Vendor Canonical Links

function jp_maybe_fix_canonical() {

	if ( get_query_var( 'vendor' ) ) {

		remove_action( 'wp_head', 'rel_canonical' );

		add_action( 'wp_head', 'jp_fix_canonical' );

	}

}

add_action( 'template_redirect', 'jp_maybe_fix_canonical' );

function jp_fix_canonical() {

	$link = home_url( 'vendor/' );

	if ( $vendor = get_query_var( 'vendor' ) ) {

		$link .= $vendor . '/';

	}

	echo '<link rel="canonical" href="' . esc_url( $link ) . '" />';

}