Return an error if estimated deposit sweep fee is too high

cmd/maintainercli.go

@@ -567,7 +567,7 @@ var estimateDepositsSweepFeeCommandDescription = "Estimates the satoshi " +
 	"assume only P2WSH deposits are part of the transaction so the " +
 	"estimation may be underpriced if the actual transaction contains " +
 	"legacy P2SH deposits. If the estimated fee exceeds the maximum fee " +
-	"allowed by the Bridge contract, the maximum fee is returned as result"
+	"allowed by the Bridge contract, an error is returned as result"
 
 var submitDepositSweepProofCommand = cobra.Command{
 	Use:              "submit-deposit-sweep-proof",

pkg/maintainer/wallet/deposit_sweep.go

@@ -340,7 +340,7 @@ func ProposeDepositsSweep(
 			perDepositMaxFee,
 		)
 		if err != nil {
-			return fmt.Errorf("cannot estimate sweep transaction fee: [%w]", err)
+			return fmt.Errorf("cannot estimate sweep transaction fee: [%v]", err)
 		}
 
 		fee = estimatedFee
@@ -414,7 +414,7 @@ func ProposeDepositsSweep(
 //   - 1 P2WPKH output
 //
 // If any of the estimated fees exceed the maximum fee allowed by the Bridge
-// contract, the maximum fee is returned as result.
+// contract, an error is returned as result.
 func EstimateDepositsSweepFee(
 	chain Chain,
 	btcChain bitcoin.Chain,
@@ -502,8 +502,11 @@ func estimateDepositsSweepFee(
 
 	// Compute the maximum possible total fee for the entire sweep transaction.
 	totalMaxFee := uint64(depositsCount) * perDepositMaxFee
-	// Make sure the proposed total fee does not exceed the maximum possible total fee.
-	totalFee = int64(math.Min(float64(totalFee), float64(totalMaxFee)))
+
+	if uint64(totalFee) > totalMaxFee {
+		return 0, 0, fmt.Errorf("estimated fee exceeds the maximum fee")
+	}
+
 	// Compute the actual sat/vbyte fee for informational purposes.
 	satPerVByteFee := math.Round(float64(totalFee) / float64(transactionSize))
 

pkg/maintainer/wallet/deposit_sweep_test.go

@@ -1,6 +1,7 @@
 package wallet_test
 
 import (
+	"reflect"
 	"testing"
 
 	"github.com/go-test/deep"
@@ -136,13 +137,15 @@ func TestProposeDepositsSweep(t *testing.T) {
 				btcChain.SetTransactionConfirmations(deposit.FundingTxHash, tbtc.DepositSweepRequiredFundingTxConfirmations)
 			}
 
-			err := tbtcChain.SetDepositSweepProposalValidationResult(
-				scenario.ExpectedDepositSweepProposal,
-				nil,
-				true,
-			)
-			if err != nil {
-				t.Fatal(err)
+			if scenario.ExpectedDepositSweepProposal != nil {
+				err := tbtcChain.SetDepositSweepProposalValidationResult(
+					scenario.ExpectedDepositSweepProposal,
+					nil,
+					true,
+				)
+				if err != nil {
+					t.Fatal(err)
+				}
 			}
 
 			btcChain.SetEstimateSatPerVByteFee(1, scenario.EstimateSatPerVByteFee)
@@ -156,13 +159,25 @@ func TestProposeDepositsSweep(t *testing.T) {
 				scenario.DepositsReferences(),
 				false,
 			)
-			if err != nil {
-				t.Fatal(err)
+
+			if !reflect.DeepEqual(scenario.ExpectedErr, err) {
+				t.Errorf(
+					"unexpected error\n"+
+						"expected: [%+v]\n"+
+						"actual:   [%+v]",
+					scenario.ExpectedErr,
+					err,
+				)
+			}
+
+			var expectedDepositSweepProposals []*tbtc.DepositSweepProposal
+			if p := scenario.ExpectedDepositSweepProposal; p != nil {
+				expectedDepositSweepProposals = append(expectedDepositSweepProposals, p)
 			}
 
 			if diff := deep.Equal(
 				tbtcChain.DepositSweepProposals(),
-				[]*tbtc.DepositSweepProposal{scenario.ExpectedDepositSweepProposal},
+				expectedDepositSweepProposals,
 			); diff != nil {
 				t.Errorf("invalid deposits: %v", diff)
 			}

pkg/maintainer/wallet/internal/test/marshaling.go

@@ -130,6 +130,10 @@ type depositSweepProposal struct {
 }
 
 func (dsp *depositSweepProposal) convert() (*tbtc.DepositSweepProposal, error) {
+	if dsp == nil {
+		return nil, nil
+	}
+
 	result := &tbtc.DepositSweepProposal{}
 
 	if len(dsp.WalletPublicKeyHash) > 0 {
@@ -179,7 +183,8 @@ func (psts *ProposeSweepTestScenario) UnmarshalJSON(data []byte) error {
 		}
 		SweepTxFee                   int64
 		EstimateSatPerVByteFee       int64
-		ExpectedDepositSweepProposal depositSweepProposal
+		ExpectedDepositSweepProposal *depositSweepProposal
+		ExpectedErr                  string
 	}
 
 	var unmarshaled proposeSweepTestScenario
@@ -237,6 +242,11 @@ func (psts *ProposeSweepTestScenario) UnmarshalJSON(data []byte) error {
 		)
 	}
 
+	// Unmarshal expected error
+	if len(unmarshaled.ExpectedErr) > 0 {
+		psts.ExpectedErr = fmt.Errorf(unmarshaled.ExpectedErr)
+	}
+
 	return nil
 }
 

pkg/maintainer/wallet/internal/test/testdata/propose_sweep_scenario_2.json

@@ -21,23 +21,5 @@
   ],
   "SweepTxFee": 0,
   "EstimateSatPerVByteFee": 26,
-  "ExpectedDepositSweepProposal": {
-    "WalletPublicKeyHash": "0x03b74d6893ad46dfdd01b9e0e3b3385f4fce2d1e",
-    "DepositsKeys": [
-      {
-        "FundingTxHash": "d91868ca43db4deb96047d727a5e782f282864fde2d9364f8c562c8998ba64bf",
-        "FundingOutputIndex": 1
-      },
-      {
-        "FundingTxHash": "a3d1781b59d5e8680772a8bb7f897c4ff0459d3465d7fa678f80a4f0ec900574",
-        "FundingOutputIndex": 0
-      },
-      {
-        "FundingTxHash": "b822b302dab7c1fcc3292782635be133538a0f803468a2d847023c24f867f479",
-        "FundingOutputIndex": 3
-      }
-    ],
-    "SweepTxFee": 903,
-    "DepositsRevealBlocks": [11, 31, 32]
-  }
+  "ExpectedErr": "cannot estimate sweep transaction fee: [estimated fee exceeds the maximum fee]"
 }

pkg/maintainer/wallet/internal/test/wallettest.go

@@ -113,6 +113,7 @@ type ProposeSweepTestScenario struct {
 	SweepTxFee                   int64
 	EstimateSatPerVByteFee       int64
 	ExpectedDepositSweepProposal *tbtc.DepositSweepProposal
+	ExpectedErr                  error
 }
 
 func (psts *ProposeSweepTestScenario) DepositsReferences() []*walletmtr.DepositReference {