From 00bc22c33268f0765adfcdf0ce00f23c35fff136 Mon Sep 17 00:00:00 2001
From: Ali Mohammad Pur <ali.mpfard@gmail.com>
Date: Sun, 17 Nov 2024 12:48:47 +0100
Subject: [PATCH] LibRegex: Don't immediately ignore TempInverse in optimizer

fe46b2c1411 added the reset-temp-inverse flag, but set it up so all
tempinverse ops were negated at the start of the next op; this commit
makes it so these flags actually persist for one op and not zero.

Fixes #2296.
---
 Libraries/LibRegex/RegexOptimizer.cpp | 4 ++--
 Tests/LibRegex/Regex.cpp              | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/Libraries/LibRegex/RegexOptimizer.cpp b/Libraries/LibRegex/RegexOptimizer.cpp
index 857c4bbaec6..a713867e665 100644
--- a/Libraries/LibRegex/RegexOptimizer.cpp
+++ b/Libraries/LibRegex/RegexOptimizer.cpp
@@ -227,7 +227,7 @@ static bool has_overlap(Vector<CompareTypeAndValuePair> const& lhs, Vector<Compa
             break;
         case CharacterCompareType::TemporaryInverse:
             temporary_inverse = true;
-            reset_temporary_inverse = true;
+            reset_temporary_inverse = false;
             break;
         case CharacterCompareType::AnyChar:
             // Special case: if not inverted, AnyChar is always in the range.
@@ -349,7 +349,7 @@ static bool has_overlap(Vector<CompareTypeAndValuePair> const& lhs, Vector<Compa
             break;
         case CharacterCompareType::TemporaryInverse:
             temporary_inverse = true;
-            reset_temporary_inverse = true;
+            reset_temporary_inverse = false;
             break;
         case CharacterCompareType::AnyChar:
             // Special case: if not inverted, AnyChar is always in the range.
diff --git a/Tests/LibRegex/Regex.cpp b/Tests/LibRegex/Regex.cpp
index 762d52284ec..58ed080b274 100644
--- a/Tests/LibRegex/Regex.cpp
+++ b/Tests/LibRegex/Regex.cpp
@@ -1042,6 +1042,8 @@ TEST_CASE(optimizer_atomic_groups)
         // (b+)(b+) produces an intermediate block with no matching ops, the optimiser should ignore that block when looking for following matches and correctly detect the overlap between (b+) and (b+).
         // note that the second loop may be rewritten to a ForkReplace, but the first loop should not be rewritten.
         Tuple { "(b+)(b+)"sv, "bbb"sv, true },
+        // Don't treat [\S] as [\s]; see ladybird#2296.
+        Tuple { "([^\\s]+?)\\(([\\s\\S]*)\\)"sv, "a(b)"sv, true },
     };
 
     for (auto& test : tests) {