Optional file uploads

[daleif]

Since a file upload field in a multipart/form-data form always generates an Mojo::Upload object even if there is no file specified, then

$v->optional('my_file','not_empty');

will never remove my_file if there was no file specified in the upload.

I'm wondering whether it would make sense to change the not_empty filter to something similar to

not_empty => sub ($v, $name, $value) {
	    if ( ref $value && $value->can('size') ) {
		$value->size ? $value : ()
	    } else {
		length $value ? $value : ()
	    }
	}

Then at least it also works with objects that has a ->size method like Mojo::Upload.

not_empty is currently implemented using the length line.

[kraih]

Would be consistent with $v->size i guess if it worked for Mojo::Upload objects.