Additional check when ensuring wallet synchronised between chains (#3794

)

#Depends on #3793.
This PR adds an additional check when ensuring the wallet is
synchronised between chain.
The new check involves verifying if any UTXO assigned to the wallet
comes from the moved funds sweep transaction.
We only checked if the UTXO comes from a deposit sweep transaction, but
it is also possible a moved funds sweep could be the first transaction
coming from a new wallet.

Additionally, the `GetMovedFundsSweepRequest` function was updated to
follow the same pattern as functions for getting deposit sweep requests
or pending redemption requests.

pkg/chain/ethereum/tbtc.go

@@ -2026,7 +2026,7 @@ func (tc *TbtcChain) GetMovingFundsParameters() (
 func (tc *TbtcChain) GetMovedFundsSweepRequest(
 	movingFundsTxHash bitcoin.Hash,
 	movingFundsTxOutpointIndex uint32,
-) (*tbtc.MovedFundsSweepRequest, error) {
+) (*tbtc.MovedFundsSweepRequest, bool, error) {
 	movedFundsKey := buildMovedFundsKey(
 		movingFundsTxHash,
 		movingFundsTxOutpointIndex,
@@ -2036,16 +2036,21 @@ func (tc *TbtcChain) GetMovedFundsSweepRequest(
 		movedFundsKey,
 	)
 	if err != nil {
-		return nil, fmt.Errorf(
+		return nil, false, fmt.Errorf(
 			"cannot get moved funds sweep request for key [0x%x]: [%v]",
 			movedFundsKey.Text(16),
 			err,
 		)
 	}
 
+	// Moved funds sweep request not found.
+	if movedFundsSweepRequest.CreatedAt == 0 {
+		return nil, false, nil
+	}
+
 	state, err := parseMovedFundsSweepRequestState(movedFundsSweepRequest.State)
 	if err != nil {
-		return nil, fmt.Errorf(
+		return nil, false, fmt.Errorf(
 			"cannot parse state for moved funds sweep request [0x%x]: [%v]",
 			movedFundsKey.Text(16),
 			err,
@@ -2057,7 +2062,7 @@ func (tc *TbtcChain) GetMovedFundsSweepRequest(
 		Value:               movedFundsSweepRequest.Value,
 		CreatedAt:           time.Unix(int64(movedFundsSweepRequest.CreatedAt), 0),
 		State:               state,
-	}, nil
+	}, true, nil
 }
 
 func parseMovedFundsSweepRequestState(value uint8) (

pkg/maintainer/spv/chain.go

@@ -21,14 +21,8 @@ type Chain interface {
 	) error
 
 	// GetDepositRequest gets the on-chain deposit request for the given
-	// funding transaction hash and output index.The returned values represent:
-	// - deposit request which is non-nil only when the deposit request was
-	//   found,
-	// - boolean value which is true if the deposit request was found, false
-	//   otherwise,
-	// - error which is non-nil only when the function execution failed. It will
-	//   be nil if the deposit request was not found, but the function execution
-	//   succeeded.
+	// funding transaction hash and output index. The returned bool value
+	// indicates whether the request was found or not.
 	GetDepositRequest(
 		fundingTxHash bitcoin.Hash,
 		fundingOutputIndex uint32,
@@ -59,10 +53,11 @@ type Chain interface {
 
 	// GetMovedFundsSweepRequest gets the on-chain moved funds sweep request for
 	// the given moving funds transaction hash and output index.
+	// The returned bool value indicates whether the request was found or not.
 	GetMovedFundsSweepRequest(
 		movingFundsTxHash bitcoin.Hash,
 		movingFundsTxOutpointIndex uint32,
-	) (*tbtc.MovedFundsSweepRequest, error)
+	) (*tbtc.MovedFundsSweepRequest, bool, error)
 
 	// SubmitRedemptionProofWithReimbursement submits the redemption proof
 	// via MaintainerProxy. The caller is reimbursed.

