From: Timo Heister <timo.heister@gmail.com>
Date: Sun, 21 Nov 2021 22:04:49 +0000 (-0500)
Subject: add Assert to get_mg_dof_indices
X-Git-Tag: v9.4.0-rc1~815^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=691ae835193da06469e8ce2493b921112aea9f20;p=dealii.git

add Assert to get_mg_dof_indices

Calling get_mg_dof_indices currently causes a segfault when you don't
have MG DoFs distributed. Fix by adding an Assert with a nice message in
two places (why not).
---

diff --git a/include/deal.II/dofs/dof_accessor.templates.h b/include/deal.II/dofs/dof_accessor.templates.h
index 95223ebe54..96493e2dbc 100644
--- a/include/deal.II/dofs/dof_accessor.templates.h
+++ b/include/deal.II/dofs/dof_accessor.templates.h
@@ -1569,6 +1569,9 @@ DoFAccessor<structdim, dim, spacedim, level_dof_access>::mg_vertex_dof_index(
       fe_index_;
   (void)fe_index;
   Assert(this->dof_handler != nullptr, ExcInvalidObject());
+  Assert(this->dof_handler->mg_vertex_dofs.size() > 0,
+         ExcMessage("Multigrid DoF indices can only be accessed after "
+                    "DoFHandler::distribute_mg_dofs() has been called!"));
   AssertIndexRange(vertex, this->n_vertices());
   AssertIndexRange(i, this->dof_handler->get_fe(fe_index).n_dofs_per_vertex());
 
@@ -1706,6 +1709,9 @@ DoFAccessor<structdim, dim, spacedim, level_dof_access>::get_mg_dof_indices(
   const unsigned int                    fe_index_) const
 {
   Assert(this->dof_handler != nullptr, ExcInvalidObject());
+  Assert(this->dof_handler->mg_vertex_dofs.size() > 0,
+         ExcMessage("Multigrid DoF indices can only be accessed after "
+                    "DoFHandler::distribute_mg_dofs() has been called!"));
 
   const unsigned int fe_index =
     (this->dof_handler->hp_capability_enabled == false &&