PHP - Override static variable inside trait

Question

I have the following trait:

<?php

namespace App\Traits;

trait SlugGenerator
{
    public static $slugAttributes;

    public static function bootSlugGenerator()
    {
        static::creating(function ($model) {
            if(isset(self::$slugAttributes)){
                $model->slug = 'a';
            } else {
                $model->slug = 'b';
            }
        });
    }
}

And here I call my trait:

<?php

namespace App\Models;

use App\Traits\SlugGenerator;
use Illuminate\Foundation\Auth\User as Authenticatable;

class User extends Authenticatable
{
    use SlugGenerator;

    protected static $slugAttributes = [
        'first_name',
        'last_name'
    ];
}

But I get the following error:

App\Models\User and App\Traits\SlugGenerator define the same property ($slugAttributes) in the composition of App\Models\User. However, the definition differs and is considered incompatible. Class was composed

How to override the $slugAttributes variable?

You can't. Traits aren't inheritance and doesn't work in the same way as extending classes. — M. Eriksson, Apr 12 '19 at 05:40
@MagnusEriksson In Laravel, the models override variables... By example the `protected $fillable` variable located inside the `GuardsAttributes` trait... — Caio Kawasaki, Apr 12 '19 at 05:41
Possible duplicate of [Overriding Doctrine Trait Properties](https://stackoverflow.com/questions/32571920/overriding-doctrine-trait-properties) — Naveen Kumar, Apr 12 '19 at 05:41

score 2 · Answer 1 · edited Nov 08 '19 at 03:30

2

One possible solution would be not to declare $slugAttributes in your trait like in the following example:

<?php

trait Foo
{
    public function greet()
    {
        return 'hello ' . $this->target;
    }
}

class Bar
{
    use Foo;

    private $target = 'world';
}

$bar = new Bar();

var_dump($bar->greet());
// > string(11) "hello world"

edited Nov 08 '19 at 03:30

Skeets

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answered Apr 12 '19 at 06:58

Kamil Solecki

70
6

PHP - Override static variable inside trait

1 Answers1