Cleanups
* (typo) Remove `get_new_validator_registry_delta_chain_tip` from table of contents
* (typo) Update "Routines for updating validator status" in table of contents
* Update `FAR_FUTURE_SLOT` from `2**63` to `2**64 - 1`
* Put more constants in "Initial values", homogenise
* Cleanup note formatting
* Remove `ZERO_BALANCE_VALIDATOR_TTL` logic (to be possibly reintroduced in phase 2).
* Cleanup `min_empty_validator_index`
* Rename `deposit` to `amount` in `process_deposit` and `DepositData`.
* (typo) Remove new line under `process_penalties_and_exits`
* (typo) "Status codes" => "Status flags" in the table of contents
* (typo) `(state.slot - EPOCH_LENGTH) % LATEST_RANDAO_MIXES_LENGTH` => Use `SEED_LOOKAHEAD` instead.
* Put `state.validator_registry_latest_change_slot = state.slot` in `update_validator_registry`.
* Use `GENESIS_SLOT` for `last_poc_change_slot=0` and `second_last_poc_change_slot=0`.
Bugfixes
* (typo) `validator_exit` => `exit.validator_index`
* Separate initial deposits and initial activations to avoid double activations
* Replace `proposer.status != EXITED_WITH_PENALTY` with `validator.penalized_slot > state.slot` in two different places.
* Replace `status == EXITED_WITH_PENALTY` with `validator.penalized_slot <= state.slot` (and validator active) in two different places.
* Added `activation_slot`, `exit_slot`, `penalized_slot`, `withdrawal_slot`, use these to determine if a validator is active
* Universal min activation/exit delay of 256 slots
* Min exit time of ~1 day, but penalization delays this to ~18 days
* Penalty calculation period of `[time penalized - 18 days, time penalized + 18 days]`; made the total penalties array fixed size and wraparound to make calculation more fine-grained
* Processes withdrawals in all epochs, not just dynasty-changing epochs
* Change `get_shuffling` function to take slot as argument
Not yet done:
* Removed `shard_committees` from the state
* Removed persistent committees from the state
Added `latest_vdf_outputs` in `state` initialised to an array of `ZERO_HASH` of length `LATEST_RANDAO_MIXES_LENGTH // EPOCH_LENGTH`. (There's one VDF output per epoch. The VDF input is the RANDAO mix at the epoch boundary.)
Further changes to activate VDFs (in a future phase):
* Add a new beacon "VDF output and proof" transaction, e.g. with `MAX_VDF_OUTPUT_AND_PROOF := 1`.
* Adjust the `MAX_SEED_LOOKAHEAD` constant, e.g. to `2**4 * EPOCH_LENGTH`. (The `2**4` parameter is essentially `A_max`.)
* Add a `process_vdf_output_and_proof` helper function in the per-block processing:
* Verify the VDF input hasn't already been processed (check the corresponding `state.latest_vdf_outputs` entry is not `ZERO_HASH`.)
* Verify the proof is correct, i.e. matches the VDF input and output
* Save the VDF output to `state.latest_vdf_outputs`
* In the per-epoch processing set the corresponding entry in `state.latest_vdf_outputs` to `ZERO_HASH`.
* Use a VDF output for the shuffling seed.
* Fixes parameters and makes clear that the inactivity leak is on a per-epoch basis (before the leak was technically 64 times too weak as it was calculated per-slot but applied per-epoch)
* Adds a `// 2` to the inactivity leak to compensate for it being applied twice
* Changes how it is calculated (no inactivity leak for not being part of the head, only basic leak)
* Separates out early inclusion incentives into a separate incentive component rather than being multiplicative with everything else
Slight simplification. Only substantive change is that if the validator registry stays constant, we don't reshuffle 3 epochs after the last reshuffling (ie. before the reshufflings happened after 1, 2, 3, 4, 8, 16... epochs, now it's just 1, 2, 4, 8, 16...)
Removed the use of `clamp` from the spec, as there's no point in a helper function that's used exactly once; it only increases the amount people have to jump around the spec to understand what's going on.
Response to #295
Also a simplification, as two special cases get replaced: `state.randao_mix` -> `state.latest_randao_mixes[-1]`, and `state.next_seed` -> `state.latest_randao_mixes[-CYCLE_LENGTH-1]`.
vbuterin
Justin
Danny Ryan
terence tsao
Hsiao-Wei Wang
Nishant Das
Joseph Delong
Chih Cheng Liang
Akhila Raju
Anirudha Bose
Dan Burnett