When retrieving field values from content entities, it is best practice and safest to check whether the field exists first. Code can look like this:
if ($entity->hasField('field_my_field')) {
$value = $entity->get('field_my_field')->value;
}
This is because FieldableEntityInterface::get() throws an InvalidArgumentException if the field does not exist.
Since PHP 8 provides the null-safe operator, it would be nice to be able to do something like
$value = $entity->get('field_my_field')?->value instead, with get(), or some equivalent, returning NULL instead of throwing an exception for an invalid field name.
Two main approaches come to mind:
/**
* Gets a field item list.
*
* @param string $field_name
* The name of the field to get; e.g., 'title' or 'name'.
*
* @param bool $throw_exception
* Whether to throw an exception if field name is invalid or return NULL.
*
* @return \Drupal\Core\Field\FieldItemListInterface|null
* The field item list, containing the field items.
*
* @throws \InvalidArgumentException
* If an invalid field name is given.
*/
public function get($field_name, bool $throw_exception = TRUE);
/**
* Gets a field item list safely.
*
* @param string $field_name
* The name of the field to get; e.g., 'title' or 'name'.
*
* @param bool $throw_exception
* Whether to throw an exception if field name is invalid or return NULL.
*
* @return \Drupal\Core\Field\FieldItemListInterface|null
* The field item list, containing the field items.
*/
public function safeGet(string $field_name): ?FieldItemListInterface {
try {
return $this->get($field_name);
}
catch (\InvalidArgumentException) {
return NULL;
}
}
Changing the interface with either would be a breaking change, though. (Or introducing a new method could be done with a new interface.)
Either a change to the signature of FieldableEntityInterface::get() or a new method that returns NULL instead of throwing an exception.
Active
11.0 🔥
entity system
Enhances developer experience.
Another consideration that came to mind is that if there's a new method, it should be allowed to be used in Twig.
Turns out this is actually a dupe of 📌 Remove exception when accessing a non-existing field with ContentEntityInterface::get() Active .