Localized posts redirect to incorrect language

[villesiltala]

If a post is localized to the default language, Polylang does not include a 'lang' parameter in a singular main query with URL modification settings described in the attached screenshot. This causes a redirect to incorrect language if there are localized posts with the same post name and the query randomly matches to an indexed post localized to other than the default language.

This could be fixed by filtering the WP query before RediSearch does its query and adding the missing language parameter. Here's an example of adding the missing locale:

\add_action( 'redipress/before_search',
    /**
     * Fix localization for main queries on default language.
     *
     * @param Search    $search   The search instance.
     * @param \WP_Query $wp_query The query instance.
     */
    function( $search, $wp_query ) {
        if ( $wp_query->is_main_query() ) {
            // If this is not a singular page, bail early.
            if ( ! $wp_query->is_singular ) {
                return;
            }

            // If a language is set in query vars, bail early.
            if ( ! empty( $wp_query->query_vars['lang'] ) || ! empty( $wp_query->query['lang'] ) ) {
                return;
            }

            // If the post type is not translated, bail early.
            if (
                function_exists( 'pll_is_translated_post_type' ) &&
                ! pll_is_translated_post_type( $wp_query->get( 'post_type' ) )
            ) {
                return;
            }

            $tax_queries = $wp_query->get( 'tax_query' ) ?: [];

            // Try to find the language query.
            $lang_set = false;
            foreach ( $tax_queries as $idx => $tax_query ) {
                $taxonomy = $tax_query['taxonomy'] ?? '';
                if ( $taxonomy === 'language' ) {
                    $lang_set = true;
                }
            }

            // If no lang set, set the default language.
            if ( ! $lang_set && function_exists( 'pll_default_language' ) ) {
                $tax_queries[] = [
                    'taxonomy' => 'language',
                    'field'    => 'slug',
                    'terms'    => [ pll_default_language() ],
                    'operator' => 'IN',
                ];
            }

            // Recreate the tax queries.
            $wp_query->tax_query = new \WP_Tax_Query( $tax_queries );
        }
    },
    1, 2
);

URL modifications settings