 @@ __INDEXATTR__;
 			} else {
 				// Prepend the desired schema to the search path (T17816)
 				$search_path = $this->getSearchPath();
-				array_unshift( $search_path, $this->addIdentifierQuotes( $desiredSchema ) );
+				array_unshift( $search_path, $this->platform->addIdentifierQuotes( $desiredSchema ) );
 				$this->setSearchPath( $search_path );
 				$this->coreSchema = $desiredSchema;
 				$this->queryLogger->debug(

includes/libs/rdbms/database/DatabaseSqlite.php

@@ -29,6 +29,8 @@ use NullLockManager;
 use PDO;
 use PDOException;
 use RuntimeException;
+use Wikimedia\Rdbms\Platform\ISQLPlatform;
+use Wikimedia\Rdbms\Platform\SqlitePlatform;
 
 /**
  * @ingroup Database
@@ -67,6 +69,9 @@ class DatabaseSqlite extends Database {
 		'temp_store' => [ 'FILE', 'MEMORY' ]
 	];
 
+	/** @var ISQLPlatform */
+	private $platform;
+
 	/**
 	 * Additional params include:
 	 *   - dbDirectory : directory containing the DB and the lock file directory
@@ -89,6 +94,7 @@ class DatabaseSqlite extends Database {
 		$this->trxMode = strtoupper( $params['trxMode'] ?? '' );
 
 		$this->lockMgr = $this->makeLockManager();
+		$this->platform = new SqlitePlatform();
 	}
 
 	protected static function getAttributes() {
@@ -922,9 +928,9 @@ class DatabaseSqlite extends Database {
 		$sqlCreateTable = $obj->sql;
 		$sqlCreateTable = preg_replace(
 			'/(?<=\W)"?' .
-				preg_quote( trim( $this->addIdentifierQuotes( $oldName ), '"' ), '/' ) .
+				preg_quote( trim( $this->platform->addIdentifierQuotes( $oldName ), '"' ), '/' ) .
 				'"?(?=\W)/',
-			$this->addIdentifierQuotes( $newName ),
+			$this->platform->addIdentifierQuotes( $newName ),
 			$sqlCreateTable,
 			1
 		);
@@ -966,8 +972,8 @@ class DatabaseSqlite extends Database {
 			}
 			// Try to come up with a new index name, given indexes have database scope in SQLite
 			$indexName = $newName . '_' . $index->name;
-			$sqlIndex .= ' ' . $this->addIdentifierQuotes( $indexName ) .
-				' ON ' . $this->addIdentifierQuotes( $newName );
+			$sqlIndex .= ' ' . $this->platform->addIdentifierQuotes( $indexName ) .
+				' ON ' . $this->platform->addIdentifierQuotes( $newName );
 
 			$indexInfo = $this->query(
 				'PRAGMA INDEX_INFO(' . $this->addQuotes( $index->name ) . ')',
@@ -1046,7 +1052,7 @@ class DatabaseSqlite extends Database {
 			$encSeqNames[] = $this->addQuotes( $this->tableName( $table, 'raw' ) );
 		}
 
-		$encMasterTable = $this->addIdentifierQuotes( 'sqlite_sequence' );
+		$encMasterTable = $this->platform->addIdentifierQuotes( 'sqlite_sequence' );
 		$this->query(
 			"DELETE FROM $encMasterTable WHERE name IN(" . implode( ',', $encSeqNames ) . ")",
 			$fname,

includes/libs/rdbms/database/IDatabase.php

@@ -22,6 +22,7 @@ namespace Wikimedia\Rdbms;
 use Exception;
 use InvalidArgumentException;
 use stdClass;
+use Wikimedia\Rdbms\Platform\ISQLPlatform;
 use Wikimedia\ScopedCallback;
 
 /**
@@ -35,7 +36,7 @@ use Wikimedia\ScopedCallback;
  * @note IDatabase and DBConnRef should be updated to reflect any changes
  * @ingroup Database
  */
-interface IDatabase {
+interface IDatabase extends ISQLPlatform {
 	/** @var int Callback triggered immediately due to no active transaction */
 	public const TRIGGER_IDLE = 1;
 	/** @var int Callback triggered by COMMIT */
@@ -990,26 +991,6 @@ interface IDatabase {
 	 */
 	public function factorConds( $condsArray );
 
