Merge pull request #949 from ethereum/JustinDrake-patch-14

Revamp balances and incentivisation

specs/light_client/sync_protocol.md

@@ -180,8 +180,8 @@ def verify_block_validity_proof(proof: BlockValidityProof, validator_memory: Val
     assert proof.shard_parent_block.beacon_chain_root == hash_tree_root(proof.header)
     committee = compute_committee(proof.header, validator_memory)
     # Verify that we have >=50% support
-    support_balance = sum([v.high_balance for i, v in enumerate(committee) if get_bitfield_bit(proof.shard_bitfield, i) is True])
-    total_balance = sum([v.high_balance for i, v in enumerate(committee)])
+    support_balance = sum([v.effective_balance for i, v in enumerate(committee) if get_bitfield_bit(proof.shard_bitfield, i) is True])
+    total_balance = sum([v.effective_balance for i, v in enumerate(committee)])
     assert support_balance * 2 > total_balance
     # Verify shard attestations
     group_public_key = bls_aggregate_pubkeys([

specs/validator/0_beacon-chain-validator.md

@@ -138,7 +138,7 @@ A validator has two primary responsibilities to the beacon chain -- [proposing b
 
 ### Block proposal
 
-A validator is expected to propose a [`BeaconBlock`](../core/0_beacon-chain.md#beaconblock) at the beginning of any slot during which `get_beacon_proposer_index(state, slot)` returns the validator's `validator_index`. To propose, the validator selects the `BeaconBlock`, `parent`, that in their view of the fork choice is the head of the chain during `slot - 1`. The validator is to create, sign, and broadcast a `block` that is a child of `parent` and that executes a valid [beacon chain state transition](../core/0_beacon-chain.md#beacon-chain-state-transition-function).
+A validator is expected to propose a [`BeaconBlock`](../core/0_beacon-chain.md#beaconblock) at the beginning of any slot during which `get_beacon_proposer_index(state)` returns the validator's `validator_index`. To propose, the validator selects the `BeaconBlock`, `parent`, that in their view of the fork choice is the head of the chain during `slot - 1`. The validator is to create, sign, and broadcast a `block` that is a child of `parent` and that executes a valid [beacon chain state transition](../core/0_beacon-chain.md#beacon-chain-state-transition-function).
 
 There is one proposer per slot, so if there are N active validators any individual validator will on average be assigned to propose once per N slots (e.g. at 312500 validators = 10 million ETH, that's once per ~3 weeks).
 
@@ -368,7 +368,7 @@ def get_committee_assignment(
             return assignment
 ```
 
-A validator can use the following function to see if they are supposed to propose during their assigned committee slot. This function can only be run during the slot in question and can not reliably be used to predict in advance.
+A validator can use the following function to see if they are supposed to propose during their assigned committee slot. This function can only be run during the slot in question. Proposer selection is only stable within the context of the current epoch.
 
 ```python
 def is_proposer_at_slot(state: BeaconState,

test_libs/pyspec/eth2spec/phase0/state_transition.py

@@ -11,7 +11,6 @@
     BeaconState,
     BeaconBlock,
     Slot,
-    process_proposer_attestation_rewards,
 )
 
 
@@ -52,7 +51,6 @@ def process_operations(state: BeaconState, block: BeaconBlock) -> None:
         spec.MAX_ATTESTATIONS,
         spec.process_attestation,
     )
-    process_proposer_attestation_rewards(state)
 
     assert len(block.body.deposits) == expected_deposit_count(state)
     process_operation_type(

test_libs/pyspec/tests/block_processing/test_process_attester_slashing.py

@@ -3,11 +3,11 @@
 
 import eth2spec.phase0.spec as spec
 from eth2spec.phase0.spec import (
-    get_balance,
     get_beacon_proposer_index,
     process_attester_slashing,
 )
 from tests.helpers import (
+    get_balance,
     get_valid_attester_slashing,
     next_epoch,
 )

test_libs/pyspec/tests/block_processing/test_process_deposit.py

@@ -4,11 +4,11 @@
 import eth2spec.phase0.spec as spec
 
 from eth2spec.phase0.spec import (
-    get_balance,
     ZERO_HASH,
     process_deposit,
 )
 from tests.helpers import (
+    get_balance,
     build_deposit,
     privkeys,
     pubkeys,

