native: change OnPersist/PostPersist handling

Every contract now has these and they're always invoked. See
neo-project/neo#1913 and neo-project/neo#2119.

pkg/core/interop/context.go

@@ -89,6 +89,8 @@ type MethodAndPrice struct {
 type Contract interface {
 	Initialize(*Context) error
 	Metadata() *ContractMD
+	OnPersist(*Context) error
+	PostPersist(*Context) error
 }
 
 // ContractMD represents native contract instance.

pkg/core/interop/interopnames/names.go

@@ -27,6 +27,8 @@ const (
 	SystemContractDestroy                    = "System.Contract.Destroy"
 	SystemContractIsStandard                 = "System.Contract.IsStandard"
 	SystemContractGetCallFlags               = "System.Contract.GetCallFlags"
+	SystemContractNativeOnPersist            = "System.Contract.NativeOnPersist"
+	SystemContractNativePostPersist          = "System.Contract.NativePostPersist"
 	SystemContractUpdate                     = "System.Contract.Update"
 	SystemEnumeratorConcat                   = "System.Enumerator.Concat"
 	SystemEnumeratorCreate                   = "System.Enumerator.Create"
@@ -96,6 +98,8 @@ var names = []string{
 	SystemContractDestroy,
 	SystemContractIsStandard,
 	SystemContractGetCallFlags,
+	SystemContractNativeOnPersist,
+	SystemContractNativePostPersist,
 	SystemContractUpdate,
 	SystemEnumeratorConcat,
 	SystemEnumeratorCreate,

pkg/core/interops.go

@@ -67,6 +67,8 @@ var systemInterops = []interop.Function{
 	{Name: interopnames.SystemContractDestroy, Func: contractDestroy, Price: 1000000, RequiredFlags: smartcontract.WriteStates, DisallowCallback: true},
 	{Name: interopnames.SystemContractIsStandard, Func: contractIsStandard, Price: 30000, RequiredFlags: smartcontract.ReadStates, ParamCount: 1},
 	{Name: interopnames.SystemContractGetCallFlags, Func: contractGetCallFlags, Price: 30000, DisallowCallback: true},
+	{Name: interopnames.SystemContractNativeOnPersist, Func: native.OnPersist, Price: 0, DisallowCallback: true},
+	{Name: interopnames.SystemContractNativePostPersist, Func: native.PostPersist, Price: 0, DisallowCallback: true},
 	{Name: interopnames.SystemContractUpdate, Func: contractUpdate, Price: 0,
 		RequiredFlags: smartcontract.WriteStates, ParamCount: 2, DisallowCallback: true},
 	{Name: interopnames.SystemEnumeratorConcat, Func: enumerator.Concat, Price: 400, ParamCount: 2, DisallowCallback: true},

pkg/core/native/contract.go

@@ -1,15 +1,13 @@
 package native
 
 import (
-	"errors"
 	"strings"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
+	"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
 	"github.com/nspcc-dev/neo-go/pkg/io"
-	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
-	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
 )
 
 // reservedContractID represents the upper bound of the reserved IDs for native contracts.
@@ -62,9 +60,9 @@ func NewContracts(p2pSigExtensionsEnabled bool) *Contracts {
 	gas.NEO = neo
 
 	cs.GAS = gas
-	cs.Contracts = append(cs.Contracts, gas)
 	cs.NEO = neo
 	cs.Contracts = append(cs.Contracts, neo)
+	cs.Contracts = append(cs.Contracts, gas)
 
 	policy := newPolicy()
 	cs.Policy = policy
@@ -93,62 +91,24 @@ func NewContracts(p2pSigExtensionsEnabled bool) *Contracts {
 	return cs
 }
 
