Cleanup

scripts/build_spec.py

@@ -12,7 +12,7 @@ from typing import (
 
 
 PHASE0_IMPORTS = '''from typing import (
-    Any, Callable, Dict, Set, Sequence, Tuple,
+    Any, Dict, Set, Sequence, Tuple,
 )
 
 from dataclasses import (
@@ -37,7 +37,7 @@ from eth2spec.utils.bls import (
 from eth2spec.utils.hash_function import hash
 '''
 PHASE1_IMPORTS = '''from typing import (
-    Any, Callable, Dict, Optional, Set, Sequence, MutableSequence, Tuple,
+    Any, Dict, Optional, Set, Sequence, MutableSequence, Tuple,
 )
 
 from dataclasses import (

specs/core/0_beacon-chain.md

@@ -147,7 +147,7 @@ We define the following Python custom types for type hinting and readability:
 | `ValidatorIndex` | `uint64` | a validator registry index |
 | `Gwei` | `uint64` | an amount in Gwei |
 | `Version` | `Bytes4` | a fork version number |
-| `Hash` | `Bytes32` | a hashed result |
+| `Hash` | `Bytes32` | a hash |
 | `BLSPubkey` | `Bytes48` | a BLS12-381 public key |
 | `BLSSignature` | `Bytes96` | a BLS12-381 signature |
 
@@ -158,7 +158,6 @@ The following values are (non-configurable) constants used throughout the specif
 | Name | Value |
 | - | - |
 | `FAR_FUTURE_EPOCH` | `Epoch(2**64 - 1)` |
-| `ZERO_HASH` | `Hash(b'\x00' * 32)` |
 | `BASE_REWARDS_PER_EPOCH` | `5` |
 | `DEPOSIT_CONTRACT_TREE_DEPTH` | `2**5` (= 32) |
 | `SECONDS_PER_DAY` | `86400` |
@@ -542,11 +541,10 @@ class BeaconState(Container):
 #### `integer_squareroot`
 
 ```python
-def integer_squareroot(n: int) -> int:
+def integer_squareroot(n: uint64) -> uint64:
     """
     Return the largest integer ``x`` such that ``x**2 <= n``.
     """
-    assert n >= 0
     x = n
     y = (x + 1) // 2
     while y < x:
@@ -1204,7 +1202,7 @@ def process_slot(state: BeaconState) -> None:
     previous_state_root = hash_tree_root(state)
     state.state_roots[state.slot % SLOTS_PER_HISTORICAL_ROOT] = previous_state_root
     # Cache latest block header state root
-    if state.latest_block_header.state_root == ZERO_HASH:
+    if state.latest_block_header.state_root == Hash():
         state.latest_block_header.state_root = previous_state_root
     # Cache block root
     previous_block_root = signing_root(state.latest_block_header)
@@ -1527,7 +1525,7 @@ def process_block_header(state: BeaconState, block: BeaconBlock) -> None:
     state.latest_block_header = BeaconBlockHeader(
         slot=block.slot,
         parent_root=block.parent_root,
-        state_root=ZERO_HASH,  # Overwritten in the next `process_slot` call
+        state_root=Hash(),  # Overwritten in the next `process_slot` call
         body_root=hash_tree_root(block.body),
     )
     # Verify proposer is not slashed
@@ -1568,15 +1566,14 @@ def process_operations(state: BeaconState, body: BeaconBlockBody) -> None:
     # Verify that there are no duplicate transfers
     assert len(body.transfers) == len(set(body.transfers))
 
-    all_operations = (
+    for operations, function in (
         (body.proposer_slashings, process_proposer_slashing),
         (body.attester_slashings, process_attester_slashing),
         (body.attestations, process_attestation),
         (body.deposits, process_deposit),
         (body.voluntary_exits, process_voluntary_exit),
         (body.transfers, process_transfer),
-    )  # type: Sequence[Tuple[List, Callable]]
-    for operations, function in all_operations:
+    ):
         for operation in operations:
             function(state, operation)
 ```
@@ -1651,7 +1648,7 @@ def process_attestation(state: BeaconState, attestation: Attestation) -> None:
     assert data.crosslink.parent_root == hash_tree_root(parent_crosslink)
     assert data.crosslink.start_epoch == parent_crosslink.end_epoch
     assert data.crosslink.end_epoch == min(data.target.epoch, parent_crosslink.end_epoch + MAX_EPOCHS_PER_CROSSLINK)
-    assert data.crosslink.data_root == ZERO_HASH  # [to be removed in phase 1]
+    assert data.crosslink.data_root == Hash()  # [to be removed in phase 1]
 
     # Check signature
     validate_indexed_attestation(state, get_indexed_attestation(state, attestation))

specs/core/1_custody-game.md

@@ -595,7 +595,7 @@ def process_chunk_challenge_response(state: BeaconState,
     # Verify chunk index
     assert response.chunk_index == challenge.chunk_index
     # Verify bit challenge data is null
-    assert response.chunk_bits_branch == [] and response.chunk_bits_leaf == ZERO_HASH
+    assert response.chunk_bits_branch == [] and response.chunk_bits_leaf == Hash()
     # Verify minimum delay
     assert get_current_epoch(state) >= challenge.inclusion_epoch + ACTIVATION_EXIT_DELAY
     # Verify the chunk matches the crosslink data root

specs/core/1_shard-data-chains.md

@@ -309,11 +309,11 @@ def is_valid_shard_block(beacon_blocks: Sequence[BeaconBlock],
     assert beacon_block.slot <= candidate.slot
 
