1 files changed, 20 insertions, 14 deletions

diff --git a/tx.go b/tx.go
index c18fbf7..8c78184 100644
--- a/tx.go
+++ b/tx.go
@@ -97,7 +97,9 @@ func (t *Tx) Buckets() []*Bucket {
 // CreateBucket creates a new bucket.
 // Returns an error if the bucket already exists, if the bucket name is blank, or if the bucket name is too long.
 func (t *Tx) CreateBucket(name string) error {
-	if !t.writable {
+	if t.db == nil {
+		return ErrTxClosed
+	} else if !t.writable {
 		return ErrTxNotWritable
 	} else if b := t.Bucket(name); b != nil {
 		return ErrBucketExists
@@ -133,7 +135,9 @@ func (t *Tx) CreateBucketIfNotExists(name string) error {
 // DeleteBucket deletes a bucket.
 // Returns an error if the bucket cannot be found.
 func (t *Tx) DeleteBucket(name string) error {
-	if !t.writable {
+	if t.db == nil {
+		return ErrTxClosed
+	} else if !t.writable {
 		return ErrTxNotWritable
 	}
 
@@ -159,10 +163,9 @@ func (t *Tx) Commit() error {
 	if t.managed {
 		panic("managed tx commit not allowed")
 	} else if t.db == nil {
-		return nil
+		return ErrTxClosed
 	} else if !t.writable {
-		t.Rollback()
-		return nil
+		return ErrTxNotWritable
 	}
 	defer t.close()
 
@@ -196,22 +199,23 @@ func (t *Tx) Commit() error {
 }
 
 // Rollback closes the transaction and ignores all previous updates.
-func (t *Tx) Rollback() {
+func (t *Tx) Rollback() error {
 	if t.managed {
 		panic("managed tx rollback not allowed")
+	} else if t.db == nil {
+		return ErrTxClosed
 	}
 	t.close()
+	return nil
 }
 
 func (t *Tx) close() {
-	if t.db != nil {
-		if t.writable {
-			t.db.rwlock.Unlock()
-		} else {
-			t.db.removeTx(t)
-		}
-		t.db = nil
+	if t.writable {
+		t.db.rwlock.Unlock()
+	} else {
+		t.db.removeTx(t)
 	}
+	t.db = nil
 }
 
 // allocate returns a contiguous block of memory starting at a given page.
@@ -433,7 +437,9 @@ func (t *Tx) forEachPage(pgid pgid, depth int, fn func(*page, int)) {
 // Page returns page information for a given page number.
 // This is only available from writable transactions.
 func (t *Tx) Page(id int) (*PageInfo, error) {
-	if !t.writable {
+	if t.db == nil {
+		return nil, ErrTxClosed
+	} else if !t.writable {
 		return nil, ErrTxNotWritable
 	} else if pgid(id) >= t.meta.pgid {
 		return nil, nil