Add padding to gas estimations

Adds a 20% buffer to gas estimations to reduce out-of-gas errors.

eth/gasestimator/gasestimator.go

@@ -69,6 +69,8 @@ func Estimate(ctx context.Context, call *core.Message, opts *Options, gasCap uin
 	} else {
 		feeCap = common.Big0
 	}
+	// Track the maximum gas based on the account's available funds and the txn feeCap.
+	var accountGasLimit uint64
 	// Recap the highest gas limit with account's available balance.
 	if feeCap.BitLen() != 0 {
 		balance := opts.State.GetBalance(call.From).ToBig()
@@ -83,7 +85,9 @@ func Estimate(ctx context.Context, call *core.Message, opts *Options, gasCap uin
 		allowance := new(big.Int).Div(available, feeCap)
 
 		// If the allowance is larger than maximum uint64, skip checking
-		if allowance.IsUint64() && hi > allowance.Uint64() {
+		if allowance.IsUint64() {
+			accountGasLimit = allowance.Uint64()
+			if hi > allowance.Uint64() {
 				transfer := call.Value
 				if transfer == nil {
 					transfer = new(big.Int)
@@ -93,11 +97,23 @@ func Estimate(ctx context.Context, call *core.Message, opts *Options, gasCap uin
 				hi = allowance.Uint64()
 			}
 		}
+	}
 	// Recap the highest gas allowance with specified gascap.
 	if gasCap != 0 && hi > gasCap {
 		log.Debug("Caller gas above allowance, capping", "requested", hi, "cap", gasCap)
 		hi = gasCap
 	}
+
+	// Adds a 20% pad to the estimated gas usage, not exceeding account gas limit
+	// to help mitigate gas underestimations
+	padResult := func(gas uint64) uint64 {
+		gas = gas + gas/5
+		if accountGasLimit != 0 && gas > accountGasLimit {
+			gas = accountGasLimit
+		}
+		return gas
+	}
+
 	// If the transaction is a plain value transfer, short circuit estimation and
 	// directly try 21000. Returning 21000 without any execution is dangerous as
 	// some tx field combos might bump the price up even for plain transfers (e.g.
@@ -106,7 +122,7 @@ func Estimate(ctx context.Context, call *core.Message, opts *Options, gasCap uin
 		if call.To != nil && opts.State.GetCodeSize(*call.To) == 0 {
 			failed, _, err := execute(ctx, call, opts, params.TxGas)
 			if !failed && err == nil {
-				return params.TxGas, nil, nil
+				return padResult(params.TxGas), nil, nil
 			}
 		}
 	}
@@ -178,7 +194,7 @@ func Estimate(ctx context.Context, call *core.Message, opts *Options, gasCap uin
 			hi = mid
 		}
 	}
-	return hi, nil, nil
+	return padResult(hi), nil, nil
 }
 
 // execute is a helper that executes the transaction under a given gas limit and

ethclient/ethclient_test.go

@@ -553,7 +553,7 @@ func testCallContractAtHash(t *testing.T, client *rpc.Client) {
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
-	if gas != 21000 {
+	if gas != 25200 {
 		t.Fatalf("unexpected gas price: %v", gas)
 	}
 	block, err := ec.HeaderByNumber(context.Background(), big.NewInt(1))
@@ -580,7 +580,7 @@ func testCallContract(t *testing.T, client *rpc.Client) {
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
-	if gas != 21000 {
+	if gas != 25200 {
 		t.Fatalf("unexpected gas price: %v", gas)
 	}
 	// CallContract

graphql/graphql_test.go

@@ -139,7 +139,7 @@ func TestGraphQLBlockSerialization(t *testing.T) {
 		// should return `estimateGas` as decimal
 		{
 			body: `{"query": "{block{ estimateGas(data:{}) }}"}`,
-			want: `{"data":{"block":{"estimateGas":"0xd221"}}}`,
+			want: `{"data":{"block":{"estimateGas":"0xfc27"}}}`,
 			code: 200,
 		},
 		// should return `status` as decimal

