Ticket #25709: 25709.diff

src/wp-includes/query.php

@@ -1979 +1979 @@
 
                 $stopwords = $this->get_search_stopwords();
 
+                $pcre_utf8 = (bool) @preg_match( '/\pL/u', 'w' );
+
                 foreach ( $terms as $term ) {
                         // keep before/after spaces when term is for exact match
                         if ( preg_match( '/^".+"$/', $term ) )
@@ -1987 +1989 @@
                                 $term = trim( $term, "\"' " );
 
                         // \p{L} matches a single letter that is not a Chinese, Japanese, etc. char
-                        if ( ! $term || @preg_match( '/^\p{L}$/u', $term ) )
+                        if ( ! $term || ( $pcre_utf8 && preg_match( '/^\p{L}$/u', $term ) ) )
                                 continue;
 
                         if ( in_array( call_user_func( $strtolower, $term ), $stopwords, true ) )