From 5308394c930e8ff75be573c95ad4454b92f742d4 Mon Sep 17 00:00:00 2001
From: Roland Eigelsreiter <brainfoolong@users.noreply.github.com>
Date: Mon, 29 Nov 2021 07:54:50 +0100
Subject: [PATCH] fixed is_file() call with null

Calling is_file() with null will throw an error in PHP 8.1
---
 src/Attestation/Format/FormatBase.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Attestation/Format/FormatBase.php b/src/Attestation/Format/FormatBase.php
index d52ea6d..b2f1dfd 100644
--- a/src/Attestation/Format/FormatBase.php
+++ b/src/Attestation/Format/FormatBase.php
@@ -27,7 +27,7 @@ public function __construct($AttestionObject, AuthenticatorData $authenticatorDa
      */
     public function __destruct() {
         // delete X.509 chain certificate file after use
-        if (\is_file($this->_x5c_tempFile)) {
+        if ($this->_x5c_tempFile && \is_file($this->_x5c_tempFile)) {
             \unlink($this->_x5c_tempFile);
         }
     }
@@ -37,7 +37,7 @@ public function __destruct() {
      * @return string|null
      */
     public function getCertificateChain() {
-        if (\is_file($this->_x5c_tempFile)) {
+        if ($this->_x5c_tempFile && \is_file($this->_x5c_tempFile)) {
             return \file_get_contents($this->_x5c_tempFile);
         }
         return null;