From 8c4406927846ce9949c8e77e527a20750ee448a4 Mon Sep 17 00:00:00 2001
From: Marshall Crumiller <mcrumiller@gmail.com>
Date: Fri, 19 Jan 2024 11:18:46 -0500
Subject: [PATCH 1/2] Allow list creation of decimals

---
 .../polars-core/src/chunked_array/builder/list/mod.rs  |  7 +++++++
 py-polars/tests/unit/datatypes/test_list.py            | 10 ++++++++++
 2 files changed, 17 insertions(+)

diff --git a/crates/polars-core/src/chunked_array/builder/list/mod.rs b/crates/polars-core/src/chunked_array/builder/list/mod.rs
index 9abcbcaa158a..f8b1eabed644 100644
--- a/crates/polars-core/src/chunked_array/builder/list/mod.rs
+++ b/crates/polars-core/src/chunked_array/builder/list/mod.rs
@@ -130,6 +130,13 @@ pub fn get_list_builder(
             list_capacity,
             Some(inner_type_logical.clone()),
         ))),
+        #[cfg(feature = "dtype-decimal")]
+        DataType::Decimal(_, _) => Ok(Box::new(ListPrimitiveChunkedBuilder::<Int128Type>::new(
+            name,
+            list_capacity,
+            value_capacity,
+            inner_type_logical.clone(),
+        ))),
         _ => {
             macro_rules! get_primitive_builder {
                 ($type:ty) => {{
diff --git a/py-polars/tests/unit/datatypes/test_list.py b/py-polars/tests/unit/datatypes/test_list.py
index 021a8696a406..8d7053f3fae6 100644
--- a/py-polars/tests/unit/datatypes/test_list.py
+++ b/py-polars/tests/unit/datatypes/test_list.py
@@ -2,6 +2,7 @@
 
 import pickle
 from datetime import date, datetime, time
+from decimal import Decimal
 from typing import TYPE_CHECKING, Any
 
 import pandas as pd
@@ -79,6 +80,15 @@ def test_categorical() -> None:
     assert out.dtype.inner.is_nested() is False  # type: ignore[attr-defined]
 
 
+def test_decimal() -> None:
+    input = [[Decimal("1.23"), Decimal("4.56")], [Decimal("7.89"), Decimal("10.11")]]
+    s = pl.Series(input)
+    assert s.dtype == pl.List(pl.Decimal)
+    assert s.dtype.inner == pl.Decimal
+    assert s.dtype.inner.is_nested() is False
+    assert s.to_list() == input
+
+
 def test_cast_inner() -> None:
     a = pl.Series([[1, 2]])
     for t in [bool, pl.Boolean]:

From fb29346a721b98b96a71e6b38874194dadaf232a Mon Sep 17 00:00:00 2001
From: Marshall Crumiller <mcrumiller@gmail.com>
Date: Fri, 19 Jan 2024 11:28:02 -0500
Subject: [PATCH 2/2] Fix lint

---
 py-polars/tests/unit/datatypes/test_list.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/py-polars/tests/unit/datatypes/test_list.py b/py-polars/tests/unit/datatypes/test_list.py
index 8d7053f3fae6..20c6a4f4e9d9 100644
--- a/py-polars/tests/unit/datatypes/test_list.py
+++ b/py-polars/tests/unit/datatypes/test_list.py
@@ -84,8 +84,8 @@ def test_decimal() -> None:
     input = [[Decimal("1.23"), Decimal("4.56")], [Decimal("7.89"), Decimal("10.11")]]
     s = pl.Series(input)
     assert s.dtype == pl.List(pl.Decimal)
-    assert s.dtype.inner == pl.Decimal
-    assert s.dtype.inner.is_nested() is False
+    assert s.dtype.inner == pl.Decimal  # type: ignore[attr-defined]
+    assert s.dtype.inner.is_nested() is False  # type: ignore[attr-defined]
     assert s.to_list() == input