From d81cbc6e37eed18e172de1ec1c14265f7d373095 Mon Sep 17 00:00:00 2001
From: Kenneth Moreland <morelandkd@ornl.gov>
Date: Mon, 31 Oct 2022 15:56:37 -0600
Subject: [PATCH] Fix reading global ids of permuted cells

The legacy VTK reader sometimes has to permute cell data because some
VTK cells are not directly supported in VTK-m. (For example, triangle
strips are not supported. They have to be converted to triangles.)

The global and petigree identifiers were not properly getting permuted.
This is now fixed.
---
 .../read-permuted-global-cell-ids.md          |  8 +++++++
 vtkm/io/VTKDataSetReaderBase.cxx              |  6 ++---
 vtkm/io/testing/UnitTestVTKDataSetReader.cxx  | 23 +++++++++++++++++++
 3 files changed, 34 insertions(+), 3 deletions(-)
 create mode 100644 docs/changelog/read-permuted-global-cell-ids.md

diff --git a/docs/changelog/read-permuted-global-cell-ids.md b/docs/changelog/read-permuted-global-cell-ids.md
new file mode 100644
index 000000000..ba07b5165
--- /dev/null
+++ b/docs/changelog/read-permuted-global-cell-ids.md
@@ -0,0 +1,8 @@
+# Fix reading global ids of permuted cells
+
+The legacy VTK reader sometimes has to permute cell data because some VTK
+cells are not directly supported in VTK-m. (For example, triangle strips
+are not supported. They have to be converted to triangles.)
+
+The global and petigree identifiers were not properly getting permuted.
+This is now fixed.
diff --git a/vtkm/io/VTKDataSetReaderBase.cxx b/vtkm/io/VTKDataSetReaderBase.cxx
index ef613a208..03f28c7bd 100644
--- a/vtkm/io/VTKDataSetReaderBase.cxx
+++ b/vtkm/io/VTKDataSetReaderBase.cxx
@@ -664,10 +664,10 @@ void VTKDataSetReaderBase::ReadGlobalOrPedigreeIds(vtkm::cont::Field::Associatio
   std::string dataType;
   this->DataFile->Stream >> dataName >> dataType >> std::ws;
   internal::parseAssert(dataType == "vtkIdType");
+  // vtk writes vtkIdType as int
 
-  std::vector<vtkm::Int32> buffer(numElements); // vtk writes vtkIdType as int
-  this->ReadArray(buffer);
-  vtkm::cont::UnknownArrayHandle data(vtkm::cont::make_ArrayHandleMove(std::move(buffer)));
+  vtkm::cont::UnknownArrayHandle data =
+    this->DoReadArrayVariant(association, "int", numElements, 1);
   this->AddField(dataName, association, data);
 
   this->SkipArrayMetaData(1);
diff --git a/vtkm/io/testing/UnitTestVTKDataSetReader.cxx b/vtkm/io/testing/UnitTestVTKDataSetReader.cxx
index f3acc02df..0d3dadadd 100644
--- a/vtkm/io/testing/UnitTestVTKDataSetReader.cxx
+++ b/vtkm/io/testing/UnitTestVTKDataSetReader.cxx
@@ -140,6 +140,29 @@ void TestReadingV5Format(Format format)
   VTKM_TEST_ASSERT(ds.GetNumberOfCells() == 15, "Incorrect number of cells");
   VTKM_TEST_ASSERT(ds.GetCellSet().IsType<vtkm::cont::CellSetExplicit<>>(),
                    "Incorrect cellset type");
+
+  for (vtkm::IdComponent fieldIdx = 0; fieldIdx < ds.GetNumberOfFields(); ++fieldIdx)
+  {
+    vtkm::cont::Field field = ds.GetField(fieldIdx);
+    switch (field.GetAssociation())
+    {
+      case vtkm::cont::Field::Association::Points:
+        VTKM_TEST_ASSERT(field.GetData().GetNumberOfValues() == ds.GetNumberOfPoints(),
+                         "Field ",
+                         field.GetName(),
+                         " is the wrong size");
+        break;
+      case vtkm::cont::Field::Association::Cells:
+        VTKM_TEST_ASSERT(field.GetData().GetNumberOfValues() == ds.GetNumberOfCells(),
+                         "Field ",
+                         field.GetName(),
+                         " is the wrong size");
+        break;
+      default:
+        // Could be any size.
+        break;
+    }
+  }
 }
 
 void TestReadingUnstructuredGridEmpty()