native: add committee change events

Port neo-project/neo#3158.

Close #3326

Signed-off-by: Ekaterina Pavlova <ekt@morphbits.io>

pkg/core/native/native_neo.go

@@ -265,6 +265,10 @@ func newNEO(cfg config.ProtocolConfiguration) *NEO {
 		manifest.NewParameter("to", smartcontract.PublicKeyType),
 		manifest.NewParameter("amount", smartcontract.IntegerType),
 	)
+	n.AddEvent("CommitteeChanged",
+		manifest.NewParameter("old", smartcontract.ArrayType),
+		manifest.NewParameter("new", smartcontract.ArrayType),
+	)
 
 	return n
 }
@@ -425,11 +429,54 @@ func (n *NEO) OnPersist(ic *interop.Context) error {
 		cache := ic.DAO.GetRWCache(n.ID).(*NeoCache)
 		// Cached newEpoch* values always have proper value set (either by PostPersist
 		// during the last epoch block handling or by initialization code).
+
+		// Extract previous committee public keys for comparison
+		prevCommitteePublicKeys := make([]*keys.PublicKey, len(cache.committee))
+		for i, member := range cache.committee {
+			pub, err := member.PublicKey()
+			if err != nil {
+				return fmt.Errorf("failed to get public key: %w", err)
+			}
+			prevCommitteePublicKeys[i] = pub
+		}
+		// Prepare for potential committee change
 		cache.nextValidators = cache.newEpochNextValidators
 		cache.committee = cache.newEpochCommittee
 		cache.committeeHash = cache.newEpochCommitteeHash
 		cache.votesChanged = false
 
+		// Extract new committee public keys for comparison
+		newCommitteePublicKeys := make([]*keys.PublicKey, len(cache.committee))
+		for i, member := range cache.committee {
+			pub, err := member.PublicKey()
+			if err != nil {
+				return fmt.Errorf("failed to get public key: %w", err)
+			}
+			newCommitteePublicKeys[i] = pub
+		}
+		// Check if the committee has changed by comparing public keys directly
+		committeeChanged := len(prevCommitteePublicKeys) != len(newCommitteePublicKeys)
+		for i := 0; i < len(prevCommitteePublicKeys) && !committeeChanged; i++ {
+			if !prevCommitteePublicKeys[i].Equal(newCommitteePublicKeys[i]) {
+				committeeChanged = true
+			}
+		}
+
+		// Notify subscribers if the committee has changed
+		if committeeChanged {
+			publicKeysToStackItems := func(publicKeys []*keys.PublicKey) []stackitem.Item {
+				items := make([]stackitem.Item, len(publicKeys))
+				for i, pubKey := range publicKeys {
+					items[i] = stackitem.NewByteArray(pubKey.Bytes())
+				}
+				return items
+			}
+			prevCommitteeStackItems := publicKeysToStackItems(prevCommitteePublicKeys)
+			newCommitteeStackItems := publicKeysToStackItems(newCommitteePublicKeys)
+			ic.AddNotification(n.Hash, "CommitteeChanged", stackitem.NewArray([]stackitem.Item{
+				stackitem.NewArray(prevCommitteeStackItems), stackitem.NewArray(newCommitteeStackItems),
+			}))
+		}
 		// We need to put in storage anyway, as it affects dumps
 		ic.DAO.PutStorageItem(n.ID, prefixCommittee, cache.committee.Bytes(ic.DAO.GetItemCtx()))
 	}

