Deprecation of the `E_STRICT` constant in PHP 8.4

[derrabus]

Q	A
PHPUnit version	9.6.20, but the 8.5 branch seems to be affected too.
PHP version	8.4-dev
Installation Method	Composer

Summary

PHP 8.4 triggers a deprecation if we access the E_STRICT constant.

https://wiki.php.net/rfc/deprecations_php_8_4#remove_e_strict_error_level_and_deprecate_e_strict_constant

That error code is obsolete since PHP 7.0, but some core extensions did still use it in rare cases until PHP 7.4. The deprecation prepares a possible future removal of said constant.

The constant is used inside a switch block that triggers different behavior depending on the error level. This means that even if no E_STRICT errors are triggered, we get a deprecation notice because PHPUnit accesses a deprecated constant for comparison.

I'd volunteer to work on a fix, but I'm not sure about the way forward. Not handling the E_STRICT level at all feels wrong because as long as the level exists, some custom PHP extension could still trigger it. We could just use the plain value of the constant for comparison, assuming that the constant's value will never be changed or repurposed in future PHP releases.

Current behavior

PHP Deprecated:  Constant E_STRICT is deprecated in /path/to/phpunit/src/Util/ErrorHandler.php on line 99

How to reproduce

Run a test that triggers PHPUnit's error handler.

Expected behavior

No deprecation is triggered.

[sebastianbergmann]

PHPUnit 10 and PHPUnit 11 also use this constant.

[derrabus]

For reference: php/php-src#13053

[sebastianbergmann]

Could it be this simple?

diff --git a/src/Runner/ErrorHandler.php b/src/Runner/ErrorHandler.php
index 9e51f98ba..34ff5f0a2 100644
--- a/src/Runner/ErrorHandler.php
+++ b/src/Runner/ErrorHandler.php
@@ -19,7 +19,6 @@
 use const E_NOTICE;
 use const E_PARSE;
 use const E_RECOVERABLE_ERROR;
-use const E_STRICT;
 use const E_USER_DEPRECATED;
 use const E_USER_ERROR;
 use const E_USER_NOTICE;
@@ -27,7 +26,9 @@
 use const E_WARNING;
 use function array_keys;
 use function array_values;
+use function constant;
 use function debug_backtrace;
+use function defined;
 use function error_reporting;
 use function restore_error_handler;
 use function set_error_handler;
@@ -90,9 +91,12 @@ public function __invoke(int $errorNumber, string $errorString, string $errorFil
         $ignoredByBaseline = $this->ignoredByBaseline($errorFile, $errorLine, $errorString);
         $ignoredByTest     = $test->metadata()->isIgnoreDeprecations()->isNotEmpty();

+        if (defined('E_STRICT') && $errorNumber === constant('E_STRICT')) {
+            $errorNumber = E_NOTICE;
+        }
+
         switch ($errorNumber) {
             case E_NOTICE:
-            case E_STRICT:
                 Event\Facade::emitter()->testTriggeredPhpNotice(
                     $test,
                     $errorString,

As I am currently travelling, I do not have access to a build of PHP 8.4-dev with php/php-src#13053. Therefore I cannot check whether defined('E_STRICT') and/or constant('E_STRICT') also trigger the deprecation. But as these are function calls, we should be able to suppress any E_DEPRECATED raised by these using the @ operator.

[sebastianbergmann]

@mvorisek Do you have any insight? Thanks!

[mvorisek]

I support the patch above but @ is needed before constant('E_STRICT') - https://3v4l.org/qIUg9/rfc#vgit.master

you can also simplify @constant('E_STRICT') into @E_STRICT - https://3v4l.org/B60NO/rfc#vgit.master

[derrabus]

That was fast, thank you very much!