Description:
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I am using USE_ZEND_ALLOC=0 for debugging PDO

This bug somewhat relates to https://bugs.php.net/bug.php?id=73370, however it is pretty severe as it makes PDO unusable with "USE_ZEND_ALLOC=0".

PDOStatement exits the PHP process with "Out of memory" when executing ANY query that returns an empty result set.

No exception, warning or anything else is raised.

Calling the same script with "USE_ZEND_ALLOC=1" fixes the problem but is not intended as it prevents to debug PDO without memory manager.

System environment:
$ php -v
PHP 7.0.14-2 (cli) ( NTS )
Copyright (c) 1997-2016 The PHP Group
Zend Engine v3.0.0, Copyright (c) 1998-2016 Zend Technologies
    with Zend OPcache v7.0.14-2, Copyright (c) 1999-2016, by Zend Technologies
    with Xdebug v2.5.0, Copyright (c) 2002-2016, by Derick Rethans


Test script:
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$dbh = new \PDO('mysql:dbname=test;host=localhost', 'test', 'test');
$dbh->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
$stmt = $dbh->prepare('SELECT * FROM test WHERE 1=2');
$stmt->execute();


Expected result:
----------------
The execute method should return true as the query is valid and has correctly been processed by MySQL.

Actual result:
--------------
The PHP process writes "Out of memory" to STDERR and exits with status 1