-	/**
-	 * @param string|int $field
-	 * @return string
-	 */
-	public function bitNot( $field );
-
-	/**
-	 * @param string|int $fieldLeft
-	 * @param string|int $fieldRight
-	 * @return string
-	 */
-	public function bitAnd( $fieldLeft, $fieldRight );
-
-	/**
-	 * @param string|int $fieldLeft
-	 * @param string|int $fieldRight
-	 * @return string
-	 */
-	public function bitOr( $fieldLeft, $fieldRight );
-
 	/**
 	 * Build a concatenation list to feed into a SQL query
 	 * @param string[] $stringList Raw SQL expression list; caller is responsible for escaping
@@ -1210,17 +1191,6 @@ interface IDatabase {
 	 */
 	public function addQuotes( $s );
 
-	/**
-	 * Escape a SQL identifier (e.g. table, column, database) for use in a SQL query
-	 *
-	 * Depending on the database this will either be `backticks` or "double quotes"
-	 *
-	 * @param string $s
-	 * @return string
-	 * @since 1.33
-	 */
-	public function addIdentifierQuotes( $s );
-
 	/**
 	 * LIKE statement wrapper
 	 *

includes/libs/rdbms/exception/DBLanguageError.php

@@ -0,0 +1,36 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup Database
+ */
+
+namespace Wikimedia\Rdbms;
+
+use Throwable;
+
+/**
+ * @since 1.39
+ * @newable
+ * @stable to extend
+ * @ingroup Database
+ */
+class DBLanguageError extends DBUnexpectedError {
+	public function __construct( $error, Throwable $prev = null ) {
+		parent::__construct( null, $error, $prev );
+	}
+}

includes/libs/rdbms/platform/ISQLPlatform.php

@@ -0,0 +1,60 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+namespace Wikimedia\Rdbms\Platform;
+
+/**
+ * Interface for query language.
+ * Note: This is for simple SQL operations, use QueryBuilder for building
+ * full queries.
+ * @since 1.39
+ */
+interface ISQLPlatform {
+
+	/**
+	 * @param string|int $field
+	 * @return string
+	 */
+	public function bitNot( $field );
+
+	/**
+	 * @param string|int $fieldLeft
+	 * @param string|int $fieldRight
+	 * @return string
+	 */
+	public function bitAnd( $fieldLeft, $fieldRight );
+
+	/**
+	 * @param string|int $fieldLeft
+	 * @param string|int $fieldRight
+	 * @return string
+	 */
+	public function bitOr( $fieldLeft, $fieldRight );
+
+	/**
+	 * Escape a SQL identifier (e.g. table, column, database) for use in a SQL query
+	 *
+	 * Depending on the database this will either be `backticks` or "double quotes"
+	 *
+	 * @param string $s
+	 * @return string
+	 * @since 1.33
+	 */
+	public function addIdentifierQuotes( $s );
+}

includes/libs/rdbms/platform/MySQLPlatform.php

@@ -0,0 +1,38 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+namespace Wikimedia\Rdbms\Platform;
+
+/**
+ * @since 1.39
+ * @see ISQLPlatform
+ */
+class MySQLPlatform extends SQLPlatform {
+	/**
+	 * MySQL uses `backticks` for identifier quoting instead of the sql standard "double quotes".
+	 *
+	 * @param string $s
+	 * @return string
+	 */
+	public function addIdentifierQuotes( $s ) {
+		// Characters in the range \u0001-\uFFFF are valid in a quoted identifier
+		// Remove NUL bytes and escape backticks by doubling
+		return '`' . str_replace( [ "\0", '`' ], [ '', '``' ], $s ) . '`';
+	}
+}

includes/libs/rdbms/platform/PostgresPlatform.php

@@ -0,0 +1,31 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+namespace Wikimedia\Rdbms\Platform;
+
+/**
+ * @since 1.39
+ * @see ISQLPlatform
+ */
+class PostgresPlatform extends SQLPlatform {
+	/**
+	 * Empty for now
+	 */
+}

