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Date: Wed, 27 Feb 2019 11:00:42 -0300
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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] [RFC] Saner string to number comparisons
From: carusogabriel34@gmail.com (Gabriel Caruso)

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Em ter, 26 de fev de 2019 =C3=A0s 09:28, Nikita Popov <nikita.ppv@gmail.com=
>
escreveu:

> Hi internals,
>
> I think it is well known that =3D=3D in PHP is a pretty big footgun. It d=
oesn't
> have to be. I think that type juggling comparisons in a language like PHP
> have some merit, it's just that the particular semantics of =3D=3D in PHP=
 make
> it so dangerous. The biggest WTF factor is probably that 0 =3D=3D "foobar=
"
> returns true.
>
> I'd like to bring forward an RFC for PHP 8 to change the semantics of =3D=
=3D
> and other non-strict comparisons, when used between a number and a string=
:
>
> https://wiki.php.net/rfc/string_to_number_comparison
>
> The tl;dr is that if you compare a number and a numeric string, they'll b=
e
> compared as numbers. Otherwise, the number is converted into a string and
> they'll be compared as strings.
>
> This is a very significant change -- not so much because the actual BC
> breakage is expected to be particularly large, but because it is a silent
> change in core language semantics, which makes it hard to determine wheth=
er
> or not code is affected by the change. There are things we can do about
> this, for example the RFC suggests that we might want to have a transitio=
n
> mode where we perform the comparison using both the old and the new
> semantics and warn if the result differs.
>
> I think we should give serious consideration to making such a change. I'd
> be interested to hear whether other people think this is worthwhile, and
> how we could go about doing it, while minimizing breakage.
>
> Regards,
> Nikita
>

Hi Nikita,

There's only one case that I'm not sure about

> Comparison    | Before | After
> ------------------------------
>  0 =3D=3D ""      | true   | false

I know that a cast of am empty and non-empty string results into 0 (
https://3v4l.org/W0P3Z), but still, not sure about this one in specific.

Best,
--=20
Gabriel Caruso

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