Deprecation error in `HasAttributes::addDateAttributesToArray()` when `UPDATED_AT = null` and model is cast to array (PHP 8.5)

[Rodots]

Laravel Version

12.x

PHP Version

8.5.0

Database Driver & Version

MySQL9.5.0

Description

When using illuminate/database v12.4.1 with PHP 8.5, defining const UPDATED_AT = null; in an Eloquent model to disable the updated_at timestamp causes a deprecation error only when the model is converted to an array (e.g., via toArray() or (array) $model):

ErrorException: Using null as an array offset is deprecated, use an empty string instead
in vendor/illuminate/database/Eloquent/Concerns/HasAttributes.php:254

This is triggered by the line:

if (! isset($attributes[$key])) {

inside addDateAttributesToArray(), where $key is null (from UPDATED_AT = null).

According to the PHP 8.5 release notes:

"Using null as an array offset or when calling array_key_exists() is now deprecated. Use an empty string instead."

Thus, isset($attributes[null]) is no longer allowed.

Suggested Fixes:

1. Immediate fix: Skip null keys in addDateAttributesToArray():

   foreach ($this->getDates() as $key) {
       if ($key === null || ! isset($attributes[$key])) {
           continue;
       }
       // ...
   }

2. Long-term API improvement: Consider deprecating the use of null to disable timestamp fields. Instead, align with the existing pattern used by $timestamps and allow:

   const UPDATED_AT = false;

   This would be more intuitive and consistent with public $timestamps = false;.

   The getDates() method could then filter out any timestamp field explicitly set to false (or null, for backward compatibility during a transition period).

This change would improve DX and avoid edge cases tied to PHP’s evolving handling of null as an array key.

Steps To Reproduce

1. Define a model with:

   class MyModel extends Model
   {
       const UPDATED_AT = null;
       // ... other config (e.g., connection, table)
   }

2. Fetch a record: $model = MyModel::first();
3. Call $model->toArray(); (or cast to array).
4. Observe the deprecation error.

[hosni]

@crynobone I'm ready to send a PR for this. Just let me know which approach you prefer so I can implement it accordingly.

[marius-ciclistu]

Keeping the type by setting it to '' would be better and maybe would not require any changes.