From 5e0818e9c532e9c7f54f5ccd4c184dc8643e84df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marcel=20Sch=C3=BCrmann?= <marcel@schue.ch>
Date: Wed, 15 Oct 2025 23:36:09 +0200
Subject: [PATCH 1/2] replace 404 and 406 CRITICAL errors with NOTICE and
 useful information

---
 libraries/src/Exception/ExceptionHandler.php | 43 +++++++++++++++-----
 1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/libraries/src/Exception/ExceptionHandler.php b/libraries/src/Exception/ExceptionHandler.php
index 7fbe87fd4440c..a40bb56560f73 100644
--- a/libraries/src/Exception/ExceptionHandler.php
+++ b/libraries/src/Exception/ExceptionHandler.php
@@ -14,6 +14,9 @@
 use Joomla\CMS\Event\Application\AfterInitialiseDocumentEvent;
 use Joomla\CMS\Factory;
 use Joomla\CMS\Log\Log;
+use Joomla\CMS\Router\Exception\RouteNotFoundException;
+use Joomla\CMS\Application\Exception\NotAcceptable;
+use Joomla\CMS\Uri\Uri;
 
 // phpcs:disable PSR1.Files.SideEffects
 \defined('_JEXEC') or die;
@@ -221,18 +224,38 @@ protected static function isException($error)
      */
     protected static function logException(\Throwable $error)
     {
+        // Handle common client errors as notices instead of critical errors
+        if ($error instanceof RouteNotFoundException) {
+            $level   = Log::NOTICE;
+            $message = \sprintf(
+                'Page not found (404): %s. Message: "%s"',
+                Uri::getInstance()->toString(),
+                $error->getMessage()
+            );
+            $category = 'client-error';
+        } elseif ($error instanceof NotAcceptable) {
+            $level   = Log::NOTICE;
+            $message = \sprintf(
+                'Not acceptable (406): %s. Message: "%s"',
+                Uri::getInstance()->toString(),
+                $error->getMessage()
+            );
+            $category = 'client-error';
+        } else {
+            // For all other errors, log a critical error with the full stack trace.
+            $level   = Log::CRITICAL;
+            $message = \sprintf(
+                'Uncaught Throwable of type %1$s thrown with message "%2$s". Stack trace: %3$s',
+                \get_class($error),
+                $error->getMessage(),
+                $error->getTraceAsString()
+            );
+            $category = 'error';
+        }
+
         // Try to log the error, but don't let the logging cause a fatal error
         try {
-            Log::add(
-                \sprintf(
-                    'Uncaught Throwable of type %1$s thrown with message "%2$s". Stack trace: %3$s',
-                    \get_class($error),
-                    $error->getMessage(),
-                    $error->getTraceAsString()
-                ),
-                Log::CRITICAL,
-                'error'
-            );
+            Log::add($message, $level, $category);
         } catch (\Throwable) {
             // Logging failed, don't make a stink about it though
         }

From 0d09aa19575b01b5ec5eb56cc8512c9dc7c621a2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marcel=20Sch=C3=BCrmann?= <marcel@schue.ch>
Date: Thu, 16 Oct 2025 18:13:01 +0200
Subject: [PATCH 2/2] alpha sort use statements

---
 libraries/src/Exception/ExceptionHandler.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libraries/src/Exception/ExceptionHandler.php b/libraries/src/Exception/ExceptionHandler.php
index a40bb56560f73..9d29c8a5996eb 100644
--- a/libraries/src/Exception/ExceptionHandler.php
+++ b/libraries/src/Exception/ExceptionHandler.php
@@ -10,12 +10,12 @@
 namespace Joomla\CMS\Exception;
 
 use Joomla\CMS\Application\CMSApplication;
+use Joomla\CMS\Application\Exception\NotAcceptable;
 use Joomla\CMS\Error\AbstractRenderer;
 use Joomla\CMS\Event\Application\AfterInitialiseDocumentEvent;
 use Joomla\CMS\Factory;
 use Joomla\CMS\Log\Log;
 use Joomla\CMS\Router\Exception\RouteNotFoundException;
-use Joomla\CMS\Application\Exception\NotAcceptable;
 use Joomla\CMS\Uri\Uri;
 
 // phpcs:disable PSR1.Files.SideEffects