London mocked backend logic and some more refactoring

Author: fselmo

eth_tester/backends/mock/factory.py

@@ -28,6 +28,8 @@
 ZERO_32BYTES = b'\x00' * 32
 ZERO_8BYTES = b'\x00' * 8
 ZERO_ADDRESS = b'\x00' * 20
+BLOCK_ELASTICITY_MULTIPLIER = 2
+BASE_FEE_MAX_CHANGE_DENOMINATOR = 8
 
 
 @apply_to_return_value(b'|'.join)
@@ -89,66 +91,53 @@ def _fill_transaction(transaction, block, transaction_index, is_pending, overrid
     if overrides is None:
         overrides = {}
 
-    if 'nonce' in overrides:
-        yield 'nonce', overrides['nonce']
-    else:
-        yield 'nonce', 0
+    is_dynamic_fee_transaction = (
+        'gas_price' not in transaction and any(
+            _ in transaction for _ in ('max_fee_per_gas', 'max_priority_fee_per_gas')
+        )
+    )
 
     if 'hash' in overrides:
         yield 'hash', overrides['hash']
     else:
         # calculate hash after all fields are filled
         pass
 
-    if 'from' in overrides:
-        yield 'from', overrides['from']
-    else:
-        yield 'from', transaction['from']
+    # this pattern isn't the nicest to read but it keeps things clean. Here, we yield the overrides
+    # value if it exists, else either the transaction value if that exists, or a default value
+    yield 'nonce', overrides.get('nonce', 0)
+    yield 'from', overrides.get('from', transaction.get('from'))
+    yield 'to', overrides.get('to', transaction.get('to', b''))
+    yield 'data', overrides.get('data', transaction.get('data', b''))
+    yield 'value', overrides.get('value', transaction.get('value', 0))
+    yield 'nonce', overrides.get('nonce', transaction.get('nonce', 0))
+    yield 'gas', overrides.get('gas', transaction.get('gas'))
 
-    if 'gas' in overrides:
-        yield 'gas', overrides['gas']
+    if 'gas_price' in transaction or 'gas_price' in overrides:
+        # gas price is 1 gwei in order to be at least the base fee at the (London) genesis block
+        yield 'gas_price', overrides.get('gas_price', transaction.get('gas_price', 1000000000))
     else:
-        yield 'gas', transaction['gas']
+        # if no gas_price specified, default to dynamic fee txn parameters
+        is_dynamic_fee_transaction = True
 
-    if 'gas_price' in overrides:
-        yield 'gas_price', overrides['gas_price']
-    else:
-        yield 'gas_price', transaction.get('gas_price', 1)  # TODO: make configurable
+    if is_dynamic_fee_transaction:
+        yield 'max_fee_per_gas', overrides.get(
+            'max_fee_per_gas', transaction.get('max_fee_per_gas', 1000000000)
+        )
+        yield 'max_priority_fee_per_gas', overrides.get(
+            'max_priority_fee_per_gas', transaction.get('max_priority_fee_per_gas', 1000000000)
+        )
 
-    if 'to' in overrides:
-        yield 'to', overrides['to']
+    if is_dynamic_fee_transaction or 'access_list' in transaction:
+        # if is typed transaction (dynamic fee or access list transaction)
+        yield 'chain_id', overrides.get('chain_id', transaction.get('chain_id', 131277322940537))
+        yield 'access_list', overrides.get('access_list', transaction.get('access_list', []))
+        yield 'y_parity', overrides.get('y_parity', transaction.get('y_parity', 0))
     else:
-        yield 'to', transaction.get('to', b'')
+        yield 'v', overrides.get('v', transaction.get('v', 27))
 
-    if 'data' in overrides:
-        yield 'data', overrides['data']
-    else:
-        yield 'data', transaction.get('data', b'')
-
-    if 'value' in overrides:
-        yield 'value', overrides['value']
-    else:
-        yield 'value', transaction.get('value', 0)
-
-    if 'nonce' in overrides:
-        yield 'nonce', overrides['nonce']
-    else:
-        yield 'nonce', transaction.get('nonce', 0)
-
-    if 'v' in overrides:
-        yield 'v', overrides['v']
-    else:
-        yield 'v', transaction.get('v', 27)
-
-    if 'r' in overrides:
-        yield 'r', overrides['r']
-    else:
-        yield 'r', transaction.get('r', 12345)
-
-    if 's' in overrides:
-        yield 's', overrides['s']
-    else:
-        yield 's', transaction.get('s', 67890)
+    yield 'r', overrides.get('r', transaction.get('r', 12345))
+    yield 's', overrides.get('s', transaction.get('s', 67890))
 
 
 @to_dict
@@ -200,7 +189,7 @@ def make_log(transaction, block, transaction_index, log_index, overrides=None):
 
