feat(src): EIP-7843 (SLOTNUM) Draft

packages/testing/src/execution_testing/cli/pytest_commands/plugins/consume/simulators/single_test_client.py

@@ -33,6 +33,9 @@ def client_genesis(fixture: BlockchainFixtureCommon) -> dict:
     alloc = to_json(fixture.pre)
     # NOTE: nethermind requires account keys without '0x' prefix
     genesis["alloc"] = {k.replace("0x", ""): v for k, v in alloc.items()}
+    # NOTE: geth expects slotNumber as plain integer, not hex string
+    if "slotNumber" in genesis:
+        genesis["slotNumber"] = int(genesis["slotNumber"], 16)
     return genesis
 
 

packages/testing/src/execution_testing/fixtures/blockchain.py

@@ -210,6 +210,10 @@ class FixtureHeader(CamelModel):
     block_access_list_hash: (
         Annotated[Hash, HeaderForkRequirement("bal_hash")] | None
     ) = Field(None, alias="blockAccessListHash")
+    slot_number: (
+        Annotated[ZeroPaddedHexNumber, HeaderForkRequirement("slot_number")]
+        | None
+    ) = Field(None)
 
     fork: Fork | None = Field(None, exclude=True)
 
@@ -361,7 +365,7 @@ def get_default_from_annotation(
     def genesis(cls, fork: Fork, env: Environment, state_root: Hash) -> Self:
         """Get the genesis header for the given fork."""
         environment_values = env.model_dump(
-            exclude_none=True, exclude={"withdrawals"}
+            exclude_none=True, exclude={"withdrawals", "slot_number"}
         )
         if env.withdrawals is not None:
             environment_values["withdrawals_root"] = Withdrawal.list_root(
@@ -378,6 +382,11 @@ def genesis(cls, fork: Fork, env: Environment, state_root: Hash) -> Self:
                 if fork.header_bal_hash_required(block_number=0, timestamp=0)
                 else None
             ),
+            "slot_number": (
+                0
+                if fork.header_slot_number_required(block_number=0, timestamp=0)
+                else None
+            ),
             "fork": fork,
         }
         return cls(**environment_values, **extras)
@@ -418,6 +427,7 @@ class FixtureExecutionPayload(CamelModel):
     block_access_list: Bytes | None = Field(
         None, description="RLP-serialized EIP-7928 Block Access List"
     )
+    slot_number: HexNumber | None = Field(None)
 
     @classmethod
     def from_fixture_header(

packages/testing/src/execution_testing/forks/base_fork.py

@@ -361,6 +361,14 @@ def header_bal_hash_required(
         """Return true if the header must contain block access list hash."""
         pass
 
+    @classmethod
+    @abstractmethod
+    def header_slot_number_required(
+        cls, *, block_number: int = 0, timestamp: int = 0
+    ) -> bool:
+        """Return true if the header must contain slot number (EIP-7843)."""
+        pass
+
     # Gas related abstract methods
 
     @classmethod

packages/testing/src/execution_testing/forks/forks/forks.py

@@ -976,6 +976,14 @@ def header_beacon_root_required(
         del block_number, timestamp
         return False
 
+    @classmethod
+    def header_slot_number_required(
+        cls, *, block_number: int = 0, timestamp: int = 0
+    ) -> bool:
+        """At genesis, header must not contain slot number (EIP-7843)."""
+        del block_number, timestamp
+        return False
+
     @classmethod
     def engine_new_payload_blob_hashes(
         cls, *, block_number: int = 0, timestamp: int = 0
@@ -3338,9 +3346,7 @@ class Amsterdam(BPO2):
     def header_bal_hash_required(
         cls, *, block_number: int = 0, timestamp: int = 0
     ) -> bool:
-        """
-        From Amsterdam, header must contain block access list hash (EIP-7928).
-        """
+        """BAL hash in header required from Amsterdam (EIP-7928)."""
         del block_number, timestamp
         return True
 
@@ -3367,3 +3373,36 @@ def engine_execution_payload_block_access_list(
         """
         del block_number, timestamp
         return True
+
+    @classmethod
+    def header_slot_number_required(
+        cls, *, block_number: int = 0, timestamp: int = 0
+    ) -> bool:
+        """Slot number in header required from Amsterdam (EIP-7843)."""
+        del block_number, timestamp
+        return True
+
+    @classmethod
+    def opcode_gas_map(
+        cls, *, block_number: int = 0, timestamp: int = 0
+    ) -> Dict[OpcodeBase, int | Callable[[OpcodeBase], int]]:
+        """Add SLOTNUM opcode gas cost for Amsterdam (EIP-7843)."""
+        gas_costs = cls.gas_costs(
+            block_number=block_number, timestamp=timestamp
+        )
+        base_map = super(Amsterdam, cls).opcode_gas_map(
+            block_number=block_number, timestamp=timestamp
+        )
+        return {
+            **base_map,
+            Opcodes.SLOTNUM: gas_costs.G_BASE,
+        }
+
+    @classmethod
+    def valid_opcodes(
+        cls, *, block_number: int = 0, timestamp: int = 0
+    ) -> List[Opcodes]:
+        """Add SLOTNUM opcode for Amsterdam (EIP-7843)."""
+        return [Opcodes.SLOTNUM] + super(Amsterdam, cls).valid_opcodes(
+            block_number=block_number, timestamp=timestamp
+        )

