diff --git a/specs/altair/fork.md b/specs/altair/fork.md index d789e7a8e..ac2258def 100644 --- a/specs/altair/fork.md +++ b/specs/altair/fork.md @@ -40,9 +40,9 @@ Note that for the pure Altair networks, we don't apply `upgrade_to_altair` since If `state.slot % SLOTS_PER_EPOCH == 0` and `compute_epoch_at_slot(state.slot) == ALTAIR_FORK_EPOCH`, an irregular state change is made to upgrade to Altair. -The upgrade occurs after the inner loop of `process_slots` that sets `state.slot` equal to `ALTAIR_FORK_EPOCH * SLOTS_PER_EPOCH` finishes. +The upgrade occurs after the completion of the inner loop of `process_slots` that sets `state.slot` equal to `ALTAIR_FORK_EPOCH * SLOTS_PER_EPOCH`. Care must be taken when transitioning through the fork boundary as implementations will need a modified state transition function that deviates from the Phase 0 spec. -In particular, the `state_transition` function defined in the Phase 0 spec will not expose the correct time to execute the upgrade in the presence of skipped slots at the fork boundary. +In particular, the outer `state_transition` function defined in the Phase 0 spec will not expose the precise fork slot to execute the upgrade in the presence of skipped slots at the fork boundary. Instead the logic must be within `process_slots`. ```python def upgrade_to_altair(pre: phase0.BeaconState) -> BeaconState: