Strict Standards: Declaration of ‘ ‘ should be compatible with ‘ ‘

5 comments

1. WC_Payment_Gateway is defined in abstract-wc-payment-gateway.php and declares a method

   function process_payment() {}
   

   while WC_Gateway_BACS defines it as

   function process_payment( $order_id ) { ...
   

   (maybe you mixed up WC_Payment_Gateway and WC_Payment_Gateways).

   So, different signature (0 parameters vs 1 parameter) -> strict error.
   Since it seems* to be used always with one parameter you could change

   function process_payment() {}
   

   to

   function process_payment($order_id) {}
   

   ---

   (*) keep in mind I know of woocommerce only since the last five minutes, so don’t take my word for it.

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2. Quote from PHP Manual

   In PHP 5 a new error level E_STRICT is available. Prior to PHP 5.4.0 E_STRICT was not >included within E_ALL, so you would have to explicitly enable this kind of error level in >PHP < 5.4.0. Enabling E_STRICT during development has some benefits. STRICT messages >provide suggestions that can help ensure the best interoperability and forward >compatibility of your code. These messages may include things such as calling non-static >methods statically, defining properties in a compatible class definition while defined in >a used trait, and prior to PHP 5.3 some deprecated features would issue E_STRICT errors >such as assigning objects by reference upon instantiation.

   You are receiving this error because WC_Gateway_BACS::process_payment() declaration is different than WC_Payment_Gateway::process_payment() (might be not the same amount of parameters etc). If WC_Payment_Gateway has no method process_payment, check it’s parent class 🙂

   Also, if you want to disable STRICT errors, add ^ E_STRICT to your error reporting configuration, for example:

   error_reporting(E_ALL ^ E_STRICT);
   

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3. if you wanna keep OOP form without turning any error off, you can also:

   class A
   {
       public function foo() {
           ;
       }
   }
   class B extends A
   {
       /*instead of : 
       public function foo($a, $b, $c) {*/
       public function foo() {
           list($a, $b, $c) = func_get_args();
           // ...
   
       }
   }
   

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4. When you are using the same function in a parent class and a child class, but the child class needs parameters while the parent one not, you’ll get the Strict Standards error.

   Example

   Manager:

   public function getAtPosition($position)
   {
       foreach ($this->getList() as $obj)
       {
           if ($obj->getPosition() == $position)
               return $obj;
       }
   
       return null;
   }
   

   MenuManager extends Manager:

   public function getAtPosition($position, $parent)
   {
       foreach ($this->getList() as $m)
       {
           if ($m->getParent() == $parent && $m->getPosition() == $position)
               return $m;
       }
   
       return null;
   }
   

   This example will generate an error:

   Strict standards: Declaration of MenuManager::getAtPosition() should
   be compatible with Manager::getAtPosition($position)

   Because we don’t have the same arguments to the function, so let’s trick this and add arguments, even though we’re not using them!

   Manager:

   public function getAtPosition($position, $dummy = 0) // Dummy to avoid Strict standards errors
   {
       foreach ($this->getList() as $obj)
       {
           if ($obj->getPosition() == $position)
               return $obj;
       }
   
       return null;
   }
   

   MenuManager extends Manager:

   public function getAtPosition($position, $parent = 0)
   {
       foreach ($this->getList() as $m)
       {
           if ($m->getParent() == $parent && $m->getPosition() == $position)
               return $m;
       }
   
       return null;
   }
   

   Only one to be careful is that when using getAtPosition() from MenuManager.class.php, be sure you are actually sending 2 parameters, as we have to declare $parent = 0 in order to match the parent’s declaration.

   Every class extending Manager and not containing getAtPosition() will use the method from Manager.

   If declared in a child class, php will use the method from the child class instead of the parent’s one. There is no overloading in PHP, so that is how I worked around it until it is properly implemented.

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5. Here is a better answer – https://stackoverflow.com/a/9243127/2165415

   for example,
   
   parentClass::customMethod($thing = false) and
   
   childClass::customMethod($thing)
   
   so, when you call customMethod() for the class, it may trigger the error, because the child’s method hasn’t defined a default value for the first argument.

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