Hi,
Reviewing the patch sources I found few inconsistent decisions not mentioned in
RFC.
1) static typed properties are prohibited. why?
2) The handling of multiple properties in the same declaration statement is
inconsistent.
public int $bar, string $qux; // this works
public int $bar, $qux; //this emits error: Untyped property A::$qux
must not be mixed with typed properties
It's better to allow type only before first property in the list and apply them
to all of them (like C, Java and others).
Is this just an implementation issue?
3) We already have nullable arguments without any special syntax. We should
reuse the similar approach for properties.
public int $num = null;
4) There's a mess with initialization of typed properties. (typed properties
are initialized by IS_UNDEF, untyped by IS_NULL).
I think it might be better to implicitly initialize them according to type (if
default value is not provided): bool by false, int by 0, double by 0.0, string
by "" (interned), array by [] (immutable), objects by NULL (always nullable).
Also I found a number of implementation problems:
5) We can't change property_info->type_ce for internal properties, because they
are shared between threads.
Can property of Internal class have a type of user class? This would lead to
crash on second request.
6) $x->a++; doesn't throw on overflow
7) ++$a->a; and += throw on overflow, but change the property value to "float"
8) Reference handling in ZEND_FETCH_OBJ_W is not robust. At least, EXT_NOP or
TICK may be inserted before next ASSIGN_REF. Handling of ZEND_ADD_ARRAY_ELEMENT
and ZEND_YIELD is too pessimistic, missing support for SEND_REF and may be
others.
9) Often calls to zend_object_fetch_property_type_info() are not good for
performance. Currently FETCH_OBJ_X cache "offset" to property, in general we
may go back and cache address of "property_info", but this is going to decrease
performance for each property access. It would be great to find a better
solution. May be using zval.reserved.
I assume, I didn't find all problems yet.
I think, both RFC and implementation have problems.
I may try to help with implementation.
(9) is the most difficult problem, and I'll try to solve it first.
Do you see any problems with updating RFC with (2), (3), (4)?
(1) would also make proposal more consistent, but I assume you got some
troubles implementing it and I don't know about them yet.
Thanks. Dmitry.
________________________________________
From: Dmitry Stogov <[email protected]>
Sent: Tuesday, March 29, 2016 19:24
To: Joe Watkins
Cc: Phil Sturgeon; [email protected]; [email protected]
Subject: Re: [PHP-DEV] [RFC Discussion] Typed Properties
Thanks. I'll start tomorrow morning and will try to send you update by the
evening,
________________________________
From: Joe Watkins <[email protected]>
Sent: Tuesday, March 29, 2016 19:18
To: Dmitry Stogov
Cc: Phil Sturgeon; [email protected]; [email protected]
Subject: Re: [PHP-DEV] [RFC Discussion] Typed Properties
Hi Dmitry,
The patch is pretty close to complete.
When you start to dig a bit further, you'll notice that I prepared for
using cached pointers to prop info, but, I'm not sure how to allocate those as
the handlers are using the currently allocated slots so differently.
I also patched opcache, but it's probably wrong (or not good enough, not
sure what to do about type_ce).
Please do start working on the patch, that would be great ... I'll leave it
alone for you to do your thing :)
Cheers
Joe
On Tue, Mar 29, 2016 at 5:12 PM, Dmitry Stogov
<[email protected]<mailto:[email protected]>> wrote:
Hi Phil, hi Joe,
Is your patch complete?
I took just a brief review yet, and I would like to make a deep check once
again (and may be optimization).
I saw, the patch makes some slowdown, but less than I expected.
If you are not going to modify the patch in next two days, I would start
working on it tomorrow.
RFC itself looks fine.
Thanks. Dmitry.
________________________________________
From: Phil Sturgeon <[email protected]<mailto:[email protected]>>
Sent: Tuesday, March 29, 2016 18:32
To: Andrey Andreev
Cc: [email protected]<mailto:[email protected]>
Subject: Re: [PHP-DEV] [RFC Discussion] Typed Properties
I'd like to thank everyone for their feedback on this RFC!
It looks like the majority of concerns were solved during the course
of this discussion, which is great news.
The RFC has been expanded in a few areas to take care of a few other
concerns, so please go and review it and let me know if you have any
feedback.
https://wiki.php.net/rfc/typed-properties
Voting will start in a few days.
Cheers,
Phil
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