Magento 2.4.4 admin panel - Error: Call to undefined method ReflectionUnionType::getName()

[rav-redchamps]

Summary (*)

Magento 2.4.4 running on PHP 8.1

If you create a plugin for any method of class vendor/magento/module-backend/Model/Menu.php then you will receive below error in admin panel

Error: Call to undefined method ReflectionUnionType::getName() in /magento244/vendor/magento/framework/Code/Generator/EntityAbstract.php:335
Stack trace:
#0 /magento244/vendor/magento/framework/Code/Generator/EntityAbstract.php(393): Magento\Framework\Code\Generator\EntityAbstract->extractParameterType(Object(ReflectionParameter))
#1 [internal function]: Magento\Framework\Code\Generator\EntityAbstract->_getMethodParameterInfo(Object(ReflectionParameter))
#2 /magento244/vendor/magento/framework/Interception/Code/Generator/Interceptor.php(103): array_map(Array, Array)
#3 /magento244/vendor/magento/framework/Interception/Code/Generator/Interceptor.php(76): Magento\Framework\Interception\Code\Generator\Interceptor->_getMethodInfo(Object(ReflectionMethod))
#4 /magento244/vendor/magento/framework/Code/Generator/EntityAbstract.php(226): Magento\Framework\Interception\Code\Generator\Interceptor->_getClassMethods()
#5 /magento244/vendor/magento/framework/Interception/Code/Generator/Interceptor.php(177): Magento\Framework\Code\Generator\EntityAbstract->_generateCode()
#6 /magento244/vendor/magento/framework/Code/Generator/EntityAbstract.php(106): Magento\Framework\Interception\Code\Generator\Interceptor->_generateCode()
#7 /magento244/vendor/magento/framework/Code/Generator.php(130): Magento\Framework\Code\Generator\EntityAbstract->generate()
#8 /magento244/vendor/magento/framework/Code/Generator/Autoloader.php(53): Magento\Framework\Code\Generator->generateClass('Magento\\Backend...')
#9 [internal function]: Magento\Framework\Code\Generator\Autoloader->load('Magento\\Backend...')
#10 /magento244/vendor/magento/framework/Code/Reader/ClassReader.php(34): ReflectionClass->__construct('Magento\\Backend...')
#11 /magento244/vendor/magento/framework/ObjectManager/Definition/Runtime.php(54): Magento\Framework\Code\Reader\ClassReader->getConstructor('Magento\\Backend...')
#12 /magento244/vendor/magento/framework/ObjectManager/Factory/Dynamic/Developer.php(48): Magento\Framework\ObjectManager\Definition\Runtime->getParameters('Magento\\Backend...')
#13 /magento244/vendor/magento/framework/ObjectManager/ObjectManager.php(56): Magento\Framework\ObjectManager\Factory\Dynamic\Developer->create('Magento\\Backend...', Array)
#14 /magento244/generated/code/Magento/Backend/Model/MenuFactory.php(43): Magento\Framework\ObjectManager\ObjectManager->create('\\Magento\\Backen...', Array)
#15 /magento244/vendor/magento/module-backend/Model/Menu/Config.php(140): Magento\Backend\Model\MenuFactory->create()
#16 /magento244/vendor/magento/module-backend/Model/Menu/Config.php(116): Magento\Backend\Model\Menu\Config->_initMenu()
#17 /magento244/vendor/magento/module-backend/Block/Menu.php(265): Magento\Backend\Model\Menu\Config->getMenu()
#18 /magento244/generated/code/Magento/Backend/Block/Menu/Interceptor.php(41): Magento\Backend\Block\Menu->getMenuModel()
#19 /magento244/vendor/magento/module-backend/Model/View/Result/Page.php(28): Magento\Backend\Block\Menu\Interceptor->getMenuModel()
#20 /magento244/generated/code/Magento/Backend/Model/View/Result/Page/Interceptor.php(23): Magento\Backend\Model\View\Result\Page->setActiveMenu('Magento_Backend...')

Examples (*)

Install module https://github.com/redchamps/magento2-module-backend-menu-plugin using below command to quickly repeat the problem

composer require redchamps/magento2-module-backend-menu-plugin

Proposed solution

The issue occurs to to function exchangeArray called in class \Magento\Backend\Model\Menu this method belongs to parent class \ArrayObject and has return type object|array & the Magento code doesn;t support the mix return type while creating Intercepter for the class.

This issue occurs only when the Intercepter class being created for \Magento\Backend\Model\Menu & in native Magento there is no plugin for this class so this error appears only when some third-party plugin or customisation do this.

This will be the case throughout the Magento classes not only for \Magento\Backend\Model\Menu.

---

Please provide Severity assessment for the Issue as Reporter. This information will help during Confirmation and Issue triage processes.

• Severity: S0 - Affects critical data or functionality and leaves users with no workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

Hi @rav-redchamps. Thank you for your report.
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[m2-assistant]

Hi @engcom-Hotel. Thank you for working on this issue.
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[engcom-Hotel]

Hello @rav-redchamps,

We have tried to reproduce the issue in Magento 2.4.4 but for us, the issue is not reproducible. Please have a look into the below screenshots for reference:

1. Magento Version:

2. We made a custom plugin in order to reproduce the issue on Magento\Backend\Model\Menu. Please find below the module:
   Magz.zip

3. After enabling the plugin, in the admin panel, there is no error:
   

Let us know in case we have missed anything.

Thanks

[rav-redchamps]

This still repeats for me with your attached module. I am on PHP version 8.1.2

On which PHP version you are trying?

[engcom-Hotel]

Hello @rav-redchamps,

We have again tried to reproduce the issue and the issue is reproducible for us with the given steps in the main description. Hence confirming the issue.

PHP Version:

Magento Version:

Error:

Thanks