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Message-ID: <e5aee612-f9fa-ab4d-7b4c-f6a66b6ee37a@gmail.com>
Date: Thu, 26 May 2016 10:44:40 +0100
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Subject: Re: [PHP-DEV] [RFC][Vote] Typed Properties
From: rowan.collins@gmail.com (Rowan Collins)

On 25/05/2016 22:03, Fleshgrinder wrote:
> We already have the differentiation between IS_NULL and IS_UNDEF, why
> not expose the latter to userland?

I wondered if the conversation would go in this direction. This has been 
discussed to death, and in my opinion all the reasons given in previous 
discussions why isset() is not broken, and we do not need a new magic 
value / type, are just as valid in the case of object properties as 
anywhere else.

I can see an advantage to this raising some kind of warning:

class A { ?int $foo }
$a = new A;
var_dump($a->foo); // not initialized yet!

But it should absolutely not be possible to detect the difference 
between that and this:

class A { ?int $foo }
$a = new A;
$->foo = null;
var_dump($a->foo); // null

Because that is exactly the same as this:

var_dump($foo); // not initialized yet!

vs this:

$foo = null;
var_dump($foo);


The warning or error on unitialized variables or properties is an 
assertion - code should be written such that it simply *can't* happen. 
If you're unsure if something's set, you can always do this:

if ( ! isset($this->foo) ) { $this->foo = null; }

If it's already an explicit null, you perform one unnecessary operation; 
if it's never been initialized, it has now.


Regards,
-- 
Rowan Collins
[IMSoP]