packages/testing/src/execution_testing/specs/blockchain.py

@@ -154,6 +154,7 @@ class Header(CamelModel):
     parent_beacon_block_root: Removable | Hash | None = None
     requests_hash: Removable | Hash | None = None
     bal_hash: Removable | Hash | None = None
+    slot_number: Removable | HexNumber | None = None
 
     REMOVE_FIELD: ClassVar[Removable] = Removable()
     """
@@ -325,6 +326,8 @@ def set_environment(self, env: Environment) -> Environment:
             and self.block_access_list is not None
         ):
             new_env_values["block_access_list"] = self.block_access_list
+        if not isinstance(self.slot_number, Removable):
+            new_env_values["slot_number"] = self.slot_number
         """
         These values are required, but they depend on the previous environment,
         so they can be calculated here.
@@ -651,6 +654,12 @@ def generate_block_data(
             fork=self.fork,
         )
 
+        # Clear block_access_list_hash if the fork doesn't require it
+        if not self.fork.header_bal_hash_required(
+            block_number=int(env.number), timestamp=int(env.timestamp)
+        ):
+            header.block_access_list_hash = None
+
         if block.header_verify is not None:
             # Verify the header after transition tool processing.
             try:
@@ -747,8 +756,10 @@ def generate_block_data(
             bal = block.expected_block_access_list.modify_if_invalid_test(
                 t8n_bal
             )
-            if bal != t8n_bal:
-                # If the BAL was modified, update the header hash
+            if bal != t8n_bal and self.fork.header_bal_hash_required(
+                block_number=int(env.number), timestamp=int(env.timestamp)
+            ):
+                # If the BAL was modified and the fork requires it, update the header hash
                 header.block_access_list_hash = Hash(bal.rlp.keccak256())
 
         built_block = BuiltBlock(

packages/testing/src/execution_testing/specs/state.py

@@ -310,6 +310,7 @@ def _generate_blockchain_blocks(self) -> List[Block]:
             "extra_data": self.env.extra_data,
             "withdrawals": self.env.withdrawals,
             "parent_beacon_block_root": self.env.parent_beacon_block_root,
+            "slot_number": self.env.slot_number,
             "txs": [self.tx],
             "ommers": [],
             "header_verify": self.blockchain_test_header_verify,

packages/testing/src/execution_testing/specs/static_state/environment.py

@@ -33,6 +33,7 @@ class EnvironmentInStateTestFiller(BaseModel):
     current_excess_blob_gas: ValueInFiller | None = Field(
         None, alias="currentExcessBlobGas"
     )
+    current_slot_number: ValueInFiller | None = Field(None, alias="slotNumber")
 
     model_config = ConfigDict(extra="forbid")
 
@@ -72,4 +73,6 @@ def get_environment(self, tags: TagDict) -> Environment:
             kwargs["base_fee_per_gas"] = self.current_base_fee
         if self.current_excess_blob_gas is not None:
             kwargs["excess_blob_gas"] = self.current_excess_blob_gas
+        if self.current_slot_number is not None:
+            kwargs["slot_number"] = self.current_slot_number
         return Environment(**kwargs)

packages/testing/src/execution_testing/test_types/block_types.py

@@ -101,6 +101,7 @@ class EnvironmentGeneric(CamelModel, Generic[NumberBoundTypeVar]):
     excess_blob_gas: NumberBoundTypeVar | None = Field(
         None, alias="currentExcessBlobGas"
     )
+    slot_number: NumberBoundTypeVar | None = Field(None, alias="slotNumber")
 
     parent_difficulty: NumberBoundTypeVar | None = Field(None)
     parent_timestamp: NumberBoundTypeVar | None = Field(None)
@@ -223,6 +224,14 @@ def set_fork_requirements(self, fork: Fork) -> "Environment":
         ):
             updated_values["parent_beacon_block_root"] = 0
 
+        if (
+            fork.header_slot_number_required(
+                block_number=number, timestamp=timestamp
+            )
+            and self.slot_number is None
+        ):
+            updated_values["slot_number"] = 0
+
         return self.copy(**updated_values)
 
     def __hash__(self) -> int:

packages/testing/src/execution_testing/vm/opcodes.py

@@ -2225,6 +2225,36 @@ class Opcodes(Opcode, Enum):
     Source: [EIP-7516](https://eips.ethereum.org/EIPS/eip-7516)
     """
 
