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In-Reply-To: <2c497732-96f8-3ef0-bc18-912220fbff4d@gmail.com>
Date: Sun, 10 Mar 2019 19:56:27 +0100
Cc: PHP Internals <internals@lists.php.net>
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Message-ID: <EF8808F3-262F-4EF6-9E57-7B6BF1898589@gmail.com>
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To: Rowan Collins <rowan.collins@gmail.com>
Subject: Re: [PHP-DEV] RFC: Locked Classes
From: gadelat@gmail.com (Gabriel O)

Isn=E2=80=99t unset() currently only way to remove reference? This part =
is hence very problematic.

> On 10. Mar 2019, at 19:35, Rowan Collins <rowan.collins@gmail.com> =
wrote:
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> Hi all,
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> I'd like to present a new RFC for "locked classes": classes which =
restrict dynamically adding or removing properties from their instances.
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> While it can be useful, the ability to set an object property which is =
not part of the class definition can also lead to subtle bugs. Banning =
this for all objects would be a significant and painful breaking change, =
so I propose instead the option to mark a particular class with a new =
keyword, "locked".
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> An instance of a locked class behaves like any other object, except =
that:
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> - Attempting to set a property on the instance which was not declared =
in the class (or inherited from one of its parent classes) will throw an =
error, and the instance will not be modified.
> - Attempting to read a property on the instance which was not declared =
(or inherited) will throw an error, rather than raising a Notice and =
evaluating to null.
> - Attempting to call unset() on any property of the instance will =
throw an error, and the instance will not be modified.
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> Note that ECMAScript  / JavaScript includes a similar feature, called =
"sealed objects". However, the proposed modifier applies to classes, and =
"sealed class" has a different meaning elsewhere (e.g. C#, Kotlin), so =
I've chosen "locked class" to avoid confusion.
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> For further details and examples, please check the RFC at =
https://wiki.php.net/rfc/locked-classes and the tests in the draft =
implementation at https://github.com/php/php-src/pull/3931
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> Regards,
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> --=20
> Rowan Collins
> [IMSoP]
>=20
>=20
> --=20
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>=20