-// GetPersistScript returns VM script calling "onPersist" method of every native contract.
+// GetPersistScript returns VM script calling "onPersist" syscall for native contracts.
 func (cs *Contracts) GetPersistScript() []byte {
 	if cs.persistScript != nil {
 		return cs.persistScript
 	}
 	w := io.NewBufBinWriter()
-	for i := range cs.Contracts {
+	emit.Syscall(w.BinWriter, interopnames.SystemContractNativeOnPersist)
-		md := cs.Contracts[i].Metadata()
-		// Not every contract is persisted:
-		// https://github.com/neo-project/neo/blob/master/src/neo/Ledger/Blockchain.cs#L90
-		if md.ContractID == policyContractID || md.ContractID == oracleContractID || md.ContractID == designateContractID {
-			continue
-		}
-		emit.Int(w.BinWriter, 0)
-		emit.Opcodes(w.BinWriter, opcode.NEWARRAY)
-		emit.String(w.BinWriter, "onPersist")
-		emit.AppCall(w.BinWriter, md.Hash)
-		emit.Opcodes(w.BinWriter, opcode.DROP)
-	}
 	cs.persistScript = w.Bytes()
 	return cs.persistScript
 }
 
-// GetPostPersistScript returns VM script calling "postPersist" method of some native contracts.
+// GetPostPersistScript returns VM script calling "postPersist" syscall for native contracts.
 func (cs *Contracts) GetPostPersistScript() []byte {
 	if cs.postPersistScript != nil {
 		return cs.postPersistScript
 	}
 	w := io.NewBufBinWriter()
-	for i := range cs.Contracts {
+	emit.Syscall(w.BinWriter, interopnames.SystemContractNativePostPersist)
-		md := cs.Contracts[i].Metadata()
-		// Not every contract is persisted:
-		// https://github.com/neo-project/neo/blob/master/src/neo/Ledger/Blockchain.cs#L103
-		if md.ContractID == policyContractID || md.ContractID == gasContractID || md.ContractID == designateContractID || md.ContractID == notaryContractID {
-			continue
-		}
-		emit.Int(w.BinWriter, 0)
-		emit.Opcodes(w.BinWriter, opcode.NEWARRAY)
-		emit.String(w.BinWriter, "postPersist")
-		emit.AppCall(w.BinWriter, md.Hash)
-		emit.Opcodes(w.BinWriter, opcode.DROP)
-	}
 	cs.postPersistScript = w.Bytes()
 	return cs.postPersistScript
 }
-
-func postPersistBase(ic *interop.Context) error {
-	if ic.Trigger != trigger.PostPersist {
-		return errors.New("postPersist must be trigered by system")
-	}
-	return nil
-}
-
-func onPersistBase(ic *interop.Context) error {
-	if ic.Trigger != trigger.OnPersist {
-		return errors.New("onPersist must be trigered by system")
-	}
-	return nil
-}

pkg/core/native/designate.go

@@ -87,14 +87,6 @@ func newDesignate(p2pSigExtensionsEnabled bool) *Designate {
 	md = newMethodAndPrice(s.designateAsRole, 0, smartcontract.WriteStates)
 	s.AddMethod(md, desc)
 
-	desc = newDescriptor("onPersist", smartcontract.VoidType)
-	md = newMethodAndPrice(getOnPersistWrapper(onPersistBase), 0, smartcontract.WriteStates)
-	s.AddMethod(md, desc)
-
-	desc = newDescriptor("postPersist", smartcontract.VoidType)
-	md = newMethodAndPrice(getOnPersistWrapper(postPersistBase), 0, smartcontract.WriteStates)
-	s.AddMethod(md, desc)
-
 	return s
 }
 
@@ -103,6 +95,16 @@ func (s *Designate) Initialize(ic *interop.Context) error {
 	return nil
 }
 
+// OnPersist implements Contract interface.
+func (s *Designate) OnPersist(ic *interop.Context) error {
+	return nil
+}
+
+// PostPersist implements Contract interface.
+func (s *Designate) PostPersist(ic *interop.Context) error {
+	return nil
+}
+
 // OnPersistEnd updates cached values if they've been changed.
 func (s *Designate) OnPersistEnd(d dao.DAO) error {
 	if !s.rolesChanged() {

pkg/core/native/interop.go

@@ -7,6 +7,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
 )
 
