Amount passed to Stripe should match the stored value

[canny[bot]]

Sometimes, depending on the amount donated using Stripe + Fee Recovery, GiveWP will pass the wrong amount to Stripe, although it shows the correct amount on the GiveWP dashboard. Example:

1. GiveWP shows $257.78 ($250 + $7.78 in fees) but Stripe dashboard shows a payment of $257.77 (resulting in net payment of $249.99 and $7.78 in fees)
2. GiveWP shows $74.46 ($70 + $4.46 in fees) but Stripe dashboard shows a payment of $74.45 (resulting in net payment of $69.99 and $4.46 in fees)

https://givewp.canny.io/admin/board/bug-reports/p/stripe-fee-recovery-should-round-up-the-last-digit-so-it-matches-the-amount-corr

[canny[bot]]

This issue has been linked to a Canny post: Stripe + Fee Recovery should round up the last digit so it matches the amount correctly :tada:

[kjohnson]

I think I've tracked where it is going wrong:

// includes/gateways/stripe/includes/class-give-stripe-gateway.php
public function format_amount( $amount ) {
    return Money::of( $amount, give_get_currency() )->getMinorAmount();
}

price passed in is 257.78 formatted amount returned is 25777

[kjohnson]

Failing test to confirm the bug:

public function testMinorAmountIsNotChanged() {
    $money = Money::of( 257.78, 'USD' );
    $this->assertEquals( 25778, $money->getMinorAmount() );
}

1) MoneyTest::testMinorAmountIsNotChanged
Failed asserting that 25777 matches expected 25778.

[kjohnson]

I'll add that this is not specific to Fee Recovery, rather it is related to decimal values which can be reproduced with the Legacy Form Templates (which does support a decimal value as a custom donation amount).

[kjohnson]

As I expected, there is a float value being cast as an integer, which has the potential of data loss - due to the way floating point precision is handled. I've run across this before in Ninja Forms when making charges using Stripe (off by one cent).