Prestashop: Total tax amount is wrong in order confirmation email

[Hlavtox]

To Reproduce
Steps to reproduce the behavior:

1. Setup some VAT rule, 21% for example.
2. Setup a voucher which discounts the order by X percent.
3. Add something to cart.
4. Apply a voucher with discount.
5. Order it.
6. Total tax in email is wrong. It is calculated from the amount before discounts.

Fix
'{total_tax_paid}' => Tools::displayPrice(($order->total_products_wt - $order->total_products) + ($order->total_shipping_tax_incl - $order->total_shipping_tax_excl), $this->context->currency, false)

>
'{total_tax_paid}' => Tools::displayPrice($order->total_paid_tax_incl - $order->total_paid_tax_excl, $this->context->currency, false)

I found it suprising that something crucial as calculating VAT is still not fixed after years. This problem is there since 1.6.

Additional information
PrestaShop version: 1.7.6.0
PHP version: 7.2

[khouloudbelguith]

Hi @Hlavtox,

Thanks for your report.
I manage to reproduce the issue with PS1.7.5.2 & PS1.7.6.1 & the develop branch.
In the email the Tax is incorrect.

In the FO it is OK

I’ll add this to the debug roadmap so that it’s fixed. If you have already fixed it on your end or if you think you can do it, please do send us a pull request!

PS: about your fix, we stopped using Tools::displayPrice as it is deprecated, you can follow this PR: https://github.com/PrestaShop/PrestaShop/pull/15448
Thanks!

[Hlavtox]

@khouloudbelguith PR opened #16571