impl

Author: mvorisek

Diff for: src/Type/Regex/RegexGroupParser.php

@@ -110,7 +110,7 @@ public function parseGroups(string $regex): ?RegexAstWalkResult
 			RegexGroupWalkResult::createEmpty(),
 		);
 
-		if (!$subjectAsGroupResult->mightContainEmptyStringLiteral()) {
+		if (!$subjectAsGroupResult->mightContainEmptyStringLiteral() && !$this->containsEscapeK($ast)) {
 			// we could handle numeric-string, in case we know the regex is delimited by ^ and $
 			if ($subjectAsGroupResult->isNonFalsy()->yes()) {
 				$astWalkResult = $astWalkResult->withSubjectBaseType(
@@ -171,6 +171,21 @@ private function updateCapturingAstAddEmptyToken(TreeNode $ast): void
 		$ast->setChildren([$emptyAlternationAst]);
 	}
 
+	private function containsEscapeK(TreeNode $ast): bool
+	{
+		if ($ast->getId() === 'token' && $ast->getValueToken() === 'match_point_reset') {
+			return true;
+		}
+
+		foreach ($ast->getChildren() as $child) {
+			if ($this->containsEscapeK($child)) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
 	private function walkRegexAst(
 		TreeNode $ast,
 		?RegexAlternation $alternation,