Add max epoch activation churn limit (EIP-7514) to Deneb

.gitignore

@@ -23,6 +23,7 @@ tests/core/pyspec/eth2spec/capella/
 tests/core/pyspec/eth2spec/deneb/
 tests/core/pyspec/eth2spec/eip6110/
 tests/core/pyspec/eth2spec/eip7002/
+tests/core/pyspec/eth2spec/eip7668/
 tests/core/pyspec/eth2spec/whisk/
 
 # coverage reports

configs/mainnet.yaml

@@ -56,6 +56,9 @@ EIP6110_FORK_EPOCH: 18446744073709551615
 # EIP7002
 EIP7002_FORK_VERSION: 0x05000000  # temporary stub
 EIP7002_FORK_EPOCH: 18446744073709551615
+# EIP7668
+EIP7668_FORK_VERSION: 0x05000000  # temporary stub
+EIP7668_FORK_EPOCH: 18446744073709551615
 # WHISK
 WHISK_FORK_VERSION: 0x06000000  # temporary stub
 WHISK_FORK_EPOCH: 18446744073709551615
@@ -146,3 +149,6 @@ BLOB_SIDECAR_SUBNET_COUNT: 6
 WHISK_EPOCHS_PER_SHUFFLING_PHASE: 256
 # `Epoch(2)`
 WHISK_PROPOSER_SELECTION_GAP: 2
+
+# EIP7668
+MAX_PER_EPOCH_INBOUND_CHURN_LIMIT: 12

configs/minimal.yaml

@@ -55,6 +55,9 @@ EIP6110_FORK_EPOCH: 18446744073709551615
 # EIP7002
 EIP7002_FORK_VERSION: 0x05000001
 EIP7002_FORK_EPOCH: 18446744073709551615
+# EIP7668
+EIP7668_FORK_VERSION: 0x05000001  # temporary stub
+EIP7668_FORK_EPOCH: 18446744073709551615
 # WHISK
 WHISK_FORK_VERSION: 0x06000001
 WHISK_FORK_EPOCH: 18446744073709551615
@@ -145,3 +148,6 @@ BLOB_SIDECAR_SUBNET_COUNT: 6
 # Whisk
 WHISK_EPOCHS_PER_SHUFFLING_PHASE: 4
 WHISK_PROPOSER_SELECTION_GAP: 1
+
+# EIP7668
+MAX_PER_EPOCH_INBOUND_CHURN_LIMIT: 12

pysetup/constants.py

@@ -6,6 +6,7 @@
 DENEB = 'deneb'
 EIP6110 = 'eip6110'
 EIP7002 = 'eip7002'
+EIP7668 = 'eip7668'
 WHISK = 'whisk'
 
 

pysetup/md_doc_paths.py

@@ -9,6 +9,7 @@
     EIP6110,
     WHISK,
     EIP7002,
+    EIP7668,
 )
 
 
@@ -21,6 +22,7 @@
     EIP6110: DENEB,
     WHISK: CAPELLA,
     EIP7002: CAPELLA,
+    EIP7668: CAPELLA,
 }
 
 ALL_FORKS = list(PREVIOUS_FORK_OF.keys())

pysetup/spec_builders/__init__.py

@@ -5,13 +5,14 @@
 from .deneb import DenebSpecBuilder
 from .eip6110 import EIP6110SpecBuilder
 from .eip7002 import EIP7002SpecBuilder
+from .eip7668 import EIP7668SpecBuilder
 from .whisk import WhiskSpecBuilder
 
 
 spec_builders = {
     builder.fork: builder
     for builder in (
         Phase0SpecBuilder, AltairSpecBuilder, BellatrixSpecBuilder, CapellaSpecBuilder, DenebSpecBuilder,
-        EIP6110SpecBuilder, EIP7002SpecBuilder, WhiskSpecBuilder,
+        EIP6110SpecBuilder, EIP7002SpecBuilder, EIP7668SpecBuilder, WhiskSpecBuilder,
     )
 }

