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Date: Sun, 13 Aug 2017 21:34:13 +0300
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Subject: Re: [Request][Discussion] Double value as array key improvement
From: newaltgroup@bk.ru (Andrew Nester)

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> 11 =E0=E2=E3. 2017 =E3., =E2 15:53, Andrew Nester <newaltgroup@bk.ru> =ED=E0=
=EF=E8=F1=E0=EB(=E0):
>=20
>=20
>> On Aug 11, 2017, at 2:10 PM, Andrew Nester <newaltgroup@bk.ru> wrote:
>>=20
>> Hello everyone!
>>=20
>> I was working on following request https://bugs.php.net/bug.php?id=3D7505=
3 which resulted in following pull request https://github.com/php/php-src/pu=
ll/2676
>>=20
>> The problem here is following: when we=92re using large numbers as array i=
ndex when adding new elements it could overwrite already existing value.
>> Assume we have 2 indexes 5076964154930102272 and 999999999999999999999999=
999999 with different value set for them.
>>=20
>> Because 999999999999999999999999999999 is larger than maximum long int nu=
mber 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 i=
nteger. (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=92ve got index equal to 5076964154=
930102272 and as a result - we=92re overwriting previously set value.
>>=20
>> My suggestion is following:
>> 1) when double key is less than maximum possible long integer - convert i=
t to integer
>> 2) if it=92s larger - convert it to string.
>>=20
>> That=92s what implemented in proposed PR.
>>=20
>> Another possible option is just to throw warning in this case (proposed b=
y Nikita Popov)
>>=20
>> I would happy to hear any feedback and suggestions about this solution.
>> Thanks!
>=20
> Here is the alternative solution which emits E_WARNING in case of integer a=
rray index overflow.
> https://github.com/php/php-src/pull/2677

Bumping the discussion because not everyone could see my previous email due t=
o wrong configuration on my side, sorry.

Cheers,
Andrew=

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