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Date: Fri, 25 Mar 2016 16:19:11 -0400
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To: Nikita Popov <nikita.ppv@gmail.com>
Cc: PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Allow empty property names
From: scott@paragonie.com (Scott Arciszewski)

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On Fri, Mar 25, 2016 at 1:45 PM, Nikita Popov <nikita.ppv@gmail.com> wrote:

> Hi internals,
>
> Currently we do not allow (*) creating empty property names on objects,
> i.e.
>
>     $obj->{''} =3D 42;
>
> is illegal. While empty property names are unlikely to be useful per se,
> they are problematic for deserialization of foreign formats like JSON. To
> avoid this issue {"": null} will currently decode to a property named
> "_empty_" rather than "". Notably, this means that JSON decode and encode
> do not round-trip (as we do not convert _empty_ back to an empty name whi=
le
> encoding).
>
> There is no technical reason (that I can see) for keeping this arbitrary
> restriction. I believe that the original reason for the restriction was o=
ur
> use of NUL-prefixed property names for name mangling, combined with the
> fact that an empty string at the C level happens to "start" with a NUL
> byte.
>
> A patch to drop the restriction and allow empty property names:
> https://github.com/php/php-src/pull/1836 It does not touch the JSON
> handling, as there are BC concerns involved there, I leave that to the
> ext/json maintainer.
>
> Any objections to changing this?
>
> Regards,
> Nikita
>
> (*) There are roundabout ways to create them anyway.
>

=E2=80=8BCurrently, this succeeds:

$x =3D json_decode('{"_empty_": "no", "": "foo"}', true);

While this does not:

$x =3D json_decode('{"_empty_": "no", "": "foo"}');

=E2=80=8Bhttps://3v4l.org/FJHVV
=E2=80=8Bhttps://3v4l.org/15Sfm=E2=80=8B

I'm personally 50/50 on it. =E2=80=8BI think allowing an empty property is =
kind of
weird, but not the weirdest behavior PHP allows. Overall, it might
(ironically enough!) make working with JSON _more_ consistent, and probably
have other benefits that I can't even imagine at the moment.

Scott Arciszewski
Chief Development Officer
Paragon Initiative Enterprises <https://paragonie.com/>=E2=80=8B

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