chore(tests|forks): add max blobs per tx limit in eip4844 & eip7954 (#1884)

Author: spencer-tb

docs/CHANGELOG.md

@@ -129,17 +129,18 @@ Users can select any of the artifacts depending on their testing needs for their
 
 - 🔀 Refactored `BLOBHASH` opcode context tests to use the `pre_alloc` plugin in order to avoid contract and EOA address collisions ([#1637](https://github.com/ethereum/execution-spec-tests/pull/1637)).
 - 🔀 Refactored `SELFDESTRUCT` opcode collision tests to use the `pre_alloc` plugin in order to avoid contract and EOA address collisions ([#1643](https://github.com/ethereum/execution-spec-tests/pull/1643)).
-- ✨ EIP-7594: Sanity test cases to send blob transactions and verify `engine_getBlobsVX` using the `execute` command ([#1644](https://github.com/ethereum/execution-spec-tests/pull/1644)).
+- ✨ EIP-7594: Sanity test cases to send blob transactions and verify `engine_getBlobsVX` using the `execute` command ([#1644](https://github.com/ethereum/execution-spec-tests/pull/1644),[#1884](https://github.com/ethereum/execution-spec-tests/pull/1884)).
 - 🔀 Refactored EIP-145 static tests into python ([#1683](https://github.com/ethereum/execution-spec-tests/pull/1683)).
 - ✨ EIP-7823, EIP-7883: Add test cases for ModExp precompile gas-cost updates and input limits on Osaka ([#1579](https://github.com/ethereum/execution-spec-tests/pull/1579), [#1729](https://github.com/ethereum/execution-spec-tests/pull/1729), [#1881](https://github.com/ethereum/execution-spec-tests/pull/1881)).
 - ✨ [EIP-7825](https://eips.ethereum.org/EIPS/eip-7825): Add test cases for the transaction gas limit of 2^24 gas ([#1711](https://github.com/ethereum/execution-spec-tests/pull/1711), [#1882](https://github.com/ethereum/execution-spec-tests/pull/1882)).
 - ✨ [EIP-7951](https://eips.ethereum.org/EIPS/eip-7951): add test cases for `P256VERIFY` precompile to support secp256r1 curve [#1670](https://github.com/ethereum/execution-spec-tests/pull/1670).
 - ✨ Introduce blockchain tests for benchmark to cover the scenario of pure ether transfers [#1742](https://github.com/ethereum/execution-spec-tests/pull/1742).
 - ✨ [EIP-7934](https://eips.ethereum.org/EIPS/eip-7934): Add test cases for the block RLP max limit of 10MiB ([#1730](https://github.com/ethereum/execution-spec-tests/pull/1730)).
 - ✨ [EIP-7939](https://eips.ethereum.org/EIPS/eip-7939) Add count leading zeros (CLZ) opcode tests for Osaka ([#1733](https://github.com/ethereum/execution-spec-tests/pull/1733)).
-- ✨ [EIP-7918](https://eips.ethereum.org/EIPS/eip-7918): Blob base fee bounded by execution cost test cases (initial), includes some adjustments to [EIP-4844](https://eips.ethereum.org/EIPS/eip-4844) tests ([#1685](https://github.com/ethereum/execution-spec-tests/pull/1685)). Update the blob_base_cost ([#1915](https://github.com/ethereum/EIPs/pull/1915)).
 - ✨ [EIP-7934](https://eips.ethereum.org/EIPS/eip-7934): Add additional test cases for block RLP max limit with all typed transactions and for a log-creating transactions ([#1890](https://github.com/ethereum/execution-spec-tests/pull/1890)).
 - ✨ [EIP-7825](https://eips.ethereum.org/EIPS/eip-7825): Pre-Osaka tests have been updated to either (1) dynamically adapt to the transaction gas limit cap, or (2) reduce overall gas consumption to fit the new limit ([#1928](https://github.com/ethereum/EIPs/pull/1928)).
+- ✨ [EIP-7918](https://eips.ethereum.org/EIPS/eip-7918): Blob base fee bounded by execution cost test cases (initial), includes some adjustments to [EIP-4844](https://eips.ethereum.org/EIPS/eip-4844) tests ([#1685](https://github.com/ethereum/execution-spec-tests/pull/1685)).
+- 🔀 Adds the max blob transaction limit to the tests including updates to [EIP-4844](https://eips.ethereum.org/EIPS/eip-4844) for Osaka ([#1884](https://github.com/ethereum/execution-spec-tests/pull/1884)).
 
