Multiplication of two positive numbers can result in zero

[tinchoabbate]

The wmul function does not behave as expected in certain cases. In particular, the multiplication of two positive numbers can result in zero. That is true for every a,b > 0 and b < 5*10^17 / a (as shown here).

In such cases, I was expecting the wmul function to revert the transaction instead of returning 0.
Were you aware of this behavior ? If you were, are you planning to modify the library ? I believe the way to go, for a far more reasonable behavior, would be to either revert the transaction if there's a rounding to 0, or properly document this unexpected behavior in the function's docs.

Note that a similar issue happens in rmul

[livnev]

Rounding to 0 when the result of the multiplication is less than 0.0000000000000000005 is expected behaviour, so that is not a bug. If that is a problem for the application, then it should be checked explicitly.