First steps for EIP-1559 support

- add initial EIP-1559 transaction validation
- add initial EIP-1559 transaction execution
- rename gas_target to gas_limit
- add london VM in existing tests
- update block according to latest EIP updates

Author: ftruzzi

eth/abc.py

@@ -74,6 +74,7 @@ class MiningHeaderAPI(ABC):
     gas_used: int
     timestamp: int
     extra_data: bytes
+    base_fee_per_gas: int  # EIP-1559
 
     @property
     @abstractmethod
@@ -326,14 +327,17 @@ class TransactionFieldsAPI(ABC):
     """
     A class to define all common transaction fields.
     """
+    max_fee_per_gas: int
+    max_priority_fee_per_gas: int
+
     @property
     @abstractmethod
     def nonce(self) -> int:
         ...
 
     @property
     @abstractmethod
-    def gas_price(self) -> int:
+    def gas_price(self) -> Optional[int]:
         ...
 
     @property
@@ -1684,6 +1688,14 @@ def chain_id(self) -> int:
         """
         ...
 
+    @property
+    @abstractmethod
+    def base_gas_fee(self) -> Optional[int]:
+        """
+        Return the base gas fee of the block
+        """
+        ...
+
 
 class ComputationAPI(ContextManager['ComputationAPI'], StackManipulationAPI):
     """
@@ -2865,9 +2877,8 @@ def get_computation(self,
     #
     # Transaction context
     #
-    @classmethod
     @abstractmethod
-    def get_transaction_context_class(cls) -> Type[TransactionContextAPI]:
+    def get_transaction_context_class(self) -> Type[TransactionContextAPI]:
         """
         Return the :class:`~eth.vm.transaction_context.BaseTransactionContext` class that the
         state class uses.
@@ -2917,9 +2928,8 @@ def validate_transaction(self, transaction: SignedTransactionAPI) -> None:
         """
         ...
 
-    @classmethod
     @abstractmethod
-    def get_transaction_context(cls,
+    def get_transaction_context(self,
                                 transaction: SignedTransactionAPI) -> TransactionContextAPI:
         """
         Return the :class:`~eth.abc.TransactionContextAPI` for the given ``transaction``

eth/chains/mainnet/__init__.py

@@ -12,6 +12,7 @@
 
 from .constants import (
     MAINNET_CHAIN_ID,
+    LONDON_MAINNET_BLOCK,
     BERLIN_MAINNET_BLOCK,
     BYZANTIUM_MAINNET_BLOCK,
     PETERSBURG_MAINNET_BLOCK,
@@ -39,6 +40,7 @@
     FrontierVM,
     HomesteadVM,
     IstanbulVM,
+    LondonVM,
     MuirGlacierVM,
     PetersburgVM,
     SpuriousDragonVM,
@@ -97,6 +99,7 @@ class MainnetHomesteadVM(MainnetDAOValidatorVM):
     ISTANBUL_MAINNET_BLOCK,
     MUIR_GLACIER_MAINNET_BLOCK,
     BERLIN_MAINNET_BLOCK,
+    LONDON_MAINNET_BLOCK,
 )
 MAINNET_VMS = (
     FrontierVM,
@@ -108,6 +111,7 @@ class MainnetHomesteadVM(MainnetDAOValidatorVM):
     IstanbulVM,
     MuirGlacierVM,
     BerlinVM,
+    LondonVM,
 )
 
 MAINNET_VM_CONFIGURATION = tuple(zip(MAINNET_FORK_BLOCKS, MAINNET_VMS))

eth/chains/mainnet/constants.py

@@ -57,3 +57,9 @@
 # Berlin Block
 #
 BERLIN_MAINNET_BLOCK = BlockNumber(12244000)
+
+
+#
+# London Block
+#
+LONDON_MAINNET_BLOCK = BlockNumber(12244001)  # TODO change to actual when known

eth/db/header.py

@@ -56,7 +56,13 @@
     validate_block_number,
     validate_word,
 )
+from eth.vm.forks.london.blocks import (
+    LondonBlockHeader
+)
 
