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Merge pull request #3244 from arnetheduck/back-to-the-decoupled-future
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EIP-4844: Free the blobs
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djrtwo committed Feb 20, 2023
2 parents 7fd36f7 + ac0ec66 commit ad58bfc
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Showing 7 changed files with 194 additions and 155 deletions.
4 changes: 2 additions & 2 deletions setup.py
Original file line number Diff line number Diff line change
Expand Up @@ -653,9 +653,9 @@ def preparations(cls):
@classmethod
def sundry_functions(cls) -> str:
return super().sundry_functions() + '\n\n' + '''
def retrieve_blobs_sidecar(slot: Slot, beacon_block_root: Root) -> PyUnion[BlobsSidecar, str]:
def retrieve_blobs_and_proofs(beacon_block_root: Root) -> PyUnion[Tuple[Blob, KZGProof], Tuple[str, str]]:
# pylint: disable=unused-argument
return "TEST"'''
return ("TEST", "TEST")'''

@classmethod
def hardcoded_custom_type_dep_constants(cls, spec_object) -> str:
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12 changes: 10 additions & 2 deletions specs/deneb/beacon-chain.md
Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@
- [Introduction](#introduction)
- [Custom types](#custom-types)
- [Constants](#constants)
- [Domain types](#domain-types)
- [Blob](#blob)
- [Preset](#preset)
- [Execution](#execution)
Expand Down Expand Up @@ -44,15 +45,22 @@ This upgrade adds blobs to the beacon chain as part of Deneb. This is an extensi
| Name | SSZ equivalent | Description |
| - | - | - |
| `VersionedHash` | `Bytes32` | |
| `BlobIndex` | `uint64` | |

## Constants

### Domain types

| Name | Value |
| - | - |
| `DOMAIN_BLOB_SIDECAR` | `DomainType('0x0B000000')` |

### Blob

| Name | Value |
| - | - |
| `BLOB_TX_TYPE` | `uint8(0x05)` |
| `VERSIONED_HASH_VERSION_KZG` | `Bytes1('0x01')` |
| `VERSIONED_HASH_VERSION_KZG` | `Bytes1('0x01')` |

## Preset

Expand Down Expand Up @@ -249,7 +257,7 @@ def process_blob_kzg_commitments(state: BeaconState, body: BeaconBlockBody) -> N

*Note*: The function `initialize_beacon_state_from_eth1` is modified for pure Deneb testing only.

The `BeaconState` initialization is unchanged, except for the use of the updated `deneb.BeaconBlockBody` type
The `BeaconState` initialization is unchanged, except for the use of the updated `deneb.BeaconBlockBody` type
when initializing the first body-root.

```python
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52 changes: 18 additions & 34 deletions specs/deneb/fork-choice.md
Original file line number Diff line number Diff line change
Expand Up @@ -7,9 +7,8 @@

- [Introduction](#introduction)
- [Containers](#containers)
- [`BlobsSidecar`](#blobssidecar)
- [Helpers](#helpers)
- [`validate_blobs_sidecar`](#validate_blobs_sidecar)
- [`validate_blobs`](#validate_blobs)
- [`is_data_available`](#is_data_available)
- [Updated fork-choice handlers](#updated-fork-choice-handlers)
- [`on_block`](#on_block)
Expand All @@ -23,55 +22,40 @@ This is the modification of the fork choice accompanying the Deneb upgrade.

## Containers

### `BlobsSidecar`

```python
class BlobsSidecar(Container):
beacon_block_root: Root
beacon_block_slot: Slot
blobs: List[Blob, MAX_BLOBS_PER_BLOCK]
kzg_aggregated_proof: KZGProof
```

## Helpers

#### `validate_blobs_sidecar`
#### `validate_blobs`

```python
def validate_blobs_sidecar(slot: Slot,
beacon_block_root: Root,
expected_kzg_commitments: Sequence[KZGCommitment],
blobs_sidecar: BlobsSidecar) -> None:
assert slot == blobs_sidecar.beacon_block_slot
assert beacon_block_root == blobs_sidecar.beacon_block_root
blobs = blobs_sidecar.blobs
# kzg_aggregated_proof = blobs_sidecar.kzg_aggregated_proof
def validate_blobs(expected_kzg_commitments: Sequence[KZGCommitment],
blobs: Sequence[Blob],
proofs: Sequence[KZGProof]) -> None:
assert len(expected_kzg_commitments) == len(blobs)
assert len(blobs) == len(proofs)

# Disabled because not available before switch to single blob sidecars
# assert verify_aggregate_kzg_proof(blobs, expected_kzg_commitments, kzg_aggregated_proof)
assert verify_blob_kzg_proof_batch(blobs, expected_kzg_commitments, proofs)
```

#### `is_data_available`

The implementation of `is_data_available` will become more sophisticated during later scaling upgrades.
Initially, verification requires every verifying actor to retrieve the matching `BlobsSidecar`,
and validate the sidecar with `validate_blobs_sidecar`.
Initially, verification requires every verifying actor to retrieve all matching `Blob`s and `KZGProof`s, and validate them with `validate_blobs`.

The block MUST NOT be considered valid until a valid `BlobsSidecar` has been downloaded. Blocks that have been previously validated as available SHOULD be considered available even if the associated `BlobsSidecar` has subsequently been pruned.
The block MUST NOT be considered valid until all valid `Blob`s have been downloaded. Blocks that have been previously validated as available SHOULD be considered available even if the associated `Blob`s have subsequently been pruned.

```python
def is_data_available(slot: Slot, beacon_block_root: Root, blob_kzg_commitments: Sequence[KZGCommitment]) -> bool:
# `retrieve_blobs_sidecar` is implementation and context dependent, raises an exception if not available.
def is_data_available(beacon_block_root: Root, blob_kzg_commitments: Sequence[KZGCommitment]) -> bool:
# `retrieve_blobs_and_proofs` is implementation and context dependent
# It returns all the blobs for the given block root, and raises an exception if not available
# Note: the p2p network does not guarantee sidecar retrieval outside of `MIN_EPOCHS_FOR_BLOBS_SIDECARS_REQUESTS`
sidecar = retrieve_blobs_sidecar(slot, beacon_block_root)
blobs, proofs = retrieve_blobs_and_proofs(beacon_block_root)

# For testing, `retrieve_blobs_sidecar` returns "TEST".
# TODO: Remove it once we have a way to inject `BlobsSidecar` into tests.
if isinstance(sidecar, str):
# For testing, `retrieve_blobs_and_proofs` returns ("TEST", "TEST").
# TODO: Remove it once we have a way to inject `BlobSidecar` into tests.
if isinstance(blobs, str) or isinstance(proofs, str):
return True

validate_blobs_sidecar(slot, beacon_block_root, blob_kzg_commitments, sidecar)
validate_blobs(blob_kzg_commitments, blobs, proofs)
return True
```

Expand Down Expand Up @@ -103,7 +87,7 @@ def on_block(store: Store, signed_block: SignedBeaconBlock) -> None:
# [New in Deneb]
# Check if blob data is available
# If not, this block MAY be queued and subsequently considered when blob data becomes available
assert is_data_available(block.slot, hash_tree_root(block), block.body.blob_kzg_commitments)
assert is_data_available(hash_tree_root(block), block.body.blob_kzg_commitments)

# Check the block is valid and compute the post-state
state = pre_state.copy()
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