WordPress 分類頁、標籤頁也能置頂文章：不用外掛的程式碼寫法

/**
 * 取得「屬於目前分類或標籤」的置頂文章 ID
 */
function ahwei_term_sticky_ids( $term ) {
    static $cache = array();

    $sticky = get_option( 'sticky_posts' );
    if ( ! ( $term instanceof WP_Term ) || empty( $sticky ) ) {
        return array();
    }

    if ( ! isset( $cache[ $term->term_id ] ) ) {
        $cache[ $term->term_id ] = get_posts( array(
            'post__in'            => $sticky,
            'post_type'           => 'post',
            'posts_per_page'      => -1,
            'fields'              => 'ids',
            'ignore_sticky_posts' => true,
            'no_found_rows'       => true,
            'tax_query'           => array(
                array(
                    'taxonomy' => $term->taxonomy,
                    'field'    => 'term_id',
                    'terms'    => $term->term_id,
                ),
            ),
        ) );
    }

    return $cache[ $term->term_id ];
}

/**
 * 是不是要處理的查詢:前台、主要查詢、分類頁或標籤頁、不是 RSS
 */
function ahwei_is_term_archive_query( $query ) {
    return ! is_admin()
        && $query->is_main_query()
        && ( $query->is_category() || $query->is_tag() )
        && ! $query->is_feed();
}

// 1) 從原本的列表排除置頂文章,避免重複出現
add_action( 'pre_get_posts', function ( $query ) {
    if ( ! ahwei_is_term_archive_query( $query ) ) {
        return;
    }
    $ids = ahwei_term_sticky_ids( $query->get_queried_object() );
    if ( $ids ) {
        $query->set( 'post__not_in', array_merge( (array) $query->get( 'post__not_in' ), $ids ) );
    }
} );

// 2) 在第一頁的最前面加回置頂文章
add_filter( 'the_posts', function ( $posts, $query ) {
    if ( ! ahwei_is_term_archive_query( $query ) || $query->is_paged() ) {
        return $posts;
    }
    $ids = ahwei_term_sticky_ids( $query->get_queried_object() );
    if ( ! $ids ) {
        return $posts;
    }
    $stickies = get_posts( array(
        'post__in'            => $ids,
        'orderby'             => 'post__in',
        'posts_per_page'      => count( $ids ),
        'ignore_sticky_posts' => true,
    ) );
    return array_merge( $stickies, $posts );
}, 10, 2 );

add_filter( 'post_class', function ( $classes, $class, $post_id ) {
    if ( ( is_category() || is_tag() ) && ! is_paged() && is_sticky( $post_id ) && ! in_array( 'sticky', $classes, true ) ) {
        $classes[] = 'sticky';
    }
    return $classes;
}, 10, 3 );

.category .type-post.sticky,
.tag .type-post.sticky {
  border-left: 4px solid #e67e22;
  padding-left: 1em;
}

<?php if ( is_sticky() ) : ?>
    <span class="sticky-badge">置頂</span>
<?php endif; ?>