 // Deploy deploys native contract.
@@ -70,3 +71,31 @@ func Call(ic *interop.Context) error {
 	}
 	return nil
 }
+
+// OnPersist calls OnPersist methods for all native contracts.
+func OnPersist(ic *interop.Context) error {
+	if ic.Trigger != trigger.OnPersist {
+		return errors.New("onPersist must be trigered by system")
+	}
+	for _, c := range ic.Natives {
+		err := c.OnPersist(ic)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// PostPersist calls PostPersist methods for all native contracts.
+func PostPersist(ic *interop.Context) error {
+	if ic.Trigger != trigger.PostPersist {
+		return errors.New("postPersist must be trigered by system")
+	}
+	for _, c := range ic.Natives {
+		err := c.PostPersist(ic)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}

pkg/core/native/native_gas.go

@@ -31,16 +31,11 @@ func newGAS() *GAS {
 	nep17.symbol = "gas"
 	nep17.decimals = 8
 	nep17.factor = GASFactor
-	nep17.onPersist = chainOnPersist(onPersistBase, g.OnPersist)
 	nep17.incBalance = g.increaseBalance
 	nep17.ContractID = gasContractID
 
 	g.nep17TokenNative = *nep17
 
-	onp := g.Methods["onPersist"]
-	onp.Func = getOnPersistWrapper(g.onPersist)
-	g.Methods["onPersist"] = onp
-
 	return g
 }
 
@@ -98,6 +93,11 @@ func (g *GAS) OnPersist(ic *interop.Context) error {
 	return nil
 }
 
+// PostPersist implements Contract interface.
+func (g *GAS) PostPersist(ic *interop.Context) error {
+	return nil
+}
+
 func getStandbyValidatorsHash(ic *interop.Context) (util.Uint160, error) {
 	s, err := smartcontract.CreateDefaultMultiSigRedeemScript(ic.Chain.GetStandByValidators())
 	if err != nil {
@@ -105,16 +105,3 @@ func getStandbyValidatorsHash(ic *interop.Context) (util.Uint160, error) {
 	}
 	return hash.Hash160(s), nil
 }
-
-func chainOnPersist(fs ...func(*interop.Context) error) func(*interop.Context) error {
-	return func(ic *interop.Context) error {
-		for i := range fs {
-			if fs[i] != nil {
-				if err := fs[i](ic); err != nil {
-					return err
-				}
-			}
-		}
-		return nil
-	}
-}

pkg/core/native/native_neo.go

@@ -97,8 +97,6 @@ func newNEO() *NEO {
 	nep17.symbol = "neo"
 	nep17.decimals = 0
 	nep17.factor = 1
-	nep17.onPersist = chainOnPersist(onPersistBase, n.OnPersist)
-	nep17.postPersist = chainOnPersist(nep17.postPersist, n.PostPersist)
 	nep17.incBalance = n.increaseBalance
 	nep17.ContractID = neoContractID
 
@@ -109,14 +107,6 @@ func newNEO() *NEO {
 	n.committee.Store(keysWithVotes(nil))
 	n.committeeHash.Store(util.Uint160{})
 
-	onp := n.Methods["onPersist"]
-	onp.Func = getOnPersistWrapper(n.onPersist)
-	n.Methods["onPersist"] = onp
-
-	pp := n.Methods["postPersist"]
-	pp.Func = getOnPersistWrapper(n.postPersist)
-	n.Methods["postPersist"] = pp
-
 	desc := newDescriptor("unclaimedGas", smartcontract.IntegerType,
 		manifest.NewParameter("account", smartcontract.Hash160Type),
 		manifest.NewParameter("end", smartcontract.IntegerType))

pkg/core/native/native_nep17.go

@@ -2,7 +2,6 @@ package native
 
 import (
 	"errors"
-	"fmt"
 	"math"
 	"math/big"
 
@@ -36,8 +35,6 @@ type nep17TokenNative struct {
 	symbol     string
 	decimals   int64
 	factor     int64
-	onPersist   func(*interop.Context) error
-	postPersist func(*interop.Context) error
 	incBalance func(*interop.Context, util.Uint160, *state.StorageItem, *big.Int) error
 }
 
@@ -48,8 +45,6 @@ func (c *nep17TokenNative) Metadata() *interop.ContractMD {
 	return &c.ContractMD
 }
 
