Slug rewriting with ACF Fields

Question

I have a function that when you publish a news item adds a correlative ID number to it, this is it:

  function update_post_id_contenido($post_id) {
    $post_type = get_post_type($post_id);
    if ($post_type === 'post') {
        $id_contenido = get_field('id_contenido', $post_id);
        if (empty($id_contenido)) {
            $last_id_contenido = get_posts(array(
                'post_type' => 'post',
                'meta_key' => 'id_contenido',
                'orderby' => 'meta_value_num',
                'order' => 'DESC',
                'numberposts' => 1,
            ));
            $last_id_contenido_value = get_field('id_contenido', $last_id_contenido[0]->ID);
            if (empty($last_id_contenido_value)) {
                $new_id_contenido = 1000;
            } else {
                $new_id_contenido = $last_id_contenido_value + 1;
            }
            update_field('id_contenido', $new_id_contenido, $post_id);
        }
    }
}
add_action('acf/save_post', 'update_post_id_contenido', 20);

What I intend is that it saves the slug so that at the end it is of the type domain.com/$id_contenido/$posttitle

I have tried this function but it returns a memory limit error.

function update_post_slug($post_id, $post, $update) {
  if ($post->post_type == 'post' && $post->post_status == 'publish') {
    $id_contenido = get_post_meta($post_id, 'id_contenido', true);
    $post_title = sanitize_title($post->post_title);
    $new_slug = $id_contenido . '/' . $post_title;
    wp_update_post([
      'ID' => $post_id,
      'post_name' => $new_slug,
    ]);
  }
}
add_action('save_post', 'update_post_slug', 10, 3);

Answer 1

You receive a memory limit error because your code triggers an infinite loop.

On save_post you call the function update_post_slug which calls the function wp_update_post which triggers the action save_post.

An easy workaround to make sure the function only call once per lifetime is to have update_post_slug unregister itself:

function update_post_slug($post_id, $post, $update) {
  remove_action('save_post', 'update_post_slug', 10);
  //..the rest of your function
}