Merge pull request #15811 from rapidsai/branch-24.06

Forward-merge branch-24.06 into branch-24.08

cpp/src/io/orc/writer_impl.cu

@@ -782,8 +782,16 @@ std::vector<std::vector<rowgroup_rows>> calculate_aligned_rowgroup_bounds(
         } else {
           // pushdown mask present; null mask bits w/ set pushdown mask bits will be encoded
           // Use the number of set bits in pushdown mask as size
-          auto bits_to_borrow =
-            8 - (d_pd_set_counts[rg_idx][parent_col_idx] - previously_borrowed) % 8;
+          auto bits_to_borrow = [&]() {
+            auto const parent_valid_count = d_pd_set_counts[rg_idx][parent_col_idx];
+            if (parent_valid_count < previously_borrowed) {
+              // Borrow to make an empty rowgroup
+              return previously_borrowed - parent_valid_count;
+            }
+            auto const misalignment = (parent_valid_count - previously_borrowed) % 8;
+            return (8 - misalignment) % 8;
+          }();
+
           if (bits_to_borrow == 0) {
             // Didn't borrow any bits for this rowgroup
             previously_borrowed = 0;

python/cudf/cudf/tests/test_orc.py

@@ -1954,3 +1954,16 @@ def test_writer_lz4():
 
     got = pd.read_orc(buffer)
     assert_eq(gdf, got)
+
+
+def test_row_group_alignment(datadir):
+    path = datadir / "TestOrcFile.MapManyNulls.parquet"
+
+    expected = cudf.read_parquet(path)
+
+    buffer = BytesIO()
+    expected.to_orc(buffer)
+
+    got = cudf.read_orc(buffer)
+
+    assert_eq(expected, got)