Manual Order Tax Calculation Override: Shipping Tax Resets After Coupon Application
Summary:
This bug report describes a problem in the WooCommerce manual order creation interface where the tax amount for a shipping line item is forcibly recalculated and reset after a coupon is applied, overriding any manual user input.
The core issue is likely an unintended side effect of the cart recalculation logic. When a coupon is added to a manual order, WooCommerce appears to trigger a routine that recalculates all tax totals. This routine does not check if the user has manually overridden a value and simply reapplies the default tax calculation for shipping, disregarding the user's input. This behavior breaks the manual order creation process, which is designed to allow administrators full control over order line items, including tax amounts.
The impact is significant for store administrators who need to create or modify orders with specific tax requirements. It prevents them from accurately setting up orders where the shipping tax needs to be manually adjusted (e.g., removed for a tax-exempt customer or modified to correct a calculation), effectively breaking a key administrative function.
How to Replicate:
- Navigate to WooCommerce > Orders and create a new manual order.
- Select a customer for the order.
- Add at least one product to the order.
- Add a shipping method, ensuring it has a price.
- Apply a coupon to the order.
- Attempt to manually modify the tax value for the shipping line item.
- Observe that the input field resets to its initial calculated value instead of retaining the manually entered value.