includes/libs/rdbms/platform/SQLPlatform.php

@@ -0,0 +1,61 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+namespace Wikimedia\Rdbms\Platform;
+
+/**
+ * Sql abstraction object.
+ * This class nor any of its subclasses should create or use a db connection.
+ * It also should not become stateful. Preferably the constructor should stay empty.
+ * @since 1.39
+ */
+class SQLPlatform implements ISQLPlatform {
+	/**
+	 * @inheritDoc
+	 * @stable to override
+	 */
+	public function bitNot( $field ) {
+		return "(~$field)";
+	}
+
+	/**
+	 * @inheritDoc
+	 * @stable to override
+	 */
+	public function bitAnd( $fieldLeft, $fieldRight ) {
+		return "($fieldLeft & $fieldRight)";
+	}
+
+	/**
+	 * @inheritDoc
+	 * @stable to override
+	 */
+	public function bitOr( $fieldLeft, $fieldRight ) {
+		return "($fieldLeft | $fieldRight)";
+	}
+
+	/**
+	 * @inheritDoc
+	 * @stable to override
+	 */
+	public function addIdentifierQuotes( $s ) {
+		return '"' . str_replace( '"', '""', $s ) . '"';
+	}
+
+}

includes/libs/rdbms/platform/SqlitePlatform.php

@@ -0,0 +1,31 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+namespace Wikimedia\Rdbms\Platform;
+
+/**
+ * @since 1.38
+ * @see ISQLPlatform
+ */
+class SqlitePlatform extends SQLPlatform {
+	/**
+	 * Empty for now
+	 */
+}

tests/phpunit/unit/includes/libs/rdbms/database/DatabaseMysqlBaseTest.php

@@ -28,79 +28,13 @@ use Wikimedia\Rdbms\DatabaseMysqli;
 use Wikimedia\Rdbms\IDatabase;
 use Wikimedia\Rdbms\IMaintainableDatabase;
 use Wikimedia\Rdbms\MySQLPrimaryPos;
+use Wikimedia\Rdbms\Platform\MySQLPlatform;
 use Wikimedia\TestingAccessWrapper;
 
 class DatabaseMysqlBaseTest extends PHPUnit\Framework\TestCase {
 
 	use MediaWikiCoversValidator;
 
-	/**
-	 * @dataProvider provideDiapers
-	 * @covers \Wikimedia\Rdbms\DatabaseMysqlBase::addIdentifierQuotes
-	 */
-	public function testAddIdentifierQuotes( $expected, $in ) {
-		$db = $this->getMockBuilder( DatabaseMysqli::class )
-			->disableOriginalConstructor()
-			->onlyMethods( [] )
-			->getMock();
-
-		/** @var IDatabase $db */
-		$quoted = $db->addIdentifierQuotes( $in );
-		$this->assertEquals( $expected, $quoted );
-	}
-
-	/**
-	 * Feeds testAddIdentifierQuotes
-	 *
-	 * Named per T22281 convention.
-	 */
-	public static function provideDiapers() {
-		return [
-			// Format: expected, input
-			[ '``', '' ],
-
-			// Yeah I really hate loosely typed PHP idiocies nowadays
-			[ '``', null ],
-
-			// Dear codereviewer, guess what addIdentifierQuotes()
-			// will return with thoses:
-			[ '``', false ],
-			[ '`1`', true ],
-
-			// We never know what could happen
-			[ '`0`', 0 ],
-			[ '`1`', 1 ],
-
-			// Whatchout! Should probably use something more meaningful
-			[ "`'`", "'" ],  # single quote
-			[ '`"`', '"' ],  # double quote
-			[ '````', '`' ], # backtick
-			[ '`’`', '’' ],  # apostrophe (look at your encyclopedia)
-
-			// sneaky NUL bytes are lurking everywhere
-			[ '``', "\0" ],
-			[ '`xyzzy`', "\0x\0y\0z\0z\0y\0" ],
-
-			// unicode chars
-			[
-				"`\u{0001}a\u{FFFF}b`",
-				"\u{0001}a\u{FFFF}b"
-			],
-			[
-				"`\u{0001}\u{FFFF}`",
-				"\u{0001}\u{0000}\u{FFFF}\u{0000}"
-			],
-			[ '`☃`', '☃' ],
-			[ '`メインページ`', 'メインページ' ],
-			[ '`Басты_бет`', 'Басты_бет' ],
-
-			// Real world:
-			[ '`Alix`', 'Alix' ],  # while( ! $recovered ) { sleep(); }
-			[ '`Backtick: ```', 'Backtick: `' ],
-			[ '`This is a test`', 'This is a test' ],
-		];
-	}
-
 	private function getMockForViews(): IMaintainableDatabase {
 		$db = $this->getMockBuilder( DatabaseMysqli::class )
 			->disableOriginalConstructor()
@@ -734,13 +668,18 @@ class DatabaseMysqlBaseTest extends PHPUnit\Framework\TestCase {
 	public function testIndexAliases() {
 		$db = $this->getMockBuilder( DatabaseMysqli::class )
 			->disableOriginalConstructor()
-			->onlyMethods( [ 'mysqlRealEscapeString', 'dbSchema', 'tablePrefix' ] )
+			->onlyMethods( [ 'mysqlRealEscapeString', 'dbSchema', 'tablePrefix', 'addIdentifierQuotes' ] )
 			->getMock();
 		$db->method( 'mysqlRealEscapeString' )->willReturnCallback(
 			static function ( $s ) {
 				return str_replace( "'", "\\'", $s );
 			}
 		);
+		$db->method( 'addIdentifierQuotes' )->willReturnCallback(
+			static function ( $s ) {
+				return ( new MySQLPlatform() )->addIdentifierQuotes( $s );
+			}
+		);
 
