Taxonomy Pagination Rewrite

Question

I have a custom post type named "testimonials" with a slug of reviews. I also have a taxonomy named "testimonial-department" with a slug of reviews. The goal being I will have pretty permalinks such as /reviews/sales/ or /reviews/service/.

Everything is working as I would like, with the exception of pagination. I have tried all of the many different tips and tricks to get the pagination to work as expected, but no matter what /reviews/sales/page/2 just doesn't work. However, if I manually enter /reviews/sales/?page=2 it leads to the second page of results just as one would expect. Is there a rewrite rule that I can use that will allow me to use the query string ?page=2 but rewrite it as /page/2/ or is there a way to force WordPress to use the non-pretty permalink with the page number as a query string with the normal pagination?

This is what my taxonomy and custom post type registration looks like, plus I have a rewrite rule in place for posts.

    add_action( 'init', 'create_testimonial_department_taxonomy' );

function create_testimonial_department_taxonomy() {
    $labels = array(
        'name'                           => 'Testimonial Department',
        'singular_name'                  => 'Testimonial Department',
        'search_items'                   => 'Search Testimonial Departments',
        'all_items'                      => 'All Testimonial Departments',
        'edit_item'                      => 'Edit Testimonial Department',
        'update_item'                    => 'Update Testimonial Department',
        'add_new_item'                   => 'Add New Testimonial Department',
        'new_item_name'                  => 'New Testimonial Department',
        'menu_name'                      => 'Testimonial Department',
        'view_item'                      => 'View Testimonial Department',
        'not_found'                      => 'No Testimonial Departments found'
    );

    register_taxonomy(
        'testimonial-department',
        'testimonials',
        array(
            'label' => __( 'Testimonial Departments' ),
            'hierarchical' => false,
            'labels' => $labels,
            'public' => true,
            'show_in_nav_menus' => true,
            'meta_box_cb'  => false,
            'show_tagcloud' => false,
            'show_admin_column' => true,
            'query_var' => true,
            'sort' => true,
            'rewrite' => array(
                'slug' => 'reviews',
                'hierarchical' => false
            )
        )
    );
}

function aw_testimonials_post_type() {

// Set UI labels for Testinomials post type
  $labels = array(
    'name'                => _x( 'Testimonials', 'Post Type General Name'),
    'singular_name'       => _x( 'Testimonial', 'Post Type Singular Name'),
    'menu_name'           => __( 'Testimonials'),
    'parent_item_colon'   => __( 'Testimonials Parent'),
    'all_items'           => __( 'All Testimonials'),
    'view_item'           => __( 'View Testimonial'),
    'add_new_item'        => __( 'Add New Testimonial'),
    'add_new'             => __( 'Add New'),
    'edit_item'           => __( 'Edit Testimonial'),
    'update_item'         => __( 'Update Testimonial'),
    'search_items'        => __( 'Search Testimonial'),
    'not_found'           => __( 'Testimonial Not Found'),
    'not_found_in_trash'  => __( 'Testimonial Not found in Trash'),
  );

// Set other options for Testimonials post type

  $args = array(
    'label'               => __( 'Testimonials'),
    'description'         => __( 'Posts specifically for displaying testimonials.'),
    'labels'              => $labels,
    'rewrite' => array('slug' => 'reviews/%testimonial-department%'),
        'query_var' => true,
        'menu_icon' => 'dashicons-megaphone',
    'supports'            => array('title','thumbnail'),
    'taxonomies' => array('post_tag', 'testimonial-department'),
    'hierarchical'        => false,
    'public'              => true,
    'show_ui'             => true,
    'show_in_menu'        => true,
    'show_in_nav_menus'   => true,
    'show_in_admin_bar'   => true,
    'menu_position'       => 14,
    'can_export'          => true,
    'has_archive'         => 'reviews',
    'exclude_from_search' => false,
    'publicly_queryable'  => true,
    'capability_type'     => 'post',
  );

  // Registering your Custom Post Type
  register_post_type( 'testimonials', $args );

}

add_action( 'init', 'aw_testimonials_post_type', 0 );

function testimonial_department_post_link( $post_link, $id = 0 ){
    $post = get_post($id);  
    if ( is_object( $post ) ){
        $terms = wp_get_object_terms( $post->ID, 'testimonial-department' );
        if( $terms ){
            return str_replace( '%testimonial-department%' , $terms[0]->slug , $post_link );
        }
    }
    return $post_link;  
}
add_filter( 'post_type_link', 'testimonial_department_post_link', 1, 3 );

function testimonials_posts_per_page( $query ) {
if (is_admin()) {
    return $query;
}
if ( $query->is_main_query() ) {
    if ( is_post_type_archive( 'testimonials' ) ) {
        $query->set( 'posts_per_page', 6 );
        return $query;
    }
    else if ( is_tax( 'testimonial-department' ) ) {
            $query->set( 'posts_per_page', 6 );
            $query->set('post_type','testimonials');
            return;
    }
}
}
add_action( 'pre_get_posts', 'testimonials_posts_per_page', 1 );

Answer 1

Put this code into your function.php.

add_filter('redirect_canonical','pif_disable_redirect_canonical');

function pif_disable_redirect_canonical($redirect_url) {
    if (is_singular()) $redirect_url = false;
return $redirect_url;
}

Hope this will help you