Naive aggregation for SyncCommitteeContribution (#9114)

* Copy CopySyncCommitteeContribution

* Update BUILD.bazel

* Add naive aggregation for sync contribution

* Gazelle

* Update deps.bzl

Co-authored-by: Nishant Das <nishdas93@gmail.com>

deps.bzl

@@ -2779,8 +2779,8 @@ def prysm_deps():
     go_repository(
         name = "com_github_prysmaticlabs_go_bitfield",
         importpath = "github.com/prysmaticlabs/go-bitfield",
-        sum = "h1:yALGBNFMp40DeD3qGGRgiC0FWePzy0FIhxWEXoco3ZA=",
-        version = "v0.0.0-20210628171552-0c86d791fc37",
+        sum = "h1:nc95NsZcGforJ9a3QbsAdGcG3TbFHaLfHeaHi62CMso=",
+        version = "v0.0.0-20210628211147-0d89f726b4c2",
     )
     go_repository(
         name = "com_github_prysmaticlabs_prombbolt",

go.mod

@@ -88,7 +88,7 @@ require (
 	github.com/prometheus/prom2json v1.3.0
 	github.com/prometheus/tsdb v0.10.0 // indirect
 	github.com/prysmaticlabs/eth2-types v0.0.0-20210303084904-c9735a06829d
-	github.com/prysmaticlabs/go-bitfield v0.0.0-20210628171552-0c86d791fc37
+	github.com/prysmaticlabs/go-bitfield v0.0.0-20210628211147-0d89f726b4c2
 	github.com/prysmaticlabs/prombbolt v0.0.0-20210126082820-9b7adba6db7c
 	github.com/prysmaticlabs/protoc-gen-go-cast v0.0.0-20210504233148-1e141af6a0a1
 	github.com/r3labs/sse v0.0.0-20210224172625-26fe804710bc

go.sum

@@ -1069,8 +1069,8 @@ github.com/prysmaticlabs/bazel-go-ethereum v0.0.0-20210420143944-f4dfc9744288/go
 github.com/prysmaticlabs/eth2-types v0.0.0-20210303084904-c9735a06829d h1:1dN7YAqMN3oAJ0LceWcyv/U4jHLh+5urnSnr4br6zg4=
 github.com/prysmaticlabs/eth2-types v0.0.0-20210303084904-c9735a06829d/go.mod h1:kOmQ/zdobQf7HUohDTifDNFEZfNaSCIY5fkONPL+dWU=
 github.com/prysmaticlabs/go-bitfield v0.0.0-20210108222456-8e92c3709aa0/go.mod h1:hCwmef+4qXWjv0jLDbQdWnL0Ol7cS7/lCSS26WR+u6s=
-github.com/prysmaticlabs/go-bitfield v0.0.0-20210628171552-0c86d791fc37 h1:yALGBNFMp40DeD3qGGRgiC0FWePzy0FIhxWEXoco3ZA=
-github.com/prysmaticlabs/go-bitfield v0.0.0-20210628171552-0c86d791fc37/go.mod h1:hCwmef+4qXWjv0jLDbQdWnL0Ol7cS7/lCSS26WR+u6s=
+github.com/prysmaticlabs/go-bitfield v0.0.0-20210628211147-0d89f726b4c2 h1:nc95NsZcGforJ9a3QbsAdGcG3TbFHaLfHeaHi62CMso=
+github.com/prysmaticlabs/go-bitfield v0.0.0-20210628211147-0d89f726b4c2/go.mod h1:hCwmef+4qXWjv0jLDbQdWnL0Ol7cS7/lCSS26WR+u6s=
 github.com/prysmaticlabs/grpc-gateway/v2 v2.3.1-0.20210622145107-ca3041e1b380 h1:KzQOksIZB8poBiMk8h5Txzbp/OoBLFhS3H20ZN06hWg=
 github.com/prysmaticlabs/grpc-gateway/v2 v2.3.1-0.20210622145107-ca3041e1b380/go.mod h1:IOyTYjcIO0rkmnGBfJTL0NJ11exy/Tc2QEuv7hCXp24=
 github.com/prysmaticlabs/prombbolt v0.0.0-20210126082820-9b7adba6db7c h1:9PHRCuO/VN0s9k+RmLykho7AjDxblNYI5bYKed16NPU=

