createTag() of AttributesTrait accesses a private attribute without a getter

[makoru-hikage]

Line 129 of AttributesTrait is faulty; it accesses a private attribute. The $attribute property of AttributesTrait used by Tag class is private, but it is accessed with the following:

$tag->attributes = $this->attributes;

The aforementioned line is Line 129 of AttributesTrait.

To summarize what happened: Using the AttributeTrait, class Attributes accessed the private $attributes of Tag class. Although both classes Tag and Attributes use the AttributesTrait that has private $attributes, they cannot access such property without doing a 'getter'.

Will think of a PR soon.
[The usage of PHP Traits is quite confusing, isn't it?]

[donquixote]

[The usage of PHP Traits is quite confusing, isn't it?]

Yes, I use them a lot less nowadays. They do not properly encapsulate anything, and make it really hard for an IDE to figure out what's going on. I wish PHP had real multiple inheritance.

[donquixote]

Is this not covered by any test, I wonder?

[donquixote]

Currently Tag / AttributesTrait are designed as immutable, so all the setters create copies. Nowadays I call such setters not setSomething(), but withSomething(), or withAddedSomething(). E.g. $car->withColor('blue').

Calling such methods always has a tiny little overhead.

Within a constructor or when an object is being freshly created, the immutable aspect is not really needed. I would prefer to not create object copies for no reason.

Maybe we should have a static method Tag::createWithAttributes($tagName, $attributes) ? Or add this as an optional parameter to Tag::__construct()?

One difficulty with static method constructors is always that they need to call new static or new self, so they might break in a subclass, if the subclass has a different constructor signature. I already kinda dislike AttributesTrait::create() for this reason.

[donquixote]

Or maybe a good design for immutable classes is to have a base class with protected mutable setters, and then a subclass which is immutable because it only calls those setters during construction?

[donquixote]

https://twitter.com/brain4lunch/status/786526053640482817 :)

[makoru-hikage]

"Or add this as an optional parameter to Tag::__construct()"

This solution seems elegant.

[donquixote]

Ok here is a simpler php example.
https://3v4l.org/0HNFH

trait T {
    public function __construct(private int $x = 5) {}
}

class C {
    use T;
    public function foo() {
        $d = new D();
        $d->x = 5;
    }
}

class D {
    use T;
}

(new C)->foo();

Indeed we get "Fatal error: Uncaught Error: Cannot access private property D::$x in /in/0HNFH:11"

It seems within this library the ->createTag() is not really used.
But perhaps other code wants to use it?