In-protocol deposits flow (no queue approach)

specs/_features/eip6110/beacon-chain.md

@@ -21,10 +21,7 @@
 - [Beacon chain state transition function](#beacon-chain-state-transition-function)
   - [Block processing](#block-processing)
     - [Modified `process_operations`](#modified-process_operations)
-    - [New `get_validator_from_deposit_data`](#new-get_validator_from_deposit_data)
-    - [New `apply_deposit`](#new-apply_deposit)
     - [New `process_deposit_receipt`](#new-process_deposit_receipt)
-    - [Modified `process_deposit`](#modified-process_deposit)
     - [Modified `process_execution_payload`](#modified-process_execution_payload)
 - [Testing](#testing)
 
@@ -36,7 +33,7 @@
 This is the beacon chain specification of in-protocol deposits processing mechanism.
 This mechanism relies on the changes proposed by [EIP-6110](http://eips.ethereum.org/EIPS/eip-6110).
 
-*Note:* This specification is under development and should be used with care.
+*Note:* This specification is built upon [Capella](../../capella/beacon_chain.md) and is under active development.
 
 ## Constants
 
@@ -46,7 +43,7 @@ The following values are (non-configurable) constants used throughout the specif
 
 | Name | Value |
 | - | - |
-| `NOT_SET_DEPOSIT_RECEIPTS_START_INDEX` | `uint64(2**64 - 1)` |
+| `UNSET_DEPOSIT_RECEIPTS_START_INDEX` | `uint64(2**64 - 1)` |
 
 ## Preset
 
@@ -166,7 +163,7 @@ class BeaconState(Container):
     next_withdrawal_validator_index: ValidatorIndex
     # Deep history valid from Capella onwards
     historical_summaries: List[HistoricalSummary, HISTORICAL_ROOTS_LIMIT]
-    # EIP-6110
+    # [New in EIP-6110]
     deposit_receipts_start_index: uint64
 ```
 
@@ -192,10 +189,11 @@ def process_block(state: BeaconState, block: BeaconBlock) -> None:
 
 ```python
 def process_operations(state: BeaconState, body: BeaconBlockBody) -> None:
-    # [New in EIP-6110]
-    # Prevent potential underflow introduced by mixing two deposit processing flows
-    if state.eth1_data.deposit_count > state.eth1_deposit_index:
-        assert len(body.deposits) == min(MAX_DEPOSITS, state.eth1_data.deposit_count - state.eth1_deposit_index)
+    # [Modified in EIP-6110]
+    # Disable former deposit mechanism once all prior deposits are processed
+    eth1_deposit_index_limit = min(state.eth1_data.deposit_count, state.deposit_receipts_start_index)
+    if state.eth1_deposit_index < eth1_deposit_index_limit:
+        assert len(body.deposits) == min(MAX_DEPOSITS, eth1_deposit_index_limit - state.eth1_deposit_index)
     else:
         assert len(body.deposits) == 0
 
@@ -215,68 +213,14 @@ def process_operations(state: BeaconState, body: BeaconBlockBody) -> None:
         for_ops(body.execution_payload.deposit_receipts, process_deposit_receipt)
 ```
 
-#### New `get_validator_from_deposit_data`
-
-```python
-def get_validator_from_deposit_data(pubkey: BLSPubkey, withdrawal_credentials: Bytes32, amount: uint64) -> Validator:
-    effective_balance = min(amount - amount % EFFECTIVE_BALANCE_INCREMENT, MAX_EFFECTIVE_BALANCE)
-
-    return Validator(
-        pubkey=pubkey,
-        withdrawal_credentials=withdrawal_credentials,
-        activation_eligibility_epoch=FAR_FUTURE_EPOCH,
-        activation_epoch=FAR_FUTURE_EPOCH,
-        exit_epoch=FAR_FUTURE_EPOCH,
-        withdrawable_epoch=FAR_FUTURE_EPOCH,
-        effective_balance=effective_balance,
-    )
-```
-
-#### New `apply_deposit`
-
-```python
-def apply_deposit(state: BeaconState,
-                  pubkey: BLSPubkey,
-                  withdrawal_credentials: Bytes32,
-                  amount: uint64,
-                  signature: BLSSignature,
-                  ) -> None:
-    validator_pubkeys = [validator.pubkey for validator in state.validators]
-    if pubkey not in validator_pubkeys:
-        # Verify the deposit signature (proof of possession) which is not checked by the deposit contract
-        deposit_message = DepositMessage(
-            pubkey=pubkey,
-            withdrawal_credentials=withdrawal_credentials,
-            amount=amount,
-        )
-        domain = compute_domain(DOMAIN_DEPOSIT)  # Fork-agnostic domain since deposits are valid across forks
-        signing_root = compute_signing_root(deposit_message, domain)
-        # Initialize validator if the deposit signature is valid
-        if bls.Verify(pubkey, signing_root, signature):
-            state.validators.append(get_validator_from_deposit_data(pubkey, withdrawal_credentials, amount))
-            state.balances.append(amount)
-            state.previous_epoch_participation.append(ParticipationFlags(0b0000_0000))
-            state.current_epoch_participation.append(ParticipationFlags(0b0000_0000))
-            state.inactivity_scores.append(uint64(0))
-    else:
-        # Increase balance by deposit amount
-        index = ValidatorIndex(validator_pubkeys.index(pubkey))
-        increase_balance(state, index, amount)
-```
-
-
 #### New `process_deposit_receipt`
 