shared/aggregation/sync_contribution/BUILD.bazel

@@ -0,0 +1,36 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+load("@prysm//tools/go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "contribution.go",
+        "naive.go",
+    ],
+    importpath = "github.com/prysmaticlabs/prysm/shared/aggregation/sync_contribution",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//proto/prysm/v2:go_default_library",
+        "//shared/aggregation:go_default_library",
+        "//shared/bls:go_default_library",
+        "//shared/copyutil:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
+        "@com_github_sirupsen_logrus//:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["naive_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "//proto/prysm/v2:go_default_library",
+        "//shared/aggregation:go_default_library",
+        "//shared/aggregation/testing:go_default_library",
+        "//shared/bls:go_default_library",
+        "//shared/featureconfig:go_default_library",
+        "//shared/testutil/assert:go_default_library",
+        "//shared/testutil/require:go_default_library",
+        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
+    ],
+)

shared/aggregation/sync_contribution/contribution.go

@@ -0,0 +1,41 @@
+package sync_contribution
+
+import (
+	"github.com/pkg/errors"
+	v2 "github.com/prysmaticlabs/prysm/proto/prysm/v2"
+	"github.com/prysmaticlabs/prysm/shared/aggregation"
+	"github.com/sirupsen/logrus"
+)
+
+const (
+	// NaiveAggregation is an aggregation strategy without any optimizations.
+	NaiveAggregation SyncContributionAggregationStrategy = "naive"
+
+	// MaxCoverAggregation is a strategy based on Maximum Coverage greedy algorithm.
+	MaxCoverAggregation SyncContributionAggregationStrategy = "max_cover"
+)
+
+// SyncContributionAggregationStrategy defines SyncContribution aggregation strategy.
+type SyncContributionAggregationStrategy string
+
+var _ = logrus.WithField("prefix", "aggregation.sync_contribution")
+
+// ErrInvalidSyncContributionCount is returned when insufficient number
+// of sync contributions is provided for aggregation.
+var ErrInvalidSyncContributionCount = errors.New("invalid number of sync contributions")
+
+// Aggregate aggregates sync contributions. The minimal number of sync contributions is returned.
+// Aggregation occurs in-place i.e. contents of input array will be modified. Should you need to
+// preserve input sync contributions, clone them before aggregating.
+func Aggregate(cs []*v2.SyncCommitteeContribution) ([]*v2.SyncCommitteeContribution, error) {
+	strategy := NaiveAggregation
+	switch strategy {
+	case "", NaiveAggregation:
+		return naiveSyncContributionAggregation(cs)
+	case MaxCoverAggregation:
+		// TODO: Implement max cover aggregation for sync contributions.
+		return nil, errors.New("no implemented")
+	default:
+		return nil, errors.Wrapf(aggregation.ErrInvalidStrategy, "%q", strategy)
+	}
+}

