[Libmesh-devel] Nemesis Appending not working?

[Cody P. <cod...@gm...>]

So we have a user that wants to try to start using the "recover" capability
in MOOSE to resume a long running simulation on the clusters. This
particular simulation is very large and the user is using nemesis output. I
was suprised to see that we don't have any nemesis appending tests in all
of MOOSE. It appears that all of our nemesis output is on "steady-state"
solves, or the recover flag has been explicitly set to false on any
transient simulations checked in. When I went to test this capability it
did fail with a seg fault and pointed to this line of code:

https://github.com/libMesh/libmesh/blob/master/src/mesh/nemesis_io_helper.C#L2485

I verified that the "exodus_node_num_to_libmesh" structure was empty. I can
see that at least an attempt has been made to support the "append"
functionality in Nemesis but does anyone know for sure that it works? It
appears that we might be missing some initialization call or something?

Full disclosure - We have additional wrappers around Exodus and Nemesis in
MOOSE but they aren't doing anything that I would consider illegal or bad.
Those wrappers are creating and using the main Exodus and Nemesis objects
through the public API.

Before I (or someone else) dives in, do we expect this case to work? Anyone
else doing Nemesis appends?

Thanks,
Cody