message: [core] nodedef nullptr dereference
diff: @@ -201,10 +201,12 @@ Status RewriteDataset(OpKernelContext* ctx, const DatasetBase* input,
  for (const auto& node : graph_def.node()) {
  if (node.name() == output_node) {
  node_def = &node;
  + break;
  }
  }
  if (node_def == nullptr) {
  VLOG(3) << "Failed to find node: " << output_node;
  + return;
  }
  uint64 hash = 0;
  Status s = HashNode(graph_def, *node_def, &hash);
  