From b8018aebd146bef24fd754cbabb9372084cc420c Mon Sep 17 00:00:00 2001
From: Sylvestre Ledru <sylvestre@debian.org>
Date: Wed, 18 Mar 2026 23:40:54 +0100
Subject: [PATCH] sort: add collation key arena storage to LineData

Add collation_key_buffer (arena) and collation_key_ends (offsets) to
LineData and RecycledChunk, with a collation_key() accessor. All sort
keys for a chunk are stored in a single Vec<u8> to avoid millions of
small heap allocations.
---
 src/uu/sort/src/chunks.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/uu/sort/src/chunks.rs b/src/uu/sort/src/chunks.rs
index ce6b2118b..48bd4abca 100644
--- a/src/uu/sort/src/chunks.rs
+++ b/src/uu/sort/src/chunks.rs
@@ -62,6 +62,11 @@ pub struct LineData<'a> {
 impl LineData<'_> {
     /// Get the collation sort key for a line at the given index.
     pub fn collation_key(&self, index: usize) -> &[u8] {
+        debug_assert!(
+            index < self.collation_key_ends.len(),
+            "collation_key index {index} out of bounds (len {})",
+            self.collation_key_ends.len()
+        );
         let start = if index == 0 {
             0
         } else {