Removing parent theme action on pluggable function not working

Question

I'm trying to remove a parent theme's add_action call to a pluggable function, but can't get it to work by calling remove_action() - I have to redeclare the function and just leave it empty. Is this normal? I'd think I could use remove_action to simply never call the function.

Here's the parent theme code:

add_action( 'tha_content_while_before', 'fwp_archive_header' );
if ( !function_exists('fwp_archive_header') ) {
    function fwp_archive_header() {
      // do stuff
    }
}

And in the child theme (NOT working):

add_action( 'init', 'remove_parent_actions_filters' );
function remove_parent_actions_filters() { 
  remove_action( 'tha_content_while_before', 'fwp_archive_header' );
}

I have also tried swapping out 'init' for 'after_setup_theme' and 'wp_loaded'; I've also tried lowering and raising the priority, nothing worked. The only thing that did work was this:

In the child theme (working):

function fwp_archive_header() {
  // do nothing
}

Can that be right, I have to redeclare the function to get rid of it?

Thanks!

Answer 1

The parent theme's functions.php runs after the child theme's, so in order to remove an action defined by the parent theme the remove_action call must be delayed using a hook after the parent theme registers the action. So putting the remove_action call purely inside the child's functions.php won't work. It must be attached to a hook.

However from the code excerpt in the question it is not clear if the parent's add_action( 'tha_content_while_before', 'fwp_archive_header' ); line is just in functions.php or is that inside an action? If it is inside an action, hook the remove_action call to the same action but with bigger priority (so it runs after). Note I'm talking about the action the parent add_action call is inside. Something like this:

add_action( 'some_hook', 'some_parent_function', 10 );
function some_parent_function() {
    /* ...some code... */
    add_action( 'tha_content_while_before', 'fwp_archive_header' );
    if ( !function_exists('fwp_archive_header') ) {
        function fwp_archive_header() {
          // do stuff
        }
    }
    /* ...some code... */
}

The remove would look like:

add_action( 'some_hook', 'remove_parent_actions_filters', 11 );
function remove_parent_actions_filters() { 
  remove_action( 'tha_content_while_before', 'fwp_archive_header' );
}

---

Another rule of thumb attempt is to hook your remove call to wp_loaded, e.g.: add_action( 'wp_loaded', 'remove_parent_actions_filters', 1000 );. Should be still on time to affect how pages are rendered, but would likely be late enough to override most common parent theme hooks.

---

On the other hand declaring an empty function with the name fwp_archive_header is almost as good solution. Note though it is not “redeclare”, as there's no such thing in PHP. It's more like “predeclare”, before the parent theme, so the parent theme won't declare it's own function with the same name (with appropriate checks in place).

Answer 2

Inside your remove_parent_actions_filters() function, add a test to see if the parent theme's function has been loaded. Maybe you are calling your hook too soon.

add_action( 'init', 'remove_parent_actions_filters' );
function remove_parent_actions_filters() { 
   if (!function_exists('fwp_archive_header')) {wp_die("fwp_archive_header function is not loaded");}
  remove_action( 'tha_content_while_before', 'fwp_archive_header' );
}

Added

Try using the after_setup_theme hook instead. See https://codex.wordpress.org/Plugin_API/Action_Reference/after_setup_theme .