+    SLOTNUM = Opcode(0x4B, popped_stack_items=0, pushed_stack_items=1)
+    """
+    SLOTNUM() = slotNumber
+    ----
+
+    Description
+    ----
+    Returns the current slot number as provided by the consensus layer.
+    The slot number is passed from the consensus layer to the execution
+    layer through the engine API.
+
+    Inputs
+    ----
+    - None
+
+    Outputs
+    ----
+    - slotNumber: current slot number (uint64)
+
+    Fork
+    ----
+    TBD
+
+    Gas
+    ----
+    2
+
+    Source: [EIP-7843](https://eips.ethereum.org/EIPS/eip-7843)
+    """
+
     POP = Opcode(0x50, popped_stack_items=1)
     """
     POP()

src/ethereum/forks/amsterdam/blocks.py

@@ -253,6 +253,13 @@ class Header:
     [EIP-7928]: https://eips.ethereum.org/EIPS/eip-7928
     [cbalh]: ref:ethereum.forks.amsterdam.block_access_lists.rlp_utils.compute_block_access_list_hash
     """  # noqa: E501
+    slot_number: U64
+    """
+    The slot number of this block as provided by the consensus layer.
+    Introduced in [EIP-7843].
+
+    [EIP-7843]: https://eips.ethereum.org/EIPS/eip-7843
+    """
 
 
 @slotted_freezable

src/ethereum/forks/amsterdam/fork.py

@@ -249,6 +249,7 @@ def state_transition(chain: BlockChain, block: Block) -> None:
         excess_blob_gas=block.header.excess_blob_gas,
         parent_beacon_block_root=block.header.parent_beacon_block_root,
         state_changes=StateChanges(),
+        slot_number=block.header.slot_number,
     )
 
     block_output = apply_body(

src/ethereum/forks/amsterdam/vm/__init__.py

@@ -50,6 +50,7 @@ class BlockEnvironment:
     excess_blob_gas: U64
     parent_beacon_block_root: Hash32
     state_changes: StateChanges
+    slot_number: U64
 
 
 @dataclass

src/ethereum/forks/amsterdam/vm/instructions/__init__.py

@@ -99,6 +99,7 @@ class Ops(enum.Enum):
     BASEFEE = 0x48
     BLOBHASH = 0x49
     BLOBBASEFEE = 0x4A
+    SLOTNUM = 0x4B
 
     # Control Flow Ops
     STOP = 0x00
@@ -251,6 +252,7 @@ class Ops(enum.Enum):
     Ops.PREVRANDAO: block_instructions.prev_randao,
     Ops.GASLIMIT: block_instructions.gas_limit,
     Ops.CHAINID: block_instructions.chain_id,
+    Ops.SLOTNUM: block_instructions.slot_number,
     Ops.MLOAD: memory_instructions.mload,
     Ops.MSTORE: memory_instructions.mstore,
     Ops.MSTORE8: memory_instructions.mstore8,

src/ethereum/forks/amsterdam/vm/instructions/block.py

@@ -259,3 +259,36 @@ def chain_id(evm: Evm) -> None:
 
     # PROGRAM COUNTER
     evm.pc += Uint(1)
+
+
+def slot_number(evm: Evm) -> None:
+    """
+    Push the current slot number onto the stack.
+
+    The slot number is provided by the consensus layer and passed to the
+    execution layer through the engine API.
+
+    Parameters
+    ----------
+    evm :
+        The current EVM frame.
+
+    Raises
+    ------
+    :py:class:`~ethereum.forks.amsterdam.vm.exceptions.StackOverflowError`
+        If `len(stack)` is equal to `1024`.
+    :py:class:`~ethereum.forks.amsterdam.vm.exceptions.OutOfGasError`
+        If `evm.gas_left` is less than `2`.
+
+    """
+    # STACK
+    pass
+
+    # GAS
+    charge_gas(evm, GAS_BASE)
+
+    # OPERATION
+    push(evm.stack, U256(evm.message.block_env.slot_number))
+
+    # PROGRAM COUNTER
+    evm.pc += Uint(1)

src/ethereum_spec_tools/evm_tools/loaders/fork_loader.py

@@ -268,6 +268,15 @@ def has_withdrawal(self) -> bool:
         """Check if the fork has a `Withdrawal` class."""
         return hasattr(self._module("blocks"), "Withdrawal")
 
+    @property
+    def has_slot_number(self) -> bool:
+        """Check if the fork supports the SLOTNUM opcode (EIP-7843)."""
+        try:
+            block_env = self._module("vm").BlockEnvironment
+            return "slot_number" in block_env.__dataclass_fields__
+        except (ModuleNotFoundError, AttributeError):
+            return False
+
     @property
     def decode_transaction(self) -> Any:
         """decode_transaction function of the fork."""

src/ethereum_spec_tools/evm_tools/t8n/__init__.py

@@ -311,6 +311,8 @@ def block_environment(self) -> Any:
 
         if self.fork.has_block_access_list_hash:
             kw_arguments["state_changes"] = StateChanges()
+        if self.fork.has_slot_number:
+            kw_arguments["slot_number"] = self.env.slot_number
 
         return block_environment(**kw_arguments)