Function TEST

cpp/src/arrow/compute/row/grouper_test.cc:49–85

Specialized case for GH-40997

// Specialized case for GH-40997
TEST(Grouper, ResortedColumnsWithLargeNullRows) {
  const uint64_t num_rows = 1024;

  // construct random array with plenty of null values
  const int32_t kSeed = 42;
  const int32_t min = 0;
  const int32_t max = 100;
  const double null_probability = 0.3;
  const double true_probability = 0.5;
  auto rng = random::RandomArrayGenerator(kSeed);
  auto b_arr = rng.Boolean(num_rows, true_probability, null_probability);
  auto i32_arr = rng.Int32(num_rows, min, max, null_probability);
  auto i64_arr = rng.Int64(num_rows, min, max * 10, null_probability);

  // construct batches with columns which will be resorted in the grouper make
  std::vector<ExecBatch> exec_batches = {ExecBatch({i64_arr, i32_arr, b_arr}, num_rows),
                                         ExecBatch({i32_arr, i64_arr, b_arr}, num_rows),
                                         ExecBatch({i64_arr, b_arr, i32_arr}, num_rows),
                                         ExecBatch({i32_arr, b_arr, i64_arr}, num_rows),
                                         ExecBatch({b_arr, i32_arr, i64_arr}, num_rows),
                                         ExecBatch({b_arr, i64_arr, i32_arr}, num_rows)};

  const int num_batches = static_cast<int>(exec_batches.size());
  std::vector<uint32_t> group_num_vec;
  group_num_vec.reserve(num_batches);

  for (const auto& exec_batch : exec_batches) {
    ExecSpan span(exec_batch);
    ASSERT_OK_AND_ASSIGN(auto grouper, Grouper::Make(span.GetTypes()));
    ASSERT_OK_AND_ASSIGN(Datum group_ids, grouper->Consume(span));
    group_num_vec.emplace_back(grouper->num_groups());
  }

  for (int i = 1; i < num_batches; i++) {
    ASSERT_EQ(group_num_vec[i - 1], group_num_vec[i]);
  }
}

// Reproduction of GH-43124: Provoke var length buffer size if a grouper produces zero
// groups.