Highlighting search result excerpt causes PHP error

Question

I have the following code in a WordPress theme functions.php. I'm using PHP 7.1 both locally and remotely.

    if ( ! function_exists( 'highlight_search_results' ) ) :
    // this filter runs on the_excerpt and the_title
    // to highlight inside both locations for search result pages
    add_filter( 'the_excerpt', 'highlight_search_results' );
    add_filter( 'the_title', 'highlight_search_results' );
    function highlight_search_results( $text ) {
        if ( is_search() && ! is_admin() ) {
            $sr          = get_query_var( 's' );
            $highlighted = preg_filter( '/' . preg_quote( $sr ) . '/i', '<span class="a-search-highlight">$0</span>', $text );
            if ( ! empty( $highlighted ) ) {
                $text = $highlighted;
            }
        }
        return $text;
    }
endif;

It worked nicely in development, with no errors, until deployment to our server. It functions to highlight the user's search term in the WordPress search results page, both in the title and in the excerpt of the post. However I don't think my issue is necessarily WordPress related.

On our live server, it results in this recurring PHP error:

[php7:warn] PHP Warning:  preg_filter(): Unknown modifier 'k' in /wp-content/themes/minnpost-largo/inc/extras.php on line 209

What can I ask my host to look for? Alternatively, is there another way I should more reliably achieve this goal?

`'/' . preg_quote( $sr, '/' ) . '/i'` – Wiktor Stribiżew Aug 31 '18 at 13:46 — Wiktor Stribiżew, Aug 31 '18 at 13:46
@WiktorStribiżew thank you, I'll try this on the server. – Jonathan Stegall Aug 31 '18 at 13:51 — Jonathan Stegall, Aug 31 '18 at 13:51

Highlighting search result excerpt causes PHP error

0 Answers0