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Date: Thu, 14 Aug 2014 10:04:36 +0200
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To: Tjerk Meesters <tjerk.meesters@gmail.com>
Cc: PHP Internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Evaluation of constructor arguments if there's no constructor
From: jpauli@php.net (Julien Pauli)

On Thu, Aug 14, 2014 at 8:26 AM, Tjerk Meesters
<tjerk.meesters@gmail.com> wrote:
> Hi internals,
>
> I was sifting through the bucket o=E2=80=99 bugs and found these two rela=
ted issues:
> https://bugs.php.net/bug.php?id=3D67829
> https://bugs.php.net/bug.php?id=3D54162 (closed)
>
> They concern the behaviour of the engine when a class defines no construc=
tor or if the class to be instantiated doesn=E2=80=99t exist, which can be =
seen here: http://3v4l.org/jOQY0
>
> This is obviously a design decision, but doesn=E2=80=99t seem to have a m=
ention in the documentation nor the spec (I couldn=E2=80=99t find it under =
the =E2=80=98new=E2=80=99 operator).
>
> I can add a paragraph in the documentation for it; the question is whethe=
r it should also be added to the spec, seeing how HHVM and PHP behave diffe=
rently in this respect? It could be added as implementation dependent behav=
iour I suppose?

This is a known behavior which is part of the VM.
It is designed at http://lxr.php.net/xref/PHP_5_5/Zend/zend_vm_def.h#3383

I guess its an optimisation that prevents the compiler from compiling
a ZEND_DO_FCALL for constructors, which optimizes a bit the VM path
for object construction.
Dmitry should have more informations.

I'm +1 for a documentation or spec mention.


Julien.Pauli