better way to avoid call to a member function - php

Question

I need to know if there is a better way to avoid Call to a member function xxxx() on null
currently I'm coding as follows but it is cumbersome.
if($event->getForm()
&& $event->getForm()->getParent()
&& $event->getForm()->getParent()->getParent()
&& $event->getForm()->getParent()->getParent()->getData()
&& $event->getForm()->getParent()->getParent()->getData()->getComponente()
){
$componente = $event->getForm()->getParent()->getParent()->getData()->getComponente();
$formModifier($event->getForm(), $componente, $defaultComponente);
}

Answer 1

In PHP 7 this is actually a catchable Error (if you're using hhvm it's a regular Exception):
try {
$componente = $event->getForm()->getParent()->getParent()->getData()->getComponente();
} catch (\Error $e) {
$componente = null;
}
if ($componente !== null) {
$formModifier($event->getForm(), $componente, $defaultComponente);
}
In PHP 5 there is a workaround using intermediate variables and the and keyword instead of &&:
if (
$f = $event->getForm() and
$p = $f->getParent() and
$p2 = $p->getParent() and
$d = $p2->getData() and
$componente = $d->getComponente()
) {
$formModifier($f, $componente, $defaultComponente);
}
If you use && instead of and you'll get "undefined variable" notices and this workaround won't work.
Working examples: https://3v4l.org/0S6ps

Answer 2

no there is no way, but at least you can do some performance improvement
$form = $event->getForm();
if(!$form){
//do error handling
return;
}
$parent = $form->getParent();
if(!$parent){
//do error handling
return;
}
$p_parent = $parent->getParent();
if(!$p_parent){
//do error handling
return;
}
$data = $p_parent->getData();
if(!$data){
//do error handling
return;
}
$component = $data->getComponente();
...
this way you call each function only once and you can do better error handling

Answer 3

I think this is a great example of a bad code. By having a code like this you're breaking several rules and making your life much harder than it should be.
Your code is rigid, fragile, hard to understand and maintain etc.
Simpler is ALWAYS better.
If you can't make your $xx->getComponent() a proper object easily accessible without such ugly nested relationship, you should at least encapsulate the method into something appropriate and use that instead, so if anything changes, you don't have to go full mental and change it all over the place.

Answer 4

This class seems strange in it's creation, but if you are not extracting these methods dynamically using __call(), you can use method_exists() in a loop inside a function, something similar to:
function getMethodChain($class,$arr = ['getForm','getParent','getParent','getData','getComponente'])
{
# First check the object is set
if(!is_object($class))
return false;
# Loop intended method chain
foreach($arr as $method) {
# Check if the method exists in the current class or passed already
$useClass = (!isset($classPass))? $class : $classPass;
# Check if the method exists in the current class
if(is_object($useClass) && method_exists($useClass,$method)) {
# Assign this class/method to use next in the loop
$classPass = $useClass->{$method}();
}
else
return false;
}
# Just send back
return (isset($classPass))? $classPass : false;
}
The use would be something like:
# This will either be the data you expect or false
$componente = getMethodChain($event);