Add transfer subnet ownership functionality to wallet

wallet/chain/p/backend.go

@@ -13,6 +13,7 @@ import (
 	"github.com/ava-labs/avalanchego/utils/constants"
 	"github.com/ava-labs/avalanchego/utils/set"
 	"github.com/ava-labs/avalanchego/vms/components/avax"
+	"github.com/ava-labs/avalanchego/vms/platformvm/fx"
 	"github.com/ava-labs/avalanchego/vms/platformvm/txs"
 	"github.com/ava-labs/avalanchego/wallet/subnet/primary/common"
 )
@@ -32,16 +33,30 @@ type backend struct {
 	Context
 	common.ChainUTXOs
 
-	txsLock sync.RWMutex
-	// txID -> tx
-	txs map[ids.ID]*txs.Tx
+	subnetOwnerLock sync.RWMutex
+	subnetOwner     map[ids.ID]fx.Owner // subnetID -> owner
 }
 
-func NewBackend(ctx Context, utxos common.ChainUTXOs, txs map[ids.ID]*txs.Tx) Backend {
+func NewBackend(ctx Context, utxos common.ChainUTXOs, subnetTxs map[ids.ID]*txs.Tx) Backend {
+	subnetOwner := make(map[ids.ID]fx.Owner)
+	for txID, tx := range subnetTxs { // first get owners from the CreateSubnetTx
+		createSubnetTx, ok := tx.Unsigned.(*txs.CreateSubnetTx)
+		if !ok {
+			continue
+		}
+		subnetOwner[txID] = createSubnetTx.Owner
+	}
+	for _, tx := range subnetTxs { // then check for TransferSubnetOwnershipTx
+		transferSubnetOwnershipTx, ok := tx.Unsigned.(*txs.TransferSubnetOwnershipTx)
+		if !ok {
+			continue
+		}
+		subnetOwner[transferSubnetOwnershipTx.Subnet] = transferSubnetOwnershipTx.Owner
+	}
 	return &backend{
-		Context:    ctx,
-		ChainUTXOs: utxos,
-		txs:        txs,
+		Context:     ctx,
+		ChainUTXOs:  utxos,
+		subnetOwner: subnetOwner,
 	}
 }
 
@@ -57,16 +72,7 @@ func (b *backend) AcceptTx(ctx stdcontext.Context, tx *txs.Tx) error {
 	}
 
 	producedUTXOSlice := tx.UTXOs()
-	err = b.addUTXOs(ctx, constants.PlatformChainID, producedUTXOSlice)
-	if err != nil {
-		return err
-	}
-
-	b.txsLock.Lock()
-	defer b.txsLock.Unlock()
-
-	b.txs[txID] = tx
-	return nil
+	return b.addUTXOs(ctx, constants.PlatformChainID, producedUTXOSlice)
 }
 
 func (b *backend) addUTXOs(ctx stdcontext.Context, destinationChainID ids.ID, utxos []*avax.UTXO) error {
@@ -87,13 +93,20 @@ func (b *backend) removeUTXOs(ctx stdcontext.Context, sourceChain ids.ID, utxoID
 	return nil
 }
 
-func (b *backend) GetTx(_ stdcontext.Context, txID ids.ID) (*txs.Tx, error) {
-	b.txsLock.RLock()
-	defer b.txsLock.RUnlock()
+func (b *backend) GetSubnetOwner(_ stdcontext.Context, subnetID ids.ID) (fx.Owner, error) {
+	b.subnetOwnerLock.RLock()
+	defer b.subnetOwnerLock.RUnlock()
 
-	tx, exists := b.txs[txID]
+	owner, exists := b.subnetOwner[subnetID]
 	if !exists {
 		return nil, database.ErrNotFound
 	}
-	return tx, nil
+	return owner, nil
+}
+
+func (b *backend) setSubnetOwner(subnetID ids.ID, owner fx.Owner) {
+	b.subnetOwnerLock.Lock()
+	defer b.subnetOwnerLock.Unlock()
+
+	b.subnetOwner[subnetID] = owner
 }

wallet/chain/p/backend_visitor.go

@@ -46,6 +46,10 @@ func (b *backendVisitor) CreateChainTx(tx *txs.CreateChainTx) error {
 }
 
 func (b *backendVisitor) CreateSubnetTx(tx *txs.CreateSubnetTx) error {
+	b.b.setSubnetOwner(
+		b.txID,
+		tx.Owner,
+	)
 	return b.baseTx(&tx.BaseTx)
 }
 
