sweep: return all inputs from PendingSweeps

Previously we'd skip returning immature inputs to stay backwards
compatible. This has the downside as the node operator cannot take
actions on this input, like some customized batching strategy via
`bumpfee` RPC.

After this change, it means when calling `bumpfee` RPC, it will now
update the params for the immature input instead of returning an error
saying `output does not belong to wallet`.

We also add a `MaturityHeight` field so the user knows when this input
will be swept.

sweep/sweeper.go

@@ -305,6 +305,10 @@ type PendingInputResponse struct {
 
 	// DeadlineHeight records the deadline height of this input.
 	DeadlineHeight uint32
+
+	// MaturityHeight is the block height that this input's locktime will
+	// be expired at. For inputs with no locktime this value is zero.
+	MaturityHeight uint32
 }
 
 // updateReq is an internal message we'll use to represent an external caller's
@@ -1068,11 +1072,7 @@ func (s *UtxoSweeper) handlePendingSweepsReq(
 
 	resps := make(map[wire.OutPoint]*PendingInputResponse, len(s.inputs))
 	for _, inp := range s.inputs {
-		// Skip immature inputs for compatibility.
-		mature, _ := inp.isMature(uint32(s.currentHeight))
-		if !mature {
-			continue
-		}
+		_, maturityHeight := inp.isMature(uint32(s.currentHeight))
 
 		// Only the exported fields are set, as we expect the response
 		// to only be consumed externally.
@@ -1087,6 +1087,7 @@ func (s *UtxoSweeper) handlePendingSweepsReq(
 			BroadcastAttempts: inp.publishAttempts,
 			Params:            inp.params,
 			DeadlineHeight:    uint32(inp.DeadlineHeight),
+			MaturityHeight:    maturityHeight,
 		}
 	}