Zend\Form\Select and empty options

Hi folks,

I’ve got a form that uses a Select element with the empty_option set.

The form is bound to an object.

When the POST comes in with the empty option selected, that’s a value of “” (empty string) in HTML-land. Single-stepping through bind, populateValues, and friends, that value stays all the way through the process, and my object’s setProperty gets called with the empty string.

Is there a canonical way to convert that empty string to null so that by the time setProperty gets called, a null is passed in? Is that the hydrator’s job?

Ah, or maybe Zend\Filter\ToNull

But seems like too common a need to not be built-in somewhere.


No, at the moment the empty option is only used for the output. It would be a feature request, but with a BC break. The current behaviour with the empty string is different.

Would it be a BC break if it were just an option like ‘use_null_for_empty’ ?

The resulting code in my entity doesn’t seem to be too different from just testing for an empty string. My type hints can stay intact, which adds to expressiveness I guess…

public function setSupersedes(Competency $competency = null)
    if (null === $competency)   {
        if ($this->supersedes) {
        $this->supersedes = null;
    } else {
        $this->supersedes = $competency;

Please keep in mind, bloating the class with more options means:

  • more code to maintain
  • more tests
  • more documentation
  • more areas for problems
  • more which the user has to know

At the moment the current behaviour adapted the normal usage with POST values in PHP. Compare with all other text elements.
If you need something different, then add your own input-filter specification.

Beaut, thanks for the discussion @froschdesign