belongsToMany::sync The return primary key type is incorrect.

[seth-shi]

• Laravel Version: 5.5.40
• PHP Version: 7.1.13-nts

---

Description

There are many pairs of models. Syncing Associations.I've set my primary key to be a string, but belongsToMany::syncThe return is an integer, which overflows the integer and cannot get the correct result.This leads me to make an error on the primary key.

Steps To Reproduce:

hotelIds = $request->input('hotel_id', []);

$changes = $user->hotels()->sync($hotelIds);

event(new HotelUserEvent($user, $changes));

Screen

Steps To fix the issue:

# \Illuminate\Database\Eloquent\Relations\Concerns\InteractsWithPivotTable::class
protected function castKey($key)
{
        // whether the current key is greater than the largest integer.
        if ((int)bcsub($key, PHP_INT_MAX) > 0) {
            return (string)$key;
        }
        
        return is_numeric($key) ? (int)$key : (string)$key;
}

or directly depending on the primary key type.

[AkenRoberts]

Confirmed that castKey() is the same in the current 5.6 version as well, so this hasn't been addressed yet.

I'd like to see this method respect the $keyType defined rather than continue to cast based on value, since your fix is still returning integers. (It's late today or I'd keep poking around.)

[seth-shi]

# \Illuminate\Database\Eloquent\Relations\Concerns\InteractsWithPivotTable::class
    protected function castKey($key)
    {
        return $this->getTypeSwapValue(
            $this->related->getKeyType(),
            $key
        );
    }

    protected function getTypeSwapValue($type, $value)
    {
        switch (strtolower($type)) {
            case 'int':
            case 'integer':
                return (int) $value;
            case 'real':
            case 'float':
            case 'double':
                return (float) $value;
            case 'string':
                return (string) $value;
            default:
                return $value;
        }
    }

I try to get the correct result from the primary key type.

[tillkruss]

Can you submit a PR?

[tillkruss]

@DavidNineRoc: Just make sure you add tests for all cases, your solution LGTM.

[seth-shi]

@tillkruss Okay, I'm writing the test code.