pysetup/spec_builders/eip7668.py

@@ -0,0 +1,12 @@
+from .base import BaseSpecBuilder
+from ..constants import EIP7668
+
+
+class EIP7668SpecBuilder(BaseSpecBuilder):
+    fork: str = EIP7668
+
+    @classmethod
+    def imports(cls, preset_name: str):
+        return super().imports(preset_name) + f'''
+from eth2spec.capella import {preset_name} as capella
+'''

specs/_features/eip7668/beacon_chain.md

@@ -0,0 +1,88 @@
+Limit churn -- The Beacon Chain
+
+## 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)
+- [Configuration](#configuration)
+  - [Validator cycle](#validator-cycle)
+- [Helper functions](#helper-functions)
+  - [Beacon state accessors](#beacon-state-accessors)
+    - [New `get_validator_inbound_churn_limit`](#new-get_validator_inbound_churn_limit)
+- [Beacon chain state transition function](#beacon-chain-state-transition-function)
+  - [Epoch processing](#epoch-processing)
+    - [Registry updates](#registry-updates)
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+<!-- /TOC -->
+
+## Introduction
+
+This is the beacon chain specification to limit the max inbound churn value, motivated to limit the validator active set growth rate.
+
+*Note:* This specification is built upon [Capella](../../capella/beacon_chain.md) and is under active development.
+
+## Configuration
+
+### Validator cycle
+
+| Name | Value |
+| - | - |
+| `MAX_PER_EPOCH_INBOUND_CHURN_LIMIT` | `uint64(12)` (= 12) |
+
+## Helper functions
+
+### Beacon state accessors
+
+#### New `get_validator_inbound_churn_limit`
+
+```python
+def get_validator_inbound_churn_limit(state: BeaconState) -> uint64:
+    """
+    Return the validator inbound churn limit for the current epoch.
+    """
+    active_validator_indices = get_active_validator_indices(state, get_current_epoch(state))
+    return min(
+        MAX_PER_EPOCH_INBOUND_CHURN_LIMIT,
+        max(
+            MIN_PER_EPOCH_CHURN_LIMIT,
+            uint64(len(active_validator_indices)) // CHURN_LIMIT_QUOTIENT,
+        ),
+    )
+```
+
+## Beacon chain state transition function
+
+### Epoch processing
+
+#### Registry updates
+
+```python
+def process_registry_updates(state: BeaconState) -> None:
+    # Process activation eligibility and ejections
+    for index, validator in enumerate(state.validators):
+        if is_eligible_for_activation_queue(validator):
+            validator.activation_eligibility_epoch = get_current_epoch(state) + 1
+
+        if (
+            is_active_validator(validator, get_current_epoch(state))
+            and validator.effective_balance <= EJECTION_BALANCE
+        ):
+            initiate_validator_exit(state, ValidatorIndex(index))
+
+    # Queue validators eligible for activation and not yet dequeued for activation
+    activation_queue = sorted([
+        index for index, validator in enumerate(state.validators)
+        if is_eligible_for_activation(state, validator)
+        # Order by the sequence of activation_eligibility_epoch setting and then index
+    ], key=lambda index: (state.validators[index].activation_eligibility_epoch, index))
+    # Dequeued validators for activation up to churn limit
+    # [Modified in limit churn]
+    for index in activation_queue[:get_validator_inbound_churn_limit(state)]:
+        validator = state.validators[index]
+        validator.activation_epoch = compute_activation_exit_epoch(get_current_epoch(state))
+```
+

