Merge branch 'LayeredMeshGeneratorErrorMessages' into 'master'

Error messages in layered mesh generator.

See merge request ogs/ogs!3132

Applications/Utils/MeshEdit/createLayeredMeshFromRasters.cpp

@@ -154,8 +154,12 @@ int main (int argc, char* argv[])
     }
 
     INFO("Writing mesh '{:s}' ... ", output_name);
-    auto result_mesh = std::make_unique<MeshLib::Mesh>(
-        *(mapper.getMesh("SubsurfaceMesh").release()));
+    auto result_mesh = mapper.getMesh("SubsurfaceMesh");
+    if (result_mesh == nullptr)
+    {
+        ERR("Mapper returned empty result for 'SubsurfaceMesh'.");
+        return EXIT_FAILURE;
+    }
 
     auto const data_mode =
         use_ascii_arg.getValue() ? vtkXMLWriter::Ascii : vtkXMLWriter::Binary;

MeshLib/MeshGenerators/LayeredMeshGenerator.cpp

@@ -48,8 +48,14 @@ bool LayeredMeshGenerator::createLayers(
 std::unique_ptr<MeshLib::Mesh>
 LayeredMeshGenerator::getMesh(std::string const& mesh_name) const
 {
-    if (_nodes.empty() || _elements.empty())
+    if (_nodes.empty())
     {
+        WARN("LayeredMeshGenerator has not created any nodes.");
+        return nullptr;
+    }
+    if (_elements.empty())
+    {
+        WARN("LayeredMeshGenerator has not created any elements.");
         return nullptr;
     }