Fix cudf::repeat logic when count is zero (#13459)

Fixes logic in `cudf::repeat` to check for `count==0` before using it to check for possible out-of-bounds output size result.
Added a specific gtest for this as well.

Closes #13458 

Authors:
   - David Wendt (https://github.com/davidwendt)

Approvers:
   - Karthikeyan (https://github.com/karthikeyann)
   - Bradley Dice (https://github.com/bdice)
   - Vukasin Milovanovic (https://github.com/vuule)
   - Jason Lowe (https://github.com/jlowe)
   - Mike Wilson (https://github.com/hyperbolic2346)

cpp/src/filling/repeat.cu

@@ -137,13 +137,13 @@ std::unique_ptr<table> repeat(table_view const& input_table,
                               rmm::cuda_stream_view stream,
                               rmm::mr::device_memory_resource* mr)
 {
+  if ((input_table.num_rows() == 0) || (count == 0)) { return cudf::empty_like(input_table); }
+
   CUDF_EXPECTS(count >= 0, "count value should be non-negative");
   CUDF_EXPECTS(input_table.num_rows() <= std::numeric_limits<size_type>::max() / count,
                "The resulting table exceeds the column size limit",
                std::overflow_error);
 
-  if ((input_table.num_rows() == 0) || (count == 0)) { return cudf::empty_like(input_table); }
-
   auto output_size = input_table.num_rows() * count;
   auto map_begin   = cudf::detail::make_counting_transform_iterator(
     0, [count] __device__(auto i) { return i / count; });

cpp/tests/filling/repeat_tests.cpp

@@ -174,6 +174,21 @@ TYPED_TEST(RepeatTypedTestFixture, ZeroSizeInput)
   CUDF_TEST_EXPECT_COLUMNS_EQUAL(p_ret->view().column(0), expected);
 }
 
+TYPED_TEST(RepeatTypedTestFixture, ZeroCount)
+{
+  using T = TypeParam;
+  cudf::test::fixed_width_column_wrapper<T, int32_t> input(thrust::make_counting_iterator(0),
+                                                           thrust::make_counting_iterator(10));
+
+  auto expected = cudf::make_empty_column(cudf::type_to_id<T>());
+
+  cudf::table_view input_table{{input}};
+  auto p_ret = cudf::repeat(input_table, 0);
+
+  EXPECT_EQ(p_ret->num_columns(), 1);
+  CUDF_TEST_EXPECT_COLUMNS_EQUAL(p_ret->view().column(0), expected->view());
+}
+
 class RepeatStringTestFixture : public cudf::test::BaseFixture,
                                 cudf::test::UniformRandomGenerator<cudf::size_type> {
  public: