GH-46407: [C++] Fix IPC serialization of sliced list arrays

cpp/src/arrow/ipc/feather_test.cc

@@ -319,6 +319,24 @@ TEST_P(TestFeather, SliceBooleanRoundTrip) {
   CheckSlices(batch);
 }
 
+TEST_P(TestFeather, SliceListRoundTrip) {
+  if (GetParam().version == kFeatherV1Version) {
+    GTEST_SKIP() << "Feather V1 does not support list types";
+  }
+  std::shared_ptr<RecordBatch> batch;
+  ASSERT_OK(ipc::test::MakeListRecordBatchSized(600, &batch));
+  CheckSlices(batch);
+}
+
+TEST_P(TestFeather, SliceListViewRoundTrip) {
+  if (GetParam().version == kFeatherV1Version) {
+    GTEST_SKIP() << "Feather V1 does not support list view types";
+  }
+  std::shared_ptr<RecordBatch> batch;
+  ASSERT_OK(ipc::test::MakeListViewRecordBatchSized(600, &batch));
+  CheckSlices(batch);
+}
+
 INSTANTIATE_TEST_SUITE_P(
     FeatherTests, TestFeather,
     ::testing::Values(TestParam(kFeatherV1Version), TestParam(kFeatherV2Version),

cpp/src/arrow/ipc/read_write_test.cc

@@ -579,6 +579,29 @@ TEST_F(TestIpcRoundTrip, SpecificMetadataVersion) {
   TestMetadataVersion(MetadataVersion::V5);
 }
 
+TEST_F(TestIpcRoundTrip, ListWithSlicedValues) {
+  // This tests serialization of a sliced ListArray that got sliced "the Rust
+  // way": by slicing the value_offsets buffer, but keeping top-level offset at
+  // 0.
+  auto child_data = ArrayFromJSON(int32(), "[1, 2, 3, 4, 5]")->data();
+
+  // Offsets buffer [2, 5]
+  TypedBufferBuilder<int32_t> offsets_builder;
+  ASSERT_OK(offsets_builder.Reserve(2));
+  ASSERT_OK(offsets_builder.Append(2));
+  ASSERT_OK(offsets_builder.Append(5));
+  ASSERT_OK_AND_ASSIGN(auto offsets_buffer, offsets_builder.Finish());
+
+  auto list_data = ArrayData::Make(list(int32()),
+                                   /*num_rows=*/1,
+                                   /*buffers=*/{nullptr, offsets_buffer});
+  list_data->child_data = {child_data};
+  std::shared_ptr<Array> list_array = MakeArray(list_data);
+  ASSERT_OK(list_array->ValidateFull());
+
+  CheckRoundtrip(list_array);
+}
+
 TEST(TestReadMessage, CorruptedSmallInput) {
   std::string data = "abc";
   auto reader = io::BufferReader::FromString(data);

cpp/src/arrow/ipc/test_common.cc

@@ -421,7 +421,7 @@ Status MakeNullRecordBatch(std::shared_ptr<RecordBatch>* out) {
   return Status::OK();
 }
 
-Status MakeListRecordBatch(std::shared_ptr<RecordBatch>* out) {
+Status MakeListRecordBatchSized(const int length, std::shared_ptr<RecordBatch>* out) {
   // Make the schema
   auto f0 = field("f0", list(int32()));
   auto f1 = field("f1", list(list(int32())));
@@ -431,7 +431,6 @@ Status MakeListRecordBatch(std::shared_ptr<RecordBatch>* out) {
   // Example data
 
   MemoryPool* pool = default_memory_pool();
-  const int length = 200;
   std::shared_ptr<Array> leaf_values, list_array, list_list_array, large_list_array;
   const bool include_nulls = true;
   RETURN_NOT_OK(MakeRandomInt32Array(1000, include_nulls, pool, &leaf_values));
@@ -446,7 +445,11 @@ Status MakeListRecordBatch(std::shared_ptr<RecordBatch>* out) {
   return Status::OK();
 }
 
-Status MakeListViewRecordBatch(std::shared_ptr<RecordBatch>* out) {
+Status MakeListRecordBatch(std::shared_ptr<RecordBatch>* out) {
+  return MakeListRecordBatchSized(200, out);
+}
+
+Status MakeListViewRecordBatchSized(const int length, std::shared_ptr<RecordBatch>* out) {
   // Make the schema
   auto f0 = field("f0", list_view(int32()));
   auto f1 = field("f1", list_view(list_view(int32())));
@@ -456,7 +459,6 @@ Status MakeListViewRecordBatch(std::shared_ptr<RecordBatch>* out) {
   // Example data
 