internal/ethapi/api_test.go

@@ -663,7 +663,7 @@ func TestEstimateGas(t *testing.T) {
 				Value: (*hexutil.Big)(big.NewInt(1000)),
 			},
 			expectErr: nil,
-			want:      21000,
+			want:      25200,
 		},
 		// simple transfer with insufficient funds on latest block
 		{
@@ -674,14 +674,14 @@ func TestEstimateGas(t *testing.T) {
 				Value: (*hexutil.Big)(big.NewInt(1000)),
 			},
 			expectErr: core.ErrInsufficientFunds,
-			want:      21000,
+			want:      25200,
 		},
 		// empty create
 		{
 			blockNumber: rpc.LatestBlockNumber,
 			call:        TransactionArgs{},
 			expectErr:   nil,
-			want:        53000,
+			want:        64551,
 		},
 		{
 			blockNumber: rpc.LatestBlockNumber,
@@ -690,7 +690,7 @@ func TestEstimateGas(t *testing.T) {
 				randomAccounts[0].addr: OverrideAccount{Balance: newRPCBalance(new(big.Int).Mul(big.NewInt(1), big.NewInt(params.Ether)))},
 			},
 			expectErr: nil,
-			want:      53000,
+			want:      64551,
 		},
 		{
 			blockNumber: rpc.LatestBlockNumber,
@@ -722,7 +722,7 @@ func TestEstimateGas(t *testing.T) {
 				GasPrice: (*hexutil.Big)(big.NewInt(1_000_000_000)), // Legacy as pricing
 			},
 			expectErr: nil,
-			want:      67617,
+			want:      82171,
 		},
 		{
 			blockNumber: rpc.LatestBlockNumber,
@@ -732,7 +732,7 @@ func TestEstimateGas(t *testing.T) {
 				MaxFeePerGas: (*hexutil.Big)(big.NewInt(1_000_000_000)), // 1559 gas pricing
 			},
 			expectErr: nil,
-			want:      67617,
+			want:      82171,
 		},
 		{
 			blockNumber: rpc.LatestBlockNumber,
@@ -743,7 +743,7 @@ func TestEstimateGas(t *testing.T) {
 				MaxFeePerGas: nil, // No 1559 gas pricing
 			},
 			expectErr: nil,
-			want:      67595,
+			want:      82144,
 		},
 		// Blobs should have no effect on gas estimate
 		{
@@ -755,7 +755,7 @@ func TestEstimateGas(t *testing.T) {
 				BlobHashes: []common.Hash{common.Hash{0x01, 0x22}},
 				BlobFeeCap: (*hexutil.Big)(big.NewInt(1)),
 			},
-			want: 21000,
+			want: 25200,
 		},
 	}
 	for i, tc := range testSuite {
@@ -1008,7 +1008,7 @@ func TestSignTransaction(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	expect := `{"type":"0x2","chainId":"0x1","nonce":"0x0","to":"0x703c4b2bd70c169f5717101caee543299fc946c7","gas":"0x5208","gasPrice":null,"maxPriorityFeePerGas":"0x0","maxFeePerGas":"0x684ee180","value":"0x1","input":"0x","accessList":[],"v":"0x0","r":"0x8fabeb142d585dd9247f459f7e6fe77e2520c88d50ba5d220da1533cea8b34e1","s":"0x582dd68b21aef36ba23f34e49607329c20d981d30404daf749077f5606785ce7","yParity":"0x0","hash":"0x93927839207cfbec395da84b8a2bc38b7b65d2cb2819e9fef1f091f5b1d4cc8f"}`
+	expect := `{"type":"0x2","chainId":"0x1","nonce":"0x0","to":"0x703c4b2bd70c169f5717101caee543299fc946c7","gas":"0x6270","gasPrice":null,"maxPriorityFeePerGas":"0x0","maxFeePerGas":"0x684ee180","value":"0x1","input":"0x","accessList":[],"v":"0x0","r":"0xecde8d8a090f99fa06adcb5dacd9ca415cd31b002355b8285639e78f227fe56e","s":"0x91b92ca049b354ab795430e0d465d9901ef34fdb12a28a598be126441761dc6","yParity":"0x0","hash":"0x79368920659e6e4a5b1fca57cbe28657b4263fa447a8412bdb474347447d2ceb"}`
 	if !bytes.Equal(tx, []byte(expect)) {
 		t.Errorf("result mismatch. Have:\n%s\nWant:\n%s\n", tx, expect)
 	}