lnd+sweep: remove unused NextAttemptDeltaFunc

server.go

@@ -1078,7 +1078,6 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		Store:            sweeperStore,
 		MaxInputsPerTx:   sweep.DefaultMaxInputsPerTx,
 		MaxSweepAttempts: sweep.DefaultMaxSweepAttempts,
-		NextAttemptDeltaFunc: sweep.DefaultNextAttemptDeltaFunc,
 		MaxFeeRate:       cfg.Sweeper.MaxFeeRate,
 		Aggregator:       aggregator,
 	})

sweep/sweeper.go

@@ -359,12 +359,7 @@ type UtxoSweeperConfig struct {
 	// to the caller.
 	MaxSweepAttempts int
 
-	// NextAttemptDeltaFunc returns given the number of already attempted
+	// MaxFeeRate is the maximum fee rate allowed within the UtxoSweeper.
-	// sweeps, how many blocks to wait before retrying to sweep.
-	NextAttemptDeltaFunc func(int) int32
-
-	// MaxFeeRate is the maximum fee rate allowed within the
-	// UtxoSweeper.
 	MaxFeeRate chainfee.SatPerVByte
 
 	// Aggregator is used to group inputs into clusters based on its
@@ -1335,14 +1330,6 @@ func (s *UtxoSweeper) CreateSweepTx(inputs []input.Input,
 	return tx, err
 }
 
-// DefaultNextAttemptDeltaFunc is the default calculation for next sweep attempt
-// scheduling. It implements exponential back-off with some randomness. This is
-// to prevent a stuck tx (for example because fee is too low and can't be bumped
-// in btcd) from blocking all other retried inputs in the same tx.
-func DefaultNextAttemptDeltaFunc(attempts int) int32 {
-	return 1 + rand.Int31n(1<<uint(attempts-1))
-}
-
 // ListSweeps returns a list of the sweeps recorded by the sweep store.
 func (s *UtxoSweeper) ListSweeps() ([]chainhash.Hash, error) {
 	return s.cfg.Store.ListSweeps()

sweep/sweeper_test.go

@@ -149,10 +149,6 @@ func createSweeperTestContext(t *testing.T) *sweeperTestContext {
 		FeeEstimator:     estimator,
 		MaxInputsPerTx:   testMaxInputsPerTx,
 		MaxSweepAttempts: testMaxSweepAttempts,
-		NextAttemptDeltaFunc: func(attempts int) int32 {
-			// Use delta func without random factor.
-			return 1 << uint(attempts-1)
-		},
 		MaxFeeRate:       DefaultMaxFeeRate,
 		Aggregator:       aggregator,
 	})