From 22da1072c300839496a2a5eb13d1e357bf8fc867 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@math.tamu.edu>
Date: Fri, 27 Feb 2015 08:33:00 -0600
Subject: [PATCH] Significantly improve another exception that currently does
 not print any text.

---
 include/deal.II/grid/tria.h |  7 ++++++-
 source/grid/tria.cc         | 14 +++++++-------
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/include/deal.II/grid/tria.h b/include/deal.II/grid/tria.h
index b2198320a2..8080d6d276 100644
--- a/include/deal.II/grid/tria.h
+++ b/include/deal.II/grid/tria.h
@@ -2785,7 +2785,12 @@ public:
    *
    * @ingroup Exceptions
    */
-  DeclException0 (ExcTriangulationNotEmpty);
+  DeclException2 (ExcTriangulationNotEmpty,
+                  int, int,
+                  << "You are trying to perform an operation on a triangulation "
+                  << "that is only allowed if the triangulation is currently empty. "
+                  << "However, it currently stores " << arg1 << " vertices and has "
+                  << "cells on " << arg2 << " levels.");
   /**
    * Trying to re-read a grid, an error occurred.
    *
diff --git a/source/grid/tria.cc b/source/grid/tria.cc
index 1ad9b0a2b8..ee06cbaa4e 100644
--- a/source/grid/tria.cc
+++ b/source/grid/tria.cc
@@ -8767,7 +8767,7 @@ template <int dim, int spacedim>
 void
 Triangulation<dim, spacedim>::set_mesh_smoothing(const MeshSmoothing mesh_smoothing)
 {
-  Assert (n_levels() == 0, ExcTriangulationNotEmpty ());
+  Assert (n_levels() == 0, ExcTriangulationNotEmpty (vertices.size(), levels.size()));
   smooth_grid=mesh_smoothing;
 }
 
@@ -8932,9 +8932,9 @@ void
 Triangulation<dim, spacedim>::
 copy_triangulation (const Triangulation<dim, spacedim> &old_tria)
 {
-  Assert (vertices.size() == 0, ExcTriangulationNotEmpty());
-  Assert (levels.size () == 0, ExcTriangulationNotEmpty());
-  Assert (faces == NULL, ExcTriangulationNotEmpty());
+  Assert (vertices.size() == 0, ExcTriangulationNotEmpty(vertices.size(), levels.size()));
+  Assert (levels.size () == 0, ExcTriangulationNotEmpty(vertices.size(), levels.size()));
+  Assert (faces == NULL, ExcTriangulationNotEmpty(vertices.size(), levels.size()));
 
   Assert (old_tria.levels.size() != 0, ExcInternalError());
   Assert (old_tria.vertices.size() != 0, ExcInternalError());
@@ -9015,9 +9015,9 @@ create_triangulation (const std::vector<Point<spacedim> >    &v,
                       const std::vector<CellData<dim> > &cells,
                       const SubCellData &subcelldata)
 {
-  Assert (vertices.size() == 0, ExcTriangulationNotEmpty());
-  Assert (levels.size() == 0, ExcTriangulationNotEmpty());
-  Assert (faces == NULL, ExcTriangulationNotEmpty());
+  Assert (vertices.size() == 0, ExcTriangulationNotEmpty(vertices.size(), levels.size()));
+  Assert (levels.size() == 0, ExcTriangulationNotEmpty(vertices.size(), levels.size()));
+  Assert (faces == NULL, ExcTriangulationNotEmpty(vertices.size(), levels.size()));
   // check that no forbidden arrays
   // are used
   Assert (subcelldata.check_consistency(dim), ExcInternalError());
-- 
2.39.5