Will the __set() method be called automatically when we assign a value to an object's property?

The __set() method in PHP is called automatically only when you try to assign a value to a non-existent or inaccessible (e.g., private or protected) property of an object. If the property is declared and accessible, then __set() will not be called, and the assignment will occur directly.

Example:

class Example {
    private $data = [];

    public function __set($name, $value) {
        echo "__set called for property '$name' with value '$value'\n";
        $this->data[$name] = $value;
    }

    public $existingProp;
}

$obj = new Example();
$obj->existingProp = 123; // __set is not called
$obj->newProp = 456;      // __set is called

In this example, assigning $obj->existingProp = 123; happens directly, while $obj->newProp = 456; calls the __set() method because newProp is not declared in the class.