From cfb59b908256881868e15ced8f8b9d7cb8de3f7b Mon Sep 17 00:00:00 2001
From: kwy404 <thekaway404@gmail.com>
Date: Thu, 1 Oct 2026 13:25:45 -0300
Subject: [PATCH] fix: avoid splitting surrogate pairs in trimEnd

---
 src/common/stringUtils.test.ts | 7 ++++++-
 src/common/stringUtils.ts      | 5 ++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/common/stringUtils.test.ts b/src/common/stringUtils.test.ts
index d16bb8a98..f96cecc60 100644
--- a/src/common/stringUtils.test.ts
+++ b/src/common/stringUtils.test.ts
@@ -4,9 +4,14 @@
 
 import { expect } from 'chai';
 import { Base0Position } from './positions';
-import { PositionToOffset } from './stringUtils';
+import { PositionToOffset, trimEnd } from './stringUtils';
 
 describe('stringUtils', () => {
+  it('trimEnd does not split surrogate pairs', () => {
+    expect(trimEnd('ab\u{1F600}cd', 4)).to.equal('ab…');
+    expect(trimEnd('ab\u{1F600}cd', 5)).to.equal('ab\u{1F600}…');
+  });
+
   it('positionToOffset', () => {
     const simple = new PositionToOffset('hello\nworld');
     expect(simple.convert(new Base0Position(0, 2))).to.equal(2);
diff --git a/src/common/stringUtils.ts b/src/common/stringUtils.ts
index 6153c03d0..490434a5d 100644
--- a/src/common/stringUtils.ts
+++ b/src/common/stringUtils.ts
@@ -6,7 +6,10 @@ import { IPosition } from './positions';
 
 export function trimEnd(text: string, maxLength: number) {
   if (text.length <= maxLength) return text;
-  return text.substr(0, maxLength - 1) + '…';
+  let end = maxLength - 1;
+  const lastPoint = text.codePointAt(end - 1);
+  if (lastPoint && lastPoint >= 0x10000) --end;
+  return text.substr(0, end) + '…';
 }
 
 export function trimMiddle(text: string, maxLength: number) {