From e3d3b71e6073d853674b49a7a2aa8f016b2fdaf5 Mon Sep 17 00:00:00 2001
From: kenjis <kenji.uui@gmail.com>
Date: Sat, 12 Feb 2022 12:53:34 +0900
Subject: [PATCH] fix: do not call header() if headers have already been sent

---
 system/Debug/Exceptions.php | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/system/Debug/Exceptions.php b/system/Debug/Exceptions.php
index a65be7a2ad2f..e8249271733a 100644
--- a/system/Debug/Exceptions.php
+++ b/system/Debug/Exceptions.php
@@ -109,7 +109,9 @@ public function exceptionHandler(Throwable $exception)
 
         if (! is_cli()) {
             $this->response->setStatusCode($statusCode);
-            header(sprintf('HTTP/%s %s %s', $this->request->getProtocolVersion(), $this->response->getStatusCode(), $this->response->getReasonPhrase()), true, $statusCode);
+            if (! headers_sent()) {
+                header(sprintf('HTTP/%s %s %s', $this->request->getProtocolVersion(), $this->response->getStatusCode(), $this->response->getReasonPhrase()), true, $statusCode);
+            }
 
             if (strpos($this->request->getHeaderLine('accept'), 'text/html') === false) {
                 $this->respond(ENVIRONMENT === 'development' ? $this->collectVars($exception, $statusCode) : '', $statusCode)->send();