Safeguard against preg_replace_callback() failure

Author: sebastianbergmann

src/Exception/PharPrefixCouldNotBeStrippedException.php

@@ -0,0 +1,21 @@
+<?php declare(strict_types=1);
+/*
+ * This file is part of phpunit/php-code-coverage.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace SebastianBergmann\CodeCoverage\Serialization;
+
+use RuntimeException;
+use SebastianBergmann\CodeCoverage\Exception;
+
+final class PharPrefixCouldNotBeStrippedException extends RuntimeException implements Exception
+{
+    public function __construct()
+    {
+        parent::__construct('Failed to strip PHAR prefix from serialized data');
+    }
+}

src/Serialization/Serializer.php

@@ -57,6 +57,8 @@
 {
     /**
      * @param non-empty-string $target
+     *
+     * @throws PharPrefixCouldNotBeStrippedException
      */
     public function serialize(string $target, CodeCoverage $codeCoverage, bool $includeGitInformation = false): void
     {
@@ -120,17 +122,25 @@ public function serialize(string $target, CodeCoverage $codeCoverage, bool $incl
     /**
      * @param non-empty-string $serialized
      *
+     * @throws PharPrefixCouldNotBeStrippedException
+     *
      * @return non-empty-string
      */
     private function stripPharPrefix(string $serialized): string
     {
-        return preg_replace_callback(
+        $result = preg_replace_callback(
             '/([OCs]):(\d+):"(\x00?)PHPUnitPHAR\\\\/',
             static function (array $matches): string
             {
                 return $matches[1] . ':' . ((int) $matches[2] - 12) . ':"' . $matches[3];
             },
             $serialized,
         );
+
+        if ($result === null) {
+            throw new PharPrefixCouldNotBeStrippedException;
+        }
+
+        return $result;
     }
 }