Decimal loses precision because of internal cast to float

[Sjord]

• Laravel Version: illuminate/database 9.45
• PHP Version: PHP 8.2.0
• Database Driver & Version: none

Description:

When specifying a field to be cast as decimal, it is still internally converted to float by the call to number_format. This loses precision.

Steps To Reproduce:

<?php

require('vendor/autoload.php');

use Illuminate\Database\Eloquent\Model;

final class Member extends Model {
    public $timestamps = false;
    protected $casts = [
        'amount' => 'decimal:20',
    ];
}

$member = new Member();
$member->amount = '0.1';
var_dump($member->amount);

Outputs:

string(22) "0.10000000000000000555"

Expected:

string(22) "0.10000000000000000000"

[timacdonald]

I've opened a PR to start addressing this. We can continue the conversation in the PR instead.

See #45456