@@ -54,7 +58,10 @@ func (b *backendVisitor) RemoveSubnetValidatorTx(tx *txs.RemoveSubnetValidatorTx
 }
 
 func (b *backendVisitor) TransferSubnetOwnershipTx(tx *txs.TransferSubnetOwnershipTx) error {
-	// TODO: Correctly track subnet owners in [getSubnetSigners]
+	b.b.setSubnetOwner(
+		tx.Subnet,
+		tx.Owner,
+	)
 	return b.baseTx(&tx.BaseTx)
 }
 

wallet/chain/p/builder.go

@@ -16,6 +16,7 @@ import (
 	"github.com/ava-labs/avalanchego/utils/math"
 	"github.com/ava-labs/avalanchego/utils/set"
 	"github.com/ava-labs/avalanchego/vms/components/avax"
+	"github.com/ava-labs/avalanchego/vms/platformvm/fx"
 	"github.com/ava-labs/avalanchego/vms/platformvm/signer"
 	"github.com/ava-labs/avalanchego/vms/platformvm/stakeable"
 	"github.com/ava-labs/avalanchego/vms/platformvm/txs"
@@ -25,7 +26,6 @@ import (
 
 var (
 	errNoChangeAddress           = errors.New("no possible change address")
-	errWrongTxType               = errors.New("wrong tx type")
 	errUnknownOwnerType          = errors.New("unknown owner type")
 	errInsufficientAuthorization = errors.New("insufficient authorization")
 	errInsufficientFunds         = errors.New("insufficient funds")
@@ -134,6 +134,17 @@ type Builder interface {
 		options ...common.Option,
 	) (*txs.CreateSubnetTx, error)
 
+	// NewTransferSubnetOwnershipTx changes the owner of the named subnet.
+	//
+	// - [subnetID] specifies the subnet to be modified
+	// - [owner] specifies who has the ability to create new chains and add new
+	//   validators to the subnet.
+	NewTransferSubnetOwnershipTx(
+		subnetID ids.ID,
+		owner *secp256k1fx.OutputOwners,
+		options ...common.Option,
+	) (*txs.TransferSubnetOwnershipTx, error)
+
 	// NewImportTx creates an import transaction that attempts to consume all
 	// the available UTXOs and import the funds to [to].
 	//
@@ -250,7 +261,7 @@ type Builder interface {
 type BuilderBackend interface {
 	Context
 	UTXOs(ctx stdcontext.Context, sourceChainID ids.ID) ([]*avax.UTXO, error)
-	GetTx(ctx stdcontext.Context, txID ids.ID) (*txs.Tx, error)
+	GetSubnetOwner(ctx stdcontext.Context, subnetID ids.ID) (fx.Owner, error)
 }
 
 type builder struct {
@@ -532,6 +543,42 @@ func (b *builder) NewCreateSubnetTx(
 	return tx, b.initCtx(tx)
 }
 
