Fix segfault writing ascii .vtu files with implicit cell type arrays

Forwarded: not-yet

NewIterator() returns nullptr for the implicit cell-type arrays used
since VTK 9.6. WriteAsciiData() dereferenced that nullptr via an
unconditional iter->Delete(). Guard it. Closes yade FTBFS.

Gbp-Pq: Name fix_xmlwriter_ascii_implicit_cellarray_segfault.patch

diff --git a/IO/XML/vtkXMLWriter.cxx b/IO/XML/vtkXMLWriter.cxx
index 413f0f8852d44429219d57e463b895986b3e0061..030e96cb7d7c4eaa01034b9981f89b491ff41cc8 100644 (file)
--- a/IO/XML/vtkXMLWriter.cxx
+++ b/IO/XML/vtkXMLWriter.cxx
@@ -1978,7 +1978,10 @@ int vtkXMLWriter::WriteAsciiData(vtkAbstractArray* a, vtkIndent indent)
       ret = 0;
       break;
   }
-  iter->Delete();
+  if (iter)
+  {
+    iter->Delete();
+  }
   return ret;
 }