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Date: Wed, 25 Oct 2023 21:17:47 +0200
Message-ID: <CAPzBOBMGKSn00-tMXy8MFdrTCA6i+51N95+z6b+vubiUjcADJg@mail.gmail.com>
To: Pierre <pierre-php@processus.org>
Cc: Saki Takamachi <saki@sakiot.com>, PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Constructor promoted property and default value
From: landers.robert@gmail.com (Robert Landers)

On Mon, Oct 23, 2023 at 6:22=E2=80=AFPM Pierre <pierre-php@processus.org> w=
rote:
>
> Le 23/10/2023 =C3=A0 18:11, Saki Takamachi a =C3=A9crit :
> >> If I understand your use case properly, you should be confused by prop=
erties with default values that are not constructor-promoted as well ? Am I=
 wrong ? In this case, your problem is not with promoted properties ?
> > If we specify it the way you say, the initial values of the constructor=
 arguments will be available even when the constructor is not called.
> >
> > Such behavior felt a little counterintuitive.
>
> Which then would simply be the same behavior as properties when not
> promoted but declared in the class body instead:
>
> ```php
>
> class Foo
> {
>      public $val =3D 'abc';
> }
>
> $redis_foo =3D serialize(new Foo());
>
> $foo =3D unserialize($redis_foo);
> var_dump($foo->val);
> // string(3) "abc"
>
> ```
>
> Right ?
>
> What's the most disturbing in my opinion is that: `class Foo { public
> string $val =3D 'abc' }` and `class Foo { public function
> __construct(public string $val =3D 'abc' ) {}}` don't yield the same
> behavior at the time.
>
> Regards,
>
> --
>
> Pierre
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: https://www.php.net/unsub.php
>

Here's a nice and simple example:

https://3v4l.org/DU0tG

class A {
    public string $default =3D 'default';
}

class B {
    public function __construct(public string $default =3D 'default') {}
}

$a =3D new A();
echo "Original A: {$a->default}\n";
$b =3D new B();
echo "Original B: {$b->default}\n";

$a =3D (new ReflectionClass($a))->newInstanceWithoutConstructor();
echo "New A: {$a->default}\n";
$b =3D (new ReflectionClass($b))->newInstanceWithoutConstructor();
echo "New B: {$b->default}\n"; // crashes here

Robert Landers
Software Engineer
Utrecht NL