 ## [v4.5.0](https://github.com/ethereum/execution-spec-tests/releases/tag/v4.5.0) - 2025-05-14
 

src/ethereum_test_forks/base_fork.py

@@ -324,6 +324,12 @@ def target_blobs_per_block(cls, block_number: int = 0, timestamp: int = 0) -> in
         """Return the target blobs per block at a given fork."""
         pass
 
+    @classmethod
+    @abstractmethod
+    def max_blobs_per_tx(cls, block_number: int = 0, timestamp: int = 0) -> int:
+        """Return the max blobs per transaction at a given fork."""
+        pass
+
     @classmethod
     @abstractmethod
     def max_blobs_per_block(cls, block_number: int = 0, timestamp: int = 0) -> int:

src/ethereum_test_forks/forks/forks.py

@@ -257,6 +257,11 @@ def full_blob_tx_wrapper_version(cls, block_number: int = 0, timestamp: int = 0)
             f"Full blob transaction wrapper version is not supported in {cls.name()}"
         )
 
+    @classmethod
+    def max_blobs_per_tx(cls, block_number: int = 0, timestamp: int = 0) -> int:
+        """Return the max number of blobs per tx at a given fork."""
+        raise NotImplementedError(f"Max blobs per tx is not supported in {cls.name()}")
+
     @classmethod
     def blob_schedule(cls, block_number: int = 0, timestamp: int = 0) -> BlobSchedule | None:
         """At genesis, no blob schedule is used."""
@@ -1039,19 +1044,24 @@ def supports_blobs(cls, block_number: int = 0, timestamp: int = 0) -> bool:
 
     @classmethod
     def target_blobs_per_block(cls, block_number: int = 0, timestamp: int = 0) -> int:
-        """Blobs are enabled starting from Cancun, with a static target of 3 blobs."""
+        """Blobs are enabled starting from Cancun, with a static target of 3 blobs per block."""
         return 3
 
     @classmethod
     def max_blobs_per_block(cls, block_number: int = 0, timestamp: int = 0) -> int:
-        """Blobs are enabled starting from Cancun, with a static max of 6 blobs."""
+        """Blobs are enabled starting from Cancun, with a static max of 6 blobs per block."""
         return 6
 
     @classmethod
     def full_blob_tx_wrapper_version(cls, block_number: int = 0, timestamp: int = 0) -> int | None:
         """Pre-Osaka forks don't use tx wrapper versions for full blob transactions."""
         return None
 
+    @classmethod
+    def max_blobs_per_tx(cls, block_number: int = 0, timestamp: int = 0) -> int:
+        """Blobs are enabled starting from Cancun, with a static max equal to the max per block."""
+        return cls.max_blobs_per_block(block_number, timestamp)
+
     @classmethod
     def blob_schedule(cls, block_number: int = 0, timestamp: int = 0) -> BlobSchedule | None:
         """
@@ -1306,12 +1316,12 @@ def blob_base_fee_update_fraction(cls, block_number: int = 0, timestamp: int = 0
 
     @classmethod
     def target_blobs_per_block(cls, block_number: int = 0, timestamp: int = 0) -> int:
-        """Target blob count of 6 for Prague."""
+        """Blobs in Prague, have a static target of 6 blobs per block."""
         return 6
 
     @classmethod
     def max_blobs_per_block(cls, block_number: int = 0, timestamp: int = 0) -> int:
-        """Max blob count of 9 for Prague."""
+        """Blobs in Prague, have a static max of 9 blobs per block."""
         return 9
 
     @classmethod
@@ -1519,6 +1529,11 @@ def fn(
 
         return fn
 
+    @classmethod
+    def max_blobs_per_tx(cls, block_number: int = 0, timestamp: int = 0) -> int:
+        """Blobs in Osaka, have a static max of 6 blobs per tx. Differs from the max per block."""
+        return 6
+
 
 class EOFv1(Prague, solc_name="cancun"):
     """EOF fork."""

tests/cancun/eip4844_blobs/conftest.py

@@ -26,6 +26,12 @@ def max_blobs_per_block(fork: Fork) -> int:
     return fork.max_blobs_per_block()
 
