ComputeScalars only affects the scalar field

vtkmContour was treating `ComputeScalars` as a flag to turn on/off the
interpolation and generation of all of the fields in the output.
As per its superclass `vtkContourFilter`, it should only affect the generation
of the scalar field.

Accelerators/Vtkm/Filters/vtkmContour.cxx

@@ -211,20 +211,12 @@ int vtkmContour::RequestData(
     }
 
     // convert the input dataset to a vtkm::cont::DataSet
-    vtkm::cont::DataSet in;
-    if (this->ComputeScalars)
-    {
-      in = tovtkm::Convert(input, tovtkm::FieldsFlag::PointsAndCells);
-    }
-    else
+    vtkm::cont::DataSet in = tovtkm::Convert(input, tovtkm::FieldsFlag::PointsAndCells);
+    if (!this->ComputeScalars)
     {
-      in = tovtkm::Convert(input, tovtkm::FieldsFlag::None);
-      // explicitly convert just the field we need
-      auto inField = tovtkm::Convert(inputArray, association);
-      in.AddField(inField);
-      // don't pass this field
+      // don't pass the scalar field
       filter.SetFieldsToPass(
-        vtkm::filter::FieldSelection(vtkm::filter::FieldSelection::Mode::None));
+        vtkm::filter::FieldSelection(scalarFieldName, vtkm::filter::FieldSelection::Mode::Exclude));
     }
 
     vtkm::cont::DataSet result = filter.Execute(in);

Documentation/release/dev/vtkmContour-fixes.md

+# Fix `ComputeScalars` in vtkmContour filter
+
+The `ComputScalars` parameter was toggling the interpolation and generation of
+all of the fields in the output. Whereas, in `vtkContourFilter` it is only used
+to enable the generation of the scalar field. This has now been fixed and setting
+the option in `vtkmContour` has the same effect as `vtkContourFilter`.