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Date: Thu, 17 Aug 2017 14:01:18 -0300
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To: Andrew Nester <andrew.nester.dev@gmail.com>
Cc: PHP Internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Re: [Request][Discussion] Double value as array key improvement
From: david.proweb@gmail.com (David Rodrigues)

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Just reposting to internals:

David wrote:
> If the key is user dependent (eg. Input from form), could it causes a
warning too, right? I think that it should be considered a BC.

Andrew Nester wrote:
> Yes, warning will be emitted in this case as well but actual index will
remain the same.
> I could agree that it's minor BC break as it could affect users


2017-08-17 12:03 GMT-03:00 Andrew Nester <andrew.nester.dev@gmail.com>:

>
>
> > 13 =D0=B0=D0=B2=D0=B3. 2017 =D0=B3., =D0=B2 21:39, Andrew Nester <andre=
w.nester.dev@gmail.com>
> =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB(=D0=B0):
> >
> >
> >
> >> 11 =D0=B0=D0=B2=D0=B3. 2017 =D0=B3., =D0=B2 15:53, Andrew Nester <newa=
ltgroup@bk.ru> =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB(=D0=B0):
> >>
> >>
> >>> On Aug 11, 2017, at 2:10 PM, Andrew Nester <newaltgroup@bk.ru> wrote:
> >>>
> >>> Hello everyone!
> >>>
> >>> I was working on following request https://bugs.php.net/bug.php?
> id=3D75053 which resulted in following pull request
> https://github.com/php/php-src/pull/2676
> >>>
> >>> The problem here is following: when we=E2=80=99re using large numbers=
 as array
> index when adding new elements it could overwrite already existing value.
> >>> Assume we have 2 indexes 5076964154930102272 and
> 999999999999999999999999999999 with different value set for them.
> >>>
> >>> Because 999999999999999999999999999999 is larger than maximum long in=
t
> number for 64-bit systems, it will be converted to double. (corresponding
> code here https://github.com/php/php-src/blob/master/Zend/zend_
> language_scanner.l#L1648)
> >>> But when double value is used as array indexes, it is converted to
> long integer. (f.e., code is here https://github.com/php/php-
> src/blob/master/Zend/zend_execute.c#L1573)
> >>> At this case it causes overflow and we=E2=80=99ve got index equal to
> 5076964154930102272 and as a result - we=E2=80=99re overwriting previousl=
y set
> value.
> >>>
> >>> My suggestion is following:
> >>> 1) when double key is less than maximum possible long integer -
> convert it to integer
> >>> 2) if it=E2=80=99s larger - convert it to string.
> >>>
> >>> That=E2=80=99s what implemented in proposed PR.
> >>>
> >>> Another possible option is just to throw warning in this case
> (proposed by Nikita Popov)
> >>>
> >>> I would happy to hear any feedback and suggestions about this solutio=
n.
> >>> Thanks!
> >>
> >> Here is the alternative solution which emits E_WARNING in case of
> integer array index overflow.
> >> https://github.com/php/php-src/pull/2677
> >
> > My preferred solution is 2nd one (emitting warning) as it more obvious
> for users, doesn't break previous behaviour.
> >
> > Cheers,
> > Andrew
>
> Hello internals!
>
> I was working on solution for the problem of double to int conversion for
> array indices and would like to create an RFC for proposed solution -
> emitting warning when integer overflow happens during double to int
> conversion.
>
> Does it look like good idea?
>
> Thanks!




--=20
David Rodrigues

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