Re: SturdyRefs and boot-comm (hangs)

On Mar 10, 2010, at 14:44, Thomas Leonard wrote:

> SturdyRefs are not PassByProxy, but BootRefHandler doesn't know how to
> send them, so it pretends they are:
> [...]
> But in the constructor, only PassByProxy objects get an identity:
> [...]
> This causes a <Promise> to be sent. The receiver calls
> <Promise>.__whenMoreResolved, but when the SturdyRef tries to send
> itself back in the reply, it gets turned into a promise again, so the
> receiver calls __whenMoreResolved again, forever.

I agree that the boot-comm system shouldn't hang like this, bit I  
don't have the knowledge to judge your analysis or suggest how to fix  
this immediately.

As a pragmatic fix, I suggest you use the virtualize/1 operation on  
seedVat; it causes the user-level communication to occur over CapTP  
rather than boot-comm.

In general, boot-comm is really only for bootstrapping purposes,  
because 3-way reference shortening can only occur over a homogeneous  
comm system. If your process has vats A and B communicating over boot- 
comm, and B has a CapTP reference to C which it passes to A, it is  
impossible or impractical to shorten that into a direct CapTP  
reference from A to C; MarkM and I spent an hour some time ago working  
this out.

For cheap yet complete inter-vat communication, what *is* practical is  
to make sure CapTP doesn't use crypto when communicating between vats  
in the same process or OS -- not yet implemented.

-- 
Kevin Reid                                  <http://switchb.org/kpreid/>