   MemoryPool* pool = default_memory_pool();
-  const int length = 200;
   std::shared_ptr<Array> leaf_values, list_array, list_list_array, large_list_array;
   const bool include_nulls = true;
   RETURN_NOT_OK(MakeRandomInt32Array(1000, include_nulls, pool, &leaf_values));
@@ -471,6 +473,10 @@ Status MakeListViewRecordBatch(std::shared_ptr<RecordBatch>* out) {
   return Status::OK();
 }
 
+Status MakeListViewRecordBatch(std::shared_ptr<RecordBatch>* out) {
+  return MakeListRecordBatchSized(200, out);
+}
+
 Status MakeFixedSizeListRecordBatch(std::shared_ptr<RecordBatch>* out) {
   // Make the schema
   auto f0 = field("f0", fixed_size_list(int32(), 1));

cpp/src/arrow/ipc/test_common.h

@@ -104,9 +104,15 @@ Status MakeStringTypesRecordBatchWithNulls(std::shared_ptr<RecordBatch>* out);
 ARROW_TESTING_EXPORT
 Status MakeNullRecordBatch(std::shared_ptr<RecordBatch>* out);
 
+ARROW_TESTING_EXPORT
+Status MakeListRecordBatchSized(int length, std::shared_ptr<RecordBatch>* out);
+
 ARROW_TESTING_EXPORT
 Status MakeListRecordBatch(std::shared_ptr<RecordBatch>* out);
 
+ARROW_TESTING_EXPORT
+Status MakeListViewRecordBatchSized(int length, std::shared_ptr<RecordBatch>* out);
+
 ARROW_TESTING_EXPORT
 Status MakeListViewRecordBatch(std::shared_ptr<RecordBatch>* out);
 

cpp/src/arrow/ipc/writer.cc

@@ -324,34 +324,36 @@ class RecordBatchSerializer {
     // Share slicing logic between ListArray, BinaryArray and LargeBinaryArray
     using offset_type = typename ArrayType::offset_type;
 
-    auto offsets = array.value_offsets();
+    if (array.length() == 0) {
+      *value_offsets = array.value_offsets();
+      return Status::OK();
+    }
 
     int64_t required_bytes = sizeof(offset_type) * (array.length() + 1);
-    if (array.offset() != 0) {
-      // If we have a non-zero offset, then the value offsets do not start at
-      // zero. We must a) create a new offsets array with shifted offsets and
-      // b) slice the values array accordingly
-
+    if (array.value_offset(0) > 0) {
+      // If the offset of the first value is non-zero, then we must create a new
+      // offsets buffer with shifted offsets.
       ARROW_ASSIGN_OR_RAISE(auto shifted_offsets,
                             AllocateBuffer(required_bytes, options_.memory_pool));
 
       auto dest_offsets = shifted_offsets->mutable_span_as<offset_type>();
-      const offset_type start_offset = array.value_offset(0);
+      const offset_type* source_offsets = array.raw_value_offsets();
+      const offset_type start_offset = source_offsets[0];
 
-      for (int i = 0; i < array.length(); ++i) {
-        dest_offsets[i] = array.value_offset(i) - start_offset;
+      for (int i = 0; i <= array.length(); ++i) {
+        dest_offsets[i] = source_offsets[i] - start_offset;
       }
-      // Final offset
-      dest_offsets[array.length()] = array.value_offset(array.length()) - start_offset;
-      offsets = std::move(shifted_offsets);
+      *value_offsets = std::move(shifted_offsets);
     } else {
-      // ARROW-6046: Slice offsets to used extent, in case we have a truncated
-      // slice
-      if (offsets != nullptr && offsets->size() > required_bytes) {
-        offsets = SliceBuffer(offsets, 0, required_bytes);
+      // ARROW-6046: if we have a truncated slice with unused leading or
+      // trailing data, then we slice it.
+      if (array.offset() > 0 || array.value_offsets()->size() > required_bytes) {
+        *value_offsets = SliceBuffer(
+            array.value_offsets(), array.offset() * sizeof(offset_type), required_bytes);
+      } else {
+        *value_offsets = array.value_offsets();
       }
     }
-    *value_offsets = std::move(offsets);
     return Status::OK();
   }