From 9f9af36be87cbff54ea76f47a766274913749e49 Mon Sep 17 00:00:00 2001
From: Aadhavan Srinivasan <aadhavan@twomorecents.org>
Date: Mon, 17 Feb 2025 09:36:17 -0500
Subject: [PATCH] Fixed bug where escaped parentheses in lookarounds were
 counted as regular parentheses instead of literals

---
 regex/compile.go | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/regex/compile.go b/regex/compile.go
index 6cd0e59..c98e857 100644
--- a/regex/compile.go
+++ b/regex/compile.go
@@ -410,10 +410,10 @@ func shuntingYard(re string, flags ...ReFlag) ([]postfixNode, error) {
 				if i >= len(re_runes) {
 					return nil, fmt.Errorf("unclosed lookaround")
 				}
-				if re_runes[i] == '(' || re_runes[i] == nonCapLparenRune {
+				if (re_runes[i] == '(' && re_runes[i-1] != '\\') || re_runes[i] == nonCapLparenRune {
 					numOpenParens++
 				}
-				if re_runes[i] == ')' {
+				if re_runes[i] == ')' && re_runes[i-1] != '\\' {
 					numOpenParens--
 					if numOpenParens == 0 {
 						break
@@ -589,10 +589,10 @@ func shuntingYard(re string, flags ...ReFlag) ([]postfixNode, error) {
 				if i >= len(re_postfix) {
 					return nil, fmt.Errorf("unclosed lookaround")
 				}
-				if re_postfix[i] == '(' || re_postfix[i] == nonCapLparenRune {
+				if (re_postfix[i] == '(' && re_postfix[i-1] != '\\') || re_postfix[i] == nonCapLparenRune {
 					numOpenParens++
 				}
-				if re_postfix[i] == ')' {
+				if re_postfix[i] == ')' && re_postfix[i-1] != '\\' {
 					numOpenParens--
 					if numOpenParens == 0 {
 						break