feat(src): Initial EIP-7843 (SLOTNUM) Implementation (#2007)

* feat(amsterdam): Implement EIP-7843 SLOTNUM opcode

* mario feedback

Author: felix314159

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

@@ -214,6 +214,10 @@ 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)
 
@@ -365,7 +369,7 @@ 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(
@@ -382,6 +386,11 @@ 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)
@@ -422,6 +431,7 @@ 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

@@ -157,6 +157,7 @@ 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()
     """
@@ -328,6 +329,8 @@ 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.
@@ -667,6 +670,12 @@ 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:
@@ -763,8 +772,10 @@ 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

@@ -311,6 +311,7 @@ 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