fix reserved bytecode logic and tests for london (EIP-3541)

Don't raise VMError for reserved bytecode. Instead, set the error on the computation and return the computation.

Author: fselmo

eth/vm/forks/london/computation.py

@@ -15,7 +15,9 @@ class LondonComputation(BerlinComputation):
     opcodes = LONDON_OPCODES
 
     @classmethod
-    def validate_new_contract_code(cls, contract_code: bytes) -> None:
+    def validate_contract_code(cls, contract_code: bytes) -> None:
+        super().validate_contract_code(contract_code)
+
         if contract_code[:1] == EIP3541_RESERVED_STARTING_BYTE:
             raise ReservedBytesInCode(
                 "Contract code begins with EIP3541 reserved byte '0xEF'."

eth/vm/forks/spurious_dragon/computation.py

@@ -51,31 +51,22 @@ def apply_create_message(
         else:
             contract_code = computation.output
 
-            if contract_code and len(contract_code) >= EIP170_CODE_SIZE_LIMIT:
-                computation.error = OutOfGas(
-                    f"Contract code size exceeds EIP170 limit of {EIP170_CODE_SIZE_LIMIT}."
-                    f"  Got code of size: {len(contract_code)}"
-                )
-                state.revert(snapshot)
-            elif contract_code:
-                contract_code_gas_cost = len(contract_code) * constants.GAS_CODEDEPOSIT
+            if contract_code:
                 try:
+                    cls.validate_contract_code(contract_code)
+
+                    contract_code_gas_cost = len(contract_code) * constants.GAS_CODEDEPOSIT
                     computation.consume_gas(
                         contract_code_gas_cost,
                         reason="Write contract code for CREATE",
                     )
-                except OutOfGas as err:
+                except VMError as err:
                     # Different from Frontier: reverts state on gas failure while
                     # writing contract code.
                     computation.error = err
                     state.revert(snapshot)
+                    cls.logger.debug2(f"VMError setting contract code: {err}")
                 else:
-                    try:
-                        cls.validate_new_contract_code(contract_code)
-                    except VMError as err:
-                        state.revert(snapshot)
-                        raise err
-
                     if cls.logger:
                         cls.logger.debug2(
                             "SETTING CODE: %s -> length: %s | hash: %s",
@@ -91,6 +82,9 @@ def apply_create_message(
             return computation
 
     @classmethod
-    def validate_new_contract_code(cls, contract_code: bytes) -> None:
-        # helps facilitate EIP-3541 validation in LondonComputation
-        pass
+    def validate_contract_code(cls, contract_code: bytes) -> None:
+        if len(contract_code) >= EIP170_CODE_SIZE_LIMIT:
+            raise OutOfGas(
+                f"Contract code size exceeds EIP170 limit of {EIP170_CODE_SIZE_LIMIT}."
+                f"  Got code of size: {len(contract_code)}"
+            )

tests/core/vm/test_london.py

@@ -9,7 +9,7 @@
 from eth.chains.mainnet import (
     MAINNET_VMS,
 )
-from eth.exceptions import InvalidInstruction, ReservedBytesInCode
+from eth.exceptions import InvalidInstruction
 from eth.vm.forks import BerlinVM
 from eth.tools.factories.transaction import (
     new_dynamic_fee_transaction, new_transaction,
@@ -182,10 +182,7 @@ def test_revert_on_reserved_0xEF_byte_for_CREATE_and_CREATE2_post_london(
     )
 
     assert revert_create_computation.is_error
-    assert isinstance(revert_create_computation.error, ReservedBytesInCode)
-    assert "0xef" in repr(revert_create_computation.error).lower()
-
-    assert revert_create_computation.get_gas_used() == 40000  # assert gas is consumed
+    assert 35000 < revert_create_computation.get_gas_used() < 40000  # assert gas is still consumed
     assert revert_create_computation.get_gas_refund() == 0
 
 
@@ -259,24 +256,19 @@ def test_state_revert_on_reserved_0xEF_byte_for_create_transaction_post_london(
         data=data,
     )
 
-    with pytest.raises(ReservedBytesInCode):
-        block_import, _, computations = chain.mine_all(
-            [create_contract_txn_reserved_byte],
-            gas_limit=84082
-        )
+    block_import, _, computations = chain.mine_all(
+        [create_contract_txn_reserved_byte],
+        gas_limit=84082
+    )
 
-        reverted_computation = computations[0]
-        mined_header = block_import.imported_block.header
-        end_balance = reverted_computation.state.get_balance(funded_address)
+    reverted_computation = computations[0]
+    mined_header = block_import.imported_block.header
 
-        assert reverted_computation.is_error
-        assert isinstance(reverted_computation.error, ReservedBytesInCode)
-        assert "0xef" in repr(reverted_computation.error).lower()
+    assert reverted_computation.is_error
+    assert "0xef" in repr(reverted_computation.error).lower()
 
-        assert reverted_computation.get_nonce(funded_address) == 1  # assert nonce is still 1
-        # reverted txn consumes the gas:
-        assert mined_header.gas_used == 60000
-        assert end_balance == new_balance - 60000
+    # reverted txn consumes the gas:
+    assert mined_header.gas_used == 60000
 
 
 @pytest.mark.parametrize(