This does fix the exception from #49014 BUT it doesn't do what a browser does, and it might break the application behind the form. Instead of sending an empty/non-file, it sends the file field as a normal field with empty string:

$_POST:
Array
(
    [op] => Submit it
    [values] => Array
        (
            [text] => Oele
        )
    [file] => 
)

(see the [file]) What it should do is what a real browser does: send a non-file, or whatever you would call that:

$_POST:
Array
(
    [op] => Submit it
    [values] => Array
        (
            [text] => asd
        )
)

$_FILES:
Array
(
    [file] => Array
        (
            [name] => 
            [full_path] => 
            [type] => 
            [tmp_name] => 
            [error] => 4
            [size] => 0
        )
)

file is in the $_FILES list, with error 4: UPLOAD_ERR_NO_FILE: https://www.php.net/manual/en/features.file-upload.errors.php#features.file-upload.errors That's what happens if you submit a file field without file.

IMO deleting the file from the form is a better solution than the empty string, but sending the non-file would be even more realistic, but I don't know how symfony/curl would do that.

Closing in favor of #59752, thanks for having a look!