 
 @to_dict
-def make_receipt(transaction, block, transaction_index, overrides=None):
+def make_receipt(transaction, block, _transaction_index, overrides=None):
     if overrides is None:
         overrides = {}
 
@@ -253,12 +242,12 @@ def make_genesis_block(overrides=None):
         "total_difficulty": 131072,
         "size": 0,
         "extra_data": ZERO_32BYTES,
-        "gas_limit": 3141592,
+        "gas_limit": 30029122,  # gas limit at London fork block 12965000 on mainnet
         "gas_used": 0,
         "timestamp": int(time.time()),
         "transactions": [],
         "uncles": [],
-        "base_fee_per_gas": 1000000000,
+        "base_fee_per_gas": 1000000000,  # base fee at London fork block 12965000 on mainnet
     }
     if overrides is not None:
         genesis_block = merge_genesis_overrides(defaults=default_genesis_block,
@@ -369,3 +358,38 @@ def make_block_from_parent(parent_block, overrides=None):
         yield 'uncles', overrides['uncles']
     else:
         yield 'uncles', []
+
+    if 'base_fee_per_gas' in overrides:
+        yield 'base_fee_per_gas', overrides['base_fee_per_gas']
+    else:
+        yield 'base_fee_per_gas', _calculate_expected_base_fee_per_gas(parent_block)
+
+
+def _calculate_expected_base_fee_per_gas(parent_block) -> int:
+    """py-evm logic for calculating the base fee from parent header"""
+    parent_base_fee_per_gas = parent_block['base_fee_per_gas']
+
+    parent_gas_target = parent_block['gas_limit'] // BLOCK_ELASTICITY_MULTIPLIER
+    parent_gas_used = parent_block['gas_used']
+
+    if parent_gas_used == parent_gas_target:
+        return parent_base_fee_per_gas
+
+    elif parent_gas_used > parent_gas_target:
+        gas_used_delta = parent_gas_used - parent_gas_target
+        overburnt_wei = parent_base_fee_per_gas * gas_used_delta
+        base_fee_per_gas_delta = max(
+            overburnt_wei // parent_gas_target // BASE_FEE_MAX_CHANGE_DENOMINATOR,
+            1,
+        )
+        return parent_base_fee_per_gas + base_fee_per_gas_delta
+
+    else:
+        gas_used_delta = parent_gas_target - parent_gas_used
+        underburnt_wei = parent_base_fee_per_gas * gas_used_delta
+        base_fee_per_gas_delta = (
+            underburnt_wei
+            // parent_gas_target
+            // BASE_FEE_MAX_CHANGE_DENOMINATOR
+        )
+        return max(parent_base_fee_per_gas - base_fee_per_gas_delta, 0)

eth_tester/backends/pyevm/main.py

@@ -119,7 +119,7 @@ def generate_genesis_state_for_keys(account_keys, overrides=None):
 
 
 def get_default_genesis_params(overrides=None):
-    # commented out params became un-configurable in London
+    # commented out params became un-configurable in py-evm during London refactor
     default_genesis_params = {
         # "bloom": 0,
         "coinbase": GENESIS_COINBASE,
@@ -193,7 +193,7 @@ def get_transaction_builder(self):
     base_db = get_db_backend()
 
     chain = MainnetTesterNoProofChain.from_genesis(base_db, genesis_params, genesis_state)
-    chain.chain_id = 1337  # typed transactions need a chain_id
+    chain.chain_id = 131277322940537  # typed transactions need a chain_id
     return account_keys, chain
 
 
@@ -438,7 +438,7 @@ def get_base_fee(self, block_number='latest'):
     #
     @to_dict
     def _normalize_transaction(self, transaction, block_number='latest'):
-        is_typed_transaction = False
+        is_dynamic_fee_transaction = False
         for key in transaction:
             if key == 'from':
                 continue
@@ -448,7 +448,7 @@ def _normalize_transaction(self, transaction, block_number='latest'):
         if 'data' not in transaction:
             yield 'data', b''
         if 'gas_price' not in transaction:
-            is_typed_transaction = True
+            is_dynamic_fee_transaction = True
             if not any(_ in transaction for _ in ('max_fee_per_gas', 'max_priority_fee_per_gas')):
                 yield 'max_fee_per_gas', 1 * 10**9
                 yield 'max_priority_fee_per_gas', 1 * 10**9
@@ -459,10 +459,10 @@ def _normalize_transaction(self, transaction, block_number='latest'):
             yield 'value', 0
         if 'to' not in transaction:
             yield 'to', b''
-        if is_typed_transaction:
+        if is_dynamic_fee_transaction or 'access_list' in transaction:
             if 'access_list' not in transaction:
                 yield 'access_list', []
-            if not transaction.get('chain_id'):
+            if 'chain_id' not in transaction:
                 yield 'chain_id', self.chain.chain_id
 
