assets: make tapd macaroon path network-aware

Build the default tapd admin macaroon path from the configured Bitcoin
network while preserving explicit path overrides. Add regression tests for
tapd credential loading and network-specific path selection.

assets/client.go

@@ -49,13 +49,21 @@ type TapdConfig struct {
 // DefaultTapdConfig returns a default configuration to connect to a taproot
 // assets daemon.
 func DefaultTapdConfig() *TapdConfig {
-	defaultTapdDir := btcutil.AppDataDir("tapd", false)
+	return DefaultTapdConfigForNetwork(
+		btcutil.AppDataDir("tapd", false), "mainnet",
+	)
+}
 
+// DefaultTapdConfigForNetwork returns the default tapd configuration rooted in
+// defaultTapdDir for the given Bitcoin network. Passing the directory
+// explicitly keeps path construction testable without accessing the user's
+// real tapd data.
+func DefaultTapdConfigForNetwork(defaultTapdDir, network string) *TapdConfig {
 	return &TapdConfig{
 		Activate: false,
 		Host:     "localhost:10029",
 		MacaroonPath: filepath.Join(
-			defaultTapdDir, "mainnet", "admin.macaroon",
+			defaultTapdDir, "data", network, "admin.macaroon",
 		),
 		TLSPath:    filepath.Join(defaultTapdDir, "tls.cert"),
 		RFQtimeout: defaultRfqTimeout,

assets/client_test.go

@@ -1,6 +1,10 @@
 package assets
 
 import (
+	"encoding/pem"
+	"net/http"
+	"net/http/httptest"
+	"os"
 	"path/filepath"
 	"testing"
 
@@ -8,6 +12,7 @@ import (
 	"github.com/lightninglabs/taproot-assets/taprpc/rfqrpc"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/stretchr/testify/require"
+	"gopkg.in/macaroon.v2"
 )
 
 // TestDefaultTapdConfig tests that the default tapd connection paths match
@@ -16,10 +21,62 @@ func TestDefaultTapdConfig(t *testing.T) {
 	defaultTapdDir := btcutil.AppDataDir("tapd", false)
 	config := DefaultTapdConfig()
 
+	require.Equal(t, filepath.Join(
+		defaultTapdDir, "data", "mainnet", "admin.macaroon",
+	), config.MacaroonPath)
 	require.Equal(
-		t, filepath.Join(defaultTapdDir, "mainnet", "admin.macaroon"),
-		config.MacaroonPath,
+		t, filepath.Join(defaultTapdDir, "tls.cert"), config.TLSPath,
 	)
+}
+
+// TestTapdConfigClientConn tests that the default tapd file layout can be used
+// to construct a client connection.
+func TestTapdConfigClientConn(t *testing.T) {
+	// Use an isolated tapd root so the test never reads from or writes to a
+	// user's real tapd data directory.
+	defaultTapdDir := t.TempDir()
+	network := "regtest"
+	macaroonPath := filepath.Join(
+		defaultTapdDir, "data", network, "admin.macaroon",
+	)
+	require.NoError(t, os.MkdirAll(filepath.Dir(macaroonPath), 0o700))
+
+	// NewTapdClient parses the configured TLS certificate before creating
+	// its gRPC client. An httptest server provides a valid certificate
+	// without requiring a running tapd instance.
+	tlsServer := httptest.NewTLSServer(http.NotFoundHandler())
+	t.Cleanup(tlsServer.Close)
+	cert := tlsServer.Certificate()
+	certBytes := pem.EncodeToMemory(&pem.Block{
+		Type: "CERTIFICATE", Bytes: cert.Raw,
+	})
+	require.NoError(t, os.WriteFile(
+		filepath.Join(defaultTapdDir, "tls.cert"), certBytes, 0o600,
+	))
+
+	// Store a valid serialized macaroon at tapd's production path. This
+	// ensures connection setup tests the path itself rather than failing on
+	// malformed credentials.
+	mac, err := macaroon.New(
+		[]byte("root-key"), []byte("id"), "tapd",
+		macaroon.LatestVersion,
+	)
+	require.NoError(t, err)
+	macBytes, err := mac.MarshalBinary()
+	require.NoError(t, err)
+	require.NoError(t, os.WriteFile(macaroonPath, macBytes, 0o600))
+
+	// grpc.NewClient connects lazily, so constructing the tapd client verifies
+	// that both credentials can be loaded and parsed without needing a live
+	// tapd server.
+	config := DefaultTapdConfigForNetwork(defaultTapdDir, network)
+	client, err := NewTapdClient(config)
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		require.NoError(t, client.cc.Close())
+	})
+
+	require.Equal(t, macaroonPath, config.MacaroonPath)
 	require.Equal(
 		t, filepath.Join(defaultTapdDir, "tls.cert"), config.TLSPath,
 	)

loopd/config.go

@@ -335,6 +335,14 @@ func Validate(cfg *Config) error {
 		)
 	}
 
+	// If the user doesn't specify Tapd.MacaroonPath, reassemble it with
+	// the configured Bitcoin network.
+	if cfg.Tapd.MacaroonPath == assets.DefaultTapdConfig().MacaroonPath {
+		cfg.Tapd.MacaroonPath = assets.DefaultTapdConfigForNetwork(
+			btcutil.AppDataDir("tapd", false), cfg.Network,
+		).MacaroonPath
+	}
+
 	// We'll also update the database file location as well, if it wasn't
 	// set.
 	if cfg.Sqlite.DatabaseFileName == defaultSqliteDatabasePath {

loopd/config_test.go

@@ -0,0 +1,51 @@
+package loopd
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/lightninglabs/loop/assets"
+	"github.com/stretchr/testify/require"
+)
+
+// TestValidateTapdMacaroonPath tests that validation updates the default tapd
+// macaroon path for the configured network without changing an explicit path.
+func TestValidateTapdMacaroonPath(t *testing.T) {
+	customPath := filepath.Join(t.TempDir(), "custom.macaroon")
+	defaultConfig := assets.DefaultTapdConfig()
+	regtestConfig := assets.DefaultTapdConfigForNetwork(
+		btcutil.AppDataDir("tapd", false), "regtest",
+	)
+
+	tests := []struct {
+		name         string
+		macaroonPath string
+		expectedPath string
+	}{
+		{
+			name:         "default path",
+			macaroonPath: defaultConfig.MacaroonPath,
+			expectedPath: regtestConfig.MacaroonPath,
+		},
+		{
+			name:         "explicit path",
+			macaroonPath: customPath,
+			expectedPath: customPath,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			cfg := DefaultConfig()
+			cfg.Network = "regtest"
+			cfg.LoopDir = t.TempDir()
+			cfg.Tapd.MacaroonPath = test.macaroonPath
+
+			require.NoError(t, Validate(&cfg))
+			require.Equal(
+				t, test.expectedPath, cfg.Tapd.MacaroonPath,
+			)
+		})
+	}
+}