Description:
------------
In my function (see code below) i tried to return the value of an array at position "key"
If the value is null, i want to return null - it works as shown in the code - but if the key is not set - my function also returns "null"!

So i can't find a solution to differ "null" or "not set"!



Reproduce code:
---------------
$a = array();
// case 1:
$a["key"] = null;
// end case 1

// case 2:
// end case 2

if (isset($a["key"]))
{
	return $a["key"];
}
else
{
	if (is_null($a["key"])
            return null;
        else
            return "key not set!";
}

Expected result:
----------------
case 1:
null
case 2:
"key not set!"

Actual result:
--------------
case 1:
null
case 2:
null 
>> Undefined Index: key in XXX (in log file)