From d7172b1002e9bc2a99802866487f292048093568 Mon Sep 17 00:00:00 2001
From: zhanglangning <zln1905391059@163.com>
Date: Wed, 12 Aug 2026 04:29:56 +0800
Subject: [PATCH] Fix surround operations on selections ending at EOF

---
 helix-core/src/surround.rs | 41 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/helix-core/src/surround.rs b/helix-core/src/surround.rs
index 4dec41f17d09..db0f1e5f1bd5 100644
--- a/helix-core/src/surround.rs
+++ b/helix-core/src/surround.rs
@@ -167,7 +167,7 @@ pub fn find_nth_pairs_pos(
     if text.len_chars() < 2 {
         return Err(Error::PairNotFound);
     }
-    if range.to() >= text.len_chars() {
+    if range.to() > text.len_chars() {
         return Err(Error::RangeExceedsText);
     }
 
@@ -332,7 +332,7 @@ pub fn get_surround_pos(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::Range;
+    use crate::{Range, Transaction};
 
     use ropey::Rope;
     use smallvec::SmallVec;
@@ -352,6 +352,43 @@ mod test {
         );
     }
 
+    #[test]
+    fn test_get_surround_pos_full_range_ending_at_eof_can_be_deleted() {
+        let mut doc = Rope::from("(hello world)");
+        let selection = Selection::single(0, doc.len_chars());
+
+        let change_pos = get_surround_pos(None, doc.slice(..), &selection, Some('('), 1).unwrap();
+
+        assert_eq!(change_pos, [0, doc.len_chars() - 1]);
+
+        let transaction =
+            Transaction::change(&doc, change_pos.into_iter().map(|pos| (pos, pos + 1, None)));
+        assert!(transaction.apply(&mut doc));
+        assert_eq!(doc, "hello world");
+    }
+
+    #[test]
+    fn test_find_nth_pairs_pos_rejects_range_beyond_eof() {
+        let doc = Rope::from("(hello world)");
+        let range = Range::new(0, doc.len_chars() + 1);
+
+        assert_eq!(
+            find_nth_pairs_pos(None, doc.slice(..), '(', range, 1),
+            Err(Error::RangeExceedsText)
+        );
+    }
+
+    #[test]
+    fn test_find_nth_pairs_pos_accepts_range_within_text() {
+        let doc = Rope::from("(hello world)");
+        let range = Range::new(1, doc.len_chars() - 1);
+
+        assert_eq!(
+            find_nth_pairs_pos(None, doc.slice(..), '(', range, 1),
+            Ok((0, doc.len_chars() - 1))
+        );
+    }
+
     #[test]
     fn test_get_surround_pos_bail_different_surround_chars() {
         #[rustfmt::skip]