No uploaded file when upgrading to new Tapestry version (Spring Boot jar, embedded Tomcat...)

[Vjeran Marcinko]

 Hi,

I am upgrading my old Tapestry 4.3.7 app (java-7, standalone Tomcat...) 
to newer tech stack (java 8, Spring Boot with embeddable Tomcat deployed 
as single jar...). I wan't to leave tapestry untouched as much as 
possible, so I just upgraded from 4.3.7 to 4.3.8 because of Java-8 
requirement.

And practically everything works perfectly except that my Upload 
component stopped working. It doesn't raise any error, its just that 
after form submit, my UploadedFile instance is always null.

I debugged a bit, and found out that within Tapestry's 
MultipartDecoderImpl there is this part that should parse FileItems from 
HTTP request, but it always parses empty list. I udnerstand that here 
Taestry uses Apache Commons-FileUpload, but I have no idea what has 
changed for this to stop working properly?

protected List<FileItem>parseRequest(HttpServletRequest request)
{
    try {
        return createFileUpload().parseRequest(request); }catch 
(FileUploadException ex)
    {
        uploadException = ex; return Collections.emptyList(); }
}

Dunno if Spring Boot and its embeeded Tomcat are making some difference 
here...

Any idea?

-Vjeran