 ```python
 def process_deposit_receipt(state: BeaconState, deposit_receipt: DepositReceipt) -> None:
     # Set deposit receipt start index
-    if state.deposit_receipts_start_index == NOT_SET_DEPOSIT_RECEIPTS_START_INDEX:
+    if state.deposit_receipts_start_index == UNSET_DEPOSIT_RECEIPTS_START_INDEX:
         state.deposit_receipts_start_index = deposit_receipt.index
 
-    # Signify the end of transition to in-protocol deposit logic
-    if state.eth1_deposit_index >= state.deposit_receipts_start_index:
-        state.eth1_deposit_index = deposit_receipt.index + 1
-
     apply_deposit(
         state=state, 
         pubkey=deposit_receipt.pubkey,
@@ -286,39 +230,6 @@ def process_deposit_receipt(state: BeaconState, deposit_receipt: DepositReceipt)
     )
 ```
 
-#### Modified `process_deposit`
-
-*Note*: The function `process_deposit` is modified to prevent deposits from being processed the second time (due to `process_deposit_receipt`).
-
-```python
-def process_deposit(state: BeaconState, deposit: Deposit) -> None:
-    # [New in EIP-6110]
-    # Skip already processed deposits
-    if state.eth1_deposit_index >= state.deposit_receipts_start_index:
-        state.eth1_deposit_index += 1
-        return
-
-    # Verify the Merkle branch
-    assert is_valid_merkle_branch(
-        leaf=hash_tree_root(deposit.data),
-        branch=deposit.proof,
-        depth=DEPOSIT_CONTRACT_TREE_DEPTH + 1,  # Add 1 for the List length mix-in
-        index=state.eth1_deposit_index,
-        root=state.eth1_data.deposit_root,
-    )
-
-    # Deposits must be processed in order
-    state.eth1_deposit_index += 1
-
-    apply_deposit(
-        state=state, 
-        pubkey=deposit.data.pubkey,
-        withdrawal_credentials=deposit.data.withdrawal_credentials,
-        amount=deposit.data.amount,
-        signature=deposit.data.signature,
-    )
-```
-
 #### Modified `process_execution_payload`
 
 *Note*: The function `process_execution_payload` is modified to use the new `ExecutionPayloadHeader` type.
@@ -380,7 +291,7 @@ def initialize_beacon_state_from_eth1(eth1_block_hash: Hash32,
         eth1_data=Eth1Data(block_hash=eth1_block_hash, deposit_count=uint64(len(deposits))),
         latest_block_header=BeaconBlockHeader(body_root=hash_tree_root(BeaconBlockBody())),
         randao_mixes=[eth1_block_hash] * EPOCHS_PER_HISTORICAL_VECTOR,  # Seed RANDAO with Eth1 entropy
-        deposit_receipts_start_index=NOT_SET_DEPOSIT_RECEIPTS_START_INDEX,  # [New in EIP6110]
+        deposit_receipts_start_index=UNSET_DEPOSIT_RECEIPTS_START_INDEX,  # [New in EIP6110]
     )
 
     # Process deposits

specs/_features/eip6110/fork.md

@@ -135,7 +135,7 @@ def upgrade_to_eip6110(pre: capella.BeaconState) -> BeaconState:
         # Deep history valid from Capella onwards
         historical_summaries=pre.historical_summaries,
         # EIP-6110
-        deposit_receipts_start_index=NOT_SET_DEPOSIT_RECEIPTS_START_INDEX,  # [New in EIP-6110]
+        deposit_receipts_start_index=UNSET_DEPOSIT_RECEIPTS_START_INDEX,  # [New in EIP-6110]
     )
 
     return post

specs/_features/eip6110/validator.md

@@ -0,0 +1,42 @@
+# EIP-6110 -- Honest Validator
+
+## Table of contents
+
+<!-- TOC -->
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+
+- [Introduction](#introduction)
+- [Prerequisites](#prerequisites)
+- [Block proposal](#block-proposal)
+  - [Deposits](#deposits)
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+<!-- /TOC -->
+
+## Introduction
+
+This document represents the changes to be made in the code of an "honest validator" to implement EIP-6110.
+
+## Prerequisites
+
+This document is an extension of the [Capella -- Honest Validator](../../capella/validator.md) guide.
+All behaviors and definitions defined in this document, and documents it extends, carry over unless explicitly noted or overridden.
+
+All terminology, constants, functions, and protocol mechanics defined in the updated Beacon Chain doc of [EIP-6110](./beacon-chain.md) are requisite for this document and used throughout.
+Please see related Beacon Chain doc before continuing and use them as a reference throughout.
+
+## Block proposal
+
+### Deposits
+
+The expected number of deposits MUST be changed from `min(MAX_DEPOSITS, eth1_data.deposit_count - state.eth1_deposit_index)` to the result of the following function:
+
+```python
+def get_eth1_deposit_count(state: BeaconState) -> uint64:
+    eth1_deposit_index_limit = min(state.eth1_data.deposit_count, state.deposit_receipts_start_index)
+    if state.eth1_deposit_index < eth1_deposit_index_limit:
+        return min(MAX_DEPOSITS, eth1_deposit_index_limit - state.eth1_deposit_index)
+    else:
+        return 0
+```

specs/altair/beacon-chain.md

@@ -43,7 +43,7 @@
     - [Modified `slash_validator`](#modified-slash_validator)
   - [Block processing](#block-processing)
     - [Modified `process_attestation`](#modified-process_attestation)
-    - [Modified `process_deposit`](#modified-process_deposit)
+    - [Modified `apply_deposit`](#modified-apply_deposit)
     - [Sync aggregate processing](#sync-aggregate-processing)
   - [Epoch processing](#epoch-processing)
     - [Justification and finalization](#justification-and-finalization)
@@ -489,39 +489,29 @@ def process_attestation(state: BeaconState, attestation: Attestation) -> None:
     increase_balance(state, get_beacon_proposer_index(state), proposer_reward)
 ```
 
