LibRegex: Ensure nullable quantifiers backtrack when input remains

Makes patterns like `/(a?b??)*/` correctly match the string
Author: https://github.com/aplefull Commit: 61744322ad Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3752 Reviewed-by: https://github.com/alimpfard
2025-07-19 15:32:31 +00:00 · 2025-03-01 18:23:15 +01:00 · 2025-03-01 18:23:15 +01:00 · 61744322ad · 2025-03-02 14:20:04 +00:00
commit 61744322ad
parent 40c71ff3c0
2 changed files with 13 additions and 0 deletions
--- a/Libraries/LibRegex/RegexByteCode.cpp
+++ b/Libraries/LibRegex/RegexByteCode.cpp
@ -1118,6 +1118,10 @@ ALWAYS_INLINE ExecutionResult OpCode_JumpNonEmpty::execute(MatchInput const& inp
        }
    }

+    if (state.string_position < input.view.length()) {
+        return ExecutionResult::Failed_ExecuteLowPrioForks;
+    }
+
    return ExecutionResult::Continue;
 }