Configurable product old price with taxes displayed wrong

[kandrejevs]

I have a store for EU, by law we need to show all prices with VAT included. In the admin we enter prices without tax, we have tax rule to add 20% VAT, in configuration everything es set up properly, so all prices include tax.

When we apply catalogue rule for category to have 20% discount all prices are shown correctly except configurable product old price- it is old price without tax.

Steps to reproduce

1. create configurable product without tax, price is defined for each sku
2. create tax rule 20%
3. apply this tax rule to product
4. in tax settings set all values to display prices with tax

Expected result

1. Configurable product old price should be child price without discount and with tax

Actual result

1. for simple product old price is correct, if it is 100£ in admin and tax is 20%, on front end it is displayed as 96$ (regular price 120£) - 20% catalog rule discount applied
2. for configurable product that has prices for child products final price is correct, but old price is old price without VAT applied.

here is simple product and configurable, both has price 100$, 20% tax and 20% catalog rule discount. final price is correct for both, old price is not:
http://i.imgur.com/qP8etV6.png

[yangsystem]

I have the same problem but I figured a workaround.
If you set the product as a virtual product you have this problem: price with tax is the same as price without tax. The code does not apply tax on it.
BUT:
if you make the same product as a simple product (just check this item has weight and fill 0 as weight) all work's out. And weight 0 is the same as virtual product for us human's.

I think the problem is somewhere in virtual product's logic.

[veloraven]

@kandrejevs thank you for your report.
Please identify which version of Magento you are running.

[kandrejevs]

@veloraven this bug is present on 2.1.1 CE and EE editions.

here is my tax configuration, tax rule is 20%

INSERT INTO `core_config_data` (`scope`, `scope_id`, `path`, `value`)
VALUES
    ('default', 0, 'tax/classes/wrapping_tax_class', '0'),
    ('default', 0, 'tax/calculation/apply_after_discount', '0'),
    ('default', 0, 'tax/notification/ignore_discount', '1'),
    ('default', 0, 'tax/notification/ignore_price_display', '0'),
    ('default', 0, 'tax/calculation/discount_tax', '1'),
    ('default', 0, 'tax/calculation/cross_border_trade_enabled', '0'),
    ('default', 0, 'tax/defaults/country', 'GB'),
    ('default', 0, 'tax/defaults/postcode', NULL),
    ('default', 0, 'tax/display/type', '2'),
    ('default', 0, 'tax/display/shipping', '2'),
    ('default', 0, 'tax/cart_display/price', '2'),
    ('default', 0, 'tax/cart_display/subtotal', '2'),
    ('default', 0, 'tax/cart_display/gift_wrapping', '1'),
    ('default', 0, 'tax/cart_display/printed_card', '1'),
    ('default', 0, 'tax/cart_display/grandtotal', '1'),
    ('default', 0, 'tax/sales_display/gift_wrapping', '1'),
    ('default', 0, 'tax/sales_display/printed_card', '1');

[bordeo]

@veloraven we find this bug on last magento version 2.1.3 CE.
Like @kandrejevs I used catalog promo with 20% discount and old-price show price without tax.

[firstred]

I managed to show the correct prices by editing the file /vendor/magento/module-configurable-product/Pricing/Price/ConfigurableRegularPrice.php.
Replace (line ~89):

    public function getAmount()
    {
        return $this->getMinRegularAmount();
    }

with

    public function getAmount()
    {
        return $this->getMaxRegularAmount();
    }

At this moment I have no idea why it works for me and whether it will help in your case, but...

[6ui11em]

Following the suggestion of @firstred I fixed it changing the loop of doGetMinRegularAmount function from:

foreach ($this->lowestPriceOptionsProvider->getProducts($this->product) as $product) {

to

foreach ($this->getUsedProducts() as $product) {

Hope this quick fix helps someone else.

[PierAlex]

Same problem for me on Magento 2.1.2 CE, the workarounds above do not take effects.