How to get all functions with priority '1' attached to hook 'wp_head'

Question

How to get (loop through to disable unnecessary) all functions with priority '1' attached to hook 'wp_head' ('_wp_render_title_tag', 'wp_enqueue_scripts', 'noindex' etc.)?

It is necessary to get it automatically, so that after each new version of WordPress do not keep track of whether the priority '1' something else.

Something like:

$array_priority_1 = [];

if (doing_action('wp_head')) {
  // Here we get and iterate over all functions related to 'wp_head'
  // and immediately check their priority '1'?
  // suitable and added to the array '$array_priority_1'
  //
  // ...I do not know how to get them and check for priority
}

And here we are going through our ready array:

foreach ($array_priority_1 as ...

Thank you!

Answer 1

The global $wp_filter store the hooks and have also his arguments, include the priority. So you can create a small function to debug them. The follow function should helps to list all functions, his arguments if fired on wp_head. The foreach loop add the priority of a hook via the run, the doing. So you can list all functions for the hook wp_head with priority 10 as example via var_dump($hooked[0][10]);.

    add_action('all', function($hook) {

        if (doing_action('wp_head')) {

            global $wp_filter;
            if ( ! isset( $wp_filter[ $hook ] ) ) {
                return;
            }

            $hooked = (array) $wp_filter[ $hook ];
            foreach ( $hooked as $priority => $function ) {
                // Prevent buffer overflows of PHP_INT_MAX on array keys.
                // So reset the array keys.
                $hooked   = array_values( $hooked );
                $hooked[] = $function;
            }
            // Print all functions with priority `1`.
            print '<pre>'; print_r($hooked[0][1]); print '</pre>';
        }

        return $hook;
    });

Result

For my test example print all functions with priority 1

Array
(
    [_wp_render_title_tag] => Array
        (
            [function] => _wp_render_title_tag
            [accepted_args] => 1
        )

    [wp_enqueue_scripts] => Array
        (
            [function] => wp_enqueue_scripts
            [accepted_args] => 1
        )

    [noindex] => Array
        (
            [function] => noindex
            [accepted_args] => 1
        )

    [wp_post_preview_js] => Array
        (
            [function] => wp_post_preview_js
            [accepted_args] => 1
        )

)

Additional hint, source

Also this function inside a debug helper plugin should helps you to understand it - https://github.com/bueltge/debug-objects/blob/master/inc/class-page_hooks.php#L90