 
+@pytest.fixture
+def max_blobs_per_tx(fork: Fork) -> int:
+    """Return max number of blobs per transaction."""
+    return fork.max_blobs_per_tx()
+
+
 @pytest.fixture
 def blob_gas_per_blob(fork: Fork) -> int:
     """Return default blob gas cost per blob."""
@@ -269,6 +275,10 @@ def non_zero_blob_gas_used_genesis_block(
     genesis value, expecting an appropriate drop to the intermediate block.
     Similarly, we must add parent_blobs to the intermediate block within
     a blob tx such that an equivalent blobGasUsed field is wrote.
+
+    For forks >= Osaka where the MAX_BLOBS_PER_TX is introduced, we
+    split the blobs across multiple transactions to respect the
+    MAX_BLOBS_PER_TX limit.
     """
     if parent_blobs == 0:
         return None
@@ -287,30 +297,41 @@ def non_zero_blob_gas_used_genesis_block(
     )
 
     sender = pre.fund_eoa(10**27)
-
-    # Address that contains no code, nor balance and is not a contract.
     empty_account_destination = pre.fund_eoa(0)
-
     blob_gas_price_calculator = fork.blob_gas_price_calculator(block_number=1)
 
-    return Block(
-        txs=[
-            Transaction(
-                ty=Spec.BLOB_TX_TYPE,
-                sender=sender,
-                to=empty_account_destination,
-                value=1,
-                gas_limit=21_000,
-                max_fee_per_gas=tx_max_fee_per_gas,
-                max_priority_fee_per_gas=0,
-                max_fee_per_blob_gas=blob_gas_price_calculator(
-                    excess_blob_gas=parent_excess_blob_gas
-                ),
-                access_list=[],
-                blob_versioned_hashes=add_kzg_version(
-                    [Hash(x) for x in range(parent_blobs)],
-                    Spec.BLOB_COMMITMENT_VERSION_KZG,
-                ),
-            )
-        ]
+    # Split blobs into chunks when MAX_BLOBS_PER_TX < MAX_BLOBS_PER_BLOCK to respect per-tx limits.
+    # Allows us to keep single txs for forks where per-tx and per-block limits are equal, hitting
+    # coverage for block level blob gas validation when parent_blobs > MAX_BLOBS_PER_BLOCK.
+    max_blobs_per_tx = (
+        fork.max_blobs_per_tx()
+        if fork.max_blobs_per_tx() < fork.max_blobs_per_block()
+        else parent_blobs
     )
+    blob_chunks = [
+        range(i, min(i + max_blobs_per_tx, parent_blobs))
+        for i in range(0, parent_blobs, max_blobs_per_tx)
+    ]
+
+    def create_blob_transaction(blob_range):
+        return Transaction(
+            ty=Spec.BLOB_TX_TYPE,
+            sender=sender,
+            to=empty_account_destination,
+            value=1,
+            gas_limit=21_000,
+            max_fee_per_gas=tx_max_fee_per_gas,
+            max_priority_fee_per_gas=0,
+            max_fee_per_blob_gas=blob_gas_price_calculator(
+                excess_blob_gas=parent_excess_blob_gas,
+            ),
+            access_list=[],
+            blob_versioned_hashes=add_kzg_version(
+                [Hash(x) for x in blob_range],
+                Spec.BLOB_COMMITMENT_VERSION_KZG,
+            ),
+        )
+
+    txs = [create_blob_transaction(chunk) for chunk in blob_chunks]
+
+    return Block(txs=txs)

tests/cancun/eip4844_blobs/spec.py

@@ -120,6 +120,7 @@ def get_min_excess_blobs_for_blob_gas_price(
     def get_blob_combinations(
         cls,
         blob_count: int,
+        max_blobs_per_tx: int,
     ) -> List[Tuple[int, ...]]:
         """Get all possible combinations of blobs that result in a given blob count."""
         combinations = [
@@ -128,10 +129,11 @@ def get_blob_combinations(
                 blob_count + 1, 0, -1
             )  # We can have from 1 to at most MAX_BLOBS_PER_BLOCK blobs per block
             for seq in itertools.combinations_with_replacement(
-                range(1, blob_count + 2), i
+                range(1, min(blob_count + 1, max_blobs_per_tx) + 1), i
             )  # We iterate through all possible combinations
-            if sum(seq) == blob_count  # And we only keep the ones that match the
-            # expected invalid blob count
+            if sum(seq)
+            == blob_count  # And we only keep the ones that match the expected blob count
+            and all(tx_blobs <= max_blobs_per_tx for tx_blobs in seq)  # Validate each tx
         ]
 
