fix: Ignore duplicated finality vote err

CHANGELOG.md

@@ -37,6 +37,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ## Unreleased
 
+* [#124](https://github.com/babylonlabs-io/finality-provider/pull/124) Ignore
+duplicated finality vote error
+
 ## v0.10.0
 
 ### Improvements

clientcontroller/babylon.go

@@ -16,8 +16,6 @@ import (
 	btclctypes "github.com/babylonlabs-io/babylon/x/btclightclient/types"
 	btcstakingtypes "github.com/babylonlabs-io/babylon/x/btcstaking/types"
 	finalitytypes "github.com/babylonlabs-io/babylon/x/finality/types"
-	fpcfg "github.com/babylonlabs-io/finality-provider/finality-provider/config"
-	"github.com/babylonlabs-io/finality-provider/types"
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcec/v2/schnorr"
 	"github.com/btcsuite/btcd/btcutil"
@@ -29,6 +27,9 @@ import (
 	"github.com/cosmos/relayer/v2/relayer/provider"
 	"go.uber.org/zap"
 	protobuf "google.golang.org/protobuf/proto"
+
+	fpcfg "github.com/babylonlabs-io/finality-provider/finality-provider/config"
+	"github.com/babylonlabs-io/finality-provider/types"
 )
 
 var _ ClientController = &BabylonController{}
@@ -207,11 +208,19 @@ func (bc *BabylonController) SubmitFinalitySig(
 		btcstakingtypes.ErrFpAlreadySlashed,
 	}
 
-	res, err := bc.reliablySendMsg(msg, emptyErrs, unrecoverableErrs)
+	expectedErrs := []*sdkErr.Error{
+		finalitytypes.ErrDuplicatedFinalitySig,
+	}
+
+	res, err := bc.reliablySendMsg(msg, expectedErrs, unrecoverableErrs)
 	if err != nil {
 		return nil, err
 	}
 
+	if res == nil {
+		return &types.TxResponse{}, nil
+	}
+
 	return &types.TxResponse{TxHash: res.TxHash, Events: res.Events}, nil
 }
 
@@ -252,11 +261,19 @@ func (bc *BabylonController) SubmitBatchFinalitySigs(
 		btcstakingtypes.ErrFpAlreadySlashed,
 	}
 
-	res, err := bc.reliablySendMsgs(msgs, emptyErrs, unrecoverableErrs)
+	expectedErrs := []*sdkErr.Error{
+		finalitytypes.ErrDuplicatedFinalitySig,
+	}
+
+	res, err := bc.reliablySendMsgs(msgs, expectedErrs, unrecoverableErrs)
 	if err != nil {
 		return nil, err
 	}
 
+	if res == nil {
+		return &types.TxResponse{}, nil
+	}
+
 	return &types.TxResponse{TxHash: res.TxHash, Events: res.Events}, nil
 }
 

finality-provider/service/fp_instance.go

@@ -11,12 +11,13 @@ import (
 	"github.com/avast/retry-go/v4"
 	bbntypes "github.com/babylonlabs-io/babylon/types"
 	ftypes "github.com/babylonlabs-io/babylon/x/finality/types"
-	fppath "github.com/babylonlabs-io/finality-provider/lib/math"
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/gogo/protobuf/jsonpb"
 	"go.uber.org/atomic"
 	"go.uber.org/zap"
 
+	fppath "github.com/babylonlabs-io/finality-provider/lib/math"
+
 	"github.com/babylonlabs-io/finality-provider/clientcontroller"
 	"github.com/babylonlabs-io/finality-provider/eotsmanager"
 	fpcfg "github.com/babylonlabs-io/finality-provider/finality-provider/config"
@@ -693,12 +694,15 @@ func (fp *FinalityProviderInstance) SubmitFinalitySignature(b *types.BlockInfo)
 		return nil, fmt.Errorf("failed to send finality signature to the consumer chain: %w", err)
 	}
 
