Changes from comments on PR ethereum#285:

- Refactor block evm guessing logic into utility methods
- Use constants for transaction types for clarity
- Keep integer for transaction type internally, normalize to hex
  (as clients do) on the way out.

eth_tester/backends/mock/serializers.py

@@ -10,6 +10,9 @@
 from eth_tester.backends.mock.common import (
     calculate_effective_gas_price,
 )
+from eth_tester.constants import (
+    LEGACY_TX_TYPE,
+)
 from eth_tester.utils.transactions import (
     extract_transaction_type,
 )
@@ -52,7 +55,10 @@ def serialize_full_transaction(transaction, block, transaction_index, is_pending
         partial(assoc, key="type", value=extract_transaction_type(transaction)),
     )
 
-    if int(serialized_transaction["type"], 16) > 0:
+    if int(serialized_transaction["type"], 16) > LEGACY_TX_TYPE:
+        # if the transaction is not a legacy (type=0) transaction, `y_parity` is
+        # the correct signature field but clients commonly return both `v` and
+        # `y_parity`.
         serialized_transaction = assoc(
             serialized_transaction,
             "y_parity",

eth_tester/backends/pyevm/main.py

@@ -56,6 +56,7 @@
     merge_genesis_overrides,
 )
 from eth_tester.constants import (
+    BLOB_TX_TYPE,
     DYNAMIC_FEE_TRANSACTION_PARAMS,
 )
 from eth_tester.exceptions import (
@@ -91,6 +92,7 @@
         Revert as EVMRevert,
     )
     from eth.vm.forks import (
+        LATEST_VM,
         CancunVM,
         ParisVM,
         ShanghaiVM,
@@ -240,7 +242,7 @@ def setup_tester_chain(
     )
 
     if vm_configuration is None:
-        vm_config = ((0, CancunVM),)
+        vm_config = ((0, LATEST_VM),)
     else:
         if len(vm_configuration) > 0:
             _genesis_block_num, genesis_vm = vm_configuration[0]
@@ -751,8 +753,9 @@ def _create_type_aware_unsigned_transaction(self, normalized_txn):
     def send_raw_transaction(self, raw_transaction):
         vm = _get_vm_for_block_number(self.chain, "latest")
 
-        if raw_transaction[0] == 3:
-            # Blob transactions are handled differently
+        # first byte of rlp-encoded raw transaction indicates the transaction type
+        if raw_transaction[0] == BLOB_TX_TYPE:
+            # Blob transactions (type=3) are handled differently
             blob_transaction = BlobTransaction.from_bytes(HexBytes(raw_transaction))
 
             # Blob data is handled in consensus layer, not sent to execution layer.

eth_tester/backends/pyevm/serializers.py

@@ -7,6 +7,9 @@
 )
 
 from .utils import (
+    is_cancun_block,
+    is_london_block,
+    is_shanghai_block,
     is_supported_pyevm_version_available,
 )
 
@@ -22,7 +25,11 @@
     TypedTransaction = None
 
 from eth_tester.constants import (
+    ACCESS_LIST_TX_TYPE,
+    BLOB_TX_TYPE,
+    DYNAMIC_FEE_TX_TYPE,
     GAS_PER_BLOB,
+    LEGACY_TX_TYPE,
 )
 from eth_tester.exceptions import (
     ValidationError,
@@ -76,25 +83,18 @@ def serialize_block(block, full_transaction, is_pending):
         "uncles": [uncle.hash for uncle in block.uncles],
     }
 
-    if hasattr(block.header, "base_fee_per_gas"):
-        # london
+    # london
+    if is_london_block(block):
         base_fee = block.header.base_fee_per_gas
         block_info.update({"base_fee_per_gas": base_fee})
 
-    if hasattr(block.header, "withdrawals_root"):
-        # shanghai
+    # shanghai
+    if is_shanghai_block(block):
         block_info.update({"withdrawals": serialize_block_withdrawals(block)})
         block_info.update({"withdrawals_root": block.header.withdrawals_root})
 
-    if all(
-        hasattr(block.header, cancun_attr)
-        for cancun_attr in (
-            "blob_gas_used",
-            "excess_blob_gas",
-            "parent_beacon_block_root",
-        )
-    ):
-        # cancun
+    # cancun
+    if is_cancun_block(block):
         block_info.update(
             {"parent_beacon_block_root": block.header.parent_beacon_block_root}
         )
@@ -124,45 +124,54 @@ def serialize_transaction(block, transaction, transaction_index, is_pending):
         "gas": transaction.gas,
         "data": transaction.data,
     }
-    if int(txn_type, 16) in (0, 1):
-        type_specific_params = {"gas_price": transaction.gas_price}
 
