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Date: Fri, 28 Nov 2025 10:00:52 +0100
To: "Rowan Tommins [IMSoP]" <imsop.php@rwec.co.uk>
Cc: internals@lists.php.net
Subject: Re: [PHP-DEV] [RFC] Context Managers
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From: tim@bastelstu.be (=?UTF-8?Q?Tim_D=C3=BCsterhus?=)

Hi

Am 2025-11-06 13:18, schrieb Rowan Tommins [IMSoP]:
> I think the relationship to Iterators is significant: if you put an 
> iterator in a variable, it's perfectly possible to use it in two 
> different foreach statements, or manually call the interface methods, 
> and get very confusing results.
> 
> But most of the time, you don't take a reference to the iterator at 
> all, and the same would be true of Context Managers:
> 
> foreach ( $foo->iterate() as $item ) { ... }
> with ( $foo->guard() as $resource ) { ... }

The reference to the sibling thread probably fits even better here than 
in my previous reply. So I'm putting another reference: 
https://news-web.php.net/php.internals/129467

> there's nothing stopping you calling __construct or __destruct as 
> normal methods, and causing all sorts of unintended behaviour.

That is *technically* true and there are indeed some “expert-level” use 
cases where calling these manually - except for `parent::` I guess - is 
required (e.g. lazy objects), but there's a very significant difference: 
Those are magic methods following the naming scheme of magic methods. 
The `__` prefix is a visual indicator that the methods are somehow 
special and probably not meant to be used directly.

The documentation at 
https://www.php.net/manual/en/language.oop5.magic.php states 
(highlighting mine):

> Magic methods are special methods which **override PHP's default's 
> action** when certain actions are performed on an object.
> 
> All methods names **starting with __** are reserved by PHP.

This is not true for the context manager methods. From a developer's PoV 
these are normal methods on a class with nothing screaming “be careful”. 
The interface *could* serve as a invitation for folks to read the 
documentation on how the interface methods are meant to be used, but we 
all know how that works in practice with an IDE suggesting 
normal-looking methods that appear to do the right thing (until they 
don't).

Best regards
Tim Düsterhus