From 811be7b1ac4cafbc6ede2a4dc1b7c004247d3a00 Mon Sep 17 00:00:00 2001
From: Daniel Imms <2193314+Tyriar@users.noreply.github.com>
Date: Mon, 25 May 2026 18:02:22 -0700
Subject: [PATCH] fix(addon-search): prevent infinite loop on empty reverse
 regex matches

Advance regex lastIndex when skipping zero-length matches during reverse
search to avoid hanging on patterns like .*?

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 addons/addon-search/src/SearchEngine.ts | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/addons/addon-search/src/SearchEngine.ts b/addons/addon-search/src/SearchEngine.ts
index c14822d21..7fa09edf2 100644
--- a/addons/addon-search/src/SearchEngine.ts
+++ b/addons/addon-search/src/SearchEngine.ts
@@ -315,6 +315,10 @@ export class SearchEngine {
         const searchSubstring = searchStringLine.slice(0, offset);
         while (foundTerm = searchRegex.exec(searchSubstring)) {
           if (foundTerm[0].length === 0) {
+            if (searchRegex.lastIndex >= searchSubstring.length) {
+              break;
+            }
+            searchRegex.lastIndex++;
             continue;
           }
           resultIndex = searchRegex.lastIndex - foundTerm[0].length;
@@ -364,8 +368,13 @@ export class SearchEngine {
           let foundTerm: RegExpExecArray | null;
           if (isReverseSearch) {
             resultIndex = -1;
-            while (foundTerm = searchRegex.exec(searchStringLine.slice(0, offset))) {
+            const wholeWordSubstring = searchStringLine.slice(0, offset);
+            while (foundTerm = searchRegex.exec(wholeWordSubstring)) {
               if (foundTerm[0].length === 0) {
+                if (searchRegex.lastIndex >= wholeWordSubstring.length) {
+                  break;
+                }
+                searchRegex.lastIndex++;
                 continue;
               }
               const candidateIndex = searchRegex.lastIndex - foundTerm[0].length;