PHP TypeError Deep Dive: How to Fix 'Argument must be of type ?array, string given'

In modern PHP development, type hinting significantly improves code robustness, but it also introduces common errors like `TypeError: Argument must be of type ?array, string given`. This error occurs when a function expects a nullable array but receives an empty string, often from request data or other sources. This article provides a deep dive into the root cause of this error and offers three practical and elegant solutions to help you write more resilient and fault-tolerant code.