 		/** @var IDatabase $db */
 		$db->setIndexAliases( [ 'a_b_idx' => 'a_c_idx' ] );
@@ -768,13 +707,18 @@ class DatabaseMysqlBaseTest extends PHPUnit\Framework\TestCase {
 	public function testTableAliases() {
 		$db = $this->getMockBuilder( DatabaseMysqli::class )
 			->disableOriginalConstructor()
-			->onlyMethods( [ 'mysqlRealEscapeString', 'dbSchema', 'tablePrefix' ] )
+			->onlyMethods( [ 'mysqlRealEscapeString', 'dbSchema', 'tablePrefix', 'addIdentifierQuotes' ] )
 			->getMock();
 		$db->method( 'mysqlRealEscapeString' )->willReturnCallback(
 			static function ( $s ) {
 				return str_replace( "'", "\\'", $s );
 			}
 		);
+		$db->method( 'addIdentifierQuotes' )->willReturnCallback(
+			static function ( $s ) {
+				return ( new MySQLPlatform() )->addIdentifierQuotes( $s );
+			}
+		);
 
 		/** @var IDatabase $db */
 		$db->setTableAliases( [

tests/phpunit/unit/includes/libs/rdbms/platform/MySQLPlatformTest.php

@@ -0,0 +1,88 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+use Wikimedia\Rdbms\Platform\MySQLPlatform;
+
+class MySQLPlatformTest extends PHPUnit\Framework\TestCase {
+
+	use MediaWikiCoversValidator;
+
+	/**
+	 * @dataProvider provideDiapers
+	 * @covers \Wikimedia\Rdbms\Platform\MySQLPlatform::addIdentifierQuotes
+	 */
+	public function testAddIdentifierQuotes( $expected, $in ) {
+		$platform = new MySQLPlatform();
+		$quoted = $platform->addIdentifierQuotes( $in );
+		$this->assertEquals( $expected, $quoted );
+	}
+
+	/**
+	 * Feeds testAddIdentifierQuotes
+	 *
+	 * Named per T22281 convention.
+	 */
+	public static function provideDiapers() {
+		return [
+			// Format: expected, input
+			[ '``', '' ],
+
+			// Yeah I really hate loosely typed PHP idiocies nowadays
+			[ '``', null ],
+
+			// Dear codereviewer, guess what addIdentifierQuotes()
+			// will return with thoses:
+			[ '``', false ],
+			[ '`1`', true ],
+
+			// We never know what could happen
+			[ '`0`', 0 ],
+			[ '`1`', 1 ],
+
+			// Whatchout! Should probably use something more meaningful
+			[ "`'`", "'" ],  # single quote
+			[ '`"`', '"' ],  # double quote
+			[ '````', '`' ], # backtick
+			[ '`’`', '’' ],  # apostrophe (look at your encyclopedia)
+
+			// sneaky NUL bytes are lurking everywhere
+			[ '``', "\0" ],
+			[ '`xyzzy`', "\0x\0y\0z\0z\0y\0" ],
+
+			// unicode chars
+			[
+				"`\u{0001}a\u{FFFF}b`",
+				"\u{0001}a\u{FFFF}b"
+			],
+			[
+				"`\u{0001}\u{FFFF}`",
+				"\u{0001}\u{0000}\u{FFFF}\u{0000}"
+			],
+			[ '`☃`', '☃' ],
+			[ '`メインページ`', 'メインページ' ],
+			[ '`Басты_бет`', 'Басты_бет' ],
+
+			// Real world:
+			[ '`Alix`', 'Alix' ],  # while( ! $recovered ) { sleep(); }
+			[ '`Backtick: ```', 'Backtick: `' ],
+			[ '`This is a test`', 'This is a test' ],
+		];
+	}
+}