Search Functionality broken by the wp 4.2 update

Question

I run a blog site with posts by authors, and I implemented a search that would return results if the search was like an author's name or the search term was contained in a story. I was functioning and properly returned authors who matched the search, but now the search returns every user every single time.

I suspect it has something to do with WP_User_query since since that function was updated in 4.2, but I have no idea how I would change it to be compatible.

Here is the search code:

add_filter('user_search_columns', 'user_search_columns_bd' , 10, 3);

function user_search_columns_bd($search_columns, $search, $this){
    if(!in_array('display_name', $search_columns)){
        $search_columns[] = 'display_name';
    }
    return $search_columns;
}

add_filter( 'get_meta_sql', 'user_meta_filter', 10, 6 );

function user_meta_filter( $sql, $queries, $type, $primary_table, $primary_id_column, $context ){
    if ( $type !== 'user' ){
        return $sql;
    }

    if ( ! isset( $context->query_vars['meta_query']['replace_and'] ) || $context->query_vars['meta_query']['replace_and'] !== true ){
        return $sql;
    }

    $sql['where'] = preg_replace('/AND/', 'OR', $sql['where'], 1);
    return $sql;
}   


$args = array(
'search'         => $s,
'search_columns' => array( 'user_login', 'user_email'),
'meta_query' => array(
    'relation' => 'OR',
    'replace_and' => true, 
    array(
        'key'     => 'first_name',
        'value'   => $s,
        'compare' => 'LIKE'
    ),
    array(
        'key'     => 'last_name',
        'value'   => $s,
        'compare' => 'LIKE'
    )
)
);

// The Query
$user_query = new WP_User_Query( $args ); 

Answer 1

The problem was due to the fact that the query was restructured in this latest update. As pointed out by d79 in this question, the query changed from:

SELECT DISTINCT SQL_CALC_FOUND_ROWS wp_users.* FROM wp_users INNER JOIN wp_usermeta ON ( wp_users.ID = wp_usermeta.user_id )  INNER JOIN wp_usermeta AS mt1 ON ( wp_users.ID = mt1.user_id ) WHERE 1=1 AND (user_login LIKE 'test' OR user_email LIKE 'test' OR display_name LIKE 'test') OR ( 
  ( 
    ( 
      ( wp_usermeta.meta_key = 'first_name' AND CAST(wp_usermeta.meta_value AS CHAR) LIKE '%test%' ) 
      OR 
      ( wp_usermeta.meta_key = 'last_name' AND CAST(wp_usermeta.meta_value AS CHAR) LIKE '%test%' )
    ) 
    AND 
    mt1.meta_key = 'wp_6_capabilities'
  )
) ORDER BY user_login ASC 

to

SELECT DISTINCT SQL_CALC_FOUND_ROWS wp_users.* FROM wp_users INNER JOIN wp_usermeta ON ( wp_users.ID = wp_usermeta.user_id )  INNER JOIN wp_usermeta AS mt1 ON ( wp_users.ID = mt1.user_id ) WHERE 1=1 OR ( 
  ( 
    ( 
      ( wp_usermeta.meta_key = 'first_name' AND CAST(wp_usermeta.meta_value AS CHAR) LIKE '%test%' ) 
      OR 
      ( wp_usermeta.meta_key = 'last_name' AND CAST(wp_usermeta.meta_value AS CHAR) LIKE '%test%' )
    ) 
    AND 
    mt1.meta_key = 'wp_6_capabilities'
  )
) AND (user_login LIKE 'test' OR user_email LIKE 'test' OR display_name LIKE 'test') ORDER BY user_login ASC

Therefore, his function:

add_action('pre_user_query', 'my_custom_users_search');

function my_custom_users_search( $args ) {
    if( isset( $args->query_vars['meta_query']['replace_and'] ) && $args->query_vars['meta_query']['replace_and'] )
        $args->query_where = str_replace(') AND (', ') OR (', $args->query_where);
}

targeted the correct AND to be changed to an OR. His solution fixed the problem for me.