Skip to content

Commit

Permalink
Electra: get_next_sync_committee_indices.
Browse files Browse the repository at this point in the history
  • Loading branch information
@prestonvanloon
prestonvanloon committed Jun 28, 2024
1 parent 78cf75a commit b61491f
Show file tree
Hide file tree
Showing 2 changed files with 65 additions and 41 deletions.
47 changes: 27 additions & 20 deletions beacon-chain/core/altair/sync_committee.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ import (
"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
"github.com/prysmaticlabs/prysm/v5/math"
ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
"github.com/prysmaticlabs/prysm/v5/runtime/version"
"github.com/prysmaticlabs/prysm/v5/time/slots"
)

Expand Down Expand Up @@ -85,26 +86,27 @@ func NextSyncCommittee(ctx context.Context, s state.BeaconState) (*ethpb.SyncCom
// Spec code:
// def get_next_sync_committee_indices(state: BeaconState) -> Sequence[ValidatorIndex]:
//
// """
// Return the sync committee indices, with possible duplicates, for the next sync committee.
// """
// epoch = Epoch(get_current_epoch(state) + 1)
// """
// Return the sync committee indices, with possible duplicates, for the next sync committee.
// """
// epoch = Epoch(get_current_epoch(state) + 1)
//
// MAX_RANDOM_BYTE = 2**8 - 1
// active_validator_indices = get_active_validator_indices(state, epoch)
// active_validator_count = uint64(len(active_validator_indices))
// seed = get_seed(state, epoch, DOMAIN_SYNC_COMMITTEE)
// i = 0
// sync_committee_indices: List[ValidatorIndex] = []
// while len(sync_committee_indices) < SYNC_COMMITTEE_SIZE:
// shuffled_index = compute_shuffled_index(uint64(i % active_validator_count), active_validator_count, seed)
// candidate_index = active_validator_indices[shuffled_index]
// random_byte = hash(seed + uint_to_bytes(uint64(i // 32)))[i % 32]
// effective_balance = state.validators[candidate_index].effective_balance
// if effective_balance * MAX_RANDOM_BYTE >= MAX_EFFECTIVE_BALANCE * random_byte:
// sync_committee_indices.append(candidate_index)
// i += 1
// return sync_committee_indices
// MAX_RANDOM_BYTE = 2**8 - 1
// active_validator_indices = get_active_validator_indices(state, epoch)
// active_validator_count = uint64(len(active_validator_indices))
// seed = get_seed(state, epoch, DOMAIN_SYNC_COMMITTEE)
// i = 0
// sync_committee_indices: List[ValidatorIndex] = []
// while len(sync_committee_indices) < SYNC_COMMITTEE_SIZE:
// shuffled_index = compute_shuffled_index(uint64(i % active_validator_count), active_validator_count, seed)
// candidate_index = active_validator_indices[shuffled_index]
// random_byte = hash(seed + uint_to_bytes(uint64(i // 32)))[i % 32]
// effective_balance = state.validators[candidate_index].effective_balance
// # [Modified in Electra:EIP7251]
// if effective_balance * MAX_RANDOM_BYTE >= MAX_EFFECTIVE_BALANCE_ELECTRA * random_byte:
// sync_committee_indices.append(candidate_index)
// i += 1
// return sync_committee_indices
func NextSyncCommitteeIndices(ctx context.Context, s state.BeaconState) ([]primitives.ValidatorIndex, error) {
epoch := coreTime.NextEpoch(s)
indices, err := helpers.ActiveValidatorIndices(ctx, s, epoch)
Expand All @@ -121,6 +123,11 @@ func NextSyncCommitteeIndices(ctx context.Context, s state.BeaconState) ([]primi
cIndices := make([]primitives.ValidatorIndex, 0, syncCommitteeSize)
hashFunc := hash.CustomSHA256Hasher()

maxEB := cfg.MaxEffectiveBalanceElectra
if s.Version() < version.Electra {
maxEB = cfg.MaxEffectiveBalance
}

for i := primitives.ValidatorIndex(0); uint64(len(cIndices)) < params.BeaconConfig().SyncCommitteeSize; i++ {
if ctx.Err() != nil {
return nil, ctx.Err()
Expand All @@ -140,7 +147,7 @@ func NextSyncCommitteeIndices(ctx context.Context, s state.BeaconState) ([]primi
}

effectiveBal := v.EffectiveBalance()
if effectiveBal*maxRandomByte >= cfg.MaxEffectiveBalance*uint64(randomByte) {
if effectiveBal*maxRandomByte >= maxEB*uint64(randomByte) {
cIndices = append(cIndices, cIndex)
}
}
Expand Down
59 changes: 38 additions & 21 deletions beacon-chain/core/altair/sync_committee_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -13,31 +13,43 @@ import (
"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
"github.com/prysmaticlabs/prysm/v5/crypto/bls"
ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
"github.com/prysmaticlabs/prysm/v5/runtime/version"
"github.com/prysmaticlabs/prysm/v5/testing/assert"
"github.com/prysmaticlabs/prysm/v5/testing/require"
prysmTime "github.com/prysmaticlabs/prysm/v5/time"
)

func TestSyncCommitteeIndices_CanGet(t *testing.T) {
getState := func(t *testing.T, count uint64) state.BeaconState {
getState := func(t *testing.T, count uint64, vers int) state.BeaconState {
validators := make([]*ethpb.Validator, count)
for i := 0; i < len(validators); i++ {
validators[i] = &ethpb.Validator{
ExitEpoch: params.BeaconConfig().FarFutureEpoch,
EffectiveBalance: params.BeaconConfig().MinDepositAmount,
}
}
st, err := state_native.InitializeFromProtoAltair(&ethpb.BeaconStateAltair{
RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
})
var st state.BeaconState
var err error
switch vers {
case version.Altair:
st, err = state_native.InitializeFromProtoAltair(&ethpb.BeaconStateAltair{
RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
})
case version.Electra:
st, err = state_native.InitializeFromProtoElectra(&ethpb.BeaconStateElectra{
RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
})
default:
t.Fatal("Unknown version")
}
require.NoError(t, err)
require.NoError(t, st.SetValidators(validators))
return st
}

type args struct {
state state.BeaconState
epoch primitives.Epoch
validatorCount uint64
epoch primitives.Epoch
}
tests := []struct {
name string
Expand All @@ -48,46 +60,51 @@ func TestSyncCommitteeIndices_CanGet(t *testing.T) {
{
name: "genesis validator count, epoch 0",
args: args{
state: getState(t, params.BeaconConfig().MinGenesisActiveValidatorCount),
epoch: 0,
validatorCount: params.BeaconConfig().MinGenesisActiveValidatorCount,
epoch: 0,
},
wantErr: false,
},
{
name: "genesis validator count, epoch 100",
args: args{
state: getState(t, params.BeaconConfig().MinGenesisActiveValidatorCount),
epoch: 100,
validatorCount: params.BeaconConfig().MinGenesisActiveValidatorCount,
epoch: 100,
},
wantErr: false,
},
{
name: "less than optimal validator count, epoch 100",
args: args{
state: getState(t, params.BeaconConfig().MaxValidatorsPerCommittee),
epoch: 100,
validatorCount: params.BeaconConfig().MaxValidatorsPerCommittee,
epoch: 100,
},
wantErr: false,
},
{
name: "no active validators, epoch 100",
args: args{
state: getState(t, 0), // Regression test for divide by zero. Issue #13051.
epoch: 100,
validatorCount: 0, // Regression test for divide by zero. Issue #13051.
epoch: 100,
},
wantErr: true,
errString: "no active validator indices",
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
helpers.ClearCache()
got, err := altair.NextSyncCommitteeIndices(context.Background(), tt.args.state)
if tt.wantErr {
require.ErrorContains(t, tt.errString, err)
} else {
require.NoError(t, err)
require.Equal(t, int(params.BeaconConfig().SyncCommitteeSize), len(got))
for _, v := range []int{version.Altair, version.Electra} {
t.Run(version.String(v), func(t *testing.T) {
helpers.ClearCache()
st := getState(t, tt.args.validatorCount, v)
got, err := altair.NextSyncCommitteeIndices(context.Background(), st)
if tt.wantErr {
require.ErrorContains(t, tt.errString, err)
} else {
require.NoError(t, err)
require.Equal(t, int(params.BeaconConfig().SyncCommitteeSize), len(got))
}
})
}
})
}
Expand Down

0 comments on commit b61491f

Please sign in to comment.