shared/aggregation/sync_contribution/naive.go

@@ -0,0 +1,93 @@
+package sync_contribution
+
+import (
+	v2 "github.com/prysmaticlabs/prysm/proto/prysm/v2"
+	"github.com/prysmaticlabs/prysm/shared/aggregation"
+	"github.com/prysmaticlabs/prysm/shared/bls"
+	"github.com/prysmaticlabs/prysm/shared/copyutil"
+)
+
+// naiveSyncContributionAggregation aggregates naively, without any complex algorithms or optimizations.
+// Note: this is currently a naive implementation to the order of O(mn^2).
+func naiveSyncContributionAggregation(contributions []*v2.SyncCommitteeContribution) ([]*v2.SyncCommitteeContribution, error) {
+	if len(contributions) <= 1 {
+		return contributions, nil
+	}
+
+	// Naive aggregation. O(n^2) time.
+	for i, a := range contributions {
+		if i >= len(contributions) {
+			break
+		}
+		for j := i + 1; j < len(contributions); j++ {
+			b := contributions[j]
+			if a.AggregationBits.Len() == b.AggregationBits.Len() && !a.AggregationBits.Overlaps(b.AggregationBits) {
+				var err error
+				a, err = aggregate(a, b)
+				if err != nil {
+					return nil, err
+				}
+				// Delete b
+				contributions = append(contributions[:j], contributions[j+1:]...)
+				j--
+				contributions[i] = a
+			}
+		}
+	}
+
+	// Naive deduplication of identical contributions. O(n^2) time.
+	for i, a := range contributions {
+		for j := i + 1; j < len(contributions); j++ {
+			b := contributions[j]
+
+			if a.AggregationBits.Len() != b.AggregationBits.Len() {
+				continue
+			}
+
+			if a.AggregationBits.Contains(b.AggregationBits) {
+				// If b is fully contained in a, then b can be removed.
+				contributions = append(contributions[:j], contributions[j+1:]...)
+				j--
+			} else if b.AggregationBits.Contains(a.AggregationBits) {
+				// if a is fully contained in b, then a can be removed.
+				contributions = append(contributions[:i], contributions[i+1:]...)
+				break // Stop the inner loop, advance a.
+			}
+		}
+	}
+
+	return contributions, nil
+}
+
+// aggregates pair of sync contributions c1 and c2 together.
+func aggregate(c1, c2 *v2.SyncCommitteeContribution) (*v2.SyncCommitteeContribution, error) {
+	if c1.AggregationBits.Overlaps(c2.AggregationBits) {
+		return nil, aggregation.ErrBitsOverlap
+	}
+
+	baseContribution := copyutil.CopySyncCommitteeContribution(c1)
+	newContribution := copyutil.CopySyncCommitteeContribution(c2)
+	if newContribution.AggregationBits.Count() > baseContribution.AggregationBits.Count() {
+		baseContribution, newContribution = newContribution, baseContribution
+	}
+
+	if baseContribution.AggregationBits.Contains(newContribution.AggregationBits) {
+		return baseContribution, nil
+	}
+
+	newBits := baseContribution.AggregationBits.Or(newContribution.AggregationBits)
+	newSig, err := bls.SignatureFromBytes(newContribution.Signature)
+	if err != nil {
+		return nil, err
+	}
+	baseSig, err := bls.SignatureFromBytes(baseContribution.Signature)
+	if err != nil {
+		return nil, err
+	}
+
+	aggregatedSig := bls.AggregateSignatures([]bls.Signature{baseSig, newSig})
+	baseContribution.Signature = aggregatedSig.Marshal()
+	baseContribution.AggregationBits = newBits
+
+	return baseContribution, nil
+}

