From db2e3e89307d30e4096686083f03ef5689572bdf Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Tue, 22 Oct 2024 15:43:33 +0100
Subject: [PATCH] assert cut

---
 rich/segment.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/rich/segment.py b/rich/segment.py
index 0f0676876..edcb52dd3 100644
--- a/rich/segment.py
+++ b/rich/segment.py
@@ -161,10 +161,14 @@ def split_cells(self, cut: int) -> Tuple["Segment", "Segment"]:
         If the cut point falls in the middle of a 2-cell wide character then it is replaced
         by two spaces, to preserve the display width of the parent segment.
 
+        Args:
+            cut (int): Offset within the segment to cut.
+
         Returns:
             Tuple[Segment, Segment]: Two segments.
         """
         text, style, control = self
+        assert cut >= 0
 
         if _is_single_cell_widths(text):
             # Fast path with all 1 cell characters