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Date: Sun, 18 Aug 2019 20:23:50 +0100
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To: internals@lists.php.net
Message-ID: <DE8144F4-6F3E-449A-AC16-1ED51B222CB0@gmail.com>
Subject: Re: [PHP-DEV] get_class_vars() and typed properties
From: rowan.collins@gmail.com (Rowan Collins)

On 18 August 2019 11:14:52 BST, Nicolas Grekas <nicolas=2Egrekas@gmail=2Eco=
m> wrote:
>Le dim=2E 18 ao=C3=BBt 2019 =C3=A0 11:59, Benjamin Morel <benjamin=2Emore=
l@gmail=2Ecom>
>a
>=C3=A9crit :
>
>> Hi Internals, I just noticed the following behaviour:
>>
>>     class A {
>>         public int $a;
>>         public ?int $b;
>>         public ?int $c =3D null;
>>     }
>>
>>     $a =3D new A;
>>
>>     var_export(get_object_vars($a));
>>     var_export(get_class_vars('A'));
>>
>> Result:
>>
>>     array (
>>         'c' =3D> NULL,
>>       )
>>     array (
>>       'a' =3D> NULL,
>>       'b' =3D> NULL,
>>       'c' =3D> NULL,
>>     )

>See https://bugs=2Ephp=2Enet/78319
>get_class_var() does the most useful thing, thus the correct one to me
>and
>the use cases I have=2E


This is a nice example of something I said when typed properties were bein=
g added: "uninitialised" is a new special state, distinct from "non-existen=
t" and "null"=2E As such, a non-nullable typed property without default val=
ue is impossible to represent accurately without having a representation of=
 that state=2E

One rather ugly possiblity in this case would be to have the values return=
ed be "uninitialized", so that accessing the array keys was valid, but acce=
ssing the values gave an Unitialized Value Error=2E That would be pretty ho=
rrible for backwards compatibility, though, particularly for get_class_prop=
erties, where there's no chance for the constructor to run and set up a rea=
l value=2E

Regards,

--=20
Rowan Collins
[IMSoP]