diff --git a/src/Handler/StreamHandler.php b/src/Handler/StreamHandler.php index c76b1c605..70c646be5 100644 --- a/src/Handler/StreamHandler.php +++ b/src/Handler/StreamHandler.php @@ -517,7 +517,9 @@ private function add_progress(RequestInterface $request, array &$options, $value $params, static function ($code, $a, $b, $c, $transferred, $total) use ($value) { if ($code == \STREAM_NOTIFY_PROGRESS) { - $value($total, $transferred, null, null); + // The upload progress cannot be determined. Use 0 for cURL compatibility: + // https://curl.se/libcurl/c/CURLOPT_PROGRESSFUNCTION.html + $value($total, $transferred, 0, 0); } } );