Skip to content

GH-55295: [C++][Dataset] Reject negative num_rows in Scanner::Head #55304

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
siddiqueirshad wants to merge 1 commit into
base: main
Choose a base branch
from
Open

GH-55295: [C++][Dataset] Reject negative num_rows in Scanner::Head #55304

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 3 additions & 0 deletions cpp/src/arrow/dataset/scanner.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -593,6 +593,9 @@ Result<std::shared_ptr<Table>> AsyncScanner::TakeRows(const Array& indices) {
}

Result<std::shared_ptr<Table>> AsyncScanner::Head(int64_t num_rows) {
if (num_rows < 0) {
return Status::Invalid("num_rows must be non-negative");
}
if (num_rows == 0) {
return Table::FromRecordBatches(options()->projected_schema, {});
}
Expand Down
1 change: 1 addition & 0 deletions cpp/src/arrow/dataset/scanner_test.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1634,6 +1634,7 @@ TEST_P(TestScanner, Head) {
ASSERT_OK_AND_ASSIGN(expected, Table::FromRecordBatches(schema_, {}));
ASSERT_OK_AND_ASSIGN(actual, scanner->Head(0));
AssertTablesEqual(*expected, *actual, /*same_chunk_layout=*/false);
ASSERT_RAISES(Invalid, scanner->Head(-1));

ASSERT_OK_AND_ASSIGN(expected, Table::FromRecordBatches(schema_, {batch}));
ASSERT_OK_AND_ASSIGN(actual, scanner->Head(batch_size));
Expand Down
6 changes: 6 additions & 0 deletions python/pyarrow/tests/test_dataset.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -648,7 +648,13 @@ def test_head(dataset, dataset_reader):
result = dataset_reader.head(dataset, 1024, columns=['i64']).to_pydict()
assert result == {'i64': list(range(5)) * 2}

with pytest.raises(ValueError, match="num_rows must be non-negative"):
dataset_reader.head(dataset, -1)

fragment = next(dataset.get_fragments())
with pytest.raises(ValueError, match="num_rows must be non-negative"):
fragment.head(-1)

result = fragment.head(1, columns=['i64']).to_pydict()
assert result == {'i64': [0]}

Expand Down
Loading