-#### Modified `process_deposit`
+#### Modified `apply_deposit`
 
-*Note*: The function `process_deposit` is modified to initialize `inactivity_scores`, `previous_epoch_participation`, and `current_epoch_participation`.
+*Note*: The function `apply_deposit` is modified to initialize `inactivity_scores`, `previous_epoch_participation`, and `current_epoch_participation`.
 
 ```python
-def process_deposit(state: BeaconState, deposit: Deposit) -> None:
-    # Verify the Merkle branch
-    assert is_valid_merkle_branch(
-        leaf=hash_tree_root(deposit.data),
-        branch=deposit.proof,
-        depth=DEPOSIT_CONTRACT_TREE_DEPTH + 1,  # Add 1 for the List length mix-in
-        index=state.eth1_deposit_index,
-        root=state.eth1_data.deposit_root,
-    )
-
-    # Deposits must be processed in order
-    state.eth1_deposit_index += 1
-
-    pubkey = deposit.data.pubkey
-    amount = deposit.data.amount
+def apply_deposit(state: BeaconState,
+                  pubkey: BLSPubkey,
+                  withdrawal_credentials: Bytes32,
+                  amount: uint64,
+                  signature: BLSSignature) -> None:
     validator_pubkeys = [validator.pubkey for validator in state.validators]
     if pubkey not in validator_pubkeys:
         # Verify the deposit signature (proof of possession) which is not checked by the deposit contract
         deposit_message = DepositMessage(
-            pubkey=deposit.data.pubkey,
-            withdrawal_credentials=deposit.data.withdrawal_credentials,
-            amount=deposit.data.amount,
+            pubkey=pubkey,
+            withdrawal_credentials=withdrawal_credentials,
+            amount=amount,
         )
         domain = compute_domain(DOMAIN_DEPOSIT)  # Fork-agnostic domain since deposits are valid across forks
         signing_root = compute_signing_root(deposit_message, domain)
         # Initialize validator if the deposit signature is valid
-        if bls.Verify(pubkey, signing_root, deposit.data.signature):
-            state.validators.append(get_validator_from_deposit(deposit))
+        if bls.Verify(pubkey, signing_root, signature):
+            state.validators.append(get_validator_from_deposit(pubkey, withdrawal_credentials, amount))
             state.balances.append(amount)
             # [New in Altair]
             state.previous_epoch_participation.append(ParticipationFlags(0b0000_0000))

specs/phase0/beacon-chain.md

@@ -1835,13 +1835,12 @@ def process_attestation(state: BeaconState, attestation: Attestation) -> None:
 ##### Deposits
 
