SEOPress - Canonical URLs Not Pointing to Default Language for Untranslated Content

Overview of the issue

When using SEOPress with WPML, canonical URLs for untranslated content do not point to the default language when the “Default language as a fallback” or “Duplicating content” methods are used. This can lead to duplicate content issues.

Workaround

Please, make sure of having a full site backup of your site before proceeding.

• Open: …/wp-content/plugins/wp-seopress/inc/functions/options-titles-metas.php
• Look for line 1022
• Replace:

          function seopress_titles_canonical_hook() {
              global $wp;
  
              $current_url = user_trailingslashit(home_url(add_query_arg([], $wp->request)));
  
              if (is_search()) {
                  $seopress_titles_canonical = '';
              } elseif (is_paged() && is_singular()) {//Paginated pages
                  $seopress_titles_canonical = '';
              } elseif (is_paged()) {
                  $seopress_titles_canonical = '';
              } elseif (is_singular()) {
                  $seopress_titles_canonical = '';
              } else {
                  $seopress_titles_canonical = '';
              }
              //Hook on post canonical URL - 'seopress_titles_canonical'
              if (has_filter('seopress_titles_canonical')) {
                  $seopress_titles_canonical = apply_filters('seopress_titles_canonical', $seopress_titles_canonical);
              }
              echo $seopress_titles_canonical . "n";
          }
  

• With:

          function seopress_titles_canonical_hook() {
              global $wp;
  
              $current_url = user_trailingslashit(home_url(add_query_arg([], $wp->request)));
              // WPML Workaround for compsupp-7703
              if (class_exists('SitePress')) {
                $post_ID = get_the_ID();
                $post_type = get_post_type( $post_ID );
                $transl_status = apply_filters( 'wpml_element_translation_type', NULL, $post_ID, $post_type );
                // If the post is not translated, switch to the default language
                if ($transl_status != 1) { 
                    $my_default_lang = apply_filters('wpml_default_language', NULL );
                    $my_current_lang = apply_filters( 'wpml_current_language', NULL );
                    do_action( 'wpml_switch_language', $my_default_lang );
                } 
              }
              if (is_search()) {
                  $seopress_titles_canonical = '';
              } elseif (is_paged() && is_singular()) {//Paginated pages
                  $seopress_titles_canonical = '';
              } elseif (is_paged()) {
                  $seopress_titles_canonical = '';
              } elseif (is_singular()) {
                  $seopress_titles_canonical = '';
              } else {
                  $seopress_titles_canonical = '';
              }
              // Then switch back to the current language
              if (class_exists('SitePress')) {
                do_action( 'wpml_switch_language', $my_current_lang );
              }
              //Hook on post canonical URL - 'seopress_titles_canonical'
              if (has_filter('seopress_titles_canonical')) {
                  $seopress_titles_canonical = apply_filters('seopress_titles_canonical', $seopress_titles_canonical);
              }
              echo $seopress_titles_canonical . "n";
          }