CS-V2Gov-051: Rounding Error on Offset Calculation

[danielattilasimon]

Users can allocate their voting power to different initiatives. For each allocation two values are stored: allocated LQTY and the user's offset. Function allocateLQTY() rounds down when computing the offset that should be added to an initiative:

for (/* ... */) {
    absoluteOffsetVotes[x] =
        _absoluteLQTYVotes[x] * int256(userState.unallocatedOffset) / int256(userState.unallocatedLQTY);
    absoluteOffsetVetos[x] =
        _absoluteLQTYVetos[x] * int256(userState.unallocatedOffset) / int256(userState.unallocatedLQTY);
}

This means that, in particular, when the user allocates all of his LQTY to many initiatives, he could be left with 0 unallocatedLQTY and non-zero unallocatedOffset.

The rounding error is accounted in favor of an initiative if user allocates YES votes (against initiative if user allocates NO votes).