XForms submission: synchronous?

Current XForms 1.0 reads that submission is synchronous 
because DOMActivate on trigger "dispatches" xforms-submit.

The spec does not say "(may|should|must) launch a separate
thread to dispatch" xforms-submit.
 
Then, xforms-submit capture, bubble and default processing
occur.  The default processing then describes the occurrence
of the entire submission down to done or error.

Therefore, it is currently reasonable for an XForms author to 
assume that a send action which does an instance replacement
will actually replace the instance before the next action after
the send occurs.

To be fair, it would be *better* for that author to write the follow-on
actions after a send action into the xforms-submit-done handler
in order to ensure that the follow-on actions occur only if the
submission is successful.  And if this is done, then the resulting
form would operate correctly whether submission is synchronous
or asynchronous.

Moreover, there's a lot of benefit to being asynchronous, and some
implementations at least have already gone that route despite what
the spec says, so this email is being sent to promote discussion
about the issue so we can get alignment, either for 1.0 or 1.1.

In particular, it was stated here at the FtF that the option of 
synchronicity
was deliberately left open so as not to preclude implementation on
small devices.  So, clearly the language should be that a submissoin
MAY be asynchronous.

Moreover, if a submission is asynchronous, then how far into the
process does it get while still blocking the initiating thread?  In other
words, is the whole dispatch of xforms-submit done by a separate thread?
Or do we only branch to a separate thread some time after taking a
snapshot of the data to be submitted?   Otherwise, the sufficiently
talented user could change the data between the point where we 
prune and validate and the point where the data is transmitted.

John M. Boyer, Ph.D.
Senior Product Architect/Research Scientist
Co-Chair, W3C XForms Working Group
Workplace, Portal and Collaboration Software
IBM Victoria Software Lab
E-Mail: boyerj@ca.ibm.com  http://www.ibm.com/software/

Blog: http://www.ibm.com/developerworks/blogs/page/JohnBoyer