By adding upload.setSizeMax to JakartaMultiPartRequest (@see https://issues.apache.org/struts/browse/WW-1549), the file upload interceptor max size validation has been disabled. Furthermore, whenever there is a single file above the allowed size none of the request parameters are set on the action This happens due to upload.parseRequest(createRequestContext(servletRequest)) which throws exception (o.a.c.fileupload.FileItemIteratorImpl checks max size).
If the application requires the parameters it will fail.
There is also slight confusion and disconnect between:
struts.multipart.maxSize and fileInterceptor.maxsize
If you upload file that exceeds allowed struts.multipart.maxSize fileInterceptor will never kick in.
IMHO file upload interceptor should be responsible for max size validation (esp. that it reports errors as field errors and not as action errors).
Furthermore, we should drop 'struts.multipart.maxSize' since is confusing along with fileInterceptor.maxsize, also fileInterceptor.maxsize should get a new default max size. The other option is to use struts.multipart.maxSize to set fileInterceptor.maxsize.
This line should be removed so file interceptor can validate files:
— src/main/java/org/apache/struts2/dispatcher/multipart/JakartaMultiPartRequest.java (revision 560614)
+++ src/main/java/org/apache/struts2/dispatcher/multipart/JakartaMultiPartRequest.java (working copy)
@@ -86,7 +86,6 @@
// Parse the request
ServletFileUpload upload = new ServletFileUpload(fac);
List items = upload.parseRequest(createRequestContext(servletRequest));