feat(forks,specs,fixtures): Add Blob Schedule

src/ethereum_test_fixtures/blockchain.py

@@ -9,6 +9,7 @@
     ClassVar,
     List,
     Literal,
+    Mapping,
     Tuple,
     Union,
     cast,
@@ -126,9 +127,6 @@ class FixtureHeader(CamelModel):
         None
     )
     requests_hash: Annotated[Hash, HeaderForkRequirement("requests")] | None = Field(None)
-    target_blobs_per_block: (
-        Annotated[ZeroPaddedHexNumber, HeaderForkRequirement("target_blobs_per_block")] | None
-    ) = Field(None)
 
     fork: Fork | None = Field(None, exclude=True)
 
@@ -329,12 +327,6 @@ def from_fixture_header(
                 raise ValueError(f"Requests are required for ${fork}.")
             params.append(requests)
 
-        if fork.engine_new_payload_target_blobs_per_block(header.number, header.timestamp):
-            target_blobs_per_block = header.target_blobs_per_block
-            if target_blobs_per_block is None:
-                raise ValueError(f"Target blobs per block is required for ${fork}.")
-            params.append(target_blobs_per_block)
-
         payload_params: EngineNewPayloadParameters = cast(
             EngineNewPayloadParameters,
             tuple(params),
@@ -454,6 +446,16 @@ class InvalidFixtureBlock(CamelModel):
     rlp_decoded: FixtureBlockBase | None = Field(None, alias="rlp_decoded")
 
 
+class FixtureForkBlobSchedule(CamelModel):
+    """
+    Representation of the blob schedule within a test Fixture, which is valid throughout all the
+    blocks in the fixture.
+    """
+
+    target_blobs_per_block: HexNumber = Field(..., alias="target")
+    max_blobs_per_block: HexNumber = Field(..., alias="max")
+
+
 class FixtureCommon(BaseFixture):
     """
     Base blockchain test fixture model.
@@ -465,6 +467,8 @@ class FixtureCommon(BaseFixture):
     post_state: Alloc | None = Field(None)
     last_block_hash: Hash = Field(..., alias="lastblockhash")  # FIXME: lastBlockHash
 
+    blob_schedule: Mapping[str, FixtureForkBlobSchedule] | None = None
+
     def get_fork(self) -> str | None:
         """
         Returns the fork of the fixture as a string.

src/ethereum_test_forks/__init__.py

@@ -23,6 +23,7 @@
 )
 from .forks.transition import (
     BerlinToLondonAt5,
+    CancunToPragueAtTime15k,
     ParisToShanghaiAtTime15k,
     ShanghaiToCancunAtTime15k,
 )
@@ -44,10 +45,12 @@
     transition_fork_from_to,
     transition_fork_to,
 )
+from .transition_base_fork import TransitionFork
 
 __all__ = [
     "Fork",
     "ForkAttribute",
+    "TransitionFork",
     "ArrowGlacier",
     "Berlin",
     "BerlinToLondonAt5",
@@ -66,6 +69,7 @@
     "Shanghai",
     "ShanghaiToCancunAtTime15k",
     "Cancun",
+    "CancunToPragueAtTime15k",
     "Prague",
     "Osaka",
     "get_transition_forks",

src/ethereum_test_forks/base_fork.py

@@ -108,6 +108,27 @@ def name(cls) -> str:
         """
         return ""
 
+    def parent(cls) -> Type["BaseFork"] | None:
+        """
+        Returns the parent of the fork.
+        """
+        base_class = cls.__bases__[0]
+        assert issubclass(base_class, BaseFork)
+        if base_class == BaseFork:
+            return None
+        return base_class
+
+    def parents(cls) -> List[Type["BaseFork"]]:
+        """
+        To be implemented by the fork base class.
+        """
+        parents: List[Type["BaseFork"]] = []
+        parent = cls.parent()
+        while parent is not None:
+            parents.insert(0, parent)
+            parent = parent.parent()
+        return parents
+
     def __repr__(cls) -> str:
         """
         Used to properly print the name of the fork, instead of the class.
@@ -283,14 +304,6 @@ def transaction_intrinsic_cost_calculator(
         """
         pass
 
-    @classmethod
-    @abstractmethod
-    def header_target_blobs_per_block_required(cls, block_number: int, timestamp: int) -> bool:
-        """
-        Returns true if the header must contain target blobs per block.
-        """
-        pass
-
     @classmethod
     @abstractmethod
     def blob_gas_per_blob(cls, block_number: int, timestamp: int) -> int:
@@ -301,15 +314,15 @@ def blob_gas_per_blob(cls, block_number: int, timestamp: int) -> int:
 
