Magento\Sales\Model\Order::getFullTaxInfo() incorrectly combines percentages

[fooman]

For an order which has 6% tax rate applied to one item and 21% tax rate applied to shipping - like in the below screenshot

The method Magento\Sales\Model\Order::getFullTaxInfo() will produce:

array(2) {
  [0] =>
  array(7) {
    'hidden' =>
    string(1) "0"
    'amount' =>
    string(7) "42.4500"
    'base_amount' =>
    string(7) "42.4500"
    'base_real_amount' =>
    string(7) "42.4500"
    'rates' =>
    array(1) {
      [0] =>
      array(5) {
        'code' =>
        string(16) "NL - reduced VAT"
        'title' =>
        string(11) "reduced VAT"
        'percent' =>
        double(6)
        'position' =>
        string(1) "0"
        'priority' =>
        string(1) "2"
      }
    }
    'percent' =>
    double(6)
    'id' =>
    string(16) "NL - reduced VAT"
  }
  [1] =>
  array(7) {
    'hidden' =>
    string(1) "0"
    'amount' =>
    string(6) "0.8700"
    'base_amount' =>
    string(6) "0.8700"
    'base_real_amount' =>
    string(6) "0.8700"
    'rates' =>
    array(1) {
      [0] =>
      array(5) {
        'code' =>
        string(8) "NL - VAT"
        'title' =>
        string(3) "VAT"
        'percent' =>
        double(21)
        'position' =>
        string(1) "0"
        'priority' =>
        string(1) "1"
      }
    }
    'percent' =>
    double(22.26)
    'id' =>
    string(8) "NL - VAT"
  }
}

The percent in the second tax rate 22.26 is incorrect - it somehow combines with the first one (21 * 1.06 = 22.26) even though they are independent. While I couldn't see anywhere that this is displayed immediately it indicates to me that there is something not working correctly in the tax calculation process.

[ilol]

@fooman, thank you for bringing this up! We created a ticket in the backlog and will get back to you once the team processes your pull request

[choukalos]

@fooman, thanks for bringing this up. Given the dates I think this must have been when the teams were porting over the tax engine from 1x. We shouldn't have this issue at this point in the latest mainline in addition we should have an automated test to cover this scenario. I updated the ticket in our backlog to that effect. When the team validates & ensures we have a covering automated test they'll close out this issue.

[verklov]

@fooman, the team fixed this issue. We have deployed the fix in code update 0.1.0-alpha99. Thanks again for reporting this issue to us. Please continue helping us make Magento product better!