+func (b *builder) NewTransferSubnetOwnershipTx(
+	subnetID ids.ID,
+	owner *secp256k1fx.OutputOwners,
+	options ...common.Option,
+) (*txs.TransferSubnetOwnershipTx, error) {
+	toBurn := map[ids.ID]uint64{
+		b.backend.AVAXAssetID(): b.backend.BaseTxFee(),
+	}
+	toStake := map[ids.ID]uint64{}
+	ops := common.NewOptions(options)
+	inputs, outputs, _, err := b.spend(toBurn, toStake, ops)
+	if err != nil {
+		return nil, err
+	}
+
+	subnetAuth, err := b.authorizeSubnet(subnetID, ops)
+	if err != nil {
+		return nil, err
+	}
+
+	utils.Sort(owner.Addrs)
+	tx := &txs.TransferSubnetOwnershipTx{
+		BaseTx: txs.BaseTx{BaseTx: avax.BaseTx{
+			NetworkID:    b.backend.NetworkID(),
+			BlockchainID: constants.PlatformChainID,
+			Ins:          inputs,
+			Outs:         outputs,
+			Memo:         ops.Memo(),
+		}},
+		Subnet:     subnetID,
+		Owner:      owner,
+		SubnetAuth: subnetAuth,
+	}
+	return tx, b.initCtx(tx)
+}
+
 func (b *builder) NewImportTx(
 	sourceChainID ids.ID,
 	to *secp256k1fx.OutputOwners,
@@ -1100,20 +1147,15 @@ func (b *builder) spend(
 }
 
 func (b *builder) authorizeSubnet(subnetID ids.ID, options *common.Options) (*secp256k1fx.Input, error) {
-	subnetTx, err := b.backend.GetTx(options.Context(), subnetID)
+	ownerIntf, err := b.backend.GetSubnetOwner(options.Context(), subnetID)
 	if err != nil {
 		return nil, fmt.Errorf(
-			"failed to fetch subnet %q: %w",
+			"failed to fetch subnet owner for %q: %w",
 			subnetID,
 			err,
 		)
 	}
-	subnet, ok := subnetTx.Unsigned.(*txs.CreateSubnetTx)
-	if !ok {
-		return nil, errWrongTxType
-	}
-
-	owner, ok := subnet.Owner.(*secp256k1fx.OutputOwners)
+	owner, ok := ownerIntf.(*secp256k1fx.OutputOwners)
 	if !ok {
 		return nil, errUnknownOwnerType
 	}

wallet/chain/p/builder_with_options.go

@@ -129,6 +129,18 @@ func (b *builderWithOptions) NewCreateSubnetTx(
 	)
 }
 
+func (b *builderWithOptions) NewTransferSubnetOwnershipTx(
+	subnetID ids.ID,
+	owner *secp256k1fx.OutputOwners,
+	options ...common.Option,
+) (*txs.TransferSubnetOwnershipTx, error) {
+	return b.Builder.NewTransferSubnetOwnershipTx(
+		subnetID,
+		owner,
+		common.UnionOptions(b.options, options)...,
+	)
+}
+
 func (b *builderWithOptions) NewImportTx(
 	sourceChainID ids.ID,
 	to *secp256k1fx.OutputOwners,

wallet/chain/p/signer.go

@@ -9,6 +9,7 @@ import (
 	"github.com/ava-labs/avalanchego/ids"
 	"github.com/ava-labs/avalanchego/utils/crypto/keychain"
 	"github.com/ava-labs/avalanchego/vms/components/avax"
+	"github.com/ava-labs/avalanchego/vms/platformvm/fx"
 	"github.com/ava-labs/avalanchego/vms/platformvm/txs"
 )
 
@@ -21,7 +22,7 @@ type Signer interface {
 
 type SignerBackend interface {
 	GetUTXO(ctx stdcontext.Context, chainID, utxoID ids.ID) (*avax.UTXO, error)
-	GetTx(ctx stdcontext.Context, txID ids.ID) (*txs.Tx, error)
+	GetSubnetOwner(ctx stdcontext.Context, subnetID ids.ID) (fx.Owner, error)
 }
 
 type txSigner struct {

wallet/chain/p/signer_visitor.go

@@ -246,20 +246,15 @@ func (s *signerVisitor) getSubnetSigners(subnetID ids.ID, subnetAuth verify.Veri
 		return nil, errUnknownSubnetAuthType
 	}
 
