Validate nested iterable depth

Author: fallintoplace

python/pylibcudf/pylibcudf/column.pyx

@@ -217,8 +217,12 @@ def _infer_shape(obj: list, depth: int) -> tuple[int, ...]:
 
     shape = (len(obj),)
     if depth == 1:
+        if any(isinstance(value, list) for value in obj):
+            raise ValueError("Inconsistent inner list shapes")
         return shape
 
+    if not isinstance(obj[0], list):
+        raise ValueError("Inconsistent inner list shapes")
     first_shape = _infer_shape(obj[0], depth - 1)
     for sub in obj[1:]:
         if not isinstance(sub, list) or _infer_shape(sub, depth - 1) != first_shape:

python/pylibcudf/tests/test_column_from_iterable.py

@@ -102,6 +102,8 @@ def test_from_list_irregular_shapes_raises():
     [
         [[[1], [2]], [[3, 4], [5, 6]]],
         [[[1, 2], [3, 4]], [[5], [6, 7, 8]]],
+        [[[1]], [2]],
+        [[[1]], [[[2, 3]]]],
     ],
 )
 def test_from_list_deeply_irregular_shapes_raises(data):