Fantom-foundation/go-lachesis

package election

import (
    "errors"
)

// Chooses the decided "yes" roots with the greatest stake amount.
// This root serves as a "checkpoint" within DAG, as it's guaranteed to be final and consistent unless more than 1/3W are Byzantine.
// Other validators will come to the same Atropos not later than current highest frame + 2.
func (el *Election) chooseAtropos() (*Res, error) {
    // iterate until Yes root is met, which will be Atropos. I.e. not necessarily all the roots must be decided
    for _, validator := range el.validators.SortedIDs() {
        vote, ok := el.decidedRoots[validator]
        if !ok {
            return nil, nil // not decided
        }
        if vote.yes {
            return &Res{
                Frame:   el.frameToDecide,
                Atropos: vote.observedRoot,
            }, nil
        }
    }
    return nil, errors.New("All the roots are decided as 'no', which is possible only if more than 1/3W are Byzantine")
}