specs/_features/eip7668/fork.md

@@ -0,0 +1,139 @@
+# EIP-7668 -- Fork Logic
+
+**Notice**: This document is a work-in-progress for researchers and implementers.
+
+## Table of contents
+
+<!-- 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)
+- [Configuration](#configuration)
+- [Helper functions](#helper-functions)
+  - [Misc](#misc)
+    - [Modified `compute_fork_version`](#modified-compute_fork_version)
+- [Fork to EIP-7668](#fork-to-eip-7668)
+  - [Fork trigger](#fork-trigger)
+  - [Upgrading the state](#upgrading-the-state)
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+
+## Introduction
+
+This document describes the process of EIP-7668 upgrade.
+
+## Configuration
+
+Warning: this configuration is not definitive.
+
+| Name | Value |
+| - | - |
+| `EIP7668_FORK_VERSION` | `Version('0x05000000')` |
+| `EIP7668_FORK_EPOCH` | `Epoch(18446744073709551615)` **TBD** |
+
+## Helper functions
+
+### Misc
+
+#### Modified `compute_fork_version`
+
+```python
+def compute_fork_version(epoch: Epoch) -> Version:
+    """
+    Return the fork version at the given ``epoch``.
+    """
+    if epoch >= EIP7668_FORK_EPOCH:
+        return EIP7668_FORK_VERSION
+    if epoch >= CAPELLA_FORK_EPOCH:
+        return CAPELLA_FORK_VERSION
+    if epoch >= BELLATRIX_FORK_EPOCH:
+        return BELLATRIX_FORK_VERSION
+    if epoch >= ALTAIR_FORK_EPOCH:
+        return ALTAIR_FORK_VERSION
+    return GENESIS_FORK_VERSION
+```
+
+## Fork to EIP-7668
+
+### Fork trigger
+
+TBD. This fork is defined for testing purposes, the EIP may be combined with other consensus-layer upgrade.
+For now, we assume the condition will be triggered at epoch `EIP7668_FORK_EPOCH`.
+
+Note that for the pure EIP-7668 networks, we don't apply `upgrade_to_eip7668` since it starts with EIP-7668 version logic.
+
+### Upgrading the state
+
+If `state.slot % SLOTS_PER_EPOCH == 0` and `compute_epoch_at_slot(state.slot) == EIP7668_FORK_EPOCH`,
+an irregular state change is made to upgrade to EIP-7668.
+
+```python
+def upgrade_to_eip7668(pre: capella.BeaconState) -> BeaconState:
+    epoch = capella.get_current_epoch(pre)
+    latest_execution_payload_header = ExecutionPayloadHeader(
+        parent_hash=pre.latest_execution_payload_header.parent_hash,
+        fee_recipient=pre.latest_execution_payload_header.fee_recipient,
+        state_root=pre.latest_execution_payload_header.state_root,
+        receipts_root=pre.latest_execution_payload_header.receipts_root,
+        logs_bloom=pre.latest_execution_payload_header.logs_bloom,
+        prev_randao=pre.latest_execution_payload_header.prev_randao,
+        block_number=pre.latest_execution_payload_header.block_number,
+        gas_limit=pre.latest_execution_payload_header.gas_limit,
+        gas_used=pre.latest_execution_payload_header.gas_used,
+        timestamp=pre.latest_execution_payload_header.timestamp,
+        extra_data=pre.latest_execution_payload_header.extra_data,
+        base_fee_per_gas=pre.latest_execution_payload_header.base_fee_per_gas,
+        block_hash=pre.latest_execution_payload_header.block_hash,
+        transactions_root=pre.latest_execution_payload_header.transactions_root,
+        withdrawals_root=pre.latest_execution_payload_header.withdrawals_root,
+    )
+    post = BeaconState(
+        # Versioning
+        genesis_time=pre.genesis_time,
+        genesis_validators_root=pre.genesis_validators_root,
+        slot=pre.slot,
+        fork=Fork(
+            previous_version=pre.fork.current_version,
+            current_version=EIP7668_FORK_VERSION,  # [Modified in EIP-7668]
+            epoch=epoch,
+        ),
+        # History
+        latest_block_header=pre.latest_block_header,
+        block_roots=pre.block_roots,
+        state_roots=pre.state_roots,
+        historical_roots=pre.historical_roots,
+        # Eth1
+        eth1_data=pre.eth1_data,
+        eth1_data_votes=pre.eth1_data_votes,
+        eth1_deposit_index=pre.eth1_deposit_index,
+        # Registry
+        validators=pre.validators,
+        balances=pre.balances,
+        # Randomness
+        randao_mixes=pre.randao_mixes,
+        # Slashings
+        slashings=pre.slashings,
+        # Participation
+        previous_epoch_participation=pre.previous_epoch_participation,
+        current_epoch_participation=pre.current_epoch_participation,
+        # Finality
+        justification_bits=pre.justification_bits,
+        previous_justified_checkpoint=pre.previous_justified_checkpoint,
+        current_justified_checkpoint=pre.current_justified_checkpoint,
+        finalized_checkpoint=pre.finalized_checkpoint,
+        # Inactivity
+        inactivity_scores=pre.inactivity_scores,
+        # Sync
+        current_sync_committee=pre.current_sync_committee,
+        next_sync_committee=pre.next_sync_committee,
+        # Execution-layer
+        latest_execution_payload_header=latest_execution_payload_header,
+        # Withdrawals
+        next_withdrawal_index=pre.next_withdrawal_index,
+        next_withdrawal_validator_index=pre.next_withdrawal_validator_index,
+        # Deep history valid from Capella onwards
+        historical_summaries=pre.historical_summaries,
+    )
+
+    return post
+```