+from rlp.exceptions import (
+    ObjectDeserializationError
+)
 
 class HeaderDB(HeaderDatabaseAPI):
     def __init__(self, db: AtomicDatabaseAPI) -> None:
@@ -619,4 +625,8 @@ def _add_block_number_to_hash_lookup(db: DatabaseAPI, header: BlockHeaderAPI) ->
 # be looking up recent blocks.
 @functools.lru_cache(128)
 def _decode_block_header(header_rlp: bytes) -> BlockHeaderAPI:
-    return rlp.decode(header_rlp, sedes=BlockHeader)
+    try:
+        return rlp.decode(header_rlp, sedes=BlockHeader)
+    except ObjectDeserializationError:
+        # could be a new >=London block header
+        return rlp.decode(header_rlp, sedes=LondonBlockHeader)

eth/rlp/headers.py

@@ -1,6 +1,7 @@
 import time
 from typing import (
     Dict,
+    Optional,
     overload,
 )
 
@@ -202,3 +203,7 @@ def is_genesis(self) -> bool:
         # validate_header stops trying to check the current header against a parent header.
         # Can someone trick us into following a high difficulty header with genesis parent hash?
         return self.parent_hash == GENESIS_PARENT_HASH and self.block_number == 0
+
+    @property
+    def base_fee_per_gas(self) -> Optional[int]:
+        return 0

eth/tools/builder/chain/__init__.py

@@ -27,6 +27,7 @@
     istanbul_at,
     muir_glacier_at,
     berlin_at,
+    london_at,
     latest_mainnet_at,
 )
 

eth/tools/builder/chain/builders.py

@@ -73,6 +73,7 @@
     IstanbulVM,
     MuirGlacierVM,
     BerlinVM,
+    LondonVM,
 )
 
 
@@ -237,6 +238,7 @@ def dao_fork_at(dao_fork_block_number: BlockNumber,
 istanbul_at = fork_at(IstanbulVM)
 muir_glacier_at = fork_at(MuirGlacierVM)
 berlin_at = fork_at(BerlinVM)
+london_at = fork_at(LondonVM)
 
 latest_mainnet_at = muir_glacier_at
 

eth/validation.py

@@ -166,7 +166,7 @@ def validate_uint256(value: int, title: str = "Value") -> None:
         )
     if value > UINT_256_MAX:
         raise ValidationError(
-            f"{title} exeeds maximum UINT256 size.  Got: {value}"
+            f"{title} exceeds maximum UINT256 size.  Got: {value}"
         )
 
 

eth/vm/base.py

@@ -184,6 +184,7 @@ def create_execution_context(cls,
             gas_limit=header.gas_limit,
             prev_hashes=prev_hashes,
             chain_id=chain_context.chain_id,
+            base_gas_fee=header.base_fee_per_gas,
         )
 
     def execute_bytecode(self,
@@ -590,6 +591,7 @@ def validate_header(cls,
             validate_length_lte(
                 header.extra_data, cls.extra_data_max_bytes, title="BlockHeader.extra_data")
 
+            # TODO skip for EIP-1559, or override this whole function?
             validate_gas_limit(header.gas_limit, parent_header.gas_limit)
 
             if header.block_number != parent_header.block_number + 1:

eth/vm/execution_context.py

@@ -1,5 +1,6 @@
 from typing import (
     Iterable,
+    Optional,
 )
 
 from eth_typing import (
@@ -21,6 +22,7 @@ class ExecutionContext(ExecutionContextAPI):
     _gas_limit = None
     _prev_hashes = None
     _chain_id = None
+    _base_gas_fee = 0  # TODO check if valid
 
     def __init__(
             self,
@@ -30,14 +32,17 @@ def __init__(
             difficulty: int,
             gas_limit: int,
             prev_hashes: Iterable[Hash32],
-            chain_id: int) -> None:
+            chain_id: int,
+            base_gas_fee: Optional[int]) -> None:
         self._coinbase = coinbase
         self._timestamp = timestamp
         self._block_number = block_number
         self._difficulty = difficulty
         self._gas_limit = gas_limit
         self._prev_hashes = CachedIterable(prev_hashes)
         self._chain_id = chain_id
+        if base_gas_fee is not None:
+            self._base_gas_fee = base_gas_fee
 
     @property
     def coinbase(self) -> Address:
@@ -66,3 +71,7 @@ def prev_hashes(self) -> Iterable[Hash32]:
     @property
     def chain_id(self) -> int:
         return self._chain_id
+
+    @property
+    def base_gas_fee(self) -> Optional[int]:
+        return self._base_gas_fee