Why is my function not returning the return value?

Question

Okay, so here's my function:

function getNewJobNumber($jobPrefix, $addition = "0") {
$addition = $addition + 1;
//echo $addition . "<br />";    
$yearDate = date("Y");
$firstDigit = $yearDate[strlen($yearDate) - 1];
$db = DatabaseHelpers::getDatabaseConnection();
$jobQuery = 'SELECT jobID, jobNumber, jobPrefix FROM tblJobNumbers WHERE jobPrefix = "' . $jobPrefix . '" AND jobNumber LIKE "' . $firstDigit . '___" ORDER BY jobID DESC LIMIT 1';
//echo $jobQuery . "<br />";
$stmt1 = $db->query($jobQuery);
$stmt1->setFetchMode(PDO::FETCH_OBJ);
$firstResult = $stmt1->fetch();
//above should select the latest created job number with selected prefix
//print_r($firstResult);
$jobNumber = $firstResult->jobNumber; //top row, will be last job number
//echo "jobNumberFromDB:" . $jobNumber . "<br />";
if (!$jobNumber) {
    //no job number exists yet, create one
    //will be last digit of year followed by "000" ie in 2013 first
    //new job number is "3000"
    $newJobNumber = str_pad($firstDigit, 4, "0");
    return $newJobNumber;
} else {
    //job number already exists, try next one
    $nextJobNumber = $jobNumber + $addition;
    $nextJobQuery = 'SELECT jobID, jobNumber, jobPrefix FROM tblJobNumbers WHERE jobPrefix = "' . $jobPrefix . '" AND jobNumber = "' . $nextJobNumber . '" ORDER BY jobID DESC LIMIT 1';
    $stmt2 = $db->query($nextJobQuery);
    $stmt2->setFetchMode(PDO::FETCH_OBJ);
    $nextResult = $stmt2->fetch();
    $dbNextJobNumber = $nextResult->jobNumber;      
    if (!$dbNextJobNumber) {
        //new job number is unique, return value
        echo "return:nextJobNumber-" . $nextJobNumber . "<br />";
        return($nextJobNumber);
    } else {
        //new job number is not unique, and therefore we need another one
        if ($addition <= 99) { //don't let this recurse more than 99 times, it should never need to
            //in order to loop this programatically call function again, adding one to addition factor
            getNewJobNumber($jobPrefix, $addition+1);
        } else {
            return;
        }
    }
}
}

here's my call:

        $ourNewJobNumber = getNewJobNumber($_POST['txtJobPrefix'], 0);
        echo ":}" . $ourNewJobNumber . "{:<br />";

and here's my result:

return:nextJobNumber-3005
:}{:

The code is executing perfectly, pulling values out of the database and comparing them and doing everything just the way I want it to. It is getting the correct value in every circumstance I can test, but it just outright refuses to return that value back to the calling script. Does anyone see any stupid errors that I have glossed over? Having my debug echo immediately before my return statement seems as if it eliminates any possibility of it going wrong before the return statement but I just don't know at this point.

Edit: Just to be clear, 3005 is the value I am expecting out of my database at this point. This is to set up job numbers at work which are always Zxxx where Z is the last digit of the year. These are always created sequentially, but for jobs that span more than one year we only change Z so this is the code I use to work around the fact that 3030 can (and does) exist before 3000 is ever created.

Answer 1

You are calling your function recursively but you are not doing anything with the return value:

    if ($addition <= 99) { //don't let this recurse more than 99 times, it should never need to
        //in order to loop this programatically call function again, adding one to addition factor
        getNewJobNumber($jobPrefix, $addition+1);
    } else {
        return;
    }

Should be something like:

    if ($addition <= 99) { //don't let this recurse more than 99 times, it should never need to
        //in order to loop this programatically call function again, adding one to addition factor
        return getNewJobNumber($jobPrefix, $addition+1);
        ^^^^^^
    } else {
        return -1;    // some kind of error message?
    }

Answer 2

When you're calling

getNewJobNumber($jobPrefix, $addition+1);

you're not actually returning the value.

Change it for

return getNewJobNumber($jobPrefix, $addition+1);