PHP Warning: strpos(): Empty needle

Hello,

I keep getting tons of error of PHP Warning: strpos(): Empty needle in /home/saklikum/public_html/wp-includes/plugin.php on line 649.

How can i fix? I give the code below. 649th line is if ( strpos( $file, $realdir ) === 0 )

——-
function plugin_basename( $file ) {
global $wp_plugin_paths;

// $wp_plugin_paths contains normalized paths.
$file = wp_normalize_path( $file );

arsort( $wp_plugin_paths );
foreach ( $wp_plugin_paths as $dir => $realdir ) {
if ( strpos( $file, $realdir ) === 0 ) {
$file = $dir . substr( $file, strlen( $realdir ) );
}
}

$plugin_dir = wp_normalize_path( WP_PLUGIN_DIR );
$mu_plugin_dir = wp_normalize_path( WPMU_PLUGIN_DIR );

$file = preg_replace(‘#^’ . preg_quote($plugin_dir, ‘#’) . ‘/|^’ . preg_quote($mu_plugin_dir, ‘#’) . ‘/#’,”,$file); // get relative path from plugins dir
$file = trim($file, ‘/’);
return $file;
}