Move problematic function to compute/codegen_internal instead of comp…

…ute/kernels/codegen_internal

cpp/src/arrow/CMakeLists.txt

@@ -722,14 +722,14 @@ set(ARROW_COMPUTE_SRCS
     compute/api_scalar.cc
     compute/api_vector.cc
     compute/cast.cc
+    compute/codegen_internal.cc
     compute/exec.cc
     compute/expression.cc
     compute/function.cc
     compute/function_internal.cc
     compute/kernel.cc
     compute/ordering.cc
     compute/registry.cc
-    compute/kernels/codegen_internal.cc
     compute/kernels/ree_util_internal.cc
     compute/kernels/scalar_cast_boolean.cc
     compute/kernels/scalar_cast_dictionary.cc

cpp/src/arrow/compute/codegen_internal.cc

@@ -0,0 +1,34 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/compute/codegen_internal.h"
+
+#include "arrow/compute/api_vector.h"
+#include "arrow/result.h"
+#include "arrow/type_fwd.h"
+
+namespace arrow {
+namespace compute {
+namespace internal {
+
+Result<TypeHolder> FirstType(KernelContext*, const std::vector<TypeHolder>& types) {
+  return types.front();
+}
+
+}  // namespace internal
+}  // namespace compute
+}  // namespace arrow

cpp/src/arrow/compute/codegen_internal.h

@@ -0,0 +1,32 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "arrow/compute/api_vector.h"
+#include "arrow/result.h"
+#include "arrow/type_fwd.h"
+
+namespace arrow {
+namespace compute {
+namespace internal {
+// ----------------------------------------------------------------------
+// Reusable type resolvers
+
+Result<TypeHolder> FirstType(KernelContext*, const std::vector<TypeHolder>& types);
+
+}  // namespace internal
+}  // namespace compute
+}  // namespace arrow

cpp/src/arrow/compute/kernels/codegen_internal.cc

@@ -49,10 +49,6 @@ const std::vector<std::shared_ptr<DataType>>& ExampleParametricTypes() {
   return example_parametric_types;
 }
 
-Result<TypeHolder> FirstType(KernelContext*, const std::vector<TypeHolder>& types) {
-  return types.front();
-}
-
 Result<TypeHolder> LastType(KernelContext*, const std::vector<TypeHolder>& types) {
   return types.back();
 }