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Date: Mon, 16 Jan 2017 09:49:51 +0100
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To: Marco Pivetta <ocramius@gmail.com>
Cc: Wes <netmo.php@gmail.com>, PHP Internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Unsetting declared fields
From: michal@brzuchalski.com (=?UTF-8?Q?Micha=C5=82_Brzuchalski?=)

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Hi Marco,

2017-01-16 0:27 GMT+01:00 Marco Pivetta <ocramius@gmail.com>:

> Hi Wes,
>
> This has been discussed before, and it's currently used to intercept acce=
ss
> to properties. Since we don't have property accessors (sigh), the code
> (simplified version) would look like following:
>
> class Foo
> {
>     public $bar =3D 'baz';
> }
>
> class FooInterceptor extends Foo
> {
>     private $wrapped;
>     public function __construct(Foo $wrapped)
>     {
>         $this->wrapped =3D $wrapped;
>         unset($this->bar);
>     }
>     public function __get(string $name)
>     {
>         var_dump('reading ' . $name);
>         return $this->wrapped->$name;
>     }
> }
>
> $foo =3D new FooInterceptor(new Foo);
>
> var_dump($foo->bar);
>
> You can see a working example at https://3v4l.org/UtugD


There is one more thing might be confusing - reflection tells there still
exists bar property after unset while it's realy not.
For example https://3v4l.org/NAg1l

$class =3D new ReflectionClass(FooInterceptor::class);
$property =3D $class->getProperty('bar');
var_dump($property); // still exists while actually being unset may cause
errors

I'm sticking to extending class without magic _get method implemented.


>
>
> This behavior is protected from regressions since PHP 5.4, but has been
> working since 5.0:
> https://github.com/php/php-src/blob/cd2b462a2742c79256668d4736644e
> 34573c33d9/tests/classes/unset_properties.phpt
>
> We can most probably get rid of this weird behavior once property accesso=
rs
> are in the language.
>
> Greets,
>
> Marco Pivetta
>
> http://twitter.com/Ocramius
>
> http://ocramius.github.com/
>
> On Mon, Jan 16, 2017 at 12:20 AM, Wes <netmo.php@gmail.com> wrote:
>
> > Hello elephpants.
> >
> > Currently PHP allows explicitly declared fields (eg public $foo =3D 10;=
) to
> > be removed entirely through unset (eg unset($obj->foo)).
> >
> > Now that isn't really an issue as properties in php are currently untyp=
ed
> > and therefore nullable; at worst you would get a notice. But it would
> > become an issue with typed fields... that might get a second chance
> sooner
> > or later.
> >
> > But regardless of that, it looks very strange to me that this is allowe=
d
> > for fields that are explicitly declared. I think unset() should set the
> > field to null if it's declared in the class, and remove the field
> > altogether only if it was defined dynamically.
> >
> > On the other hand, this is just one of many ways of hacking php that ju=
st
> > exist and we accept / don't care because we have faith in other people
> not
> > doing nasty stuff with our code. This might sound ironic it is actually
> not
> > :P
> >
> > However, I am curious: what you think about this? Should PHP do somethi=
ng
> > in regard? Should this continue to work like it does now? Why do you fe=
el
> > it should do the one or the other?
> >
>



--=20
regards / pozdrawiam,
--
Micha=C5=82 Brzuchalski
about.me/brzuchal
brzuchalski.com

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