-	// update DB
-	fp.MustUpdateStateAfterFinalitySigSubmission(b.Height)
+	// it is possible that the vote is duplicate so the metrics do need to update
+	if res.TxHash != "" {
+		// update DB
+		fp.MustUpdateStateAfterFinalitySigSubmission(b.Height)
 
-	// update metrics
-	fp.metrics.RecordFpVoteTime(fp.GetBtcPkHex())
-	fp.metrics.IncrementFpTotalVotedBlocks(fp.GetBtcPkHex())
+		// update metrics
+		fp.metrics.RecordFpVoteTime(fp.GetBtcPkHex())
+		fp.metrics.IncrementFpTotalVotedBlocks(fp.GetBtcPkHex())
+	}
 
 	return res, nil
 }
@@ -785,6 +789,10 @@ func (fp *FinalityProviderInstance) TestSubmitFinalitySignatureAndExtractPrivKey
 		return nil, nil, fmt.Errorf("failed to send finality signature to the consumer chain: %w", err)
 	}
 
+	if res.TxHash == "" {
+		return res, nil, nil
+	}
+
 	// try to extract the private key
 	var privKey *btcec.PrivateKey
 	for _, ev := range res.Events {

itest/e2e_test.go

@@ -4,17 +4,19 @@
 package e2etest
 
 import (
+	"math/rand"
+	"testing"
+	"time"
+
 	sdkmath "cosmossdk.io/math"
 	"github.com/babylonlabs-io/babylon/testutil/datagen"
-	"github.com/babylonlabs-io/finality-provider/clientcontroller"
-	"github.com/babylonlabs-io/finality-provider/finality-provider/cmd/fpd/daemon"
-	"github.com/babylonlabs-io/finality-provider/types"
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/zap"
-	"math/rand"
-	"testing"
-	"time"
+
+	"github.com/babylonlabs-io/finality-provider/clientcontroller"
+	"github.com/babylonlabs-io/finality-provider/finality-provider/cmd/fpd/daemon"
+	"github.com/babylonlabs-io/finality-provider/types"
 )
 
 var (
@@ -84,26 +86,27 @@ func TestDoubleSigning(t *testing.T) {
 
 	finalizedBlocks := tm.WaitForNFinalizedBlocks(t, 1)
 
+	// test duplicate vote which should be ignored
+	res, extractedKey, err := fpIns.TestSubmitFinalitySignatureAndExtractPrivKey(finalizedBlocks[0])
+	require.NoError(t, err)
+	require.Nil(t, extractedKey)
+	require.Empty(t, res)
+	t.Logf("duplicate vote for %d is sent", finalizedBlocks[0].Height)
+
 	// attack: manually submit a finality vote over a conflicting block
 	// to trigger the extraction of finality-provider's private key
 	r := rand.New(rand.NewSource(time.Now().UnixNano()))
 	b := &types.BlockInfo{
 		Height: finalizedBlocks[0].Height,
 		Hash:   datagen.GenRandomByteArray(r, 32),
 	}
-	_, extractedKey, err := fpIns.TestSubmitFinalitySignatureAndExtractPrivKey(b)
+	_, extractedKey, err = fpIns.TestSubmitFinalitySignatureAndExtractPrivKey(b)
 	require.NoError(t, err)
 	require.NotNil(t, extractedKey)
 	localKey := tm.GetFpPrivKey(t, fpIns.GetBtcPkBIP340().MustMarshal())
 	require.True(t, localKey.Key.Equals(&extractedKey.Key) || localKey.Key.Negate().Equals(&extractedKey.Key))
 
 	t.Logf("the equivocation attack is successful")
-
-	tm.WaitForFpShutDown(t)
-
-	// try to start the finality providers and the slashed one should expect err
-	err = tm.Fpa.StartHandlingFinalityProvider(fpIns.GetBtcPkBIP340(), "")
-	require.Error(t, err)
 }
 
 // TestFastSync tests the fast sync process where the finality-provider is terminated and restarted with fast sync