Error when submitting form with empty file input

[benjaminjonard]

Hello,

I'm not sure if i'm posting on the right repository but I have an error when submitting a form with an empty file input:

RuntimeException: Cannot retrieve stream due to upload error in /ppm/vendor/react/http/src/Io/UploadedFile.php:85
Stack trace:
#1 /ppm/vendor/php-pm/httpkernel-adapter/Bridges/HttpKernel.php(162): React\Http\Io\UploadedFile->getStream()

It seems to happen because when submitting the form, browsers send the following param for the file:
Content-Disposition: form-data; name="author[photo]"; filename="" Content-Type: application/octet-stream

Any idea on how to fix this ?
Thanks

[andig]

The underlying library throws. I‘m wondering if we can find out if file is empty (no stream) vs any kind of other error?