test_libs/pyspec/tests/block_processing/test_process_proposer_slashing.py

@@ -3,11 +3,11 @@
 
 import eth2spec.phase0.spec as spec
 from eth2spec.phase0.spec import (
-    get_balance,
     get_current_epoch,
     process_proposer_slashing,
 )
 from tests.helpers import (
+    get_balance,
     get_valid_proposer_slashing,
 )
 

test_libs/pyspec/tests/block_processing/test_process_transfer.py

@@ -5,11 +5,9 @@
 
 from eth2spec.phase0.spec import (
     get_active_validator_indices,
-    get_balance,
     get_beacon_proposer_index,
     get_current_epoch,
     process_transfer,
-    set_balance,
 )
 from tests.helpers import (
     get_valid_transfer,
@@ -75,7 +73,7 @@ def test_success_withdrawable(state):
 def test_success_active_above_max_effective(state):
     sender_index = get_active_validator_indices(state, get_current_epoch(state))[-1]
     amount = spec.MAX_EFFECTIVE_BALANCE // 32
-    set_balance(state, sender_index, spec.MAX_EFFECTIVE_BALANCE + amount)
+    state.balances[sender_index] = spec.MAX_EFFECTIVE_BALANCE + amount
     transfer = get_valid_transfer(state, sender_index=sender_index, amount=amount, fee=0)
 
     pre_state, post_state = run_transfer_processing(state, transfer)
@@ -86,7 +84,7 @@ def test_success_active_above_max_effective(state):
 def test_active_but_transfer_past_effective_balance(state):
     sender_index = get_active_validator_indices(state, get_current_epoch(state))[-1]
     amount = spec.MAX_EFFECTIVE_BALANCE // 32
-    set_balance(state, sender_index, spec.MAX_EFFECTIVE_BALANCE)
+    state.balances[sender_index] = spec.MAX_EFFECTIVE_BALANCE
     transfer = get_valid_transfer(state, sender_index=sender_index, amount=amount, fee=0)
 
     pre_state, post_state = run_transfer_processing(state, transfer, False)
@@ -107,7 +105,7 @@ def test_incorrect_slot(state):
 def test_insufficient_balance(state):
     sender_index = get_active_validator_indices(state, get_current_epoch(state))[-1]
     amount = spec.MAX_EFFECTIVE_BALANCE
-    set_balance(state, sender_index, spec.MAX_EFFECTIVE_BALANCE)
+    state.balances[sender_index] = spec.MAX_EFFECTIVE_BALANCE
     transfer = get_valid_transfer(state, sender_index=sender_index, amount=amount + 1, fee=0)
 
     # un-activate so validator can transfer
@@ -140,4 +138,4 @@ def test_invalid_pubkey(state):
 
     pre_state, post_state = run_transfer_processing(state, transfer, False)
 
-    return pre_state, transfer, post_state
+    return pre_state, transfer, post_state

test_libs/pyspec/tests/helpers.py

@@ -26,9 +26,9 @@
     # functions
     convert_to_indexed,
     get_active_validator_indices,
-    get_balance,
     get_attesting_indices,
     get_block_root,
+    get_block_root_at_slot,
     get_crosslink_committees_at_slot,
     get_current_epoch,
     get_domain,
@@ -53,6 +53,10 @@
 pubkey_to_privkey = {pubkey: privkey for privkey, pubkey in zip(privkeys, pubkeys)}
 
 
+def get_balance(state, index):
+    return state.balances[index]
+
+
 def set_bitfield_bit(bitfield, i):
     """
     Set the bit in ``bitfield`` at position ``i`` to ``1``.
@@ -150,16 +154,16 @@ def build_attestation_data(state, slot, shard):
     if slot == state.slot:
         block_root = build_empty_block_for_next_slot(state).previous_block_root
     else:
-        block_root = get_block_root(state, slot)
+        block_root = get_block_root_at_slot(state, slot)
 