-var _ interop.Contract = (*nep17TokenNative)(nil)
-
 func newNEP17Native(name string) *nep17TokenNative {
 	n := &nep17TokenNative{ContractMD: *interop.NewContractMD(name)}
 	n.Manifest.SupportedStandards = []string{manifest.NEP17StandardName}
@@ -82,14 +77,6 @@ func newNEP17Native(name string) *nep17TokenNative {
 	md = newMethodAndPrice(n.Transfer, 8000000, smartcontract.WriteStates|smartcontract.AllowCall|smartcontract.AllowNotify)
 	n.AddMethod(md, desc)
 
-	desc = newDescriptor("onPersist", smartcontract.VoidType)
-	md = newMethodAndPrice(getOnPersistWrapper(onPersistBase), 0, smartcontract.WriteStates)
-	n.AddMethod(md, desc)
-
-	desc = newDescriptor("postPersist", smartcontract.VoidType)
-	md = newMethodAndPrice(getOnPersistWrapper(postPersistBase), 0, smartcontract.WriteStates)
-	n.AddMethod(md, desc)
-
 	n.AddEvent("Transfer", transferParams...)
 
 	return n
@@ -333,13 +320,3 @@ func toUint32(s stackitem.Item) uint32 {
 	}
 	return uint32(int64Value)
 }
-
-func getOnPersistWrapper(f func(ic *interop.Context) error) interop.Method {
-	return func(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
-		err := f(ic)
-		if err != nil {
-			panic(fmt.Errorf("OnPersist for native contract: %w", err))
-		}
-		return stackitem.Null{}
-	}
-}

pkg/core/native/notary.go

@@ -98,14 +98,6 @@ func newNotary() *Notary {
 	md = newMethodAndPrice(n.setMaxNotValidBeforeDelta, 300_0000, smartcontract.WriteStates)
 	n.AddMethod(md, desc)
 
-	desc = newDescriptor("onPersist", smartcontract.VoidType)
-	md = newMethodAndPrice(getOnPersistWrapper(n.OnPersist), 0, smartcontract.WriteStates)
-	n.AddMethod(md, desc)
-
-	desc = newDescriptor("postPersist", smartcontract.VoidType)
-	md = newMethodAndPrice(getOnPersistWrapper(postPersistBase), 0, smartcontract.WriteStates)
-	n.AddMethod(md, desc)
-
 	return n
 }
 
@@ -179,6 +171,11 @@ func (n *Notary) OnPersistEnd(dao dao.DAO) error {
 	return nil
 }
 
+// PostPersist implements Contract interface.
+func (n *Notary) PostPersist(ic *interop.Context) error {
+	return nil
+}
+
 // onPayment records deposited amount as belonging to "from" address with a lock
 // till the specified chain's height.
 func (n *Notary) onPayment(ic *interop.Context, args []stackitem.Item) stackitem.Item {

pkg/core/native/oracle.go

@@ -122,15 +122,6 @@ func newOracle() *Oracle {
 	md = newMethodAndPrice(o.verify, 100_0000, smartcontract.NoneFlag)
 	o.AddMethod(md, desc)
 
-	pp := chainOnPersist(postPersistBase, o.PostPersist)
-	desc = newDescriptor("postPersist", smartcontract.VoidType)
-	md = newMethodAndPrice(getOnPersistWrapper(pp), 0, smartcontract.WriteStates)
-	o.AddMethod(md, desc)
-
-	desc = newDescriptor("onPersist", smartcontract.VoidType)
-	md = newMethodAndPrice(getOnPersistWrapper(onPersistBase), 0, smartcontract.WriteStates)
-	o.AddMethod(md, desc)
-
 	o.AddEvent("OracleRequest", manifest.NewParameter("Id", smartcontract.IntegerType),
 		manifest.NewParameter("RequestContract", smartcontract.Hash160Type),
 		manifest.NewParameter("Url", smartcontract.StringType),
@@ -141,6 +132,11 @@ func newOracle() *Oracle {
 	return o
 }
 
