From 2b01bc7a94237334fbc5d07bfe59dce47ef8e7a8 Mon Sep 17 00:00:00 2001
From: Roland Reichwein <Roland.Reichwein@bmw.de>
Date: Sun, 8 Mar 2026 20:45:30 +0100
Subject: [PATCH] Guard against past-end iterator in etl::rotate()

And fix scope of rotate_right_by_one for etl::rotate()
---
 include/etl/algorithm.h | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/etl/algorithm.h b/include/etl/algorithm.h
index d6b144d5..c52d445c 100644
--- a/include/etl/algorithm.h
+++ b/include/etl/algorithm.h
@@ -1366,6 +1366,15 @@ namespace etl
   ETL_CONSTEXPR14
   TIterator rotate(TIterator first, TIterator middle, TIterator last)
   {
+    if (first == middle)
+    {
+      return last;
+    }
+    if (middle == last)
+    {
+      return first;
+    }
+
     if (etl::next(first) == middle)
     {
       return private_algorithm::rotate_left_by_one(first, last);
@@ -1374,7 +1383,7 @@ namespace etl
 #if ETL_USING_CPP20
     if (etl::next(middle) == last)
     {
-      if ETL_IF_CONSTEXPR(!etl::is_forward_iterator<TIterator>::value)
+      if ETL_IF_CONSTEXPR(etl::is_bidirectional_iterator_concept<TIterator>::value)
       {
         return private_algorithm::rotate_right_by_one(first, last);
       }