Copilot commented on code in PR #45001: URL: https://github.com/apache/arrow/pull/45001#discussion_r3990193663
########## cpp/src/arrow/compute/kernels/scalar_hash.cc: ########## @@ -0,0 +1,562 @@ +// 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 <algorithm> +#include <limits> +#include <memory> +#include <string> +#include <utility> +#include <vector> + +#include "arrow/array/array_base.h" +#include "arrow/array/util.h" +#include "arrow/compute/cast.h" +#include "arrow/compute/kernels/common_internal.h" +#include "arrow/compute/key_hash_internal.h" +#include "arrow/compute/light_array_internal.h" +#include "arrow/compute/registry_internal.h" +#include "arrow/compute/util.h" +#include "arrow/result.h" +#include "arrow/util/bit_util.h" +#include "arrow/util/bitmap_ops.h" + +namespace arrow { +namespace compute { +namespace internal { + +// Define symbols visible within `arrow::compute::internal` in this file; +// these symbols are not visible outside of this file. +namespace { + +// ------------------------------ +// Kernel implementations +// It is expected that HashArrowType is either UInt32Type or UInt64Type (default) + +// Free function (not dependent on ArrowType/Hasher) to avoid codegen per instantiation. +// Only called with a plain column; HashArray routes everything else (see +// NeedsRecursiveHash) elsewhere first. +Result<KeyColumnArray> ToColumnArray(const ArraySpan& array) { + KeyColumnMetadata metadata; + const uint8_t* validity_buffer = nullptr; + const uint8_t* fixed_length_buffer = nullptr; + const uint8_t* var_length_buffer = nullptr; + + if (array.GetBuffer(0) != nullptr) { + validity_buffer = array.GetBuffer(0)->data(); + } + if (array.GetBuffer(1) != nullptr) { + fixed_length_buffer = array.GetBuffer(1)->data(); + } + + auto type = array.type; + auto type_id = type->id(); + if (type_id == Type::NA) { + metadata = KeyColumnMetadata(true, 0, true); + } else if (type_id == Type::BOOL) { + metadata = KeyColumnMetadata(true, 0); + } else if (is_fixed_width(type_id)) { + metadata = KeyColumnMetadata(true, type->bit_width() / 8); + } else if (is_binary_like(type_id)) { + metadata = KeyColumnMetadata(false, sizeof(uint32_t)); + if (array.GetBuffer(2) != nullptr) { + var_length_buffer = array.GetBuffer(2)->data(); + } + } else if (is_large_binary_like(type_id)) { + metadata = KeyColumnMetadata(false, sizeof(uint64_t)); + if (array.GetBuffer(2) != nullptr) { + var_length_buffer = array.GetBuffer(2)->data(); Review Comment: `HashVarLen` unconditionally reads the values pointer even for zero-length rows. `ToColumnArray` leaves that pointer null when the input has no values buffer, which is valid for an all-null/empty binary array and for an invalid `BinaryScalar`/`StringScalar`; hashing such inputs can therefore dereference null (and the Hypothesis tests can generate these cases). Please supply a sufficiently padded empty backing buffer or skip the varlen hash when no bytes are present, and add all-null/empty array and null-scalar regressions. This issue also appears in the following locations of the same file: - line 289 - line 375 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
