From 60c76120829d6a62c63d820446d81e13db8134d5 Mon Sep 17 00:00:00 2001
From: Colin Jermain <cjermain@gmail.com>
Date: Wed, 7 Jun 2023 21:02:07 -0400
Subject: [PATCH 1/2] Adding new constructor for MutableListArray

---
 src/array/list/mutable.rs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/array/list/mutable.rs b/src/array/list/mutable.rs
index 8841ceaf53..6a4aa623a0 100644
--- a/src/array/list/mutable.rs
+++ b/src/array/list/mutable.rs
@@ -142,6 +142,22 @@ impl<O: Offset, M: MutableArray> MutableListArray<O, M> {
         Self::new_from(values, data_type, capacity)
     }
 
+    /// Creates a new [`MutableListArray`] from a [`MutableArray`], [`Offsets`] and
+    /// [`MutableBitmap`].
+    pub fn new_from_mutable(
+        values: M,
+        offsets: Offsets<O>,
+        validity: Option<MutableBitmap>,
+    ) -> Self {
+        let data_type = values.data_type().clone();
+        Self {
+            data_type,
+            offsets,
+            values,
+            validity,
+        }
+    }
+
     #[inline]
     /// Needs to be called when a valid value was extended to this array.
     /// This is a relatively low level function, prefer `try_push` when you can.

From 3557894fa4e79504e204ae2c1ee2d757714aec48 Mon Sep 17 00:00:00 2001
From: Colin Jermain <cjermain@gmail.com>
Date: Sun, 18 Jun 2023 21:09:22 -0400
Subject: [PATCH 2/2] Asserting values length equals last element of offset

---
 src/array/list/mutable.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/array/list/mutable.rs b/src/array/list/mutable.rs
index 6a4aa623a0..2bb39dea87 100644
--- a/src/array/list/mutable.rs
+++ b/src/array/list/mutable.rs
@@ -149,6 +149,7 @@ impl<O: Offset, M: MutableArray> MutableListArray<O, M> {
         offsets: Offsets<O>,
         validity: Option<MutableBitmap>,
     ) -> Self {
+        assert_eq!(values.len(), offsets.last().to_usize());
         let data_type = values.data_type().clone();
         Self {
             data_type,