Uncaught Error: Cannot access protected property

This error occurs when the property in a class is defined as protected, but accessed outside the class.

For example take the following program, where we have a class Person with protected property $fullname. protected means the visibility of this property is only within the class. If we try to access this property outside the class, then this fatal error is thrown.

PHP Program

<?php
  class Person {
    protected string $fullname;
    protected int $age;

    public function __construct(string $fullname = null, int $age = null) {
      $this->fullname = $fullname;
      $this->age = $age;
    }

    public function printDetails() {
      echo "Name : " . $this->fullname . "<br>Age : " . $this->age;
    }
  }
  
  //create object of type Person with arguments passed for constructor
  $person1 = new Person("Mike Turner", 24);

  //try to access protected property of class
  echo $person1->fullname;
?>

Output – xampp/logs/php_error_log

[28-Feb-2023 15:33:53 Europe/Berlin] PHP Fatal error:  Uncaught Error: Cannot access protected property Person::$fullname in /Applications/XAMPP/xamppfiles/htdocs/tutorialkart.php:20
Stack trace:
#0 {main}
  thrown in /Applications/XAMPP/xamppfiles/htdocs/tutorialkart.php on line 20
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Solution

If we would like to get the value of a property, we can define a getter method in the class to return the value of this property, or else define the property as public.

Solution 1 – Define a getter method to access the property

We shall define a getter method getFullname() in the Person class that returns the value of the property $fullname.

PHP Program

<?php
  class Person {
    protected string $fullname;
    protected int $age;

    public function __construct(string $fullname = null, int $age = null) {
      $this->fullname = $fullname;
      $this->age = $age;
    }

    public function getFullname() {
      return $this->fullname;
    }

    public function printDetails() {
      echo "Name : " . $this->fullname . "<br>Age : " . $this->age;
    }
  }
  
  //create object of type Person with arguments passed for constructor
  $person1 = new Person("Abc Defg", 24);

  //try to access protected property of class
  echo $person1->getFullname();
?>

Output

Uncaught Error: Cannot access protected property

Solution 2 – Make the property public

If we can make the property $fullname as public, then we can access the property outside the class as well.

PHP Program

<?php
  class Person {
    public string $fullname;
    protected int $age;

    public function __construct(string $fullname = null, int $age = null) {
      $this->fullname = $fullname;
      $this->age = $age;
    }

    public function printDetails() {
      echo "Name : " . $this->fullname . "<br>Age : " . $this->age;
    }
  }
  
  //create object of type Person with arguments passed for constructor
  $person1 = new Person("Abc Defg", 24);

  //try to access protected property of class
  echo $person1->fullname;
?>

Output

Uncaught Error: Cannot access protected property

Conclusion

In this PHP Tutorial, we learned how to solve a PHP fatal error Uncaught Error: Cannot access protected property with two possible solutions.