Merge pull request #297 from benbjohnson/seq

Persist sequence-only changes

bucket.go

@@ -332,6 +332,12 @@ func (b *Bucket) NextSequence() (uint64, error) {
 		return 0, ErrTxNotWritable
 	}
 
+	// Materialize the root node if it hasn't been already so that the
+	// bucket will be saved during commit.
+	if b.rootNode == nil {
+		_ = b.node(b.root, nil)
+	}
+
 	// Increment and return the sequence.
 	b.bucket.sequence++
 	return b.bucket.sequence, nil

bucket_test.go

@@ -490,6 +490,33 @@ func TestBucket_NextSequence(t *testing.T) {
 	})
 }
 
+// Ensure that a bucket will persist an autoincrementing sequence even if its
+// the only thing updated on the bucket.
+// https://github.com/boltdb/bolt/issues/296
+func TestBucket_NextSequence_Persist(t *testing.T) {
+	db := NewTestDB()
+	defer db.Close()
+	db.Update(func(tx *bolt.Tx) error {
+		_, _ = tx.CreateBucket([]byte("widgets"))
+		return nil
+	})
+
+	db.Update(func(tx *bolt.Tx) error {
+		_, _ = tx.Bucket([]byte("widgets")).NextSequence()
+		return nil
+	})
+
+	db.Update(func(tx *bolt.Tx) error {
+		seq, err := tx.Bucket([]byte("widgets")).NextSequence()
+		if err != nil {
+			t.Fatalf("unexpected error: %s", err)
+		} else if seq != 2 {
+			t.Fatalf("unexpected sequence: %d", seq)
+		}
+		return nil
+	})
+}
+
 // Ensure that retrieving the next sequence on a read-only bucket returns an error.
 func TestBucket_NextSequence_ReadOnly(t *testing.T) {
 	db := NewTestDB()

db.go

@@ -694,13 +694,8 @@ func _assert(condition bool, msg string, v ...interface{}) {
 	}
 }
 
-func warn(v ...interface{}) {
-	fmt.Fprintln(os.Stderr, v...)
-}
-
-func warnf(msg string, v ...interface{}) {
-	fmt.Fprintf(os.Stderr, msg+"\n", v...)
-}
+func warn(v ...interface{})              { fmt.Fprintln(os.Stderr, v...) }
+func warnf(msg string, v ...interface{}) { fmt.Fprintf(os.Stderr, msg+"\n", v...) }
 
 func printstack() {
 	stack := strings.Join(strings.Split(string(debug.Stack()), "\n")[2:], "\n")

db_test.go

@@ -696,3 +696,6 @@ func fileSize(path string) int64 {
 	}
 	return fi.Size()
 }
+
+func warn(v ...interface{})              { fmt.Fprintln(os.Stderr, v...) }
+func warnf(msg string, v ...interface{}) { fmt.Fprintf(os.Stderr, msg+"\n", v...) }