Emit: "Code coverage might produce unreliable results when OPCache is enabled"

Author: staabm

src/Runner/CodeCoverage.php

@@ -11,6 +11,8 @@
 
 use function assert;
 use function file_put_contents;
+use function function_exists;
+use function ini_get;
 use function sprintf;
 use function sys_get_temp_dir;
 use PHPUnit\Event\Facade as EventFacade;
@@ -124,6 +126,16 @@ public function init(Configuration $configuration, CodeCoverageFilterRegistry $c
             $this->codeCoverage()->excludeUncoveredFiles();
         }
 
+        if (
+            // opcache is built-in since 8.5
+            function_exists('opcache_compile_file') &&
+            ini_get('opcache.enable_cli') === '1'
+        ) {
+            EventFacade::emitter()->testRunnerTriggeredPhpunitWarning(
+                'Code coverage might produce unreliable results when OPCache is enabled.',
+            );
+        }
+
         if ($codeCoverageFilterRegistry->get()->isEmpty()) {
             if (!$codeCoverageFilterRegistry->configured()) {
                 EventFacade::emitter()->testRunnerTriggeredPhpunitWarning(