tests/core/pyspec/eth2spec/test/context.py

@@ -10,12 +10,13 @@
 from eth2spec.deneb import mainnet as spec_deneb_mainnet, minimal as spec_deneb_minimal
 from eth2spec.eip6110 import mainnet as spec_eip6110_mainnet, minimal as spec_eip6110_minimal
 from eth2spec.eip7002 import mainnet as spec_eip7002_mainnet, minimal as spec_eip7002_minimal
+from eth2spec.eip7668 import mainnet as spec_eip7668_mainnet, minimal as spec_eip7668_minimal
 from eth2spec.utils import bls
 
 from .exceptions import SkippedTest
 from .helpers.constants import (
     PHASE0, ALTAIR, BELLATRIX, CAPELLA, DENEB,
-    EIP6110, EIP7002,
+    EIP6110, EIP7002, EIP7668,
     MINIMAL, MAINNET,
     ALL_PHASES,
     ALL_FORK_UPGRADES,
@@ -85,6 +86,7 @@ class ForkMeta:
         DENEB: spec_deneb_minimal,
         EIP6110: spec_eip6110_minimal,
         EIP7002: spec_eip7002_minimal,
+        EIP7668: spec_eip7668_minimal,
     },
     MAINNET: {
         PHASE0: spec_phase0_mainnet,
@@ -94,6 +96,7 @@ class ForkMeta:
         DENEB: spec_deneb_mainnet,
         EIP6110: spec_eip6110_mainnet,
         EIP7002: spec_eip7002_mainnet,
+        EIP7668: spec_eip7668_mainnet,
     },
 }
 

tests/core/pyspec/eth2spec/test/helpers/constants.py

@@ -18,6 +18,7 @@
 DAS = SpecForkName('das')
 EIP6110 = SpecForkName('eip6110')
 EIP7002 = SpecForkName('eip7002')
+EIP7668 = SpecForkName('eip7668')
 
 #
 # SpecFork settings
@@ -34,6 +35,7 @@
     # Experimental patches
     EIP6110,
     EIP7002,
+    EIP7668,
 )
 # The forks that have light client specs
 LIGHT_CLIENT_TESTING_FORKS = (*[item for item in MAINNET_FORKS if item != PHASE0], DENEB)

tests/core/pyspec/eth2spec/test/helpers/forks.py

@@ -1,10 +1,12 @@
 from .constants import (
     PHASE0, ALTAIR, BELLATRIX, CAPELLA, DENEB,
-    EIP6110, EIP7002,
+    EIP6110, EIP7002, EIP7668,
 )
 
 
 def is_post_fork(a, b):
+    if a == EIP7668:
+        return b in [PHASE0, ALTAIR, BELLATRIX, CAPELLA, EIP7668]
     if a == EIP7002:
         return b in [PHASE0, ALTAIR, BELLATRIX, CAPELLA, EIP7002]
     if a == EIP6110: