forms

gistfile1.php

<?php

class Field {
    protected static $options = array('a', 'b');
    public static function getOptions() {
        return static::$options;
    }
    
    public static $options2 = array('a', 'b');
}

class SubField extends Field {
    protected static $options = array('c');
    public static $options2 = array('c');
}

class SubField2 extends Field {
}

var_dump(Field::getOptions());
var_dump(SubField::getOptions());
var_dump(SubField2::getOptions());

if (isset(Field::$options2)) {
    var_dump(Field::$options2);
}
if (isset(SubField::$options2)) {
    var_dump(SubField::$options2);
}
if (isset(SubField2::$options2)) {
    var_dump(SubField2::$options2);
}

$start = microtime(true);

for ($i = 0; $i < 100000; $i++) {
    Field::getOptions();
    SubField::getOptions();
    SubField2::getOptions();
}

var_dump(microtime(true) - $start);

$start = microtime(true);

for ($i = 0; $i < 100000; $i++) {
    if (isset(Field::$options2)) {
        Field::$options2;
    }
    if (isset(SubField::$options2)) {
        SubField::$options2;
    }
    if (isset(SubField2::$options2)) {
        SubField2::$options2;
    }
}

var_dump(microtime(true) - $start);

results

array
  0 => string 'a' (length=1)
  1 => string 'b' (length=1)
array
  0 => string 'c' (length=1)
array
  0 => string 'a' (length=1)
  1 => string 'b' (length=1)
array
  0 => string 'a' (length=1)
  1 => string 'b' (length=1)
array
  0 => string 'c' (length=1)
array
  0 => string 'a' (length=1)
  1 => string 'b' (length=1)

float 1.0107119083405
float 0.22810196876526