polylang-pro-slugs-sync-acf

Polylang Pro Slugs, Sync, and ACF

Use this skill when compatibility depends on Pro-only behavior rather than the core Polylang API.

Polylang Pro 3.8.5 adds major behavior in three areas:

• translated and shared slugs;
• duplicate/sync workflows;
• ACF Pro integration.

Guard Pro-only code:

if ( ! defined( 'POLYLANG_PRO' ) ) {
    return;
}

Translated rewrite slugs

Polylang Pro translates rewrite slugs through strings translation. The model scans registered post types, archives, taxonomies, post formats, and miscellaneous bases such as author, search, attachment, page, and the front base.

It stores the computed map in the transient pll_translated_slugs and refreshes rewrite rules after string translations are saved.

Add your plugin's custom slug source with:

add_filter(
    'pll_translated_slugs',
    static function ( array $slugs, PLL_Language $language, PLL_MO $mo ): array {
        $source = 'courses';

        $slugs['myplugin_courses']['slug'] = $source;
        $translated = $mo->translate( $source );
        $slugs['myplugin_courses']['translations'][ $language->slug ] = $translated ?: $source;

        return $slugs;
    },
    10,
    3
);

Rules:

• Register CPTs and taxonomies before wp_loaded; Pro initializes translated slugs on wp_loaded priority 1.
• Flush rewrite rules when your base slug changes, not on every request.
• Do not read get_option( 'rewrite_rules' ) and mutate rules manually. Hook Polylang's slug filters and let the model rebuild.
• Expect object caches: Pro deletes the transient option row explicitly when an external object cache is active.

Shared slugs

Polylang Pro can allow translated posts or terms to share the same slug in different languages. It filters slug uniqueness and query resolution by language.

Compatibility rule: never assume post_name or term slug is globally unique.

Bad:

$post = get_page_by_path( $slug, \OBJECT, 'page' );

Safer:

$post_id = pll_get_post( $source_post_id, $target_lang );