ActionFileUploadInterceptor Issue

Hi Guys,

We have started migrating our apps to 6.7.4 and have run into an issue 
with file uploads. We have migrated our actions to use the new 
ActionFileUploadInterceptor but we are seeing an issue where the upload 
requests are being incorrectly bypassed.

I have reduced it to a simple example which I will include at the end 
but the key bits are the debug logs from struts. We are seeing the 
request processed correctly, except for the last step where the upload 
is bypassed:

dispatcher.Dispatcher (Dispatcher.java:1054) - Support for multipart request is enabled: true
dispatcher.Dispatcher (Dispatcher.java:1072) - Validating if this is a proper Multipart request. Request is POST: true and ContentType matches pattern (^multipart/form-data(?:\s*;\s*boundary=[0-9a-zA-Z'"()+_,\-./:=?]{1,70})?(?:\s*;\s*charset=[a-zA-Z\-0-9]{3,14})?): true
dispatcher.Dispatcher (Dispatcher.java:1030) - Wrapping multipart request with: MultiPartRequestWrapper

multipart.JakartaMultiPartRequest (JakartaMultiPartRequest.java:105) - Found file item: [document]
multipart.JakartaMultiPartRequest (JakartaMultiPartRequest.java:116) - Item is a file upload

interceptor.FileUploadInterceptor (FileUploadInterceptor.java:197) - Bypassing /action/...
interceptor.ActionFileUploadInterceptor (ActionFileUploadInterceptor.java:139) - Bypassing /action/...

The struts dispatcher sees the request as being a valid Multipart POST 
request and and wraps it with the MultipartRequestMapper.
The JakartaMultiPartRequest finds and recognises the uploaded file 
parameter [document]
But then the two upload interceptors Bypass processing which means the 
withUploadedFiles method on the action is not called.

I had a look at the source for the ActionFileUploadInterceptor and the 
request is only bypassed if it is not an instance of 
MultipartRequestMapper, which according to the logs it is. I'm very 
confused. I setup a simple test to prove we weren't going mad.

Form is a simple form:

     <s:form action="saveStockItem" method="POST" enctype="multipart/form-data">
         <s:hidden name="item.itemId"/>
         <s:textfield name="item.name" key="stock.name"></s:textfield>
         <s:textarea name="item.description" key="stock.description"></s:textarea>
         <s:file name="document" key="stock.image"></s:file>
         <s:submit >upload</s:submit>
     </s:form>

The stack is the struts standard defaultStack from the core 
struts-default.xml

     <action name="saveStockItem" class="stockAction" method="save">
         <interceptor-ref name="defaultStack"/>
         <result name="input">/WEB-INF/pages/formStock.jsp</result>
         <result name="success" type="redirectAction">stockItems</result>
     </action>

The action class implements UploadedFilesAware and has an appropriate 
withUploadedFiles method.

Has anyone experienced this or is it obvious what we are missing. Any 
help would be appreciated.

Zoran