[PATCH] Generate warning when using PDO::setAttribute() and ATTR_PERSISTENT

For a while, we were scratching our heads over why persistent connections were not being created when using PDO_OCI, even though we were explicitly calling PDO::setAttribute() to set PDO::ATTR_PERSISTENT. My colleague Brian DeShong further explains the issue on his blog: http://www.deshong.net/?p=61 "You must set PDO::ATTR_PERSISTENT => true in the array of options you pass to the PDO constructor! If you call $pdo->setAttribute(PDO::ATTR_PERSISTENT, true) after the instantiation of the object, you won’t be using persistent connections." He goes on to say: "It’d be nice if PDO::setAttribute() raised a warning if you try to set PDO::ATTR_PERSISTENT, by the way." I'm submitting the attached patch to do just that. :-) -- Ben Ramsey http://benramsey.com/