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Date: Fri, 15 Sep 2017 13:50:35 -0400
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To: Ilija Tovilo <ilija.tovilo@me.com>
Cc: Marco Pivetta <ocramius@gmail.com>, PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Deprecate the extract function in PHP 7.3
From: pollita@php.net (Sara Golemon)

On Fri, Sep 15, 2017 at 1:35 PM,  <ilija.tovilo@me.com> wrote:
> The `extract` function takes an associative array and
> puts it into the local symbol table.
> http://php.net/manual/en/function.extract.php
>
> I seriously doubt the usefulness of this function,
> especially looking at the potential risks. The fact
> that overwriting the local variables is the default
> behaviour doesn=E2=80=99t make it any better. I suggest
> deprecating it in PHP 7.3 and removing it in 8.
>
Preface: I despise extract() as well.  It's breaks assumptions for
both the developer and the runtime.  I save some of my frowniest of
faces for extract().

That said...

> I can see it=E2=80=99s usefulness in this case.
> But wouldn=E2=80=99t it be better to implement this by hand
> in these rare cases (it=E2=80=99s 3 lines of code) instead of
> encouraging the pollution of the symbol table by
> unknown input? It=E2=80=99s also clearer since people who
> don=E2=80=99t know the `extract` function probably don=E2=80=99t
> expect it to mutate the local symbol table.
>
Let's be clear on what that looks like: foreach ($data as $key =3D>
$value) { $$key =3D $value; }

This is SO MUCH WORSE for several reasons, no least of all what
happens when $data contains keys named 'data', 'key', or 'value'.

I'd like to kill extract(), but it does have a reason for being, and I
couldn't in any good conscience support removing it without a
replacement that's at least marginally better.

-Sara