     # Check state root
-    assert candidate.state_root == ZERO_HASH  # [to be removed in phase 2]
+    assert candidate.state_root == Hash()  # [to be removed in phase 2]
 
     # Check parent block
     if candidate.slot == PHASE_1_FORK_SLOT:
-        assert candidate.parent_root == ZERO_HASH
+        assert candidate.parent_root == Hash()
     else:
         parent_block = next(
             (block for block in valid_shard_blocks if signing_root(block) == candidate.parent_root),
@@ -395,7 +395,7 @@ def is_valid_beacon_attestation(shard: Shard,
 
     # Check previous attestation
     if candidate.data.previous_crosslink.epoch <= PHASE_1_FORK_EPOCH:
-        assert candidate.data.previous_crosslink.data_root == ZERO_HASH
+        assert candidate.data.previous_crosslink.data_root == Hash()
     else:
         previous_attestation = next(
             (attestation for attestation in valid_attestations if

test_libs/pyspec/eth2spec/test/helpers/attestations.py

@@ -43,7 +43,7 @@ def build_attestation_data(spec, state, slot, shard):
             shard=shard,
             start_epoch=parent_crosslink.end_epoch,
             end_epoch=min(spec.slot_to_epoch(slot), parent_crosslink.end_epoch + spec.MAX_EPOCHS_PER_CROSSLINK),
-            data_root=spec.ZERO_HASH,
+            data_root=spec.Hash(),
             parent_root=hash_tree_root(parent_crosslink),
         ),
     )

test_libs/pyspec/eth2spec/test/helpers/block.py

@@ -59,7 +59,7 @@ def build_empty_block(spec, state, slot=None, signed=False):
     empty_block.slot = slot
     empty_block.body.eth1_data.deposit_count = state.eth1_deposit_index
     previous_block_header = deepcopy(state.latest_block_header)
-    if previous_block_header.state_root == spec.ZERO_HASH:
+    if previous_block_header.state_root == spec.Hash():
         previous_block_header.state_root = state.hash_tree_root()
     empty_block.parent_root = signing_root(previous_block_header)
 

test_libs/pyspec/eth2spec/test/helpers/genesis.py

@@ -27,7 +27,7 @@ def create_genesis_state(spec, num_validators):
         eth1_data=spec.Eth1Data(
             deposit_root=deposit_root,
             deposit_count=num_validators,
-            block_hash=spec.ZERO_HASH,
+            block_hash=spec.Hash(),
         ),
         latest_block_header=spec.BeaconBlockHeader(body_root=spec.hash_tree_root(spec.BeaconBlockBody())),
     )

test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_deposit.py

@@ -195,7 +195,7 @@ def test_bad_merkle_proof(spec, state):
     deposit = prepare_state_and_deposit(spec, state, validator_index, amount)
 
     # mess up merkle branch
-    deposit.proof[5] = spec.ZERO_HASH
+    deposit.proof[5] = spec.Hash()
 
     sign_deposit_data(spec, deposit.data, privkeys[validator_index], state=state)
 

test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_transfer.py

@@ -360,7 +360,7 @@ def test_non_existent_recipient(spec, state):
 @spec_state_test
 def test_invalid_pubkey(spec, state):
     transfer = get_valid_transfer(spec, state, signed=True)
-    state.validators[transfer.sender].withdrawal_credentials = spec.ZERO_HASH
+    state.validators[transfer.sender].withdrawal_credentials = spec.Hash()
 
     # un-activate so validator can transfer
     state.validators[transfer.sender].activation_eligibility_epoch = spec.FAR_FUTURE_EPOCH

test_libs/pyspec/eth2spec/test/sanity/test_blocks.py

@@ -63,7 +63,7 @@ def test_empty_block_transition(spec, state):
 
     assert len(state.eth1_data_votes) == pre_eth1_votes + 1
     assert spec.get_block_root_at_slot(state, pre_slot) == block.parent_root
-    assert spec.get_randao_mix(state, spec.get_current_epoch(state)) != spec.ZERO_HASH
+    assert spec.get_randao_mix(state, spec.get_current_epoch(state)) != spec.Hash()
 
 
 @with_all_phases
@@ -98,7 +98,7 @@ def test_skipped_slots(spec, state):
     yield 'post', state
 
     assert state.slot == block.slot
-    assert spec.get_randao_mix(state, spec.get_current_epoch(state)) != spec.ZERO_HASH
+    assert spec.get_randao_mix(state, spec.get_current_epoch(state)) != spec.Hash()
     for slot in range(pre_slot, state.slot):
         assert spec.get_block_root_at_slot(state, slot) == block.parent_root