ReflectionParameter::allowsNull

(PHP 5, PHP 7, PHP 8)

ReflectionParameter::allowsNull — Verifica si el valor null está permitido como valor del argumento

Descripción

public ReflectionParameter::allowsNull(): bool

Verifica si el valor null está permitido como valor del argumento.

Parámetros

Esta función no contiene ningún parámetro.

Valores devueltos

true si el valor null está permitido como valor del argumento, false en caso contrario.

Ver también

ReflectionParameter::isOptional() - Verifica si el parámetro es opcional

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User Contributed Notes 2 notes

down

Geoffrey LAURENT ¶

12 years ago

The allowsNull method look if arguments have a type. 
If a type is defined, null is allowed only if default value is null.

 <?php 
function myfunction ( $param ) {
    
}

echo (new ReflectionFunction("myfunction"))->getParameters()[0]->allowsNull() ? "true":"false";

?>

Result : true

<?php 
function myfunction ( stdClass $param ) {
    
}

echo (new ReflectionFunction("myfunction"))->getParameters()[0]->allowsNull() ? "true":"false";

?>

Result : false

<?php
function myfunction ( stdClass $param = null ) {
    
}

echo (new ReflectionFunction("myfunction"))->getParameters()[0]->allowsNull() ? "true":"false";
?>

Result : true

down

those-cradle-frays at duck dot com ¶

1 day ago

The note about detecting nullability on a parameter predates "?type" and other union types. Null isn't expected to be the default if there's a defined type that allows it ("?int", "mixed", "int|string|null", etc.).

<?php
function foo($bar) { }
(new ReflectionFunction('foo'))->getParameters()[0]->allowsNull();
// true

function foo(string $bar) { }
(new ReflectionFunction('foo'))->getParameters()[0]->allowsNull();
// false

function foo(?string $bar) { }
(new ReflectionFunction('foo'))->getParameters()[0]->allowsNull();
// true

function foo(?string $bar = 'baz') { }
(new ReflectionFunction('foo'))->getParameters()[0]->allowsNull();
// true (default string doesn't matter)

// Note: Raises E_DEPRECATED, implicitly making parameter nullable
function foo(string $bar = null) { }
(new ReflectionFunction('foo'))->getParameters()[0]->allowsNull();
// true (even in strict mode, PHP <= 8)
?>

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