Bug: Entity::jsonSerialize() returns strange dates

[kenjis]

PHP Version

8.1

CodeIgniter4 Version

4.4.3 and develop

CodeIgniter4 Installation Method

Git

Which operating systems have you tested for this bug?

macOS

Which server did you use?

cli-server (PHP built-in webserver)

Database

MySQL 8.0.34

What happened?

Entity with dates returns JSON with strange format of dates.

    "created_at": {
        "date": "2023-12-07 04:00:48.000000",
        "timezone_type": 3,
        "timezone": "UTC"
    },

Steps to Reproduce

+----+------------+--------------------+---------+--------------------+--------------------+------------+
| id | name       | email              | country | created_at         | updated_at         | deleted_at |
+----+------------+--------------------+---------+--------------------+--------------------+------------+
| 1  | John Smith | john@example.co... | US      | 2023-12-07 04:0... | 2023-12-07 04:0... |            |
+----+------------+--------------------+---------+--------------------+--------------------+------------+

<?php

namespace App\Models;

use App\Entities\User;
use CodeIgniter\Model;

class UserModel extends Model
{
    protected $table            = 'user';
    protected $returnType       = User::class;
    protected $allowedFields    = [
        'name',
        'email',
        'country',
    ];

    // Dates
    protected $useTimestamps = true;
    protected $dateFormat    = 'datetime';
    protected $createdField  = 'created_at';
    protected $updatedField  = 'updated_at';
    protected $deletedField  = 'deleted_at';
}

<?php

namespace App\Entities;

use CodeIgniter\Entity\Entity;

class User extends Entity
{
    protected $datamap = [];
    protected $dates   = ['created_at', 'updated_at', 'deleted_at'];
    protected $casts   = [];
}

    public function index()
    {
        $users = new UserModel();
        /** @var User $user */
        $user = $users->find(1);
        echo json_encode($user, JSON_PRETTY_PRINT);
    }

{
    "id": "1",
    "name": "John Smith",
    "email": "john@example.com",
    "country": "US",
    "created_at": {
        "date": "2023-12-07 04:00:48.000000",
        "timezone_type": 3,
        "timezone": "UTC"
    },
    "updated_at": {
        "date": "2023-12-07 04:00:48.000000",
        "timezone_type": 3,
        "timezone": "UTC"
    },
    "deleted_at": null
}

Expected Output

{
    "id": "1",
    "name": "John Smith",
    "email": "john@example.com",
    "country": "US",
    "created_at": "2023-12-07 04:00:48",
    "updated_at": "2023-12-07 04:00:48",
    "deleted_at": null
}

Anything else?

See also #8302

[michalsn]

Seems like the default behavior for the DateTime object.

If we want to change it, the question is, do we really want to lose the time zone information?

[neznaika0]

Yes, it defaut action for JSON dates. Timezone may be set
2023-12-07 04:00:48 +1:00
2023-12-07 04:00:48 Europe/Berlin
?

[kenjis]

If we want to change it, the question is, do we really want to lose the time zone information?

Yes. Because this issue is about the default behavior.
And (string) Time::now() returns a string without timezone like 2023-12-08 00:58:44.

Whether timezone is required or not depends on requirement.
If it is needed, a dev can override the jsonSerialize() method.

[michalsn]

I don't have a strong opinion about this, but I wouldn't call it a bug.

If we want to change this behavior that should be considered as a breaking change since the default value for JSON will change. Developers who have built an API may rely on this because this is the default behavior in PHP.

[kenjis]

While it may be true that changing this will be a breaking change, it seems unreasonable to say that this is a specification.
The contents of DateTime are exposed and we don't even know what timezone_type is.

[neznaika0]

Why don't we know? This shows what type of zone is displayed. To restore an object, it is not important, you only need the date and timezone.

Why not add array support with these keys to Time()? It works for me

[kenjis]

Why don't we know?

Because it is not documented. I don't know the exact meaning.

Why not add array support with these keys to Time()? It works for me

What do you mean?

[kenjis]

There seem to be maybe three values for timezone_type.
https://3v4l.org/gDGst

[neznaika0]

A DateTimeZone object provides access to three different types of timezone rules: UTC offset (type 1), timezone abbreviation (type 2), and [timezone identifiers](https://www.php.net/manual/en/timezones.php) as published in the IANA timezone database (type 3).
https://www.php.net/manual/en/datetimezone.construct.php#refsect1-datetimezone.construct-description

[neznaika0]

We studied this when there was a bug with Datetime serialization. Don't you remember?
#7780 (comment)

[neznaika0]

Why not add array support with these keys to Time()? It works for me

What do you mean?

<?php

namespace App\Entities\Cast;

use CodeIgniter\Entity\Cast\BaseCast;
use CodeIgniter\Entity\Cast\DatetimeCast;
use CodeIgniter\I18n\Time;
use DateTimeZone;

/**
 * Adds date conversion from a JSON array as:
 * [
 *     'date'          => '2000-11-25 10:20:35.000000'
 *     'timezone_type' =>  3
 *     'timezone'      => 'Europe/Moscow'
 * ]
 */
class ExtendedDatetimeCast extends BaseCast
{
    public static function get($value, array $params = [])
    {
        return DatetimeCast::get($value, $params);
    }

    public static function set($value, array $params = [])
    {
        if (is_array($value) && array_key_exists('date', $value) && array_key_exists('timezone', $value)) {
            return DatetimeCast::get(new Time($value['date'], new DateTimeZone($value['timezone'])));
        }

        return DatetimeCast::set($value, $params);
    }
}

[crustamet]

I don't think it is a bug because if you want the expected output you can just remove the

class User extends Entity
{
    protected $datamap = [];
    //protected $dates   = ['created_at', 'updated_at', 'deleted_at'];
    protected $dates = [];
    protected $casts   = [];
}

and it should work as you wanted.

[kenjis]

The current behavior is the behavior of PHP's DateTime.
So we can think this is not a bug.

echo json_encode(new DateTime('now'));
// {"date":"2024-02-08 22:57:15.503235","timezone_type":3,"timezone":"UTC"}