Unexpected behavior while trying to fill and save a non-db property

[FabianoLothor]

Laravel Version

12

PHP Version

8.4

Database Driver & Version

SQLite

Description

I might be missing something but today I noticed something weird while trying to fill and save an object where the fillable attribute is a mutator.

Steps To Reproduce

This works fine:

// ...
class Task extends Model
{
    protected $fillable = [
        // ...
        'tags',
    ];

    protected $appends = [
        'tags',
    ];

    // ...

    public function tags(): Attribute
    {
        return Attribute::make(
            get: fn() => $this->categories()->pluck('name'),
        );
    }

    public function setTagsAttribute($value)
    {
        // Do something...
    }
}

This throws an error onSave/Update:

// ...
class Task extends Model
{
    protected $fillable = [
        // ...
        'tags',
    ];

    protected $appends = [
        'tags',
    ];

    // ...

    public function tags(): Attribute
    {
        return Attribute::make(
            get: fn() => $this->categories()->pluck('name'),
            set: function ($value) {
                // Do something...
            },
        );
    }
}

Error message:

SQLSTATE[HY000]: General error: 1 no such column: tags (Connection: sqlite, SQL: update "tasks" set "tags" = ?, ...

What am I missing? Why the Attribute->set behavior is different from the old fashion mutator?

[rodrigopedra]

Can you share your mutator's body?

A mutator should return either a value or an associative array with the columns to be updated as keys.

In your case, I assume you don't want any columns to be updated, as it seems to be a convenience attribute to ease the relation access, right?

But every function in PHP returns something. Even when no explicit return is given, or even when a function or method has a return type of void, it returns null.

Reference: https://www.php.net/manual/en/language.types.void.php

To tell Eloquent the setter should not touch any columns in the database, you can return an empty array:

public function tags(): Attribute
{
    return Attribute::make(
        get: fn () => $this->categories()->pluck('name'),
        set: function ($value) {
            $this->categories()
                ->sync(Category::query()->whereIn('name', $value)->pluck('id'));
            
            // no columns should be updated
            return [];
        },
    );
}

[FabianoLothor]

Can you share your mutator's body?

A mutator should return either a value or an associative array with the columns to be updated as keys.

In your case, I assume you don't want any columns to be updated, as it seems to be a convenience attribute to ease the relation access, right?

But every function in PHP returns something. Even when no explicit return is given, or even when a function or method has a return type of void, it returns null.

Reference: https://www.php.net/manual/en/language.types.void.php

To tell Eloquent the setter should not touch any columns in the database, you can return an empty array:

public function tags(): Attribute
{
return Attribute::make(
get: fn () => $this->categories()->pluck('name'),
set: function ($value) {
$this->categories()
->sync(Category::query()->whereIn('name', $value)->pluck('id'));

        // no columns should be updated
        return [];
    },
);

}

So, my main question is to understand why the tags(): Attribute->set is not called while the setTagsAttribute() is called when I try to ->fill(...) my model.

I did not get it, I thought the new : Attribute mutators were a replacement of the old fashioned mutators, but their behavior are different.

[rodrigopedra]

On the test app I made for this, it is called when fill() is called.

I added a dump() call into the mutator:

public function tags(): Attribute
{
    return Attribute::make(
        get: fn () => $this->categories()->pluck('name'),
        set: function ($value) {
            \dump([__METHOD__ => $value]);

            $this->categories()->sync(Category::query()->whereIn('name', $value)->pluck('id'));

            // no columns should be updated
            return [];
        },
    );
}

The calling code is like this:

<?php

use Illuminate\Support\Facades\Artisan;

Artisan::command('app:test', function () {
    $task = \App\Models\Task::query()->first();

    $task->fill([
        'tags' => ['Lime', 'Pink'],
    ])->save();

    \dump($task->fresh('categories')->tags);
});

And this is the output:

$ php artisan app:test
array:1 [
  "App\Models\{closure}" => array:2 [
    0 => "Lime"
    1 => "Pink"
  ]
] // app/Models/Task.php:29
Illuminate\Support\Collection^ {#957
  #items: array:2 [
    0 => "Pink"
    1 => "Lime"
  ]
  #escapeWhenCastingToString: false
} // routes/console.php:12

You can see the first dump is from the model's mutator.

I uploaded the test app to a public repository in case you want to share what is done differently:

https://github.com/rodrigopedra/issues-57043

[FabianoLothor]

Thank you for take the time to do this test Rodrigo, I'll retry in a small version of my current scenario as you did and review from there.

I'll report my findings here.

For more context, I'm on greenfield, my project setup is laravel 12.x, filament 4.x, php 8.4, tailwind 4.x.