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CC: PHP internals <internals@lists.php.net>, Phil Sturgeon
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Date: Wed, 25 May 2016 10:06:17 +0300
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Subject: Re: [PHP-DEV] [RFC][Vote] Typed Properties
From: dmitry@zend.com (Dmitry Stogov)

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On 05/25/2016 09:06 AM, Joe Watkins wrote:
> Morning Dmitry,
>
>    There's no section for nullables, but there is mention of them, 
> specifically in relation to your query:
>
>    > While parameters allow null to be accepted as the default value, 
> null is only a valid value for nullable properties.
>
>    Is there something wrong with that rule ?

It's OK. This just should be defined and it's defined in RFC (I missed)
>
>    Having explicit nullability means the declaration tells you all you 
> need to know, all the time.
>
>    Being able to set null any typed property means you can never be 
> sure of the type; You can't tell by looking at the declaration what 
> type the variable will be because anything is allowed to set it null.
>
>    We waited for explicit nullability to avoid this.
>
>    You'll have to have a really good reason for me to change that rule :)
>
>    > Inheritance rules for typed nullable properties are also missed.
>
>    That's true, but shouldn't they use the same rules as nullable 
> parameters, will discussion change how they should work ?
I made this check(s) to be invariant. You may like to do this differently...
It's  better to define this in RFC, check implementation and add tests.

>
>    > but still have unsolved problems.
>
>    If you have discussed these somewhere, can you send/show the 
> transcript ? (I missed all comms after yesterday morning, due to illness).

We are working with Bob, trying to improve the patch. I added new tests 
fixing the problems, and also added few comments o github.
>
>    If it emerges that the RFC needs to be modified heavily, then I'm 
> happy to stop the voting.

RFC doesn't define how uninitialized nullable typed properties should 
behave.

class C {
   public $a;
   public int $b;
   public ?int $c;
}
$obj = new C;
var_dump($obj->a); // NULL
var_dump($obj->b); // throw Error("")
var_dump($obj->c); // first or second??? (currently throw Error("")).
$obj->$a = null;
$obj->$b = null; // throw Error("")
$obj->$c = null;
var_dump($obj->a); // NULL
var_dump($obj->b); // throw Error("")
var_dump($obj->c); // NULL
unset($obj->$a);
unset($obj->$b);
unset($obj->$c);
var_dump($obj->a); // notice + NULL
var_dump($obj->b); // throw Error("")
var_dump($obj->c); // first or second??? (currently throw Error("")).

This should be defined.

>
>
>    But, so far, we haven't actually deviated from the RFC, only 
> changed implementation details that are not part of the design of the 
> feature.

I'm not so sure.
Anyway, I hope you are better and we will able to speak today or tomorrow.

Thanks. Dmitry.

>
>    Sorry if it seems like I'm missing information, I don't know what 
> you and Bob found out yet ...
>
>    I super appreciate you guys working on it, obviously. Thanks for 
> that :)
>
> Cheers
> Joe
>
> On Tue, May 24, 2016 at 8:04 PM, Dmitry Stogov <dmitry@zend.com 
> <mailto:dmitry@zend.com>> wrote:
>
>     Hi Joe,
>
>     I've add implementation for nullable typed properties (as they fit
>     into the patch design), but RFC missed any description of nullable
>     properties.
>     See tests Zend/tests/type_declarations/typed_properties_047.phpt,
>     Zend/tests/type_declarations/typed_properties_048.phpt,
>     Zend/tests/type_declarations/typed_properties_049.phpt
>
>     I'm not sure, if this is what the voters expect. At least I don't
>     like the facts that "?int $foo;" declares uninitialized property;
>     "?int $foo = NULL" may be unset() and became uninitialized; and
>     it's an open question if "int $foo = NULL;" should be supported as
>     nullable. Inheritance rules for typed nullable properties are also
>     missed.
>
>     Personally, I think the RFC was moved into voting state too early
>     (without good enough implementation, and with missing topics).
>     The current implementation is better (performance penalty reduced
>     to ~2%), but still have unsolved problems.
>
>     May be it's better to cancel voting, solve problems, finish the
>     implementation and add missing questions into RFC...
>     I'm going to help with implementation in any case, but we should
>     agree on what we are doing.
>
>     Thanks. Dmitry.
>
>     ________________________________________
>     From: Joe Watkins <pthreads@pthreads.org
>     <mailto:pthreads@pthreads.org>>
>     Sent: Friday, May 20, 2016 9:05:34 AM
>     To: PHP internals; Phil Sturgeon
>     Subject: [PHP-DEV] [RFC][Vote] Typed Properties
>
>     Morning internals,
>
>         Since we have our answer on nullable types, typed properties
>     can now go
>     to vote.
>
>     https://wiki.php.net/rfc/typed-properties#vote
>
>         Note that, support for nullability as RFC'd will be merged
>     when the
>     implementation for nullable_types is merged into master.
>
>         Please participate.
>
>     Cheers
>     Joe
>
>


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