pkg/core/native/native_test/neo_test.go

@@ -117,6 +117,60 @@ func TestNEO_CandidateEvents(t *testing.T) {
 	aer = e.GetTxExecResult(t, tx)
 	require.Equal(t, 0, len(aer.Events))
 }
+func TestNEO_CommitteeEvents(t *testing.T) {
+	neoCommitteeInvoker := newNeoCommitteeClient(t, 100_0000_0000)
+	neoValidatorsInvoker := neoCommitteeInvoker.WithSigners(neoCommitteeInvoker.Validator)
+	e := neoCommitteeInvoker.Executor
+
+	cfg := e.Chain.GetConfig()
+	committeeSize := cfg.GetCommitteeSize(0)
+	validatorsCount := cfg.GetNumOfCNs(0)
+	freq := validatorsCount + committeeSize
+	advanceChain := func(t *testing.T) {
+		for i := 0; i < freq-1; i++ {
+			neoCommitteeInvoker.AddNewBlock(t)
+		}
+	}
+	voters := make([]neotest.Signer, committeeSize+1)
+	candidates := make([]neotest.Signer, committeeSize+1)
+	for i := 0; i < committeeSize+1; i++ {
+		voters[i] = e.NewAccount(t, 10_0000_0000)
+		candidates[i] = e.NewAccount(t, 2000_0000_0000) // enough for one registration
+	}
+	txes := make([]*transaction.Transaction, 0, committeeSize*4-2)
+	for i := 0; i < committeeSize+1; i++ {
+		transferTx := neoValidatorsInvoker.PrepareInvoke(t, "transfer", e.Validator.ScriptHash(), voters[i].(neotest.SingleSigner).Account().PrivateKey().GetScriptHash(), int64(committeeSize+1-i)*1000000, nil)
+		txes = append(txes, transferTx)
+		if i > 0 {
+			registerTx := neoValidatorsInvoker.WithSigners(candidates[i]).PrepareInvoke(t, "registerCandidate", candidates[i].(neotest.SingleSigner).Account().PublicKey().Bytes())
+			txes = append(txes, registerTx)
+			voteTx := neoValidatorsInvoker.WithSigners(voters[i]).PrepareInvoke(t, "vote", voters[i].(neotest.SingleSigner).Account().PrivateKey().GetScriptHash(), candidates[i].(neotest.SingleSigner).Account().PublicKey().Bytes())
+			txes = append(txes, voteTx)
+		}
+	}
+	//for _, tx := range txes {
+	//	e.CheckHalt(t, tx.Hash(), stackitem.Make(true))
+	//}
+	prevCommitteePublicKeys := make([]*keys.PublicKey, committeeSize)
+	for i, member := range neoCommitteeInvoker.Signers {
+		prevCommitteePublicKeys[i] = member.Script()
+		//member.(neotest.SingleSigner).Account().PublicKey()
+	}
+	advanceChain(t)
+	newCommitteePublicKeys := make([]*keys.PublicKey, committeeSize)
+	for i, member := range neoCommitteeInvoker.Signers {
+		newCommitteePublicKeys[i] = member.(neotest.SingleSigner).Account().PublicKey()
+	}
+	tx := neoCommitteeInvoker.WithSigners(candidates[0]).Invoke(t, true, "unregisterCandidate", candidates[0].(neotest.SingleSigner).Account().PublicKey().Bytes())
+	e.CheckTxNotificationEvent(t, tx, 0, state.NotificationEvent{
+		ScriptHash: neoCommitteeInvoker.Hash,
+		Name:       "CommitteeChanged",
+		Item: stackitem.NewArray([]stackitem.Item{
+			stackitem.NewArray([]stackitem.Item{}),
+			stackitem.NewArray([]stackitem.Item{}),
+		}),
+	})
+}
 
 func TestNEO_Vote(t *testing.T) {
 	neoCommitteeInvoker := newNeoCommitteeClient(t, 100_0000_0000)

pkg/rpcclient/neo/neo.go

@@ -75,6 +75,12 @@ type CandidateStateEvent struct {
 	Votes      *big.Int
 }
 
+// CommitteeChangedEvent represents a CommitteeChanged NEO event.
+type CommitteeChangedEvent struct {
+	Old []keys.PublicKey
+	New []keys.PublicKey
+}
+
 // VoteEvent represents a Vote NEO event.
 type VoteEvent struct {
 	Account util.Uint160