From 93f06e0f9d30d1259abdfce1f7f63e170a92ea30 Mon Sep 17 00:00:00 2001
From: Ben Johnson <benbjohnson@yahoo.com>
Date: Thu, 7 Jan 2021 11:28:46 -0700
Subject: [PATCH] Fix rbf.Cursor.Close() panic

---
 rbf/cursor.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/rbf/cursor.go b/rbf/cursor.go
index 3920ffaec..5ffcaddf7 100644
--- a/rbf/cursor.go
+++ b/rbf/cursor.go
@@ -1388,7 +1388,10 @@ func (c *Cursor) difference(key uint64, data *roaring.Container) (bool, error) {
 func (c *Cursor) Close() {
 	if c == nil {
 		panic("cannot Close nil Cursor")
+	} else if c.tx == nil || c.tx.db == nil {
+		return // already closed
 	}
+
 	tx := c.tx
 	c.tx = nil // allow tx to be garbage collected.