Money#to_s converts number to float before formatting

[dylanahsmith]

irb> Money.new("100000000000000000000000000").to_s
=> "100000000000000004764729344.00"

This is because sprintf("%.2f", value) or sprintf("%.#{currency.minor_units}f", value) is being used to format the string the string, which is converting the number to a float before formatting the string, which loses precision.

We could instead use BigDecimal#to_s to format the string, although it doesn't support specifying the number of digits after the decimal to output.

[elfassy]

Floats are dangerous for really large numbers or if no rounding is happening. sprintf will automatically round so even though

129.95 * 100 => 12994.999999999998

we still get the correct value

sprintf("%.2f", 129.95 * 100) => "12995.00"

We still have the issue of really big numbers (greater than 15 digits). For money that's somewhat less of a concern since the max 15 digit number is

nine hundred ninety-nine trillion, nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine

https://www.calculatorsoup.com/calculators/conversions/numberstowords.php

So somewhat unlikely... but then again

LOL, will FIX. Thanks for flagging this!

[elfassy]

this issue has been fixed for a while

> Money.new("100000000000000000000000000", "USD").to_s
=> "100000000000000000000000000.00"