Passing function into add_action always returns the first argument

Question

I'm building a plugin that iterates across and parses the arguments of various WordPress hooks, and because of the flexibility needed I'm passing a function as the callable parameter in add_action:

foreach ($events as $event) {
  add_action($event, function() use($event) {
    $args = func_get_args();

    // Do something with $event and $args
  }, 100);
}

The problem I'm experiencing is that this only ever seems to retrieve the first argument passed to the action.

Take profile_update, for example. It should pass the User ID, as well as an object of old user data, but if I inspect I only get the User ID:

var_dump($args)
// array(1) { [0]=> int(3) } 

This isn't limited to that specific hook, either; I can't seem to get more than the first argument for any hook set up this way. Any suggestions are appreciated!

Answer 1

I think you are headed down the right path, but I think that func_get_args() is only going to give you the arguments passed to that function. That is how I have always used it in the past.

I took a different approach that I think might work. I found debug_backtrace() to be helpful in debugging Actions and Filters before. And the 4th element in that array it returns you is the do_action call with all the arguments that live inside of the call you are looking to make.

Here is a snippet I put together with a few actions I tested:

<?php

// Here are the Actions I tested against.
$events = array(
    'profile_personal_options',
    'profile_update',
    'show_user_profile',
    'show_user_profile'
);

foreach ($events as $event) {
  add_action($event, function($args = null) {

    $backtrace = debug_backtrace();

    // This element is going to be the do_action call
    echo '<pre>';
    print_r($backtrace[3]['function']);
    echo '</pre>';

    $action_arguments = $backtrace[3]['args'];
    // The first element of this is going to be the $event
    array_shift($action_arguments);

    // Leaving you with the rest of the parameters available to that action
    echo '<pre>';
    print_r($action_arguments);
    echo '</pre>';

  }, 100);
}

If this is not what you are looking for, or I am off...let me know and I'd be happy to take my answer down!!