pkg/maintainer/spv/chain_test.go

@@ -666,7 +666,7 @@ func (lc *localChain) setMovedFundsSweepRequest(
 func (lc *localChain) GetMovedFundsSweepRequest(
 	movingFundsTxHash bitcoin.Hash,
 	movingFundsTxOutpointIndex uint32,
-) (*tbtc.MovedFundsSweepRequest, error) {
+) (*tbtc.MovedFundsSweepRequest, bool, error) {
 	lc.mutex.Lock()
 	defer lc.mutex.Unlock()
 
@@ -677,10 +677,10 @@ func (lc *localChain) GetMovedFundsSweepRequest(
 
 	request, ok := lc.movedFundsSweepRequests[requestKey]
 	if !ok {
-		return nil, fmt.Errorf("request not found")
+		return nil, false, nil
 	}
 
-	return request, nil
+	return request, true, nil
 }
 
 type mockBlockCounter struct {

pkg/maintainer/spv/moved_funds_sweep.go

@@ -275,7 +275,7 @@ func isUnprovenMovedFundsSweepTransaction(
 	requestTransactionHash := transaction.Inputs[0].Outpoint.TransactionHash
 	requestOutputIndex := transaction.Inputs[0].Outpoint.OutputIndex
 
-	movedFundsSweepRequest, err := spvChain.GetMovedFundsSweepRequest(
+	movedFundsSweepRequest, isRequest, err := spvChain.GetMovedFundsSweepRequest(
 		requestTransactionHash,
 		requestOutputIndex,
 	)
@@ -286,6 +286,12 @@ func isUnprovenMovedFundsSweepTransaction(
 		)
 	}
 
+	// Check if it's a moved funds sweep request at all.
+	if !isRequest {
+		return false, nil
+	}
+
+	// Check if it's a pending moved funds sweep request.
 	if movedFundsSweepRequest.State != tbtc.MovedFundsStatePending {
 		return false, nil
 	}

pkg/tbtc/chain.go

@@ -209,18 +209,20 @@ type BridgeChain interface {
 	) (*RedemptionRequest, bool, error)
 
 	// GetDepositRequest gets the on-chain deposit request for the given
-	// funding transaction hash and output index.The returned values represent:
-	// - deposit request which is non-nil only when the deposit request was
-	//   found,
-	// - boolean value which is true if the deposit request was found, false
-	//   otherwise,
-	// - error which is non-nil only when the function execution failed. It will
-	//   be nil if the deposit request was not found, but the function execution
-	//   succeeded.
+	// funding transaction hash and output index. The returned bool value
+	// indicates whether the request was found or not.
 	GetDepositRequest(
 		fundingTxHash bitcoin.Hash,
 		fundingOutputIndex uint32,
 	) (*DepositChainRequest, bool, error)
+
+	// GetMovedFundsSweepRequest gets the on-chain moved funds sweep request for
+	// the given moving funds transaction hash and output index.
+	// The returned bool value indicates whether the request was found or not.
+	GetMovedFundsSweepRequest(
+		movingFundsTxHash bitcoin.Hash,
+		movingFundsTxOutpointIndex uint32,
+	) (*MovedFundsSweepRequest, bool, error)
 }
 
 // NewWalletRegisteredEvent represents a new wallet registered event.

pkg/tbtc/chain_test.go

@@ -69,6 +69,9 @@ type localChain struct {
 	movingFundsProposalValidationsMutex sync.Mutex
 	movingFundsProposalValidations      map[[32]byte]bool
 
+	movedFundsSweepRequestsMutex sync.Mutex
+	movedFundsSweepRequests      map[[32]byte]*MovedFundsSweepRequest
+
 	movedFundsSweepProposalValidationsMutex sync.Mutex
 	movedFundsSweepProposalValidations      map[[32]byte]bool
 
@@ -202,6 +205,41 @@ func (lc *localChain) IsBetaOperator() (bool, error) {
 	panic("unsupported")
 }
 
