Fixed Possible bug in XenForo_DataWriter::get()

[Yoskaldyr]

Datawriter get() method returns existing data if new data setted to null.
Example:

$dw = XenForo_DataWriter::create('Some_DataWriter_Class');
$dw->setExistingData($someId);
$a = $dw->get('somekey'); //$a = 'somedata';
$dw->set('somekey', 'newdata');
$a = $dw->get('somekey'); //$a = 'newdata';
$dw->set('somekey', null);
$a = $dw->get('somekey'); //$a = 'somedata'; not null as expected
$dw->save(); //in db somekey field saved as null

Possible fix for this, replace XenForo_DataWriter::get() with code:

    public function get($field, $tableName = '')
    {
        $tables = $this->_getTableList($tableName);
 
        foreach ($tables AS $tableName)
        {
            if (
                isset($this->_newData[$tableName])
                && is_array($this->_newData[$tableName])
                && array_key_exists($field, $this->_newData[$tableName])
            )
            {
                return $this->_newData[$tableName][$field];
            }
            else if (
                isset($this->_existingData[$tableName])
                && is_array($this->_existingData[$tableName])
                && array_key_exists($field, $this->_existingData[$tableName])
            )
            {
                return $this->_existingData[$tableName][$field];
            }
        }
 
        return null;
    }

 

[xf_phantom]

I've never seen setting something to null inside of the DW, but nevermind

This change breaks at least one DataWriter method (isChanged), so this would need to be changed too if this is considered as bug and gets implemented

public function isChanged($field, $tableName = '')
{
return ($this->getNew($field, $tableName) !== null);
}

if you set the new field to null, it's changed, but the method isChanged would return false

$dw = XenForo_DataWriter::create('XenForo_DataWriter_User');
$dw->setExistingData(array('user_id' => 1));
$dw->set('custom_title', 'new title');
echo '1 ' . $dw->get('custom_title') ;
$dw->set('custom_title', null);
echo "\n2 " .  $dw->get('custom_title');
if ($dw->isChanged('custom_title')){
echo "\n isChanged";
}
$dw->set('custom_title', 'new one');
echo "\n3 ".  $dw->get('custom_title') ;
if ($dw->isChanged('custom_title')){
echo "\n isChanged";
}
$dw->preSave();

would output

1 new title
2
3 new one
4 isChanged

your code fixes the problem and line 2 is empty, but the isChanged method returned false instead of true

 

[Mike]

I've changed this for 1.2. There are actually a lot more changes needed than this: there are a lot of isset() changes to array_key_exists().