Thank you for your report. This was a known issue and is already fixed, though not deployed on mainnet yet.
You can find the updated logic in our public repository here:Â https://github.com/BeanstalkFarms/Beanstalk/tree/beanstalk-3
roots = stalk == s.a[sender].s.stalk
? s.a[sender].roots
@> : s.s.roots.sub(1).mul(stalk).div(s.s.stalk).add(1);
...
s.a[sender].roots = s.a[sender].roots.sub(roots);
// Rain roots cannot be transferred, burn them
@> if (s.a[sender].sop.roots > s.a[sender].roots) {
uint256 deltaRoots = s.a[sender].sop.roots.sub(s.a[sender].roots);
s.a[sender].sop.roots = s.a[sender].roots;
s.r.roots = s.r.roots.sub(deltaRoots);
}describe.only('Silo TransferStalk Rounding Issue', function () {
it('should demonstrate the rounding issue in transferStalk', async function () {
// Initialize example values for stalk and roots
const stalk = toBN('500'); // 500 stalk to transfer
const wrongStalkExample = toBN('3'); // 3 stalk as in the example
// Simulate transferring stalk
const senderStalkBefore = await this.siloGetters.balanceOfStalk(userAddress);
const recipientStalkBefore = await this.siloGetters.balanceOfStalk(user2Address);
// Apply incorrect formula
const incorrectRoots = wrongStalkExample.sub(1).mul(stalk).div(toBN('3')).add(1); // Incorrect rounding
// Apply correct formula for comparison
const correctRoots = wrongStalkExample.mul(stalk).sub(1).div(toBN('3')).add(1); // Correct rounding
console.log(`Incorrect roots calculated: ${incorrectRoots.toString()}`);
console.log(`Correct roots calculated: ${correctRoots.toString()}`);
});
});