WherePivot = is null on FK

[Grazouillis]

Hello Mr. Korop,

Hello everybody. I've been noticing a bug in my app for days and I'm unable to understand and fix it.

I try to create a social network, and I have a "connections" table in my database, which is a pivot table with extra fields.
Here is my migration file:

            // $table->id();
            $table->comment('self table users-users friendships');

            $table->unsignedInteger('requester_user_id');
            $table->unsignedInteger('recipient_user_id');
            $table->enum('status', ['pending', 'approved', 'declined'])->default('pending');
            $table->date('connected_since')->nullable();

            $table->foreign('requester_user_id')->references('id')->on('users')
                ->constrained()
                ->onUpdate('cascade')
                ->onDelete('cascade');

            $table->foreign('recipient_user_id')->references('id')->on('users')
                ->constrained()
                ->onUpdate('cascade')
                ->onDelete('cascade');

            $table->timestamps();
        });

DB-table capture : https://user-images.githubusercontent.com/8795284/211657973-b2fd4325-52da-44aa-80cd-c564feb68b00.png

My Model:

public function connections()
    // relation M-M
    {
        $query =  $this->belongsToMany(
            self::class,
            'connections',
            'requester_user_id',
            'recipient_user_id'
        )->withTimestamps()
        ->withPivot('status')
        ->withPivot('connected_since');

dd($query->toSql());

return $query;
}

When my dd() is executed, I have this sql query:
"select * from users inner join connections on users.id = connections.recipient_user_id where connections.requester_user_id is null" // app/Models/User.php:73
I don't understand why I have a "connections.requester_user_id is null" because I didn't emit this info in my code.
With this condition I always have an empty collection/array as result

complete dd()

I tried to export my model from User to Connection

User.php:

$query = $this->belongsToMany(
            User::class,
            'connections',
            'requester_user_id',
            'recipient_user_id'
        )->withTimestamps()
            ->using(Connection::class);

Connection.php:

{
    use HasFactory;

    protected $primaryKey = null;

 public function connections()
    {
        return $this->belongsToMany(
            User::class,
            'connections',
            'recipient_user_id',
            'requester_user_id'
        )->withTimestamps()
            ->withPivot('status', 'connected_since'); // nécessaire : permet de trouver les valeurs externes de la table M-M hors FK
    }

    public function sendConnectionInvitation()
    {
        return $this->connections()
            ->withPivotValue('requester_user_id', auth()->id());
    }

    // connexions reçues
    public function approvedConnections()
    {        
        return $this->belongsToMany(
            User::class,
            'connections',
            'requester_user_id',
            'recipient_user_id'
            )->withTimestamps()
            ->withPivot('status', 'connected_since')
            ->wherePivot('status', '=', 'approved');
}
[...]
}

That mention : protected $primaryKey = null; doesn't solve my problem... it still doesn't work... wherePivotNotNull either
I also tried to create a primary ID next to the 2 FK in case of via my migrations, but the problem still the same.

Lastly, I tried your method,

public function following()
    {
        return $this->belongsToMany(User::class, 'connections', 'requester_user_id', 'recipient_user_id');
    }

    public function followed()
    {
        return $this->belongsToMany(User::class, 'connections', 'recipient_user_id', 'requester_user_id');
    }

// Connections

    public function followingRequest()
    {
        return $this->following()
            ->withPivotValue('requester_user_id', auth()->id())
            ->withTimestamps();
    }

public function approvedConnections() {

    $q = $this->following()
 //   ->wherePivot('status', '=', 'approved')
    ->where('status', '=', 'approved')
    ->toSql();

    dd($q);
}

I was hopeful with this way to help me...
but the result still the same : "select * from usersinner joinconnectionsonusers.id=connections.requester_user_idwhereconnections.recipient_user_id**is null** andconnections.status = ? ◀" // app/Models/User.php:99

I found a few questions which have the same result than mine, but nothing fixes my problem.
I guess you won't have the time to read such a pamphlet, but when in doubt, I leave it to you, Mr. Laravel
Thank you at least for reading me!