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fix(row): apply array offsets in ArrowArray wrappers #1039

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Merged
wgtmac merged 1 commit into from
Oct 21, 2026
Merged

fix(row): apply array offsets in ArrowArray wrappers #1039

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21 changes: 14 additions & 7 deletions src/iceberg/row/arrow_array_wrapper.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -134,7 +134,8 @@ class ArrowArrayStructLike::Impl {
const ArrowArray* child_array = array_.get().children[pos];
const ArrowArrayView* child_view = array_view_.children[pos];

return ExtractValue(child_schema, child_array, child_view, row_index_);
return ExtractValue(child_schema, child_array, child_view,
array_view_.offset + row_index_);
}

size_t num_fields() const { return static_cast<size_t>(schema_.n_children); }
Expand Down Expand Up @@ -252,8 +253,9 @@ class ArrowArrayArrayLike::Impl {
array_.get().length);
}

offset_ = ArrowArrayViewListChildOffset(&array_view_, row_index_);
length_ = ArrowArrayViewListChildOffset(&array_view_, row_index_ + 1) - offset_;
const int64_t row = array_view_.offset + row_index_;
offset_ = ArrowArrayViewListChildOffset(&array_view_, row);
length_ = ArrowArrayViewListChildOffset(&array_view_, row + 1) - offset_;
return {};
}

Expand Down Expand Up @@ -312,7 +314,7 @@ class ArrowArrayMapLike::Impl {
const ArrowArrayView* keys_view = array_view_.children[0]->children[0];

return ExtractValue(keys_schema, keys_array, keys_view,
offset_ + static_cast<int64_t>(pos));
EntryIndex(static_cast<int64_t>(pos)));
}

Result<Scalar> GetValue(size_t pos) const {
Expand All @@ -326,7 +328,7 @@ class ArrowArrayMapLike::Impl {
const ArrowArrayView* values_view = array_view_.children[0]->children[1];

return ExtractValue(values_schema, values_array, values_view,
offset_ + static_cast<int64_t>(pos));
EntryIndex(static_cast<int64_t>(pos)));
}

size_t size() const { return static_cast<size_t>(length_); }
Expand Down Expand Up @@ -365,12 +367,17 @@ class ArrowArrayMapLike::Impl {
// XXX: ArrowArrayViewListChildOffset does not work for map types.
// We need to directly access the offsets buffer instead.
auto* offsets_buffer = array_view_.buffer_views[1].data.as_int32;
offset_ = offsets_buffer[row_index_];
length_ = offsets_buffer[row_index_ + 1] - offset_;
const int64_t row = array_view_.offset + row_index_;
offset_ = offsets_buffer[row];

@shangxinli shangxinli Oct 20, 2026 •
edited
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The XXX note above is stale - ArrowArrayViewListChildOffset does handle NANOARROW_TYPE_MAP, see inline_array.h 1114-1120. The helper would drop exactly the arithmetic this PR is fixing.

length_ = offsets_buffer[row + 1] - offset_;

return {};
}

int64_t EntryIndex(int64_t pos) const {
return array_view_.children[0]->offset + offset_ + pos;
}

ArrowArrayView array_view_;
internal::ArrowArrayViewGuard array_view_guard_{&array_view_};

Expand Down
119 changes: 119 additions & 0 deletions src/iceberg/test/struct_like_test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -22,9 +22,12 @@
#include <array>
#include <memory>
#include <optional>
#include <string>
#include <utility>
#include <vector>

#include <arrow/array.h>
#include <arrow/buffer.h>
#include <arrow/c/bridge.h>
#include <arrow/json/from_string.h>
#include <arrow/type.h>
Expand Down Expand Up @@ -663,4 +666,120 @@ TEST(ArrowArrayStructLike, Accessor) {
}
}

TEST(ArrowArrayStructLike, SlicedStruct) {
auto person_type =
::arrow::struct_({::arrow::field("name", ::arrow::utf8(), /*nullable=*/false)});
auto root_type = ::arrow::struct_(
{::arrow::field("id", ::arrow::int64(), /*nullable=*/false),
::arrow::field("person", person_type, /*nullable=*/false),
::arrow::field("tags", ::arrow::list(::arrow::int32()), /*nullable=*/false)});

auto arrow_array = ::arrow::json::ArrayFromJSONString(root_type, R"([
{"id": 1, "person": {"name": "Alice"}, "tags": [1]},
{"id": 2, "person": {"name": "Bob"}, "tags": [2, 3]},
{"id": 3, "person": {"name": "Carol"}, "tags": []}])")
.ValueOrDie();
auto sliced = arrow_array->Slice(1);

ArrowSchema c_schema;
ArrowArray c_array;
internal::ArrowSchemaGuard schema_guard(&c_schema);
internal::ArrowArrayGuard array_guard(&c_array);
ASSERT_TRUE(::arrow::ExportType(*root_type, &c_schema).ok());
ASSERT_TRUE(::arrow::ExportArray(*sliced, &c_array).ok());
ASSERT_EQ(c_array.offset, 1);

@shangxinli shangxinli Oct 20, 2026 •
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This slices only the parent, so no child ever carries its own offset. The map test asserts children[0]->offset is 1 - worth the same here.


