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Date: Mon, 26 Feb 2018 14:05:24 +0100
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To: =?UTF-8?Q?Pedro_Magalh=C3=A3es?= <mail@pmmaga.net>
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Subject: Re: [PHP-DEV] [RFC] [Discussion] Arrays starting with a negative index
From: nikita.ppv@gmail.com (Nikita Popov)

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On Tue, Feb 13, 2018 at 9:03 PM, Pedro Magalh=C3=A3es <mail@pmmaga.net> wro=
te:

> Hi internals,
>
> I want to bring up this RFC once again given that now seems to be the rig=
ht
> timing for it. I have previously canceled the vote when I initially
> proposed this to land on 7.2 which was seen as too big of a BC for a mino=
r
> version. On a second attempt targeting 8.0 I have also canceled the vote =
as
> the inclusion of a deprecation notice in cases where the behavior will
> change warranted further discussion.
>
> To address these issues, the current version of the RFC will have 2
> separate votes:
> - Introduce the new behavior on 8.0
> - Introduce a deprecation notice on 7.3
>
> For those not familiar with the RFC, the general idea is that currently,
> any array that has a number n as it's first numeric key will have for it'=
s
> next implicit key either n+1 if n >=3D 0 or 0 if n < 0. This RFC proposes=
 to
> make this consistent by always using n+1 regardless of the sign of n.
> In code:
> $a[-2] =3D true; // Current: Key is -2, RFC: Key is -2
> $a[] =3D true; // Current: Key is 0, RFC: Key is -1
> $a[] =3D true; // Current: Key is 1, RFC: Key is 0
>
> I invite you to read the full RFC:
> https://wiki.php.net/rfc/negative_array_index and bring up any issues you
> see with the current version before the voting period starts.
>
> Looking forward for any feedback.
>
> Regards,
> Pedro Magalh=C3=A3es
>

I like the change, but I'm concerned about the technical impact that
deprecation notice will have. An error handler can convert the notice into
an exception, which means that zend_hash_next_index_insert is now going to
be a throwing operation. Apart from the fact that the currently linked
implementation is not exception-safe (if the deprecation notice throws, the
element is still inserted), it's quite likely that at least some of the
>250 uses of zend_hash_next_index_insert will not deal with exceptions
correctly.

Nikita

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