2.4.5 - Interceptor code generation fails on Union return types

[Skullsneeze]

Summary

Similar to the issue described in #39502 code generation for interceptors also fails when union return types are used (eg. int|string). In the current 2.4 develop branch this is already refactored, and the responsible logic is moved to lib/internal/Magento/Framework/GetReflectionMethodReturnTypeValueTrait.php. However, for 2.4.5-p10, this is still an existing issue.

Examples

Create a new class which extends \Magento\Framework\App\ActionInterface. In the implemented execute() method add the return types to the method signature:

public function execute(): ResponseInterface|Json|ResultInterface

Run the setup:di:compile command.

You should now receive an error when the Interceptor code for the class is generated.

Call to undefined method ReflectionUnionType::getName() in vendor/magento/framework/Interception/Code/Generator/Interceptor.php

Proposed solution

The following patch applies a change similar to the fix done in the issue #39502. The original commit was e4d1043

Patch:

diff --git a/vendor/magento/framework/Interception/Code/Generator/Interceptor.php b/vendor/magento/framework/Interception/Code/Generator/Interceptor.php
--- a/vendor/magento/framework/Interception/Code/Generator/Interceptor.php
+++ b/vendor/magento/framework/Interception/Code/Generator/Interceptor.php
@@ -212,10 +212,17 @@
         $returnTypeValue = null;
         $returnType = $method->getReturnType();
         if ($returnType) {
-            $returnTypeValue = ($returnType->allowsNull() ? '?' : '');
-            $returnTypeValue .= ($returnType->getName() === 'self')
-                ? $this->_getFullyQualifiedClassName($method->getDeclaringClass()->getName())
-                : $returnType->getName();
+            if ($returnType instanceof \ReflectionUnionType) {
+                $returnTypeValue = implode('|', $returnType->getTypes());
+            } elseif ($returnType->getName() === 'self') {
+                $returnTypeValue = $this->_getFullyQualifiedClassName($method->getDeclaringClass()->getName());
+            } else {
+                $returnTypeValue = $returnType->getName();
+            }
+
+            if ($returnType->allowsNull()) {
+                $returnTypeValue = "?$returnTypeValue";
+            }
         }
 
         return $returnTypeValue;

Release note

No response

Triage and priority

• Severity: S0 - Affects critical data or functionality and leaves users without 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 @Skullsneeze. Thank you for your report.
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[Skullsneeze]

Closing this as this is fixed in the latest develop version, but I did want to provide a patch for those who might still face this issue.