fix: prevent nil pointer panic during pruning on shutdown

app/app.go

@@ -964,13 +964,8 @@ func (app *App) HandleClose() error {
 		}
 	}
 
-	// Close state store (SeiDB) - critical for cleaning up background goroutines
-	if app.stateStore != nil {
-		if err := app.stateStore.Close(); err != nil {
-			app.Logger().Error("failed to close state store", "error", err)
-			errs = append(errs, fmt.Errorf("failed to close state store: %w", err))
-		}
-	}
+	// Note: stateStore (ssStore) is already closed by cms.Close() in BaseApp.Close()
+	// No need to close it again here.
 
 	if len(errs) > 0 {
 		return fmt.Errorf("errors during close: %v", errs)

sei-db/ss/pebbledb/db.go

@@ -59,6 +59,7 @@ var (
 
 type Database struct {
 	storage      *pebble.DB
+	closed       atomic.Bool // Set to true when Close() is called, checked by Prune()
 	asyncWriteWG sync.WaitGroup
 	config       config.StateStoreConfig
 	// Earliest version for db after pruning
@@ -187,6 +188,12 @@ func New(dataDir string, config config.StateStoreConfig) (*Database, error) {
 }
 
 func (db *Database) Close() error {
+	// Mark as closed first to signal pruning to skip/return early
+	// Use CompareAndSwap to ensure Close is idempotent
+	if !db.closed.CompareAndSwap(false, true) {
+		return nil
+	}
+
 	// Stop background metrics collection
 	if db.metricsCancel != nil {
 		db.metricsCancel()
@@ -201,6 +208,7 @@ func (db *Database) Close() error {
 		_ = db.streamHandler.Close()
 		db.streamHandler = nil
 	}
+
 	var err error
 	if db.storage != nil {
 		err = db.storage.Close()
@@ -634,6 +642,11 @@ func (db *Database) writeAsyncInBackground() {
 // it has been updated. This occurs when that module's keys are updated in between pruning runs, the node after is restarted.
 // This is not a large issue given the next time that module is updated, it will be properly pruned thereafter.
 func (db *Database) Prune(version int64) (_err error) {
+	// Check if database is closed
+	if db.closed.Load() {
+		return errors.New("pebbledb: database is closed")
+	}
+
 	startTime := time.Now()
 	defer func() {
 		otelMetrics.pruneLatency.Record(

sei-db/ss/pebbledb/db_test.go

@@ -6,6 +6,7 @@ import (
 	"github.com/sei-protocol/sei-db/config"
 	sstest "github.com/sei-protocol/sei-db/ss/test"
 	"github.com/sei-protocol/sei-db/ss/types"
+	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"
 )
 
@@ -22,3 +23,28 @@ func TestStorageTestSuite(t *testing.T) {
 
 	suite.Run(t, s)
 }
+
+// TestPruneAfterClose verifies that calling Prune() after Close() returns an error
+// instead of causing a panic due to nil pointer dereference.
+// This is a regression test for the nil pointer panic during node shutdown.
+func TestPruneAfterClose(t *testing.T) {
+	dir := t.TempDir()
+	cfg := config.DefaultStateStoreConfig()
+	cfg.Backend = "pebbledb"
+
+	db, err := New(dir, cfg)
+	require.NoError(t, err)
+
+	// Write some data
+	err = db.SetLatestVersion(1)
+	require.NoError(t, err)
+
+	// Close the database
+	err = db.Close()
+	require.NoError(t, err)
+
+	// Prune should return error, not panic
+	err = db.Prune(1)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "database is closed")
+}

sei-db/ss/rocksdb/db.go

@@ -49,6 +49,7 @@ type VersionedChangesets struct {
 
 type Database struct {
 	storage  *grocksdb.DB
+	closed   atomic.Bool // Set to true when Close() is called, checked by Prune()
 	config   config.StateStoreConfig
 	cfHandle *grocksdb.ColumnFamilyHandle
 
@@ -293,6 +294,11 @@ func (db *Database) writeAsyncInBackground() {
 // lazy prune. Future compactions will honor the increased full_history_ts_low
 // and trim history when possible.
 func (db *Database) Prune(version int64) error {
+	// Check if database is closed
+	if db.closed.Load() {
+		return fmt.Errorf("rocksdb: database is closed")
+	}
+
 	tsLow := version + 1 // we increment by 1 to include the provided version
 
 	var ts [TimestampSize]byte
@@ -494,6 +500,12 @@ func (db *Database) WriteBlockRangeHash(storeKey string, beginBlockRange, endBlo
 }
 
 func (db *Database) Close() error {
+	// Mark as closed first to signal pruning goroutine to stop
+	// Use CompareAndSwap to ensure Close is idempotent
+	if !db.closed.CompareAndSwap(false, true) {
+		return nil
+	}
+
 	if db.streamHandler != nil {
 		// Close the pending changes channel to signal the background goroutine to stop
 		close(db.pendingChanges)
@@ -504,6 +516,7 @@ func (db *Database) Close() error {
 		// Only set to nil after background goroutine has finished
 		db.streamHandler = nil
 	}
+
 	db.cfHandle = nil
 	if db.storage != nil {
 		db.storage.Close()

sei-db/ss/rocksdb/db_test.go

@@ -9,6 +9,7 @@ import (
 	"github.com/sei-protocol/sei-db/config"
 	sstest "github.com/sei-protocol/sei-db/ss/test"
 	"github.com/sei-protocol/sei-db/ss/types"
+	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"
 )
 
@@ -25,3 +26,28 @@ func TestStorageTestSuite(t *testing.T) {
 
 	suite.Run(t, s)
 }
+
+// TestPruneAfterClose verifies that calling Prune() after Close() returns an error
+// instead of causing a panic due to nil pointer dereference.
+// This is a regression test for the nil pointer panic during node shutdown.
+func TestPruneAfterClose(t *testing.T) {
+	dir := t.TempDir()
+	cfg := config.DefaultStateStoreConfig()
+	cfg.Backend = "rocksdb"
+
+	db, err := New(dir, cfg)
+	require.NoError(t, err)
+
+	// Write some data
+	err = db.SetLatestVersion(1)
+	require.NoError(t, err)
+
+	// Close the database
+	err = db.Close()
+	require.NoError(t, err)
+
+	// Prune should return error, not panic
+	err = db.Prune(1)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "database is closed")
+}