+func buildMovedFundsSweepRequestKey(
+	movingFundsTxHash bitcoin.Hash,
+	movingFundsTxOutpointIndex uint32,
+) [32]byte {
+	var buffer bytes.Buffer
+
+	buffer.Write(movingFundsTxHash[:])
+
+	outputIndex := make([]byte, 4)
+	binary.BigEndian.PutUint32(outputIndex, movingFundsTxOutpointIndex)
+	buffer.Write(outputIndex)
+
+	return sha256.Sum256(buffer.Bytes())
+}
+
+func (lc *localChain) GetMovedFundsSweepRequest(
+	movingFundsTxHash bitcoin.Hash,
+	movingFundsTxOutpointIndex uint32,
+) (*MovedFundsSweepRequest, bool, error) {
+	lc.movedFundsSweepRequestsMutex.Lock()
+	defer lc.movedFundsSweepRequestsMutex.Unlock()
+
+	requestKey := buildMovedFundsSweepRequestKey(
+		movingFundsTxHash,
+		movingFundsTxOutpointIndex,
+	)
+
+	request, ok := lc.movedFundsSweepRequests[requestKey]
+	if !ok {
+		return nil, false, nil
+	}
+
+	return request, true, nil
+}
+
 func (lc *localChain) GetOperatorID(
 	operatorAddress chain.Address,
 ) (chain.OperatorID, error) {

pkg/tbtc/wallet.go

@@ -7,11 +7,12 @@ import (
 	"crypto/elliptic"
 	"encoding/hex"
 	"fmt"
-	"golang.org/x/exp/slices"
 	"math/big"
 	"sync"
 	"time"
 
+	"golang.org/x/exp/slices"
+
 	"github.com/ipfs/go-log/v2"
 	"github.com/keep-network/keep-core/pkg/bitcoin"
 	"github.com/keep-network/keep-core/pkg/chain"
@@ -579,8 +580,15 @@ func EnsureWalletSyncedBetweenChains(
 		}
 
 		for _, utxo := range allUtxos {
-			// We know that valid first transaction of the wallet always
-			// have just one output. Any utxos with output index other
+			// The first valid transaction of a wallet is most likely a deposit
+			// sweep, but there is a small chance it could be a moved funds sweep.
+			// It could happen if the wallet was selected as a target wallet and
+			// some funds were moved to it by the source wallet. In that case the
+			// wallet could create a moved fund sweep transaction even before
+			// sweeping any deposits.
+
+			// In any case, we know that valid first transaction of the wallet
+			// always have just one output. Any utxos with output index other
 			// than 0 are certainly not produced by the wallet and, we should
 			// not take them into account.
 			if utxo.Outpoint.OutputIndex != 0 {
@@ -596,11 +604,10 @@ func EnsureWalletSyncedBetweenChains(
 				)
 			}
 
-			// We know that valid first transaction of the wallet have all their
-			// inputs referring to revealed deposits. We need to check just
-			// one input. If it points to a revealed deposit, that means
-			// the given transaction is produced by our wallet. Otherwise,
-			// such a transaction is a spam.
+			// The transaction could be a deposit sweep. In that case all the
+			// transaction's inputs must refer to revealed deposits. We can
+			// check one input. If it points to a revealed deposit, that means
+			// the given transaction is produced by our wallet.
 			input := transaction.Inputs[0]
 			_, isDeposit, err := bridgeChain.GetDepositRequest(
 				input.Outpoint.TransactionHash,
@@ -617,11 +624,40 @@ func EnsureWalletSyncedBetweenChains(
 			}
 
