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
