概述

_update_term_count_on_transition_post_status() 是一个 WordPress 函数，用于在文章状态变更时更新自定义分类法的术语计数。它确保术语计数仅包含特定状态的文章，例如默认仅统计“publish”状态。

关键要点

• 函数在文章状态从 $old_status 变为 $new_status 时触发，更新关联的自定义分类法术语计数。
• 通过 get_object_taxonomies() 获取文章类型的所有分类法对象，并遍历处理。
• 使用 update_post_term_count_statuses 过滤器（默认包含 'publish'）来确定哪些状态应计入术语计数。
• 逻辑优化：如果新旧状态都不在计数状态中（如 draft -> pending），或都在计数状态中（通过过滤器扩展），则跳过重新计算。
• 核心操作：通过 wp_get_object_terms() 获取术语的 tt_ids，然后调用 wp_update_term_count() 更新计数。

代码示例

function _update_term_count_on_transition_post_status( $new_status, $old_status, $post ) {
    if ( $new_status === $old_status ) {
        return;
    }

    // Update counts for the post's terms.
    foreach ( (array) get_object_taxonomies( $post->post_type, 'objects' ) as $taxonomy ) {
        /** This filter is documented in wp-includes/taxonomy.php */
        $counted_statuses = apply_filters( 'update_post_term_count_statuses', array( 'publish' ), $taxonomy );

        /*
         * Do not recalculate term count if both the old and new status are not included in term counts.
         * This accounts for a transition such as draft -> pending.
         */
        if ( ! in_array( $old_status, $counted_statuses, true ) && ! in_array( $new_status, $counted_statuses, true ) ) {
            continue;
        }

        /*
         * Do not recalculate term count if both the old and new status are included in term counts.
         *
         * This accounts for transitioning between statuses which are both included in term counts. This can only occur
         * if the `update_post_term_count_statuses` filter is in use to count more than just the 'publish' status.
         */
        if ( in_array( $old_status, $counted_statuses, true ) && in_array( $new_status, $counted_statuses, true ) ) {
            continue;
        }

        $tt_ids = wp_get_object_terms( $post->ID, $taxonomy->name, array( 'fields' => 'tt_ids' ) );
        wp_update_term_count( $tt_ids, $taxonomy->name );
    }
}

注意事项

• 函数在 WordPress 3.3.0 版本引入，用于处理自定义分类法术语计数的动态更新。
• 默认情况下，术语计数仅包括“publish”状态的文章，但可通过 update_post_term_count_statuses 过滤器扩展。
• 相关函数包括 wp_update_term_count()、wp_get_object_terms()、get_object_taxonomies() 和 apply_filters()，用于实现计数逻辑。