Throw error when using union types for LiveProps

Author: Bart Vanderstukken

src/LiveComponent/src/Metadata/LiveComponentMetadataFactory.php

@@ -71,6 +71,15 @@ public function createPropMetadatas(\ReflectionClass $class): array
             }
 
             $type = $property->getType();
+            if ($type instanceof \ReflectionUnionType) {
+                throw new \LogicException(
+                    sprintf(
+                        'Union types are not supported for LiveProps. You may want to change the type of property %s in %s.',
+                        $property->getName(),
+                        $property->getDeclaringClass()->getName()
+                    )
+                );
+            }
             $metadatas[$property->getName()] = new LivePropMetadata(
                 $property->getName(),
                 $attribute->newInstance(),