ICEBERG_UNWRAP_OR_FAIL(auto struct_like, ArrowArrayStructLike::Make(c_schema, c_array));

constexpr int64_t kNumRows = 2;
std::array<int64_t, kNumRows> ids = {2, 3};
std::array<std::string, kNumRows> names = {"Bob", "Carol"};
std::array<std::vector<int32_t>, kNumRows> tags = {std::vector<int32_t>{2, 3},
std::vector<int32_t>{}};

for (int64_t i = 0; i < kNumRows; ++i) {
ASSERT_THAT(struct_like->Reset(i), IsOk());
EXPECT_SCALAR_EQ(struct_like->GetField(0), int64_t, ids[i]);

ICEBERG_UNWRAP_OR_FAIL(auto person_scalar, struct_like->GetField(1));
auto person = std::get<std::shared_ptr<StructLike>>(person_scalar);
EXPECT_SCALAR_EQ(person->GetField(0), std::string_view, names[i]);

ICEBERG_UNWRAP_OR_FAIL(auto tags_scalar, struct_like->GetField(2));
auto tags_like = std::get<std::shared_ptr<ArrayLike>>(tags_scalar);
ASSERT_EQ(tags_like->size(), tags[i].size());
for (size_t j = 0; j < tags[i].size(); ++j) {
EXPECT_SCALAR_EQ(tags_like->GetElement(j), int32_t, tags[i][j]);
}
}
}

TEST(ArrowArrayStructLike, SlicedList) {
auto list_type = ::arrow::list(::arrow::int32());
auto arrow_array =
::arrow::json::ArrayFromJSONString(list_type, R"([[1], [2, 3], [4]])").ValueOrDie();
auto sliced = arrow_array->Slice(1);

ArrowSchema c_schema;
ArrowArray c_array;
internal::ArrowSchemaGuard schema_guard(&c_schema);
internal::ArrowArrayGuard array_guard(&c_array);
ASSERT_TRUE(::arrow::ExportType(*list_type, &c_schema).ok());
ASSERT_TRUE(::arrow::ExportArray(*sliced, &c_array).ok());

ICEBERG_UNWRAP_OR_FAIL(auto array_like, ArrowArrayArrayLike::Make(c_schema, c_array));
ASSERT_EQ(array_like->size(), 2);
EXPECT_SCALAR_EQ(array_like->GetElement(0), int32_t, 2);
EXPECT_SCALAR_EQ(array_like->GetElement(1), int32_t, 3);

ASSERT_THAT(array_like->Reset(1), IsOk());
ASSERT_EQ(array_like->size(), 1);
EXPECT_SCALAR_EQ(array_like->GetElement(0), int32_t, 4);
}

TEST(ArrowArrayStructLike, SlicedMap) {
auto map_type = std::make_shared<::arrow::MapType>(
::arrow::field("key", ::arrow::utf8(), /*nullable=*/false),
::arrow::field("value", ::arrow::int32(), /*nullable=*/false));
auto entries_source =
::arrow::json::ArrayFromJSONString(map_type, R"([[["X", 0], ["Foo", 1],
["Bar", 2], ["Baz", 3]]])")
.ValueOrDie();
auto entries =
std::static_pointer_cast<::arrow::MapArray>(entries_source)->values()->Slice(1);
auto offsets = ::arrow::Buffer::FromVector(std::vector<int32_t>{0, 0, 2, 3, 3});
auto map_data = ::arrow::ArrayData::Make(map_type, /*length=*/4, {nullptr, offsets},
{entries->data()}, /*null_count=*/0);
auto sliced = ::arrow::MakeArray(map_data)->Slice(1);
ASSERT_TRUE(sliced->ValidateFull().ok());

ArrowSchema c_schema;
ArrowArray c_array;
internal::ArrowSchemaGuard schema_guard(&c_schema);
internal::ArrowArrayGuard array_guard(&c_array);
ASSERT_TRUE(::arrow::ExportType(*map_type, &c_schema).ok());
ASSERT_TRUE(::arrow::ExportArray(*sliced, &c_array).ok());
ASSERT_EQ(c_array.offset, 1);
ASSERT_EQ(c_array.children[0]->offset, 1);

ICEBERG_UNWRAP_OR_FAIL(auto map_like, ArrowArrayMapLike::Make(c_schema, c_array));

constexpr int64_t kNumRows = 3;
std::array<std::vector<std::pair<std::string, int32_t>>, kNumRows> expected_maps = {
std::vector<std::pair<std::string, int32_t>>{{"Foo", 1}, {"Bar", 2}},
std::vector<std::pair<std::string, int32_t>>{{"Baz", 3}},
std::vector<std::pair<std::string, int32_t>>{},
};

for (int64_t i = 0; i < kNumRows; ++i) {
ASSERT_THAT(map_like->Reset(i), IsOk());
const auto& expected_map = expected_maps[i];
ASSERT_EQ(map_like->size(), expected_map.size());
for (size_t j = 0; j < expected_map.size(); ++j) {
EXPECT_SCALAR_EQ(map_like->GetKey(j), std::string_view, expected_map[j].first);
EXPECT_SCALAR_EQ(map_like->GetValue(j), int32_t, expected_map[j].second);
}
}
}

} // namespace iceberg
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