ir/internal: add possibility to deploy custom native contract

Also, implement new MetaData contract and GAS contract implementation without
economic.

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

Author: carpawell

go.mod

@@ -91,7 +91,9 @@ require (
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/crypto v0.48.0 // indirect
 	golang.org/x/exp v0.0.0-20250911091902-df9299821621 // indirect
+	golang.org/x/mod v0.32.0 // indirect
 	golang.org/x/text v0.34.0 // indirect
+	golang.org/x/tools v0.41.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	lukechampine.com/blake3 v1.2.1 // indirect

pkg/core/metachain/contracts.go

@@ -0,0 +1,55 @@
+package metachain
+
+import (
+	neogoconfig "github.com/nspcc-dev/neo-go/pkg/config"
+	"github.com/nspcc-dev/neo-go/pkg/core/interop"
+	"github.com/nspcc-dev/neo-go/pkg/core/native"
+	"github.com/nspcc-dev/neofs-node/pkg/core/metachain/gas"
+	"github.com/nspcc-dev/neofs-node/pkg/core/metachain/meta"
+)
+
+// NewCustomNatives returns custom list of native contracts for metadata
+// side chain. Returned contracts:
+//   - Management
+//   - Ledger
+//   - NEO
+//   - redefined GAS (see [gas.NewGAS] for details)
+//   - Policy
+//   - Designate
+//   - Notary
+//   - new native metadata contract (see [meta.NewMetadata] for details).
+func NewCustomNatives(cfg neogoconfig.ProtocolConfiguration) []interop.Contract {
+	mgmt := native.NewManagement()
+	ledger := native.NewLedger()
+
+	g := gas.NewGAS()
+	n := native.NewNEO(cfg)
+	p := native.NewPolicy()
+
+	n.GAS = g
+	n.Policy = p
+
+	mgmt.NEO = n
+	mgmt.Policy = p
+	ledger.Policy = p
+
+	desig := native.NewDesignate(cfg.Genesis.Roles)
+	desig.NEO = n
+
+	notary := native.NewNotary()
+	notary.Policy = p
+	notary.GAS = g
+	notary.NEO = n
+	notary.Desig = desig
+
+	return []interop.Contract{
+		mgmt,
+		ledger,
+		n,
+		g,
+		p,
+		desig,
+		notary,
+		meta.NewMetadata(n),
+	}
+}