     def _get_normalized_and_unsigned_evm_transaction(self, transaction, block_number='latest'):

eth_tester/utils/backend_testing.py

@@ -105,7 +105,6 @@
 
 def _validate_serialized_block(block):
     missing_keys = BLOCK_KEYS.difference(block.keys())
-    missing_keys = dissoc(missing_keys, 'base_fee_per_gas')
     if missing_keys:
         error_message = "Serialized block is missing the following keys: {}".format(
             "|".join(sorted(missing_keys)),
@@ -124,13 +123,22 @@ def _send_and_check_transaction(self, eth_tester, test_transaction, _from):
         txn = eth_tester.get_transaction_by_hash(txn_hash)
         self._check_transactions(transaction, txn)
 
-    def _check_transactions(self, expected_transaction, actual_transaction):
+    @staticmethod
+    def _check_transactions(expected_transaction, actual_transaction):
         assert is_same_address(actual_transaction['from'], expected_transaction['from'])
         if 'to' not in expected_transaction or expected_transaction['to'] == '':
             assert actual_transaction['to'] == ''
         else:
             assert is_same_address(actual_transaction['to'], expected_transaction['to'])
-        # assert actual_transaction['gas_price'] == expected_transaction['gas_price']
+
+        if expected_transaction.get('gas_price'):
+            assert actual_transaction['gas_price'] == expected_transaction['gas_price']
+        else:
+            assert actual_transaction['max_fee_per_gas'] == expected_transaction['max_fee_per_gas']
+            assert (
+                actual_transaction['max_priority_fee_per_gas'] ==
+                expected_transaction['max_priority_fee_per_gas']
+            )
         assert actual_transaction['gas'] == expected_transaction['gas']
         assert actual_transaction['value'] == expected_transaction['value']
 
@@ -330,7 +338,7 @@ def test_send_access_list_transaction(self, eth_tester):
         assert accounts, "No accounts available for transaction sending"
 
         access_list_transaction = {
-            'chain_id': 123456789,
+            'chain_id': 131277322940537,
             'from': accounts[0],
             'to': accounts[0],
             'value': 1,
@@ -361,7 +369,7 @@ def test_send_dynamic_fee_transaction(self, eth_tester):
         assert accounts, "No accounts available for transaction sending"
 
         dynamic_fee_transaction = {
-            'chain_id': 123456789,
+            'chain_id': 131277322940537,
             'from': accounts[0],
             'to': accounts[0],
             'value': 1,
@@ -596,6 +604,7 @@ def test_get_block_by_hash(self, eth_tester):
             block = eth_tester.get_block_by_hash(block_hash)
             assert block['number'] == block_number
             assert block['hash'] == block_hash
+            assert block['base_fee_per_gas'] is not None
 
     def test_get_block_by_hash_full_transactions(self, eth_tester):
         eth_tester.mine_blocks(2)

eth_tester/validation/outbound.py

@@ -87,6 +87,12 @@ def validate_signature_v(value):
         raise ValidationError("The `v` portion of the signature must be 0, 1, 27, 28 or >= 35")
 
 
+def validate_y_parity(value):
+    validate_positive_integer(value)
+    if value not in (0, 1):
+        raise ValidationError('y_parity must be either 0 or 1')
+
+
 def _validate_outbound_access_list(access_list):
     if not is_list_like(access_list):
         raise ValidationError('access_list is not list-like.')
@@ -128,7 +134,7 @@ def _validate_outbound_access_list(access_list):
     dissoc(LEGACY_TRANSACTION_VALIDATORS, 'v'),  # y_parity in place of v for typed transactions
     {
         "chain_id": validate_uint256,
-        "y_parity": validate_signature_v,
+        "y_parity": validate_y_parity,
         "access_list": if_not_null(_validate_outbound_access_list),
     }
 )
@@ -175,7 +181,7 @@ def _validate_outbound_access_list(access_list):
 
 BLOCK_VALIDATORS = {
     "number": validate_positive_integer,
-    'base_fee_per_gas': if_not_null(validate_positive_integer),
+    'base_fee_per_gas': validate_positive_integer,
     "hash": validate_block_hash,
     "parent_hash": validate_block_hash,
     "nonce": validate_nonce,

tests/core/validation/test_inbound_validation.py

@@ -1,7 +1,5 @@
 from __future__ import unicode_literals
 
-import time
-
 import pytest
 
 try:
@@ -65,7 +63,7 @@ def test_time_travel_input_timestamp_validation(validator, timestamp, is_valid):
         (b"earliest", False),
     ),
 )
-def test_block_number_intput_validation(validator, block_number, is_valid):
+def test_block_number_input_validation(validator, block_number, is_valid):
     if is_valid:
         validator.validate_inbound_block_number(block_number)
     else: