How to define default attribute as empty array in lumen

Question

currently i am using mongodb as database, i have created a collection in which every field needs to be typed array,also i want them to be set as default empty array if value not provided.

class Scores extends Eloquent
{
    /**
     * The table associated with the model.
     *
     * @var string
     */
    protected $table = 'AllScore';

    /**
     * The attributes that should be cast.
     *
     * @var array
     *
     */
    protected $casts = [
        
        'y3_score'   => 'array',
        'y4_score'   => 'array',
        'y5_score'   => 'array',
        'y6_score'   => 'array',
    ];

    /**
     * The model's default values for attributes.
     *
     * @var array
     */
    protected $attributes = [
        'y3_score'   => [],
        'y4_score'   => [],
        'y5_score'   => [],
        'y6_score'   => [],
    ];
    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'y3_score',
        'y4_score',
        'y5_score',
        'y6_score',
    ];

    /**
     * The attributes excluded from the model's JSON form.
     *
     * @var array
     */
    protected $hidden = [
    ];
}

But at the time of post request, creating the data for this collection it return the error

(1/1) ErrorException
json_decode() expects parameter 1 to be string, array given

in HasAttributes.php line 715

at Application->Laravel\Lumen\Concerns\{closure}(2, 'json_decode() expects parameter 1 to be string, array given', '/var/www/html/pathway_ws/LumenConnection/vendor/illuminate/database/Eloquent/Concerns/HasAttributes.php', 715, array('value' => array(), 'asObject' => false))

But when i removed these default empty array for attributes everything works fine

Answer 1

I have faced the similar error (but Laravel with MySql) Decision was simple:

    protected $attributes = [
    'y3_score'   => '[]',
    ...
];

Pay attention to apostrophes around the []