Ticket #14671: 14671.4.diff

wp-includes/plugin.php

@@ -59 +59 @@
  * @param string $tag The name of the filter to hook the $function_to_add to.
  * @param callback $function_to_add The name of the function to be called when the filter is applied.
  * @param int $priority optional. Used to specify the order in which the functions associated with a particular action are executed (default: 10). Lower numbers correspond with earlier execution, and functions with the same priority are executed in the order in which they were added to the action.
- * @param int $accepted_args optional. The number of arguments the function accept (default 1).
+ * @param int $accepted_args optional. The number of arguments the function accept (default: number of required arguments introspected from $function_to_add via the PHP Reflection API).
  * @return boolean true
  */
-function add_filter($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
+function add_filter($tag, $function_to_add, $priority = 10, $accepted_args = null) {
         global $wp_filter, $merged_filters;
 
         $idx = _wp_filter_build_unique_id($tag, $function_to_add, $priority);
@@ -167 +167 @@
                 $args = func_get_args();
 
         do {
-                foreach( (array) current($wp_filter[$tag]) as $the_ )
+                foreach( (array) current($wp_filter[$tag]) as $the_ ) {
                         if ( !is_null($the_['function']) ){
+                                $accepted_args = _wp_get_hook_handler_accepted_arg_count($the_['function'], $the_['accepted_args']);
                                 $args[1] = $value;
-                                $value = call_user_func_array($the_['function'], array_slice($args, 1, (int) $the_['accepted_args']));
+                                $value = call_user_func_array($the_['function'], array_slice($args, 1, $accepted_args));
                         }
+                }
 
         } while ( next($wp_filter[$tag]) !== false );
 
@@ -226 +228 @@
 
         do {
                 foreach( (array) current($wp_filter[$tag]) as $the_ )
-                        if ( !is_null($the_['function']) )
-                                $args[0] = call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
+                        if ( !is_null($the_['function']) ) {
+                                $accepted_args = _wp_get_hook_handler_accepted_arg_count($the_['function'], $the_['accepted_args']);
+                                $args[0] = call_user_func_array($the_['function'], array_slice($args, 0, $accepted_args));
+                        }
 
         } while ( next($wp_filter[$tag]) !== false );
 
@@ -254 +258 @@
  * @param string $tag The filter hook to which the function to be removed is hooked.
  * @param callback $function_to_remove The name of the function which should be removed.
  * @param int $priority optional. The priority of the function (default: 10).
- * @param int $accepted_args optional. The number of arguments the function accepts (default: 1).
  * @return boolean Whether the function existed before it was removed.
  */
 function remove_filter( $tag, $function_to_remove, $priority = 10 ) {
@@ -328 +331 @@
  * @param string $tag The name of the action to which the $function_to_add is hooked.
  * @param callback $function_to_add The name of the function you wish to be called.
  * @param int $priority optional. Used to specify the order in which the functions associated with a particular action are executed (default: 10). Lower numbers correspond with earlier execution, and functions with the same priority are executed in the order in which they were added to the action.
- * @param int $accepted_args optional. The number of arguments the function accept (default 1).
+ * @param int $accepted_args Optional. The number of arguments the function accept (default: number of required arguments introspected from $function_to_add via the PHP Reflection API).
  */
-function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
+function add_action($tag, $function_to_add, $priority = 10, $accepted_args = null) {
         return add_filter($tag, $function_to_add, $priority, $accepted_args);
 }
 
@@ -402 +405 @@
 
         do {
                 foreach ( (array) current($wp_filter[$tag]) as $the_ )
-                        if ( !is_null($the_['function']) )
-                                call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
+                        if ( !is_null($the_['function']) ){
+                                $accepted_args = _wp_get_hook_handler_accepted_arg_count($the_['function'], $the_['accepted_args']);
+                                call_user_func_array($the_['function'], array_slice($args, 0, $accepted_args));
+                        }
 
         } while ( next($wp_filter[$tag]) !== false );
 
@@ -483 +488 @@
 
         do {
                 foreach( (array) current($wp_filter[$tag]) as $the_ )
-                        if ( !is_null($the_['function']) )
-                                call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));
+                        if ( !is_null($the_['function']) ) {
+                                $accepted_args = _wp_get_hook_handler_accepted_arg_count($the_['function'], $the_['accepted_args']);
+                                call_user_func_array($the_['function'], array_slice($args, 0, $accepted_args));
+                        }
 
         } while ( next($wp_filter[$tag]) !== false );
 
@@ -787 +794 @@
                 return $function[0].$function[1];
         }
 }
+
+/**
+ * Obtain the argument count for a hook callback (function/method/closure) via Reflection
+ *
+ * It used to be that if hook (filter/action) is called with more than one
+ * argument, you would have to supply a 4th argument to
+ * add_action()/add_filter() in order for those extra arguments to be passed
+ * into the function. This is painful because it usually violates DRY
+ * principles since the number of arguments that a function takes is already
+ * defined when the function was defined and so it should already be known. It
+ * is also painful to have to pass in the number of arguments because
+ * add_action() and add_filter() take positional arguments and so you always
+ * have to define the 3rd argument ($priority) in order to be able to specify
+ * the 4th ($accepted_args). PHP now has an always-included Reflection
+ * extension that allows it to introspect to programmatically determine the
+ * number of arguments that a function or method takes. In older versions of
+ * WordPress when support for PHP 4 was required, WordPress was not able to
+ * take advantage of Reflection because it was first introduced in PHP 5. But
+ * now that PHP 5.2 is required, we can take advantage of Reflection and
+ * simplify the calls to add_action() and add_filter().
+ *
+ * This function is a helper that is re-used in do_action(), apply_filters(),
+ * and do_action_ref_array(). If the accepted_args has been supplied when
+ * add_action()/add_filter() was called (and it is not the default of null)
+ * then it will return that instead of trying to introspect for the number of
+ * args.
+ *
+ * @package WordPress
+ * @subpackage Plugin
+ * @access private
+ * @since 3.6
+ * @link http://core.trac.wordpress.org/ticket/14671
+ * @link http://php.net/manual/en/book.reflection.php
+ *
+ * @param callable $function The filter/action handler supplied when calling add_action()/add_filter()
+ * @param int $accepted_args The 4th argument passed into add_action()/add_filter()
+ * @return int The number of arguments to pass into hook handler
+ */
+function _wp_get_hook_handler_accepted_arg_count($function, $accepted_args) {
+        // Note is_callable() is better for methods than method_exists() because it will work with __call magic methods
+        if ( is_null($accepted_args) && is_callable($function) ) {
+                if ( is_array($function) ) {
+                        list( $object, $method ) = $function;
+                        $reflection = new ReflectionMethod( $object, $method );
+                } else {
+                        $reflection = new ReflectionFunction( $function );
+                }
+                $accepted_args = $reflection->getNumberOfParameters();
+        }
+        return (int) $accepted_args;
+}