In php, should I return false, null, or an empty array in a method that would usually return an array?

Question

I\'ve found several responses to this, but none pertaining to PHP (which is an extremely weak typed language):

With regards to PHP, is it appropriate to return

Answer 1

Just speaking for myself, I normally prefer to return an empty array, because if the function always returns an array, it's safe to use it with PHP's array functions and foreach (they'll accept empty arrays). If you return null or false, then you'll have to check the type of the result before passing it to an array function.

If you need to distinguish between the case where the method executed correctly but didn't find any results, and the case where an error occurred in the method, then that's where exceptions come in. In the former case it's safe to return an empty array. In the latter simply returning an empty array is insufficient to notify you of the fact an error occurred. However if you return something other than an array then you'll have to deal with that in the calling code. Throwing an exception lets you handle errors elsewhere in an appropriate error handler and lets you attach a message and a code to the exception to describe why the failure happened.

The below pseudo-code will simply return an empty array if we don't find anything of interest. However, if something goes wrong when processing the list of things we got back then an exception is thrown.

method getThings () {
    $things = array ();
    if (get_things_we_are_interested_in ()) {
        $things [] = something_else ();
    } 
    if (!empty ($things)) {
        if (!process_things ($things)) {
            throw new RuntimeExcpetion ('Things went wrong when I tried to process your things for the things!');
        }
    }
    return $things;
}