-        if _field_in_transaction(transaction, "access_list"):
-            # access list transaction
-            type_specific_params = merge(
-                type_specific_params,
-                {
-                    "chain_id": transaction.chain_id,
-                    "access_list": transaction.access_list or (),
-                },
-            )
-    elif int(txn_type, 16) >= 2:
-        # dynamic fee transaction
+    type_specific_params = {}
+    if txn_type in (LEGACY_TX_TYPE, ACCESS_LIST_TX_TYPE):
         type_specific_params = {
-            "chain_id": transaction.chain_id,
-            "max_fee_per_gas": transaction.max_fee_per_gas,
-            "max_priority_fee_per_gas": transaction.max_priority_fee_per_gas,
-            "access_list": transaction.access_list or (),
-            # TODO: Sometime in 2022 the inclusion of gas_price may be removed from
-            #  dynamic fee transactions and we can get rid of this behavior.
-            #  https://github.com/ethereum/execution-specs/pull/251
-            "gas_price": (
-                transaction.max_fee_per_gas
-                if is_pending
-                else _calculate_effective_gas_price(transaction, block, txn_type)
-            ),
+            "gas_price": transaction.gas_price,
         }
-        if int(txn_type, 16) == 3:
-            # blob transaction
+
+    if txn_type > LEGACY_TX_TYPE:
+        # handle access list transaction type and above
+        type_specific_params = merge(
+            type_specific_params,
+            {
+                "chain_id": transaction.chain_id,
+                "access_list": transaction.access_list or (),
+            },
+        )
+
+        if txn_type >= DYNAMIC_FEE_TX_TYPE:
+            # handle dynamic fee transaction type and above
             type_specific_params = merge(
                 type_specific_params,
                 {
-                    "max_fee_per_blob_gas": transaction.max_fee_per_blob_gas,
-                    "blob_versioned_hashes": transaction.blob_versioned_hashes,
+                    "max_fee_per_gas": transaction.max_fee_per_gas,
+                    "max_priority_fee_per_gas": transaction.max_priority_fee_per_gas,
+                    # TODO: Sometime in 2022 the inclusion of gas_price may be removed
+                    #  from dynamic fee transactions and we can get rid of this
+                    #  behavior. https://github.com/ethereum/execution-specs/pull/251
+                    "gas_price": (
+                        transaction.max_fee_per_gas
+                        if is_pending
+                        else _calculate_effective_gas_price(
+                            transaction, block, txn_type
+                        )
+                    ),
                 },
             )
+            if txn_type == BLOB_TX_TYPE:
+                # handle blob transaction (txn_type=3)
+                type_specific_params = merge(
+                    type_specific_params,
+                    {
+                        "max_fee_per_blob_gas": transaction.max_fee_per_blob_gas,
+                        "blob_versioned_hashes": transaction.blob_versioned_hashes,
+                    },
+                )
     else:
-        raise ValidationError("Invariant: code path should be unreachable")
+        if txn_type != LEGACY_TX_TYPE:
+            raise ValidationError("Invariant: code path should be unreachable")
 
     # the signature fields are commonly the last fields in a node's JSON-RPC response
     signed_tx_params = {
@@ -174,7 +183,9 @@ def serialize_transaction(block, transaction, transaction_index, is_pending):
         "s": transaction.s,
         "r": transaction.r,
     }
-    if txn_type != "0x0":
+    if txn_type > LEGACY_TX_TYPE:
+        # If anything other than a legacy tx, `y_parity` is the correct signature field.
+        # Clients commonly return both `v` and `y_parity` for these transactions.
         signed_tx_params["y_parity"] = signed_tx_params["v"]
 
     return merge(common_transaction_params, type_specific_params, signed_tx_params)
@@ -240,7 +251,7 @@ def serialize_transaction_receipt(
         "type": _txn_type,
     }
 
-    if int(_txn_type, 16) == 3:
+    if _txn_type == BLOB_TX_TYPE:
         # blob transaction
         blob_gas_used = GAS_PER_BLOB * len(transaction.blob_versioned_hashes)
         receipt_fields["blob_gas_used"] = blob_gas_used
@@ -265,10 +276,10 @@ def serialize_log(block, transaction, transaction_index, log, log_index, is_pend
 
 def _extract_transaction_type(transaction):
     if isinstance(transaction, TypedTransaction):
-        return hex(transaction.type_id)
+        return transaction.type_id
 
