lncfg: don't warn user about existing bbolt DB if SQLite files exist

docs/release-notes/release-notes-0.19.0.md

@@ -121,6 +121,9 @@ when running LND with an aux component injected (custom channels).
 * [Fixed a bug](https://github.com/lightningnetwork/lnd/pull/9750): if a Taproot
   address is added to LND using the `ImportTapscript` RPC, LND previously failed
   to perform a cooperative close to that address.
+* [Fixed a bug](https://github.com/lightningnetwork/lnd/pull/9744) where unnecessary
+  warnings about existing bbolt database files would appear when using SQLite backend
+  with already migrated databases.
 
 # New Features
 

lncfg/db.go

@@ -3,6 +3,7 @@ package lncfg
 import (
 	"context"
 	"fmt"
+	"os"
 	"path"
 	"path/filepath"
 	"time"
@@ -68,6 +69,10 @@ const (
 
 	// NSNeutrinoDB is the namespace name that we use for the neutrino DB.
 	NSNeutrinoDB = "neutrinodb"
+
+	// MigrationMarkerFile is a marker file created by lndinit migrate-db
+	// that indicates successful database migration.
+	MigrationMarkerFile = ".migration-complete"
 )
 
 // DB holds database configuration for LND.
@@ -484,6 +489,13 @@ func (db *DB) GetBackends(ctx context.Context, chanDBPath,
 		warnExistingBoltDBs(
 			logger, "postgres", chanDBPath, ChannelDBName,
 		)
+		// Also check for macaroons.db and sphinxreplay.db bbolt files
+		warnExistingBoltDBs(
+			logger, "postgres", walletDBPath, MacaroonDBName,
+		)
+		warnExistingBoltDBs(
+			logger, "postgres", chanDBPath, DecayedLogDbName,
+		)
 
 		returnEarly = false
 
@@ -599,14 +611,29 @@ func (db *DB) GetBackends(ctx context.Context, chanDBPath,
 			closeFuncs[SqliteBackend] = nativeSQLiteStore.Close
 		}
 
-		// Warn if the user is trying to switch over to a sqlite DB
-		// while there is a wallet or channel bbolt DB still present.
-		warnExistingBoltDBs(
-			logger, "sqlite", walletDBPath, WalletDBName,
-		)
-		warnExistingBoltDBs(
-			logger, "sqlite", chanDBPath, ChannelDBName,
-		)
+		// Check if migration has been completed before warning about
+		// existing bbolt databases
+		migrationComplete := hasMigrationCompleted(walletDBPath) || 
+			hasMigrationCompleted(chanDBPath)
+
+		// Only show warnings if migration hasn't been completed
+		if !migrationComplete {
+			// Warn if the user is trying to switch over to a sqlite DB
+			// while there is a wallet or channel bbolt DB still present.
+			warnExistingBoltDBs(
+				logger, "sqlite", walletDBPath, WalletDBName,
+			)
+			warnExistingBoltDBs(
+				logger, "sqlite", chanDBPath, ChannelDBName,
+			)
+			// Also check for macaroons.db and sphinxreplay.db bbolt files
+			warnExistingBoltDBs(
+				logger, "sqlite", walletDBPath, MacaroonDBName,
+			)
+			warnExistingBoltDBs(
+				logger, "sqlite", chanDBPath, DecayedLogDbName,
+			)
+		}
 
 		returnEarly = false
 
@@ -735,6 +762,30 @@ func (db *DB) GetBackends(ctx context.Context, chanDBPath,
 	}, nil
 }
 
+// hasMigrationCompleted checks if migration has been completed by looking for
+// SQLite files with substantial size or a migration marker file.
+func hasMigrationCompleted(dbPath string) bool {
+	// Check for marker file (which lndinit could create after migration)
+	markerPath := filepath.Join(dbPath, MigrationMarkerFile)
+	if _, err := os.Stat(markerPath); err == nil {
+		return true
+	}
+
+	// Check for non-empty SQLite files
+	sqliteFiles := []string{SqliteChainDBName, SqliteChannelDBName}
+	for _, fileName := range sqliteFiles {
+		filePath := filepath.Join(dbPath, fileName)
+		fileInfo, err := os.Stat(filePath)
+
+		// If file exists and has substantial size (not just created empty)
+		if err == nil && fileInfo.Size() > 1024 {
+			return true
+		}
+	}
+
+	return false
+}
+
 // warnExistingBoltDBs checks if there is an existing bbolt database in the
 // given location and logs a warning if so.
 func warnExistingBoltDBs(log btclog.Logger, dbType, dir, fileName string) {