pkg/core/metachain/gas/gas.go

@@ -0,0 +1,174 @@
+package gas
+
+import (
+	"fmt"
+	"math/big"
+
+	"github.com/nspcc-dev/neo-go/pkg/config"
+	"github.com/nspcc-dev/neo-go/pkg/core/dao"
+	"github.com/nspcc-dev/neo-go/pkg/core/interop"
+	"github.com/nspcc-dev/neo-go/pkg/core/interop/contract"
+	"github.com/nspcc-dev/neo-go/pkg/core/native"
+	"github.com/nspcc-dev/neo-go/pkg/core/native/nativeids"
+	"github.com/nspcc-dev/neo-go/pkg/core/native/nativenames"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+)
+
+// DefaultBalance is a balance of every account in redefined [GAS] native
+// contract.
+const DefaultBalance = 100 * native.GASFactor
+
+var _ = (native.IGAS)(&GAS{})
+
+func (g *GAS) Metadata() *interop.ContractMD {
+	return &g.ContractMD
+}
+
+// GAS represents GAS custom native contract. It always returns [DefaultBalance] as a
+// balance, has no-op `Burn`, `Mint`, `Transfer` operations.
+type GAS struct {
+	interop.ContractMD
+	symbol   string
+	decimals int64
+}
+
+// NewGAS returns [GAS] custom native contract.
+func NewGAS() *GAS {
+	g := &GAS{}
+	defer g.BuildHFSpecificMD(g.ActiveIn())
+
+	g.ContractMD = *interop.NewContractMD(nativenames.Gas, nativeids.GasToken, func(m *manifest.Manifest, hf config.Hardfork) {
+		m.SupportedStandards = []string{manifest.NEP17StandardName}
+	})
+	g.symbol = "GAS"
+	g.decimals = 8
+
+	desc := native.NewDescriptor("symbol", smartcontract.StringType)
+	md := native.NewMethodAndPrice(g.Symbol, 0, callflag.NoneFlag)
+	g.AddMethod(md, desc)
+
+	desc = native.NewDescriptor("decimals", smartcontract.IntegerType)
+	md = native.NewMethodAndPrice(g.Decimals, 0, callflag.NoneFlag)
+	g.AddMethod(md, desc)
+
+	desc = native.NewDescriptor("totalSupply", smartcontract.IntegerType)
+	md = native.NewMethodAndPrice(g.TotalSupply, 1<<15, callflag.ReadStates)
+	g.AddMethod(md, desc)
+
+	desc = native.NewDescriptor("balanceOf", smartcontract.IntegerType,
+		manifest.NewParameter("account", smartcontract.Hash160Type))
+	md = native.NewMethodAndPrice(g.balanceOf, 1<<15, callflag.ReadStates)
+	g.AddMethod(md, desc)
+
+	transferParams := []manifest.Parameter{
+		manifest.NewParameter("from", smartcontract.Hash160Type),
+		manifest.NewParameter("to", smartcontract.Hash160Type),
+		manifest.NewParameter("amount", smartcontract.IntegerType),
+	}
+	desc = native.NewDescriptor("transfer", smartcontract.BoolType,
+		append(transferParams, manifest.NewParameter("data", smartcontract.AnyType))...,
+	)
+	md = native.NewMethodAndPrice(g.Transfer, 1<<17, callflag.States|callflag.AllowCall|callflag.AllowNotify)
+	g.AddMethod(md, desc)
+
+	eDesc := native.NewEventDescriptor("Transfer", transferParams...)
+	eMD := native.NewEvent(eDesc)
+	g.AddEvent(eMD)
+
+	return g
+}
+
+// Initialize initializes a GAS contract.
+func (g *GAS) Initialize(ic *interop.Context, hf *config.Hardfork, newMD *interop.HFSpecificContractMD) error {
+	return nil
+}
+
+// InitializeCache implements the [interop.Contract] interface.
+func (g *GAS) InitializeCache(_ interop.IsHardforkEnabled, blockHeight uint32, d *dao.Simple) error {
+	return nil
+}
+
+// OnPersist implements the [interop.Contract] interface.
+func (g *GAS) OnPersist(ic *interop.Context) error {
+	return nil
+}
+
+// PostPersist implements the [interop.Contract] interface.
+func (g *GAS) PostPersist(ic *interop.Context) error {
+	return nil
+}
+
+// ActiveIn implements the [interop.Contract] interface.
+func (g *GAS) ActiveIn() *config.Hardfork {
+	return nil
+}
+
+// BalanceOf returns native GAS token balance for the acc.
+func (g *GAS) BalanceOf(d *dao.Simple, acc util.Uint160) *big.Int {
+	return big.NewInt(DefaultBalance * native.GASFactor)
+}
+
+func (g *GAS) Symbol(_ *interop.Context, _ []stackitem.Item) stackitem.Item {
+	return stackitem.NewByteArray([]byte(g.symbol))
+}
+
+func (g *GAS) Decimals(_ *interop.Context, _ []stackitem.Item) stackitem.Item {
+	return stackitem.NewBigInteger(big.NewInt(g.decimals))
+}
+
+func (g *GAS) TotalSupply(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
+	return stackitem.NewBigInteger(big.NewInt(DefaultBalance))
+}
+
+func toUint160(s stackitem.Item) util.Uint160 {
+	u, err := stackitem.ToUint160(s)
+	if err != nil {
+		panic(err)
+	}
+	return u
+}
+
+func toBigInt(s stackitem.Item) *big.Int {
+	bi, err := s.TryInteger()
+	if err != nil {
+		panic(err)
+	}
+	return bi
+}
+
+func (g *GAS) Transfer(ic *interop.Context, args []stackitem.Item) stackitem.Item {
+	from := toUint160(args[0])
+	to := toUint160(args[1])
+	amount := toBigInt(args[2])
+
+	paymentArgs := []stackitem.Item{
+		stackitem.NewByteArray(from.BytesBE()),
+		stackitem.NewBigInteger(amount),
+		args[3],
+	}
+	cs, err := ic.GetContract(to)
+	if err == nil {
+		err = contract.CallFromNative(ic, g.Hash, cs, manifest.MethodOnNEP17Payment, paymentArgs, false)
+		if err != nil {
+			panic(fmt.Errorf("failed to call %s: %w", manifest.MethodOnNEP17Payment, err))
+		}
+	}
+
+	return stackitem.NewBool(true)
+}
+
+// balanceOf is the only difference with default native GAS implementation:
+// it always returns fixed number of tokens.
+func (g *GAS) balanceOf(ic *interop.Context, args []stackitem.Item) stackitem.Item {
+	return stackitem.NewBigInteger(g.BalanceOf(nil, util.Uint160{}))
+}
+
+func (g *GAS) Mint(ic *interop.Context, h util.Uint160, amount *big.Int, callOnPayment bool) {
+}
+
+func (g *GAS) Burn(ic *interop.Context, h util.Uint160, amount *big.Int) {
+}

