Session destroy error for SaveHandler/DbTableGateway on regenerateId()

[robob4him]

I've been getting an error: session_regenerate_id(): Session object destruction failed. ID: user (path: )

I can replicate by adding the following test to test/SaveHandler/DbTableGatewayTest.php:

    /**
     * @runInSeparateProcess
     */
    public function testRegenerateWithSessionManager()
    {
        $sm = new \Zend\Session\SessionManager(null, null, new DbTableGateway($this->tableGateway, $this->options));
        $sm->start();
        $sm->regenerateId();
    }

PHPUnit 5.2.10 by Sebastian Bergmann and contributors.

...E                                                               4 / 4 (100%)

Time: 1.7 seconds, Memory: 6.00MB

There was 1 error:

1) ZendTest\Session\SaveHandler\DbTableGatewayTest::testRegenerateWithSessionMan
ager
session_regenerate_id(): Session object destruction failed.  ID: user (path: )

C:\.home\.workspace\zend-session\src\SessionManager.php:323
C:\.home\.workspace\zend-session\test\SaveHandler\DbTableGatewayTest.php:133

I'm still trying to track down what changed since 2.5 but I do know DbTableGateway is being called to delete a record it hasn't created yet, and because it returns zero (the number of records it removed in the delete) the save_handler call fails. Apparently this hadn't happened back in 2.5.