Add include for <functional>

There are some files that use `std::function` and it seems they were relying on transitive includes from CCCL headers because building cudf fails with CCCL 2.8, which is the next CCCL release in line for rapids

cpp/benchmarks/common/random_distribution_factory.cuh

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2020-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,6 +29,7 @@
 #include <thrust/tabulate.h>
 
 #include <algorithm>
+#include <functional>
 #include <memory>
 #include <type_traits>
 

cpp/src/column/column_device_view.cu

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2019-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,6 +25,7 @@
 #include <thrust/iterator/counting_iterator.h>
 #include <thrust/iterator/transform_iterator.h>
 
+#include <functional>
 #include <numeric>
 
 namespace cudf {

cpp/src/io/functions.cpp

@@ -36,6 +36,7 @@
 #include <cudf/utilities/error.hpp>
 
 #include <algorithm>
+#include <functional>
 #include <utility>
 
 namespace cudf::io {

cpp/src/io/json/host_tree_algorithms.cu

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024, NVIDIA CORPORATION.
+ * Copyright (c) 2024-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -46,6 +46,7 @@
 
 #include <algorithm>
 #include <deque>
+#include <functional>
 
 namespace cudf::io::json::detail {
 

cpp/src/io/json/read_json.cu

@@ -43,6 +43,7 @@
 #include <BS_thread_pool.hpp>
 #include <BS_thread_pool_utils.hpp>
 
+#include <functional>
 #include <numeric>
 
 namespace cudf::io::json::detail {

cpp/src/io/orc/aggregate_orc_metadata.cpp

@@ -19,6 +19,7 @@
 #include "io/utilities/row_selection.hpp"
 
 #include <algorithm>
+#include <functional>
 #include <numeric>
 
 namespace cudf::io::orc::detail {

cpp/src/io/orc/writer_impl.cu

@@ -64,6 +64,7 @@
 
 #include <algorithm>
 #include <cstring>
+#include <functional>
 #include <numeric>
 #include <tuple>
 #include <utility>

cpp/src/io/parquet/reader_impl_chunking.cu

@@ -40,6 +40,7 @@
 #include <thrust/transform_scan.h>
 #include <thrust/unique.h>
 
+#include <functional>
 #include <numeric>
 
 namespace cudf::io::parquet::detail {

cpp/src/io/parquet/writer_impl.cu

@@ -53,6 +53,7 @@
 
 #include <algorithm>
 #include <cstring>
+#include <functional>
 #include <iterator>
 #include <numeric>
 #include <utility>

cpp/src/lists/dremel.cu

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2022-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -36,6 +36,8 @@
 #include <thrust/iterator/counting_iterator.h>
 #include <thrust/iterator/discard_iterator.h>
 
+#include <functional>
+
 namespace cudf::detail {
 namespace {
 /**

cpp/src/strings/regex/regex.cuh

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2024, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2019-2025, NVIDIA CORPORATION.  All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,6 +27,7 @@
 #include <cuda_runtime.h>
 #include <thrust/pair.h>
 
+#include <functional>
 #include <memory>
 
 namespace cudf {

cpp/src/strings/replace/multi_re.cu

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2019-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -39,6 +39,7 @@
 #include <thrust/pair.h>
 
 #include <algorithm>
+#include <functional>
 
 namespace cudf {
 namespace strings {

cpp/src/table/row_operators.cu

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2022-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,6 +33,8 @@
 
 #include <thrust/iterator/transform_iterator.h>
 
+#include <functional>
+
 namespace cudf {
 namespace experimental {
 

cpp/src/text/bpe/load_merge_pairs.cu

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2022-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,6 +33,7 @@
 #include <cuda/functional>
 
 #include <fstream>
+#include <functional>
 #include <iostream>
 #include <vector>
 

cpp/tests/groupby/tdigest_tests.cu

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2021-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,6 +30,8 @@
 #include <thrust/fill.h>
 #include <thrust/iterator/counting_iterator.h>
 
+#include <functional>
+
 namespace {
 /**
  * @brief Functor to generate a tdigest by key.

cpp/tests/io/metadata_utilities.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2021-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,8 @@
 #include <cudf_test/cudf_gtest.hpp>
 #include <cudf_test/io_metadata_utilities.hpp>
 
+#include <functional>
+
 namespace cudf::test {
 
 void expect_metadata_equal(cudf::io::table_input_metadata in_meta,

cpp/tests/io/parquet_writer_test.cpp

@@ -33,6 +33,7 @@
 
 #include <array>
 #include <fstream>
+#include <functional>
 
 using cudf::test::iterators::no_nulls;
 

cpp/tests/reductions/scan_tests.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2019-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -28,6 +28,7 @@
 #include <thrust/tuple.h>
 
 #include <algorithm>
+#include <functional>
 #include <numeric>
 
 using aggregation      = cudf::aggregation;