-	subnetTx, err := s.backend.GetTx(s.ctx, subnetID)
+	ownerIntf, err := s.backend.GetSubnetOwner(s.ctx, subnetID)
 	if err != nil {
 		return nil, fmt.Errorf(
-			"failed to fetch subnet %q: %w",
+			"failed to fetch subnet owner for %q: %w",
 			subnetID,
 			err,
 		)
 	}
-	subnet, ok := subnetTx.Unsigned.(*txs.CreateSubnetTx)
-	if !ok {
-		return nil, errWrongTxType
-	}
-
-	owner, ok := subnet.Owner.(*secp256k1fx.OutputOwners)
+	owner, ok := ownerIntf.(*secp256k1fx.OutputOwners)
 	if !ok {
 		return nil, errUnknownOwnerType
 	}

wallet/chain/p/wallet.go

@@ -122,6 +122,18 @@ type Wallet interface {
 		options ...common.Option,
 	) (*txs.Tx, error)
 
+	// IssueTransferSubnetOwnershipTx creates, signs, and issues a transaction that
+	// changes the owner of the named subnet.
+	//
+	// - [subnetID] specifies the subnet to be modified
+	// - [owner] specifies who has the ability to create new chains and add new
+	//   validators to the subnet.
+	IssueTransferSubnetOwnershipTx(
+		subnetID ids.ID,
+		owner *secp256k1fx.OutputOwners,
+		options ...common.Option,
+	) (*txs.Tx, error)
+
 	// IssueImportTx creates, signs, and issues an import transaction that
 	// attempts to consume all the available UTXOs and import the funds to [to].
 	//
@@ -359,6 +371,18 @@ func (w *wallet) IssueCreateSubnetTx(
 	return w.IssueUnsignedTx(utx, options...)
 }
 
+func (w *wallet) IssueTransferSubnetOwnershipTx(
+	subnetID ids.ID,
+	owner *secp256k1fx.OutputOwners,
+	options ...common.Option,
+) (*txs.Tx, error) {
+	utx, err := w.builder.NewTransferSubnetOwnershipTx(subnetID, owner, options...)
+	if err != nil {
+		return nil, err
+	}
+	return w.IssueUnsignedTx(utx, options...)
+}
+
 func (w *wallet) IssueImportTx(
 	sourceChainID ids.ID,
 	to *secp256k1fx.OutputOwners,

wallet/chain/p/wallet_with_options.go

@@ -124,6 +124,18 @@ func (w *walletWithOptions) IssueCreateSubnetTx(
 	)
 }
 
+func (w *walletWithOptions) IssueTransferSubnetOwnershipTx(
+	subnetID ids.ID,
+	owner *secp256k1fx.OutputOwners,
+	options ...common.Option,
+) (*txs.Tx, error) {
+	return w.Wallet.IssueTransferSubnetOwnershipTx(
+		subnetID,
+		owner,
+		common.UnionOptions(w.options, options)...,
+	)
+}
+
 func (w *walletWithOptions) IssueImportTx(
 	sourceChainID ids.ID,
 	to *secp256k1fx.OutputOwners,

wallet/subnet/primary/examples/get-p-chain-balance/main.go

@@ -8,11 +8,9 @@ import (
 	"log"
 	"time"
 
-	"github.com/ava-labs/avalanchego/ids"
 	"github.com/ava-labs/avalanchego/utils/constants"
 	"github.com/ava-labs/avalanchego/utils/formatting/address"
 	"github.com/ava-labs/avalanchego/utils/set"
-	"github.com/ava-labs/avalanchego/vms/platformvm/txs"
 	"github.com/ava-labs/avalanchego/wallet/chain/p"
 	"github.com/ava-labs/avalanchego/wallet/subnet/primary"
 )
@@ -38,7 +36,7 @@ func main() {
 	log.Printf("fetched state of %s in %s\n", addrStr, time.Since(fetchStartTime))
 
 	pUTXOs := primary.NewChainUTXOs(constants.PlatformChainID, state.UTXOs)
-	pBackend := p.NewBackend(state.PCTX, pUTXOs, make(map[ids.ID]*txs.Tx))
+	pBackend := p.NewBackend(state.PCTX, pUTXOs, nil)
 	pBuilder := p.NewBuilder(addresses, pBackend)
 
 	currentBalances, err := pBuilder.GetBalance()