     @classmethod
     @abstractmethod
-    def target_blobs_per_block(cls, block_number: int, timestamp: int) -> int:
+    def target_blobs_per_block(cls, block_number: int, timestamp: int) -> int | None:
         """
         Returns the target blobs per block for a given fork.
         """
         pass
 
     @classmethod
     @abstractmethod
-    def max_blobs_per_block(cls, block_number: int, timestamp: int) -> int:
+    def max_blobs_per_block(cls, block_number: int, timestamp: int) -> int | None:
         """
         Returns the max blobs per block for a given fork.
         """
@@ -532,6 +545,13 @@ def fork_at(cls, block_number: int = 0, timestamp: int = 0) -> Type["BaseFork"]:
         """
         return cls
 
+    @classmethod
+    def is_transition_fork(cls) -> bool:
+        """
+        Returns whether the fork is a transition fork or not.
+        """
+        return False
+
     @classmethod
     @abstractmethod
     def transition_tool_name(cls, block_number: int = 0, timestamp: int = 0) -> str:

src/ethereum_test_forks/forks/forks.py

@@ -252,18 +252,18 @@ def blob_gas_per_blob(cls, block_number: int, timestamp: int) -> int:
         return 0
 
     @classmethod
-    def target_blobs_per_block(cls, block_number: int, timestamp: int) -> int:
+    def target_blobs_per_block(cls, block_number: int, timestamp: int) -> int | None:
         """
         Returns the target number of blobs per block for a given fork.
         """
-        return 0
+        return None
 
     @classmethod
-    def max_blobs_per_block(cls, block_number: int, timestamp: int) -> int:
+    def max_blobs_per_block(cls, block_number: int, timestamp: int) -> int | None:
         """
         Returns the max number of blobs per block for a given fork.
         """
-        return 0
+        return None
 
     @classmethod
     def header_requests_required(cls, block_number: int, timestamp: int) -> bool:
@@ -288,17 +288,6 @@ def header_beacon_root_required(cls, block_number: int = 0, timestamp: int = 0)
         """
         return False
 
-    @classmethod
-    def header_target_blobs_per_block_required(
-        cls,
-        block_number: int = 0,
-        timestamp: int = 0,
-    ) -> bool:
-        """
-        At genesis, header must not contain target blobs per block.
-        """
-        return False
-
     @classmethod
     def engine_new_payload_blob_hashes(cls, block_number: int = 0, timestamp: int = 0) -> bool:
         """
@@ -1018,14 +1007,14 @@ def blob_gas_per_blob(cls, block_number: int, timestamp: int) -> int:
         return 2**17
 
     @classmethod
-    def target_blobs_per_block(cls, block_number: int, timestamp: int) -> int:
+    def target_blobs_per_block(cls, block_number: int, timestamp: int) -> int | None:
         """
         Blobs are enabled starting from Cancun, with a static target of 3 blobs.
         """
         return 3
 
     @classmethod
-    def max_blobs_per_block(cls, block_number: int, timestamp: int) -> int:
+    def max_blobs_per_block(cls, block_number: int, timestamp: int) -> int | None:
         """
         Blobs are enabled starting from Cancun, with a static max of 6 blobs.
         """
@@ -1324,18 +1313,6 @@ def header_requests_required(cls, block_number: int, timestamp: int) -> bool:
         """
         return True
 
-    @classmethod
-    def header_target_blobs_per_block_required(
-        cls,
-        block_number: int = 0,
-        timestamp: int = 0,
-    ) -> bool:
-        """
-        Prague requires that the execution layer header contains the beacon
-        chain target blobs per block.
-        """
-        return True
-
     @classmethod
     def engine_new_payload_requests(cls, block_number: int = 0, timestamp: int = 0) -> bool:
         """

src/ethereum_test_forks/tests/test_forks.py

@@ -125,6 +125,8 @@ def test_forks():
     assert cast(Fork, ParisToShanghaiAtTime15k).header_withdrawals_required(0, 15_000) is True
     assert cast(Fork, ParisToShanghaiAtTime15k).header_withdrawals_required() is True
 
+
+def test_fork_comparison():  # noqa: D103
     # Test fork comparison
     assert Paris > Berlin
     assert not Berlin > Paris
@@ -159,6 +161,15 @@ def test_forks():
     assert fork == Berlin
 
 
+def test_fork_parents():  # noqa: D103
+    assert London.parent() == Berlin
+    assert Paris.parent() == London
+
+    assert London.parents()[-1] == Berlin
+    assert London.parents()[0] == Frontier
+    assert len(London.parents()) == 7
+
+
 def test_get_forks():  # noqa: D103
     all_forks = get_forks()
     assert all_forks[0] == FIRST_DEPLOYED

src/ethereum_test_forks/transition_base_fork.py

@@ -30,6 +30,13 @@ def transitions_from(cls) -> Fork:
         """
         raise Exception("Not implemented")
 