-    # legacy transactions are now considered "0x0" type
-    return "0x0"
+    # legacy transactions are now considered type=0
+    return 0
 
 
 def _calculate_effective_gas_price(transaction, block, transaction_type):
@@ -277,7 +288,7 @@ def _calculate_effective_gas_price(transaction, block, transaction_type):
             transaction.max_fee_per_gas,
             transaction.max_priority_fee_per_gas + block.header.base_fee_per_gas,
         )
-        if int(transaction_type, 16) >= 2
+        if transaction_type >= 2
         else transaction.gas_price
     )
 

eth_tester/backends/pyevm/utils.py

@@ -2,6 +2,15 @@
     absolute_import,
 )
 
+from typing import (
+    Any,
+    Dict,
+    Union,
+)
+
+from eth.abc import (
+    BlockAPI,
+)
 import pkg_resources
 from semantic_version import (
     Version,
@@ -21,3 +30,57 @@ def get_pyevm_version():
 def is_supported_pyevm_version_available():
     version = get_pyevm_version()
     return version and version >= Version("0.5.0")
+
+
+# --- network utils --- #
+
+
+def is_london_block(block: Union[Dict[str, Any], BlockAPI]) -> bool:
+    if isinstance(block, BlockAPI):
+        try:
+            # it's not enough to check hasattr because the attribute could be
+            # defined in earlier VM's while raising an AttributeError until implemented
+            return block.header.base_fee_per_gas is not None
+        except AttributeError:
+            return False
+
+    elif isinstance(block, dict) and "base_fee_per_gas" in block:
+        return True
+
+    return False
+
+
+def is_shanghai_block(block: Union[Dict[str, Any], BlockAPI]) -> bool:
+    if isinstance(block, BlockAPI):
+        try:
+            # it's not enough to check hasattr because the attribute could be
+            # defined in earlier VM's while raising an AttributeError until implemented
+            return block.header.withdrawals_root is not None
+        except AttributeError:
+            return False
+    elif isinstance(block, dict) and "withdrawals_root" in block:
+        return True
+
+    return False
+
+
+def is_cancun_block(block: Union[Dict[str, Any], BlockAPI]) -> bool:
+    if isinstance(block, BlockAPI):
+        try:
+            # it's not enough to check hasattr because the attribute could be
+            # defined in earlier VM's while raising an AttributeError until implemented
+            return block.header.parent_beacon_block_root is not None
+        except AttributeError:
+            return False
+
+    elif isinstance(block, dict) and all(
+        cancun_field in block
+        for cancun_field in (
+            "parent_beacon_block_root",
+            "blob_gas_used",
+            "excess_blob_gas",
+        )
+    ):
+        return True
+
+    return False

eth_tester/constants.py

@@ -74,9 +74,16 @@
 )
 SECPK1_G = (SECPK1_Gx, SECPK1_Gy)
 
-#
-# EIP CONSTANTS
-#
+
+# -- KNOWN TRANSACTION TYPES -- #
+LEGACY_TX_TYPE = 0
+ACCESS_LIST_TX_TYPE = 1
+DYNAMIC_FEE_TX_TYPE = 2
+BLOB_TX_TYPE = 3
+
+
+# -- EIP CONSTANTS -- #
+
 # EIP-1559
 DYNAMIC_FEE_TRANSACTION_PARAMS = ("max_fee_per_gas", "max_priority_fee_per_gas")
 

eth_tester/normalization/outbound.py

@@ -20,6 +20,9 @@
     assoc,
     dissoc,
 )
+from web3._utils.method_formatters import (
+    to_hex_if_integer,
+)
 
 from ..utils.encoding import (
     int_to_32byte_big_endian,
@@ -56,7 +59,7 @@ def _normalize_outbound_access_list(access_list):
 
 
 TRANSACTION_NORMALIZERS = {
-    "type": identity,
+    "type": to_hex_if_integer,
     "blob_versioned_hashes": partial(
         normalize_array,
         normalizer=partial(
@@ -214,7 +217,7 @@ def _normalize_contract_address(receipt):
     "state_root": identity,
     "status": identity,
     "to": to_empty_or_checksum_address,
-    "type": identity,
+    "type": to_hex_if_integer,
     "base_fee_per_gas": identity,
     "blob_gas_used": identity,
     "blob_gas_price": identity,