order: allow account version upgrade during batch

order/batch.go

@@ -119,6 +119,12 @@ type AccountDiff struct {
 	// NewExpiry is the new expiry height for this account. This field
 	// can be safely ignored if its value is 0.
 	NewExpiry uint32
+
+	// NewVersion is the version of the account that should be used after
+	// the batch went through. This field influences the type of account
+	// output that is created by this batch. If this differs from the
+	// CurrentVersion, then the account was upgraded in this batch.
+	NewVersion account.Version
 }
 
 // validateEndingState validates that the ending state of an account as

order/batch_storer.go

@@ -110,6 +110,17 @@ func (s *batchStorer) StorePendingBatch(batch *Batch) error {
 				)
 			}
 
+			// The account version can be upgraded during the batch
+			// if the client supports it.
+			if batch.Version.SupportsAccountTaprootUpgrade() &&
+				diff.NewVersion > acct.Version {
+
+				modifiers = append(
+					modifiers,
+					account.VersionModifier(diff.NewVersion),
+				)
+			}
+
 		// The account was fully spent on-chain. We need to wait for the
 		// batch (spend) TX to be confirmed still.
 		case auctioneerrpc.AccountDiff_OUTPUT_FULLY_SPENT,

order/batch_verifier.go

@@ -248,6 +248,13 @@ func (v *batchVerifier) Verify(batch *Batch, bestHeight uint32) error {
 			acct.Expiry = diff.NewExpiry
 		}
 
+		// Update account version if needed.
+		if batch.Version.SupportsAccountTaprootUpgrade() &&
+			diff.NewVersion > acct.Version {
+
+			acct.Version = diff.NewVersion
+		}
+
 		// Make sure the ending state of the account is correct.
 		err := diff.validateEndingState(batch.BatchTX, acct)
 		if err != nil {

order/rpc_parse.go

@@ -11,6 +11,7 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/wire"
+	"github.com/lightninglabs/pool/account"
 	"github.com/lightninglabs/pool/auctioneerrpc"
 	"github.com/lightninglabs/pool/poolrpc"
 	"github.com/lightninglabs/pool/terms"
@@ -386,6 +387,7 @@ func ParseRPCBatch(prepareMsg *auctioneerrpc.OrderMatchPrepare) (*Batch,
 				EndingBalance: btcutil.Amount(diff.EndingBalance),
 				OutpointIndex: diff.OutpointIndex,
 				NewExpiry:     diff.NewExpiry,
+				NewVersion:    account.Version(diff.NewVersion),
 			},
 		)
 	}