         # We also add the reversed version of each combination, only if it's not
@@ -146,12 +148,14 @@ def get_blob_combinations(
     def all_valid_blob_combinations(cls, fork: Fork) -> List[Tuple[int, ...]]:
         """
         Return all valid blob tx combinations for a given block,
-        assuming the given MAX_BLOBS_PER_BLOCK.
+        assuming the given MAX_BLOBS_PER_BLOCK, whilst respecting MAX_BLOBS_PER_TX.
         """
         max_blobs_per_block = fork.max_blobs_per_block()
+        max_blobs_per_tx = fork.max_blobs_per_tx()
+
         combinations: List[Tuple[int, ...]] = []
         for i in range(1, max_blobs_per_block + 1):
-            combinations += cls.get_blob_combinations(i)
+            combinations += cls.get_blob_combinations(i, max_blobs_per_tx)
         return combinations
 
     @classmethod
@@ -161,4 +165,10 @@ def invalid_blob_combinations(cls, fork: Fork) -> List[Tuple[int, ...]]:
         MAX_BLOBS_PER_BLOCK+1 blobs.
         """
         max_blobs_per_block = fork.max_blobs_per_block()
-        return cls.get_blob_combinations(max_blobs_per_block + 1)
+        max_blobs_per_tx = fork.max_blobs_per_tx()
+        invalid_combinations = cls.get_blob_combinations(
+            max_blobs_per_block + 1,
+            max_blobs_per_tx,
+        )
+        invalid_combinations.append((max_blobs_per_block + 1,))
+        return invalid_combinations

tests/cancun/eip4844_blobs/test_blob_txs.py

@@ -651,7 +651,7 @@ def test_insufficient_balance_blob_tx(
     "blobs_per_tx",
     lambda fork: [
         pytest.param([1], id="single_blob"),
-        pytest.param([fork.max_blobs_per_block()], id="max_blobs"),
+        pytest.param([fork.max_blobs_per_tx()], id="max_blobs"),
     ],
 )
 @pytest.mark.parametrize(
@@ -699,7 +699,7 @@ def test_sufficient_balance_blob_tx(
     "blobs_per_tx",
     lambda fork: [
         pytest.param([1], id="single_blob"),
-        pytest.param([fork.max_blobs_per_block()], id="max_blobs"),
+        pytest.param([fork.max_blobs_per_tx()], id="max_blobs"),
     ],
 )
 @pytest.mark.parametrize(
@@ -764,7 +764,7 @@ def test_sufficient_balance_blob_tx_pre_fund_tx(
     "blobs_per_tx",
     lambda fork: [
         pytest.param([1], id="single_blob"),
-        pytest.param([fork.max_blobs_per_block()], id="max_blobs"),
+        pytest.param([fork.max_blobs_per_tx()], id="max_blobs"),
     ],
 )
 @pytest.mark.parametrize(
@@ -875,7 +875,7 @@ def generate_invalid_tx_blob_count_tests(
             id="too_few_blobs",
         ),
         pytest.param(
-            [fork.max_blobs_per_block() + 1],
+            [fork.max_blobs_per_tx() + 1],
             [
                 TransactionException.TYPE_3_TX_MAX_BLOB_GAS_ALLOWANCE_EXCEEDED,
                 TransactionException.TYPE_3_TX_BLOB_COUNT_EXCEEDED,

tests/cancun/eip4844_blobs/test_blob_txs_full.py

@@ -241,11 +241,8 @@ def blocks(
 def generate_full_blob_tests(
     fork: Fork,
 ) -> List:
-    """
-    Return a list of tests for invalid blob transactions due to insufficient max fee per blob gas
-    parametrized for each different fork.
-    """
-    max_blobs = fork.max_blobs_per_block()
+    """Return a list of test cases for full blob transactions."""
+    max_blobs = fork.max_blobs_per_tx()
     return [
         pytest.param(
             [  # Txs