Closes #6797

Author: sebastianbergmann

ChangeLog-8.5.md

@@ -2,6 +2,12 @@
 
 All notable changes of the PHPUnit 8.5 release series are documented in this file using the [Keep a CHANGELOG](https://keepachangelog.com/) principles.
 
+## [8.5.53] - 2026-MM-DD
+
+### Changed
+
+* [#6797](https://github.com/sebastianbergmann/phpunit/issues/6797): Adapt code generated for test double of interface with constructor for PHP 8.6
+
 ## [8.5.52] - 2026-01-27
 
 ### Changed
@@ -380,6 +386,7 @@ All notable changes of the PHPUnit 8.5 release series are documented in this fil
 * [#3967](https://github.com/sebastianbergmann/phpunit/issues/3967): Cannot double interface that extends interface that extends `\Throwable`
 * [#3968](https://github.com/sebastianbergmann/phpunit/pull/3968): Test class run in a separate PHP process are passing when `exit` called inside
 
+[8.5.53]: https://github.com/sebastianbergmann/phpunit/compare/8.5.52...8.5
 [8.5.52]: https://github.com/sebastianbergmann/phpunit/compare/8.5.51...8.5.52
 [8.5.51]: https://github.com/sebastianbergmann/phpunit/compare/8.5.50...8.5.51
 [8.5.50]: https://github.com/sebastianbergmann/phpunit/compare/8.5.49...8.5.50

src/Framework/MockObject/MockMethod.php

@@ -17,6 +17,7 @@
 use function preg_replace;
 use function sprintf;
 use function str_replace;
+use function strtolower;
 use function substr_count;
 use function trim;
 use function var_export;
@@ -186,7 +187,7 @@ public function generateCode(): string
     {
         if ($this->static) {
             $templateFile = 'mocked_static_method.tpl';
-        } elseif ($this->returnType instanceof VoidType) {
+        } elseif ($this->returnType instanceof VoidType || $this->mustNotReturnValue()) {
             $templateFile = sprintf(
                 '%s_method_void.tpl',
                 $this->callOriginalMethod ? 'proxied' : 'mocked'
@@ -257,6 +258,16 @@ private function getTemplate(string $template): Text_Template
         return self::$templates[$filename];
     }
 
+    /**
+     * @see https://wiki.php.net/rfc/deprecate-return-value-from-construct
+     */
+    private function mustNotReturnValue(): bool
+    {
+        $methodName = strtolower($this->methodName);
+
+        return $methodName === '__construct' || $methodName === '__destruct';
+    }
+
     /**
      * Returns the parameters of a function or method.
      *

tests/end-to-end/mock-objects/generator/4139-php7.phpt

@@ -40,12 +40,10 @@ class %s implements PHPUnit\Framework\MockObject\MockObject, InterfaceWithConstr
             }
         }
 
-        $__phpunit_result = $this->__phpunit_getInvocationHandler()->invoke(
+        $this->__phpunit_getInvocationHandler()->invoke(
             new \PHPUnit\Framework\MockObject\Invocation(
                 'InterfaceWithConstructor', '__construct', $__phpunit_arguments, '', $this, true
             )
         );
-
-        return $__phpunit_result;
     }
 }

tests/end-to-end/mock-objects/generator/4139-php8.phpt

@@ -40,12 +40,10 @@ class %s implements PHPUnit\Framework\MockObject\MockObject, InterfaceWithConstr
             }
         }
 
-        $__phpunit_result = $this->__phpunit_getInvocationHandler()->invoke(
+        $this->__phpunit_getInvocationHandler()->invoke(
             new \PHPUnit\Framework\MockObject\Invocation(
                 'InterfaceWithConstructor', '__construct', $__phpunit_arguments, '', $this, true
             )
         );
-
-        return $__phpunit_result;
     }
 }

tests/end-to-end/regression/6797.phpt

@@ -0,0 +1,19 @@
+--TEST--
+https://github.com/sebastianbergmann/phpunit/issues/6797
+--FILE--
+<?php declare(strict_types=1);
+$_SERVER['argv'][] = '--do-not-cache-result';
+$_SERVER['argv'][] = '--no-configuration';
+$_SERVER['argv'][] = __DIR__ . '/6797/Issue6797Test.php';
+
+require_once __DIR__ . '/../../bootstrap.php';
+
+PHPUnit\TextUI\Command::main();
+--EXPECTF--
+PHPUnit %s by Sebastian Bergmann and contributors.
+
+..                                                                  2 / 2 (100%)
+
+Time: %s, Memory: %s
+
+OK (2 tests, 2 assertions)

tests/end-to-end/regression/6797/Issue6797Test.php

@@ -0,0 +1,34 @@
+<?php declare(strict_types=1);
+/*
+ * This file is part of PHPUnit.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace PHPUnit\TestFixture\Issue6797;
+
+use PHPUnit\Framework\TestCase;
+
+interface InterfaceWithConstructor
+{
+    public function __construct();
+}
+
+final class Issue6797Test extends TestCase
+{
+    public function testStubCanBeCreatedForInterfaceWithConstructor(): void
+    {
+        $stub = $this->createStub(InterfaceWithConstructor::class);
+
+        $this->assertInstanceOf(InterfaceWithConstructor::class, $stub);
+    }
+
+    public function testMockCanBeCreatedForInterfaceWithConstructor(): void
+    {
+        $mock = $this->createMock(InterfaceWithConstructor::class);
+
+        $this->assertInstanceOf(InterfaceWithConstructor::class, $mock);
+    }
+}