WooCommerce Fractional Quantities for PayPal

woocommerce_filters.php

/* ---------------------------------
 *  Paypal Args.  Paypal only accepts integer quantities, so we have to update the 
 * information that's sent from the order, but only for metals.
 * --------------------------------- */

add_filter('woocommerce_paypal_args', 'tl_paypal_args', 100, 1);

function tl_paypal_args( $args ){
	$counter = 1;
	while(isset( $args[ 'quantity_' . $counter])){
		$quantity = $args['quantity_' . $counter];
		// fractional amount
		if (strpos($quantity, '.')){
			 $args[ 'amount_' . $counter ] = number_format( $quantity * $args[ 'amount_' . $counter ], 2, '.', '' );
			 $args[ 'quantity_' . $counter ] = 1;
			 $args[ 'item_name_' . $counter ] .= " $quantity Troy Oz.";
		}
		$counter++;
	}
	return $args;
}

// this filter is applied in woocommerce/includes/gateways/paypal/includes/class-wc-gateway-paypal-request.php

With Woocommerce 3.7.0 you need to update the line item to be a float. Because when it get's to the woocommerce_paypal_args a fractional qty will be 0. This is because in woocommerce_paypal_line_item woo parses qty (int) $quantity. I added the code below and you're snippet worked like a charm! Thanks.

add_filter('woocommerce_paypal_line_item', 'tl_paypal_line_item', 100, 5);
function tl_paypal_line_item( $item, $item_name, $quantity, $amount, $item_number ){
	if (strpos($quantity, '.')) {
		$item['quantity'] = (float) $quantity;
	}
	return $item;
}

Oh wow, that's really helpful, @dwayneparton! Thanks for the update, you've probably saved me a bunch of time when I finally upgrade this site to WooCommerce 3.7.x!