tapfreighter+itest: store change script key to DB

To make sure the vPSBT flows work correctly (where we don't serialize
the script key type, so that info is lost when using virtual packets),
we store the script key directly after deriving it.
That way it will be recognized correctly when the transfer is being
processed.

Author: guggero

itest/psbt_test.go

@@ -2878,6 +2878,20 @@ func testPsbtExternalCommit(t *harnessTest) {
 	AssertBalanceByID(
 		t.t, bobTapd, targetAssetGenesis.AssetId, assetsToSend,
 	)
+
+	// We make sure the change and the passive are shown properly in the
+	// sender's wallet.
+	AssertBalances(
+		t.t, aliceTapd, targetAsset.Amount-assetsToSend,
+		WithAssetID(targetAssetGenesis.AssetId), WithNumUtxos(1),
+		WithScriptKeyType(asset.ScriptKeyBip86),
+	)
+	passiveAsset := assets[1]
+	AssertBalances(
+		t.t, aliceTapd, passiveAsset.Amount,
+		WithAssetID(passiveAsset.AssetGenesis.AssetId), WithNumUtxos(1),
+		WithScriptKeyType(asset.ScriptKeyBip86),
+	)
 }
 
 // testPsbtLockTimeSend tests that we can send minted assets into a ScriptKey

tapfreighter/fund.go

@@ -121,7 +121,7 @@ func createFundedPacketWithInputs(ctx context.Context, exporter proof.Exporter,
 			}
 		}
 
-		err = deriveChangeOutputKey(ctx, vPkt, keyRing)
+		err = deriveChangeOutputKey(ctx, vPkt, keyRing, addrBook)
 		if err != nil {
 			return nil, fmt.Errorf("unable to derive change "+
 				"output key: %w", err)
@@ -201,7 +201,7 @@ func annotateLocalScriptKeys(ctx context.Context, vPkt *tappsbt.VPacket,
 // back to the local node, assuming there is a change output and it isn't a
 // zero-value tombstone.
 func deriveChangeOutputKey(ctx context.Context, vPkt *tappsbt.VPacket,
-	keyRing KeyRing) error {
+	keyRing KeyRing, addrBook AddrBook) error {
 
 	// If we don't have a split output then there's no change.
 	if !vPkt.HasSplitRootOutput() {
@@ -238,6 +238,16 @@ func deriveChangeOutputKey(ctx context.Context, vPkt *tappsbt.VPacket,
 		changeOut.ScriptKey = asset.NewScriptKeyBip86(
 			changeScriptKey,
 		)
+
+		// To make sure we recognize the script key again if it is
+		// used over the vPSBT RPCs (where we don't encode the script
+		// key type), we now also store the key in the DB.
+		err = addrBook.InsertScriptKey(
+			ctx, changeOut.ScriptKey, changeOut.ScriptKey.Type,
+		)
+		if err != nil {
+			return fmt.Errorf("cannot insert script key: %w", err)
+		}
 	}
 
 	return nil

tapfreighter/fund_test.go

@@ -66,6 +66,18 @@ type mockAddrBook struct {
 	scriptKeys []asset.TweakedScriptKey
 }
 
+func (m *mockAddrBook) InsertScriptKey(_ context.Context,
+	scriptKey asset.ScriptKey, _ asset.ScriptKeyType) error {
+
+	if scriptKey.TweakedScriptKey == nil {
+		return fmt.Errorf("script key must be tweaked")
+	}
+
+	m.scriptKeys = append(m.scriptKeys, *scriptKey.TweakedScriptKey)
+
+	return nil
+}
+
 func (m *mockAddrBook) FetchScriptKey(_ context.Context,
 	tweakedScriptKey *btcec.PublicKey) (*asset.TweakedScriptKey, error) {
 

tapfreighter/wallet.go

@@ -152,6 +152,12 @@ type AddrBook interface {
 	// ErrInternalKeyNotFound is returned.
 	FetchInternalKeyLocator(ctx context.Context,
 		rawKey *btcec.PublicKey) (keychain.KeyLocator, error)
+
+	// InsertScriptKey inserts an address related script key into the
+	// database, so it can be recognized as belonging to the wallet when a
+	// transfer comes in later on.
+	InsertScriptKey(ctx context.Context,
+		scriptKey asset.ScriptKey, keyType asset.ScriptKeyType) error
 }
 
 // AnchorVTxnsParams holds all the parameters needed to create a BTC level