+    @classmethod
+    def is_transition_fork(cls) -> bool:
+        """
+        Returns whether the fork is a transition fork or not.
+        """
+        return True
+
 
 def base_fork_abstract_methods() -> List[str]:
     """
@@ -109,3 +116,15 @@ def transition_method(
         return NewTransitionClass
 
     return decorator
+
+
+class TransitionForkCombinedBase(TransitionBaseClass, BaseFork):
+    """
+    Combined base class
+    """
+
+    pass
+
+
+# Transition Fork Type
+TransitionFork = Type[TransitionForkCombinedBase]

src/ethereum_test_specs/blockchain.py

@@ -3,7 +3,7 @@
 """
 
 from pprint import pprint
-from typing import Any, Callable, ClassVar, Dict, Generator, List, Optional, Tuple, Type
+from typing import Any, Callable, ClassVar, Dict, Generator, List, Mapping, Optional, Tuple, Type
 
 import pytest
 from pydantic import ConfigDict, Field, field_validator
@@ -35,12 +35,13 @@
     FixtureBlock,
     FixtureBlockBase,
     FixtureEngineNewPayload,
+    FixtureForkBlobSchedule,
     FixtureHeader,
     FixtureTransaction,
     FixtureWithdrawal,
     InvalidFixtureBlock,
 )
-from ethereum_test_forks import Fork
+from ethereum_test_forks import Fork, TransitionFork
 from ethereum_test_types import Alloc, Environment, Removable, Requests, Transaction, Withdrawal
 
 from .base import BaseTest, verify_result
@@ -119,7 +120,6 @@ class Header(CamelModel):
     excess_blob_gas: Removable | HexNumber | None = None
     parent_beacon_block_root: Removable | Hash | None = None
     requests_hash: Removable | Hash | None = None
-    target_blobs_per_block: Removable | HexNumber | None = None
 
     REMOVE_FIELD: ClassVar[Removable] = Removable()
     """
@@ -270,8 +270,6 @@ def set_environment(self, env: Environment) -> Environment:
             new_env_values["blob_gas_used"] = self.blob_gas_used
         if not isinstance(self.parent_beacon_block_root, Removable):
             new_env_values["parent_beacon_block_root"] = self.parent_beacon_block_root
-        if not isinstance(self.target_blobs_per_block, Removable):
-            new_env_values["target_blobs_per_block"] = self.target_blobs_per_block
         """
         These values are required, but they depend on the previous environment,
         so they can be calculated here.
@@ -515,6 +513,36 @@ def network_info(self, fork: Fork, eips: Optional[List[int]] = None):
             else fork.blockchain_test_network_name()
         )
 
+    def blob_schedule(
+        self, fork: Fork | TransitionFork, eips: Optional[List[int]] = None
+    ) -> Mapping[str, FixtureForkBlobSchedule] | None:
+        """
+        Returns the blob schedule for the given fork and EIPs.
+        """
+        if fork.is_transition_fork():
+            fork: Fork = fork.transitions_to()  # type: ignore
+        blob_schedule: Dict[str, FixtureForkBlobSchedule] = {}
+        last_fork_blob_schedule: FixtureForkBlobSchedule | None = None
+        for fork in fork.parents() + [fork]:
+            if fork.target_blobs_per_block(0, 0) is None or fork.max_blobs_per_block(0, 0) is None:
+                continue
+            current_fork_blob_schedule = FixtureForkBlobSchedule(
+                target_blobs_per_block=fork.target_blobs_per_block(0, 0),
+                max_blobs_per_block=fork.max_blobs_per_block(0, 0),
+            )
+            if (
+                last_fork_blob_schedule is None
+                or current_fork_blob_schedule != last_fork_blob_schedule
+            ):
+                blob_schedule[fork.name()] = current_fork_blob_schedule
+
+            last_fork_blob_schedule = current_fork_blob_schedule
+
+        if not blob_schedule:
+            return None
+
+        return blob_schedule
+
     def verify_post_state(self, t8n, alloc: Alloc):
         """
         Verifies the post alloc after all block/s or payload/s are generated.
@@ -607,6 +635,7 @@ def make_fixture(
             last_block_hash=head,
             pre=pre,
             post_state=alloc,
+            blob_schedule=self.blob_schedule(fork, eips),
         )
 
     def make_hive_fixture(
@@ -697,6 +726,7 @@ def make_hive_fixture(
             post_state=alloc,
             sync_payload=sync_payload,
             last_block_hash=head_hash,
+            blob_schedule=self.blob_schedule(fork, eips),
         )
 
     def generate(