Closes #6521

Author: sebastianbergmann

ChangeLog-11.5.md

@@ -2,6 +2,12 @@
 
 All notable changes of the PHPUnit 11.5 release series are documented in this file using the [Keep a CHANGELOG](https://keepachangelog.com/) principles.
 
+## [11.5.55] - 2026-MM-DD
+
+### Fixed
+
+* [#6521](https://github.com/sebastianbergmann/phpunit/issues/6521): Performance regression in PHPUnit 11.5.54, PHPUnit 12.5.13, and PHPUnit 13.0.4
+
 ## [11.5.54] - 2026-02-18
 
 ### Fixed
@@ -448,6 +454,7 @@ All notable changes of the PHPUnit 11.5 release series are documented in this fi
 * [#6055](https://github.com/sebastianbergmann/phpunit/issues/6055): `assertNotContainsOnly()` (use `assertContainsNotOnlyArray()`, `assertContainsNotOnlyBool()`, `assertContainsNotOnlyCallable()`, `assertContainsNotOnlyFloat()`, `assertContainsNotOnlyInt()`, `assertContainsNotOnlyIterable()`, `assertContainsNotOnlyNumeric()`, `assertContainsNotOnlyObject()`, `assertContainsNotOnlyResource()`, `assertContainsNotOnlyClosedResource()`, `assertContainsNotOnlyScalar()`, or `assertContainsNotOnlyString()` instead)
 * [#6059](https://github.com/sebastianbergmann/phpunit/issues/6059): `containsOnly()` (use `containsOnlyArray()`, `containsOnlyBool()`, `containsOnlyCallable()`, `containsOnlyFloat()`, `containsOnlyInt()`, `containsOnlyIterable()`, `containsOnlyNumeric()`, `containsOnlyObject()`, `containsOnlyResource()`, `containsOnlyClosedResource()`, `containsOnlyScalar()`, or `containsOnlyString()` instead)
 
+[11.5.55]: https://github.com/sebastianbergmann/phpunit/compare/11.5.54...11.5
 [11.5.54]: https://github.com/sebastianbergmann/phpunit/compare/11.5.53...11.5.54
 [11.5.53]: https://github.com/sebastianbergmann/phpunit/compare/11.5.52...11.5.53
 [11.5.52]: https://github.com/sebastianbergmann/phpunit/compare/11.5.51...11.5.52

src/Runner/ErrorHandler.php

@@ -56,7 +56,6 @@ final class ErrorHandler
     private static ?self $instance      = null;
     private ?Baseline $baseline         = null;
     private ExcludeList $excludeList;
-    private SourceFilter $sourceFilter;
     private bool $enabled                     = false;
     private ?int $originalErrorReportingLevel = null;
     private readonly bool $identifyIssueTrigger;
@@ -86,7 +85,6 @@ public static function instance(): self
     private function __construct(bool $identifyIssueTrigger)
     {
         $this->excludeList          = new ExcludeList;
-        $this->sourceFilter         = SourceFilter::instance();
         $this->identifyIssueTrigger = $identifyIssueTrigger;
     }
 
@@ -324,7 +322,7 @@ private function categorizeFile(string $file, TestMethod $test): Code
             return Code::Test;
         }
 
-        if ($this->sourceFilter->includes($file)) {
+        if (SourceFilter::instance()->includes($file)) {
             return Code::FirstParty;
         }