Mantis - Quercus
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ID: Category: Severity: Reproducibility: Date Submitted: Last Update:
3822 block always 12-20-09 19:46 12-21-09 05:23
Reporter: domdorn Platform:  
Assigned To: OS:  
Priority: normal OS Version:  
Status: new Product Version: 4.0.2  
Product Build: Resolution: open  
Projection: none      
ETA: none Fixed in Version:  
Summary: 0003822: Variable scoping issues in loops!!!!
Description: I have lots of code like this:

    while(list($dnow, $nusernr, $stitle, $stext, $nuserguestbooknr,$nstatusnr) = $rSQLGetEntries->fetchRow() )
    {
        include("$sDocumentRoot/ly/tmpl/elements/dsp_GuestbookEntry.php");
        unset($dnow, $nusernr, $stitle, $stext, $nuserguestbooknr,$nstatusnr);
    }

where $rSQLGetEntries is a Pear::DB Object and fetchRow() is a method, returning an array (see http://pear.php.net/manual/en/package.database.db.db-result.fetchrow.php [^] )

this code does not work, because the list expression is not implemented correctly OR the scoping of variables in Loops is broken!

I've narrowed it down to something like this (10 is the correct number of rows returned)

    for($i = 0; $i < 10; $i++)
    {
        $res = $rSQLGetEntries->fetchRow();
        print_r($res);
        echo "<hr/>";
    }
this correctly executes print_r on each of the 10 rows... however, as soon as I do this:
    for($i = 0; $i < 10; $i++)
    {
        $res = $rSQLGetEntries->fetchRow();
        print_r($res);
        echo "<hr/>";
        $dnow = $res[0];
    }
the code stops after the first loop execution
Steps To Reproduce:
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Notes
(0004362)
domdorn   
12-21-09 05:23   
I thought a bit about this and this came to my mind:

The problem here is, that $res is bound to an object that does not exist in the next iteration of the loop ... when using print_r, a copy of that object gets created, the first assignment from $res to $dnow works, because the object is still in memory, the loop finishes... in the next loop, quercus somehow tries to access the old data but thats invalid and stops.. if I copy the data first to an array and use it like this

$lResult = array();
while( $row = $rSQLGetEntries->fetchRow() )
{
  $lResult[] = $row;
}

I can iterate over $lResult the normal way, because the data in $row gets _copied_ into $lResult.