[11.x] MySQL transaction isolation level fix (#50689)

* Fix transaction isolation level in MySqlConnector.php

* Update DatabaseConnectorTest.php

* Style fix

* Code style fix

---------

Co-authored-by: Graham Campbell <[email protected]>

Author: mwikberg-virta

src/Illuminate/Database/Connectors/MySqlConnector.php

@@ -93,12 +93,12 @@ protected function getHostDsn(array $config)
      */
     protected function configureConnection(PDO $connection, array $config)
     {
-        $statements = [];
-
         if (isset($config['isolation_level'])) {
-            $statements[] = sprintf('SESSION TRANSACTION ISOLATION LEVEL %s', $config['isolation_level']);
+            $connection->exec(sprintf('SET SESSION TRANSACTION ISOLATION LEVEL %s;', $config['isolation_level']));
         }
 
+        $statements = [];
+
         if (isset($config['charset'])) {
             if (isset($config['collation'])) {
                 $statements[] = sprintf("NAMES '%s' COLLATE '%s'", $config['charset'], $config['collation']);

tests/Database/DatabaseConnectorTest.php

@@ -62,7 +62,8 @@ public function testMySqlConnectCallsCreateConnectionWithIsolationLevel()
         $connector->expects($this->once())->method('getOptions')->with($this->equalTo($config))->willReturn(['options']);
         $connector->expects($this->once())->method('createConnection')->with($this->equalTo($dsn), $this->equalTo($config), $this->equalTo(['options']))->willReturn($connection);
         $connection->shouldReceive('exec')->once()->with('use `bar`;')->andReturn(true);
-        $connection->shouldReceive('exec')->once()->with("SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ, NAMES 'utf8' COLLATE 'utf8_unicode_ci';")->andReturn(true);
+        $connection->shouldReceive('exec')->once()->with('SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ;')->andReturn(true);
+        $connection->shouldReceive('exec')->once()->with("SET NAMES 'utf8' COLLATE 'utf8_unicode_ci';")->andReturn(true);
         $result = $connector->connect($config);
 
         $this->assertSame($result, $connection);