     current_epoch_start_slot = get_epoch_start_slot(get_current_epoch(state))
     if slot < current_epoch_start_slot:
         print(slot)
-        epoch_boundary_root = get_block_root(state, get_epoch_start_slot(get_previous_epoch(state)))
+        epoch_boundary_root = get_block_root(state, get_previous_epoch(state))
     elif slot == current_epoch_start_slot:
         epoch_boundary_root = block_root
     else:
-        epoch_boundary_root = get_block_root(state, current_epoch_start_slot)
+        epoch_boundary_root = get_block_root(state, get_current_epoch(state))
 
     if slot < current_epoch_start_slot:
         justified_epoch = state.previous_justified_epoch

test_libs/pyspec/tests/test_sanity.py

@@ -15,16 +15,13 @@
     VoluntaryExit,
     # functions
     get_active_validator_indices,
-    get_balance,
     get_beacon_proposer_index,
-    get_block_root,
+    get_block_root_at_slot,
+    get_state_root,
     get_current_epoch,
     get_domain,
-    get_state_root,
     advance_slot,
     cache_state,
-    set_balance,
-    slot_to_epoch,
     verify_merkle_branch,
     hash,
 )
@@ -37,6 +34,7 @@
     get_merkle_root,
 )
 from .helpers import (
+    get_balance,
     build_deposit_data,
     build_empty_block_for_next_slot,
     fill_aggregate_attestation,
@@ -52,7 +50,6 @@
 # mark entire file as 'sanity'
 pytestmark = pytest.mark.sanity
 
-
 def check_finality(state,
                    prev_state,
                    current_justified_changed,
@@ -96,7 +93,7 @@ def test_empty_block_transition(state):
     state_transition(test_state, block)
 
     assert len(test_state.eth1_data_votes) == len(state.eth1_data_votes) + 1
-    assert get_block_root(test_state, state.slot) == block.previous_block_root
+    assert get_block_root_at_slot(test_state, state.slot) == block.previous_block_root
 
     return state, [block], test_state
 
@@ -110,7 +107,7 @@ def test_skipped_slots(state):
 
     assert test_state.slot == block.slot
     for slot in range(state.slot, test_state.slot):
-        assert get_block_root(test_state, slot) == block.previous_block_root
+        assert get_block_root_at_slot(test_state, slot) == block.previous_block_root
 
     return state, [block], test_state
 
@@ -124,7 +121,7 @@ def test_empty_epoch_transition(state):
 
     assert test_state.slot == block.slot
     for slot in range(state.slot, test_state.slot):
-        assert get_block_root(test_state, slot) == block.previous_block_root
+        assert get_block_root_at_slot(test_state, slot) == block.previous_block_root
 
     return state, [block], test_state
 
@@ -303,6 +300,7 @@ def test_deposit_top_up(state):
 
 
 def test_attestation(state):
+    state.slot = spec.SLOTS_PER_EPOCH
     test_state = deepcopy(state)
     attestation = get_valid_attestation(state)
 
@@ -316,8 +314,6 @@ def test_attestation(state):
 
     assert len(test_state.current_epoch_attestations) == len(state.current_epoch_attestations) + 1
 
-    proposer_index = get_beacon_proposer_index(test_state)
-    assert test_state.balances[proposer_index] > state.balances[proposer_index]
 
     #
     # Epoch transition should move to previous_epoch_attestations
@@ -441,7 +437,7 @@ def test_balance_driven_status_transitions(state):
     assert pre_state.validator_registry[validator_index].exit_epoch == spec.FAR_FUTURE_EPOCH
 
     # set validator balance to below ejection threshold
-    set_balance(pre_state, validator_index, spec.EJECTION_BALANCE - 1)
+    pre_state.validator_registry[validator_index].effective_balance = spec.EJECTION_BALANCE
 
     post_state = deepcopy(pre_state)
     #

tests/phase0/helpers.py

@@ -16,6 +16,7 @@
     VoluntaryExit,
     # functions
     get_block_root,
+    get_block_root_at_slot,
     get_current_epoch,
     get_domain,
     get_empty_block,
@@ -141,7 +142,7 @@ def build_attestation_data(state, slot, shard):
     if epoch_start_slot == slot:
         epoch_boundary_root = block_root
     else:
-        get_block_root(state, epoch_start_slot)
+        epoch_boundary_root = get_block_root(state, get_current_epoch(state))
 
     if slot < epoch_start_slot:
         justified_block_root = state.previous_justified_root