Closes #5956

ChangeLog-8.5.md

@@ -6,6 +6,7 @@ All notable changes of the PHPUnit 8.5 release series are documented in this fil
 
 ### Changed
 
+* [#5956](https://github.com/sebastianbergmann/phpunit/issues/5956): Deprecation of the `E_STRICT` constant in PHP 8.4
 * Removed `.phpstorm.meta.php` file as methods such as `TestCase::createStub()` use generics / template types for their return types and PhpStorm, for example, uses that information
 
 ## [8.5.39] - 2024-07-10

src/Util/ErrorHandler.php

@@ -16,6 +16,7 @@
 use const E_USER_NOTICE;
 use const E_USER_WARNING;
 use const E_WARNING;
+use function defined;
 use function error_reporting;
 use function restore_error_handler;
 use function set_error_handler;
@@ -93,10 +94,18 @@ public function __invoke(int $errorNumber, string $errorString, string $errorFil
             return false;
         }
 
+        /**
+         * E_STRICT is deprecated since PHP 8.4.
+         *
+         * @see https://github.com/sebastianbergmann/phpunit/issues/5956
+         */
+        if (defined('E_STRICT') && $errorNumber === @E_STRICT) {
+            $errorNumber = E_NOTICE;
+        }
+
         switch ($errorNumber) {
             case E_NOTICE:
             case E_USER_NOTICE:
-            case E_STRICT:
                 if (!$this->convertNoticesToExceptions) {
                     return false;
                 }