pkg/core/metachain/gas/gas_test.go

@@ -0,0 +1,44 @@
+package gas_test
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/core/native"
+	"github.com/nspcc-dev/neo-go/pkg/core/native/nativenames"
+	"github.com/nspcc-dev/neo-go/pkg/neotest"
+	"github.com/nspcc-dev/neo-go/pkg/neotest/chain"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+	"github.com/nspcc-dev/neofs-node/pkg/core/metachain"
+)
+
+func newGasClient(t *testing.T) (*neotest.ContractInvoker, *neotest.ContractInvoker) {
+	ch, validators, committee := chain.NewMultiWithOptions(t, &chain.Options{
+		NewNatives: metachain.NewCustomNatives,
+	})
+	e := neotest.NewExecutor(t, ch, validators, committee)
+
+	return e.ValidatorInvoker(e.NativeHash(t, nativenames.Gas)), e.CommitteeInvoker(e.NativeHash(t, nativenames.Gas))
+}
+
+const defaultBalance = 100
+
+func TestGAS(t *testing.T) {
+	gasValidatorsI, gasCommitteeI := newGasClient(t)
+	hardcodedBalance := stackitem.NewBigInteger(big.NewInt(defaultBalance * native.GASFactor))
+
+	t.Run("committee balance", func(t *testing.T) {
+		gasCommitteeI.Invoke(t, hardcodedBalance, "balanceOf", gasCommitteeI.Hash)
+	})
+
+	t.Run("new account balance", func(t *testing.T) {
+		s := gasValidatorsI.NewAccount(t, defaultBalance*native.GASFactor+1)
+		gasCommitteeI.WithSigners(s).Invoke(t, hardcodedBalance, "balanceOf", s.ScriptHash())
+	})
+
+	t.Run("transfer does not change balance", func(t *testing.T) {
+		newAcc := gasValidatorsI.NewAccount(t, defaultBalance*native.GASFactor+1)
+		gasCommitteeI.Invoke(t, stackitem.Bool(true), "transfer", gasCommitteeI.Hash, newAcc.ScriptHash(), 1, stackitem.Null{})
+		gasCommitteeI.Invoke(t, hardcodedBalance, "balanceOf", newAcc.ScriptHash())
+	})
+}

pkg/core/metachain/meta/const.go

@@ -0,0 +1,26 @@
+package meta
+
+import (
+	"math"
+)
+
+const (
+	// Metadata contract identifiers.
+	MetaDataContractID   = math.MinInt32
+	MetaDataContractName = "MetaData"
+)
+
+const (
+	// storage prefixes.
+	metaContainersPrefix = iota
+	containerPlacementPrefix
+
+	// object prefixes.
+	addrIndex
+	lockedByIndex
+)
+
+const (
+	// event names.
+	putObjectEvent = "ObjectPut"
+)