shared/aggregation/sync_contribution/naive_test.go

@@ -0,0 +1,173 @@
+package sync_contribution
+
+import (
+	"fmt"
+	"sort"
+	"testing"
+
+	"github.com/prysmaticlabs/go-bitfield"
+	prysmv2 "github.com/prysmaticlabs/prysm/proto/prysm/v2"
+	"github.com/prysmaticlabs/prysm/shared/aggregation"
+	aggtesting "github.com/prysmaticlabs/prysm/shared/aggregation/testing"
+	"github.com/prysmaticlabs/prysm/shared/bls"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestAggregateAttestations_aggregate(t *testing.T) {
+	tests := []struct {
+		a1   *prysmv2.SyncCommitteeContribution
+		a2   *prysmv2.SyncCommitteeContribution
+		want *prysmv2.SyncCommitteeContribution
+	}{
+		{
+			a1:   &prysmv2.SyncCommitteeContribution{AggregationBits: bitfield.Bitvector128{0x02}, Signature: bls.NewAggregateSignature().Marshal()},
+			a2:   &prysmv2.SyncCommitteeContribution{AggregationBits: bitfield.Bitvector128{0x01}, Signature: bls.NewAggregateSignature().Marshal()},
+			want: &prysmv2.SyncCommitteeContribution{AggregationBits: bitfield.Bitvector128{0x03}},
+		},
+		{
+			a1:   &prysmv2.SyncCommitteeContribution{AggregationBits: bitfield.Bitvector128{0x01}, Signature: bls.NewAggregateSignature().Marshal()},
+			a2:   &prysmv2.SyncCommitteeContribution{AggregationBits: bitfield.Bitvector128{0x02}, Signature: bls.NewAggregateSignature().Marshal()},
+			want: &prysmv2.SyncCommitteeContribution{AggregationBits: bitfield.Bitvector128{0x03}},
+		},
+	}
+	for _, tt := range tests {
+		got, err := aggregate(tt.a1, tt.a2)
+		require.NoError(t, err)
+		require.DeepSSZEqual(t, tt.want.AggregationBits, got.AggregationBits)
+	}
+}
+
+func TestAggregateAttestations_aggregate_OverlapFails(t *testing.T) {
+	tests := []struct {
+		a1 *prysmv2.SyncCommitteeContribution
+		a2 *prysmv2.SyncCommitteeContribution
+	}{
+		{
+			a1: &prysmv2.SyncCommitteeContribution{AggregationBits: bitfield.Bitvector128{0x1F}},
+			a2: &prysmv2.SyncCommitteeContribution{AggregationBits: bitfield.Bitvector128{0x11}},
+		},
+		{
+			a1: &prysmv2.SyncCommitteeContribution{AggregationBits: bitfield.Bitvector128{0xFF, 0x85}},
+			a2: &prysmv2.SyncCommitteeContribution{AggregationBits: bitfield.Bitvector128{0x13, 0x8F}},
+		},
+	}
+	for _, tt := range tests {
+		_, err := aggregate(tt.a1, tt.a2)
+		require.ErrorContains(t, aggregation.ErrBitsOverlap.Error(), err)
+	}
+}
+
+func TestAggregateAttestations_Aggregate(t *testing.T) {
+	tests := []struct {
+		name   string
+		inputs []bitfield.Bitvector128
+		want   []bitfield.Bitvector128
+	}{
+		{
+			name:   "empty list",
+			inputs: []bitfield.Bitvector128{},
+			want:   []bitfield.Bitvector128{},
+		},
+		{
+			name: "single attestation",
+			inputs: []bitfield.Bitvector128{
+				{0b00000010},
+			},
+			want: []bitfield.Bitvector128{
+				{0b00000010},
+			},
+		},
+		{
+			name: "two attestations with no overlap",
+			inputs: []bitfield.Bitvector128{
+				{0b00000001},
+				{0b00000010},
+			},
+			want: []bitfield.Bitvector128{
+				{0b00000011},
+			},
+		},
+		{
+			name: "two attestations with overlap",
+			inputs: []bitfield.Bitvector128{
+				{0b00000101},
+				{0b00000110},
+			},
+			want: []bitfield.Bitvector128{
+				{0b00000101},
+				{0b00000110},
+			},
+		},
+		{
+			name: "some attestations overlap",
+			inputs: []bitfield.Bitvector128{
+				{0b00001001},
+				{0b00010110},
+				{0b00001010},
+				{0b00110001},
+			},
+			want: []bitfield.Bitvector128{
+				{0b00111011},
+				{0b00011111},
+			},
+		},
+		{
+			name: "some attestations produce duplicates which are removed",
+			inputs: []bitfield.Bitvector128{
+				{0b00000101},
+				{0b00000110},
+				{0b00001010},
+				{0b00001001},
+			},
+			want: []bitfield.Bitvector128{
+				{0b00001111}, // both 0&1 and 2&3 produce this bitlist
+			},
+		},
+		{
+			name: "two attestations where one is fully contained within the other",
+			inputs: []bitfield.Bitvector128{
+				{0b00000001},
+				{0b00000011},
+			},
+			want: []bitfield.Bitvector128{
+				{0b00000011},
+			},
+		},
+		{
+			name: "two attestations where one is fully contained within the other reversed",
+			inputs: []bitfield.Bitvector128{
+				{0b00000011},
+				{0b00000001},
+			},
+			want: []bitfield.Bitvector128{
+				{0b00000011},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		runner := func() {
+			got, err := Aggregate(aggtesting.MakeSyncContributionsFromBitVector(tt.inputs))
+			require.NoError(t, err)
+			sort.Slice(got, func(i, j int) bool {
+				return got[i].AggregationBits.Bytes()[0] < got[j].AggregationBits.Bytes()[0]
+			})
+			sort.Slice(tt.want, func(i, j int) bool {
+				return tt.want[i].Bytes()[0] < tt.want[j].Bytes()[0]
+			})
+			assert.Equal(t, len(tt.want), len(got))
+			for i, w := range tt.want {
+				assert.DeepEqual(t, w.Bytes(), got[i].AggregationBits.Bytes())
+			}
+		}
+		t.Run(fmt.Sprintf("%s/%s", tt.name, NaiveAggregation), func(t *testing.T) {
+			resetCfg := featureconfig.InitWithReset(&featureconfig.Flags{
+				AttestationAggregationStrategy: string(NaiveAggregation),
+			})
+			defer resetCfg()
+			runner()
+		})
+	}
+}

shared/aggregation/testing/BUILD.bazel

@@ -7,8 +7,10 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//proto/eth/v1alpha1:go_default_library",
+        "//proto/prysm/v2:go_default_library",
         "//shared/bls:go_default_library",
         "//shared/timeutils:go_default_library",
+        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
     ],
 )