+// OnPersist implements Contract interface.
+func (o *Oracle) OnPersist(ic *interop.Context) error {
+	return nil
+}
+
 // PostPersist represents `postPersist` method.
 func (o *Oracle) PostPersist(ic *interop.Context) error {
 	var nodes keys.PublicKeys

pkg/core/native/policy.go

@@ -124,13 +124,6 @@ func newPolicy() *Policy {
 	md = newMethodAndPrice(p.unblockAccount, 3000000, smartcontract.WriteStates)
 	p.AddMethod(md, desc)
 
-	desc = newDescriptor("onPersist", smartcontract.VoidType)
-	md = newMethodAndPrice(getOnPersistWrapper(p.OnPersist), 0, smartcontract.WriteStates)
-	p.AddMethod(md, desc)
-
-	desc = newDescriptor("postPersist", smartcontract.VoidType)
-	md = newMethodAndPrice(getOnPersistWrapper(postPersistBase), 0, smartcontract.WriteStates)
-	p.AddMethod(md, desc)
 	return p
 }
 
@@ -157,6 +150,11 @@ func (p *Policy) OnPersist(ic *interop.Context) error {
 	return nil
 }
 
+// PostPersist implements Contract interface.
+func (p *Policy) PostPersist(ic *interop.Context) error {
+	return nil
+}
+
 // OnPersistEnd updates cached Policy values if they've been changed
 func (p *Policy) OnPersistEnd(dao dao.DAO) error {
 	if p.isValid {

pkg/core/native_contract_test.go

@@ -1,6 +1,7 @@
 package core
 
 import (
+	"errors"
 	"math/big"
 	"testing"
 
@@ -33,18 +34,19 @@ func (tn *testNative) Metadata() *interop.ContractMD {
 	return &tn.meta
 }
 
-func (tn *testNative) OnPersist(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
+func (tn *testNative) OnPersist(ic *interop.Context) error {
-	if ic.Trigger != trigger.OnPersist {
-		panic("invalid trigger")
-	}
 	select {
 	case tn.blocks <- ic.Block.Index:
-		return stackitem.NewBool(true)
+		return nil
 	default:
-		return stackitem.NewBool(false)
+		return errors.New("can't send index")
 	}
 }
 
+func (tn *testNative) PostPersist(ic *interop.Context) error {
+	return nil
+}
+
 var _ interop.Contract = (*testNative)(nil)
 
 // registerNative registers native contract in the blockchain.
@@ -106,10 +108,6 @@ func newTestNative() *testNative {
 		RequiredFlags: smartcontract.NoneFlag}
 	tn.meta.AddMethod(md, desc)
 
-	desc = &manifest.Method{Name: "onPersist", ReturnType: smartcontract.BoolType}
-	md = &interop.MethodAndPrice{Func: tn.OnPersist, RequiredFlags: smartcontract.WriteStates}
-	tn.meta.AddMethod(md, desc)
-
 	return tn
 }
 
@@ -252,18 +250,28 @@ func TestNativeContract_InvokeOtherContract(t *testing.T) {
 	})
 	require.NoError(t, err)
 
+	var drainTN = func(t *testing.T) {
+		select {
+		case <-tn.blocks:
+		default:
+			require.Fail(t, "testNative didn't send us block")
+		}
+	}
+
 	cs, _ := getTestContractState()
 	require.NoError(t, chain.dao.PutContractState(cs))
 
 	t.Run("non-native, no return", func(t *testing.T) {
 		res, err := invokeContractMethod(chain, testSumPrice*4+10000, tn.Metadata().Hash, "callOtherContractNoReturn", cs.Hash, "justReturn", []interface{}{})
 		require.NoError(t, err)
+		drainTN(t)
 		checkResult(t, res, stackitem.Null{}) // simple call is done with EnsureNotEmpty
 	})
 	t.Run("non-native, with return", func(t *testing.T) {
 		res, err := invokeContractMethod(chain, testSumPrice*4+10000, tn.Metadata().Hash,
 			"callOtherContractWithReturn", cs.Hash, "ret7", []interface{}{})
 		require.NoError(t, err)
+		drainTN(t)
 		checkResult(t, res, stackitem.Make(8))
 	})
 }