Why Does My PHP Child Class Throw a 'Declaration of childClass::customMethod() should be compatible with that of parentClass::customMethod()' Error?

PHP Method Declaration Compatibility Error

The error message "Strict Standards: Declaration of childClass::customMethod() should be compatible with that of parentClass::customMethod()" occurs in PHP when a method declared in a child class is not compatible with the corresponding method in the parent class.

To determine the cause of this error, it is important to understand what constitutes "compatibility" between two methods:

• Number and Type of Arguments: The child class method must have the same number and type of arguments as the parent class method. For example, if the parent class method takes two integer arguments, the child class method cannot take one integer and one string argument.
• Return Type: The return type of the child class method must be either the same as or a subtype of the parent class method's return type. For example, if the parent class method returns a boolean, the child class method can also return a boolean, but it cannot return an integer.
• Access Level: The access level of the child class method must be equal to or less restrictive than the access level of the parent class method. In other words, a protected method in the parent class cannot be made private in the child class.

To resolve this error, ensure that the child class method meets these compatibility guidelines. For more detailed information on PHP method declaration compatibility, refer to the official documentation.

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