 			if isDeposit {
-				// If that's the case, the wallet was already done their
-				// first Bitcoin transaction and the Bridge is awaiting the
-				// SPV proof.
+				// If that's the case, the wallet has already created a deposit
+				// sweep as their first Bitcoin transaction and the Bridge is
+				// awaiting the SPV proof.
+				return fmt.Errorf("wallet already produced their first " +
+					"Bitcoin transaction (deposit sweep); Bridge is probably " +
+					"awaiting the SPV proof",
+				)
+			}
+
+			// The transaction could be a moved funds sweep request. In that
+			// case the transaction's input must refer to a moved funds sweep
+			// request. If the input points to a moved funds sweep request, that
+			// means the given transaction is produced by our wallet.
+			_, isRequest, err := bridgeChain.GetMovedFundsSweepRequest(
+				input.Outpoint.TransactionHash,
+				input.Outpoint.OutputIndex,
+			)
+			if err != nil {
+				return fmt.Errorf(
+					"cannot get moved funds sweep request for hash [%s] "+
+						"and output index [%v]: [%v]",
+					input.Outpoint.TransactionHash.String(),
+					input.Outpoint.OutputIndex,
+					err,
+				)
+			}
+
+			if isRequest {
+				// If that's the case, the wallet has already created a moved
+				// funds sweep as their first Bitcoin transaction and the Bridge
+				// is awaiting the SPV proof.
 				return fmt.Errorf("wallet already produced their first " +
-					"Bitcoin transaction; Bridge is probably awaiting the SPV proof",
+					"Bitcoin transaction (moved funds sweep); Bridge is " +
+					"probably awaiting the SPV proof",
 				)
 			}
 

pkg/tbtcpg/chain.go

@@ -148,13 +148,6 @@ type Chain interface {
 		err error,
 	)
 
-	// GetMovedFundsSweepRequest gets the on-chain moved funds sweep request for
-	// the given moving funds transaction hash and output index.
-	GetMovedFundsSweepRequest(
-		movingFundsTxHash bitcoin.Hash,
-		movingFundsTxOutpointIndex uint32,
-	) (*tbtc.MovedFundsSweepRequest, error)
-
 	// PastMovingFundsCommitmentSubmittedEvents fetches past moving funds
 	// commitment submitted events according to the provided filter or
 	// unfiltered if the filter is nil. Returned events are sorted by the block

pkg/tbtcpg/chain_test.go

@@ -770,7 +770,7 @@ func (lc *LocalChain) GetMovingFundsParameters() (
 func (lc *LocalChain) GetMovedFundsSweepRequest(
 	movingFundsTxHash bitcoin.Hash,
 	movingFundsTxOutpointIndex uint32,
-) (*tbtc.MovedFundsSweepRequest, error) {
+) (*tbtc.MovedFundsSweepRequest, bool, error) {
 	lc.mutex.Lock()
 	defer lc.mutex.Unlock()
 
@@ -781,10 +781,10 @@ func (lc *LocalChain) GetMovedFundsSweepRequest(
 
 	request, ok := lc.movedFundsSweepRequests[requestKey]
 	if !ok {
-		return nil, fmt.Errorf("request not found")
+		return nil, false, nil
 	}
 
-	return request, nil
+	return request, true, nil
 }
 
 func (lc *LocalChain) SetMovedFundsSweepRequest(

pkg/tbtcpg/moved_funds_sweep.go

@@ -174,7 +174,7 @@ func (mfst *MovedFundsSweepTask) FindMovingFundsTxData(
 	// Find the first outpoint that represents an unproven moved funds sweep
 	// request and return it.
 	for _, outpoint := range movingFundsTxOutpoints {
-		movedFundsSweepRequest, err := mfst.chain.GetMovedFundsSweepRequest(
+		movedFundsSweepRequest, isRequest, err := mfst.chain.GetMovedFundsSweepRequest(
 			outpoint.TransactionHash,
 			outpoint.OutputIndex,
 		)
@@ -185,6 +185,12 @@ func (mfst *MovedFundsSweepTask) FindMovingFundsTxData(
 			)
 		}
 
+		// Check just in case. It should not happen, as all the outpoint should
+		// represent a valid request.
+		if !isRequest {
+			continue
+		}
+
 		if movedFundsSweepRequest.State == tbtc.MovedFundsStatePending {
 			return outpoint.TransactionHash, outpoint.OutputIndex, nil
 		}