test: gracefully handle warnings on broken regexes

Author: g105b

phpunit.xml

@@ -6,6 +6,7 @@
 	cacheDirectory="test/phpunit/.phpunit.cache"
 	bootstrap="vendor/autoload.php"
 	displayDetailsOnTestsThatTriggerDeprecations="true"
+	displayDetailsOnTestsThatTriggerWarnings="true"
 >
 	<coverage />
 

src/Redirection/RedirectMap.php

@@ -59,8 +59,8 @@ private function matchRegex(string $oldUri):?RedirectUri {
 					throw new RedirectException("Invalid regex pattern in redirect file: $pattern");
 				}
 				if($matchResult === 1) {
-					$newUri = (string)preg_replace("~$pattern~", $replacement, $oldUri, 1);
-					if($newUri !== $oldUri) {
+					$newUri = preg_replace("~$pattern~", $replacement, $oldUri, 1);
+					if(is_string($newUri) && $newUri !== $oldUri) {
 						return new RedirectUri($newUri, (int)$code);
 					}
 				}

test/phpunit/Redirection/RedirectMapTest.php

@@ -4,6 +4,8 @@
 use Gt\WebEngine\Redirection\RedirectException;
 use Gt\WebEngine\Redirection\RedirectMap;
 use Gt\WebEngine\Redirection\RedirectUri;
+use PHPUnit\Framework\Attributes\IgnorePhpunitWarnings;
+use PHPUnit\Framework\Attributes\WithoutErrorHandler;
 use PHPUnit\Framework\TestCase;
 
 class RedirectMapTest extends TestCase {
@@ -42,20 +44,13 @@ public function testMatch_invalidRegexThrows():void {
 		$map->addRule(307, '~^/broken/([)$', '/x');
 		self::expectException(RedirectException::class);
 		self::expectExceptionMessage('Invalid regex pattern in redirect file: ^/broken/([)$');
-		$prevHandler = set_error_handler(function(int $severity, string $message) {
-			// Swallow regex compilation warnings from preg_match; exception is asserted below.
-			return ($severity === E_WARNING);
-		});
+
+		set_error_handler(static fn(int $errno) => $errno === E_WARNING);
 		try {
 			$map->match('/broken/anything');
 		}
 		finally {
-			if($prevHandler !== null) {
-				set_error_handler($prevHandler);
-			}
-			else {
-				restore_error_handler();
-			}
+			restore_error_handler();
 		}
 	}