 ```python
-def get_validator_from_deposit(deposit: Deposit) -> Validator:
-    amount = deposit.data.amount
+def get_validator_from_deposit(pubkey: BLSPubkey, withdrawal_credentials: Bytes32, amount: uint64) -> Validator:
     effective_balance = min(amount - amount % EFFECTIVE_BALANCE_INCREMENT, MAX_EFFECTIVE_BALANCE)
 
     return Validator(
-        pubkey=deposit.data.pubkey,
-        withdrawal_credentials=deposit.data.withdrawal_credentials,
+        pubkey=pubkey,
+        withdrawal_credentials=withdrawal_credentials,
         activation_eligibility_epoch=FAR_FUTURE_EPOCH,
         activation_epoch=FAR_FUTURE_EPOCH,
         exit_epoch=FAR_FUTURE_EPOCH,
@@ -1851,43 +1850,56 @@ def get_validator_from_deposit(deposit: Deposit) -> Validator:
 ```
 
 ```python
-def process_deposit(state: BeaconState, deposit: Deposit) -> None:
-    # Verify the Merkle branch
-    assert is_valid_merkle_branch(
-        leaf=hash_tree_root(deposit.data),
-        branch=deposit.proof,
-        depth=DEPOSIT_CONTRACT_TREE_DEPTH + 1,  # Add 1 for the List length mix-in
-        index=state.eth1_deposit_index,
-        root=state.eth1_data.deposit_root,
-    )
-
-    # Deposits must be processed in order
-    state.eth1_deposit_index += 1
-
-    pubkey = deposit.data.pubkey
-    amount = deposit.data.amount
+def apply_deposit(state: BeaconState,
+                  pubkey: BLSPubkey,
+                  withdrawal_credentials: Bytes32,
+                  amount: uint64,
+                  signature: BLSSignature) -> None:
     validator_pubkeys = [v.pubkey for v in state.validators]
     if pubkey not in validator_pubkeys:
         # Verify the deposit signature (proof of possession) which is not checked by the deposit contract
         deposit_message = DepositMessage(
-            pubkey=deposit.data.pubkey,
-            withdrawal_credentials=deposit.data.withdrawal_credentials,
-            amount=deposit.data.amount,
+            pubkey=pubkey,
+            withdrawal_credentials=withdrawal_credentials,
+            amount=amount,
         )
         domain = compute_domain(DOMAIN_DEPOSIT)  # Fork-agnostic domain since deposits are valid across forks
         signing_root = compute_signing_root(deposit_message, domain)
-        if not bls.Verify(pubkey, signing_root, deposit.data.signature):
+        if not bls.Verify(pubkey, signing_root, signature):
             return
 
         # Add validator and balance entries
-        state.validators.append(get_validator_from_deposit(deposit))
+        state.validators.append(get_validator_from_deposit(pubkey, withdrawal_credentials, amount))
         state.balances.append(amount)
     else:
         # Increase balance by deposit amount
         index = ValidatorIndex(validator_pubkeys.index(pubkey))
         increase_balance(state, index, amount)
 ```
 
+```python
+def process_deposit(state: BeaconState, deposit: Deposit) -> None:
+    # Verify the Merkle branch
+    assert is_valid_merkle_branch(
+        leaf=hash_tree_root(deposit.data),
+        branch=deposit.proof,
+        depth=DEPOSIT_CONTRACT_TREE_DEPTH + 1,  # Add 1 for the List length mix-in
+        index=state.eth1_deposit_index,
+        root=state.eth1_data.deposit_root,
+    )
+
+    # Deposits must be processed in order
+    state.eth1_deposit_index += 1
+
+    apply_deposit(
+        state=state,
+        pubkey=deposit.data.pubkey,
+        withdrawal_credentials=deposit.data.withdrawal_credentials,
+        amount=deposit.data.amount,
+        signature=deposit.data.signature,
+    )
+```
+
 ##### Voluntary exits
 
 ```python