We didn't have a test for that before - one of our post-docs ran into this. But now, we do have such a test.

Roy Stogner <roystgnr@ices.utexas.edu> wrote on 08/01/2011 09:26:03 AM:

> On Mon, 25 Jul 2011, David Andrs wrote:
> > We bumped into an issue with XDA restart here at INL. We ran a
> > simulation that had one system in EquationSystems object and we
> > saved the result (as XDA). Then we wanted to restart with more
> > variables but also with more systems in the EquationSystems. We were
> > not able to do that, because the loop in ES::read() went over all
> > systems there and we already had more than that.
> >
> > Attached patch is fixing this issue by storing a list of systems
> > that were found in the XDA file and than using it instead of the
> > member variable for setting the system vectors.
> Excellent fix; thanks!
> Are you guys hitting this in your regression tests?  We've got one
> application regression test that covers the "adding more variables
> while restarting" case; in the long run we really ought to get an
> "adding more variables and more systems while restarting" test into
> the libMesh examples.
> ---
> Roy