iter_dup_of returns other values after a delete (#80)

src/cursor.rs

@@ -118,7 +118,11 @@ pub trait Cursor<'txn> {
         K: AsRef<[u8]>,
     {
         match self.get(Some(key.as_ref()), None, ffi::MDB_SET) {
-            Ok(_) | Err(Error::NotFound) => (),
+            Ok(_) => (),
+            Err(Error::NotFound) => {
+                self.get(None, None, ffi::MDB_LAST).ok();
+                return Iter::new(self.cursor(), ffi::MDB_NEXT, ffi::MDB_NEXT);
+            },
             Err(error) => return Iter::Err(error),
         };
         Iter::new(self.cursor(), ffi::MDB_GET_CURRENT, ffi::MDB_NEXT_DUP)
@@ -652,6 +656,44 @@ mod test {
         assert_eq!(0, cursor.iter_dup_of(b"foo").count());
     }
 
+    #[test]
+    fn test_iter_del_get() {
+        let dir = TempDir::new("test").unwrap();
+        let env = Environment::new().open(dir.path()).unwrap();
+        let db = env.create_db(None, DatabaseFlags::DUP_SORT).unwrap();
+
+        let items: Vec<(&[u8], &[u8])> = vec![(b"a", b"1"), (b"b", b"2")];
+        let r: Vec<(&[u8], &[u8])> = Vec::new();
+        {
+            let txn = env.begin_ro_txn().unwrap();
+            let mut cursor = txn.open_ro_cursor(db).unwrap();
+            assert_eq!(r, cursor.iter_dup_of(b"a").collect::<Result<Vec<_>>>().unwrap());
+        }
+
+        {
+            let mut txn = env.begin_rw_txn().unwrap();
+            for &(ref key, ref data) in &items {
+                txn.put(db, key, data, WriteFlags::empty()).unwrap();
+            }
+            txn.commit().unwrap();
+        }
+
+        let mut txn = env.begin_rw_txn().unwrap();
+        let mut cursor = txn.open_rw_cursor(db).unwrap();
+        assert_eq!(items, cursor.iter_dup().flat_map(|x| x).collect::<Result<Vec<_>>>().unwrap());
+
+        assert_eq!(
+            items.clone().into_iter().take(1).collect::<Vec<(&[u8], &[u8])>>(),
+            cursor.iter_dup_of(b"a").collect::<Result<Vec<_>>>().unwrap()
+        );
+
+        assert_eq!((None, &b"1"[..]), cursor.get(Some(b"a"), Some(b"1"), MDB_SET).unwrap());
+
+        cursor.del(WriteFlags::empty()).unwrap();
+
+        assert_eq!(r, cursor.iter_dup_of(b"a").collect::<Result<Vec<_>>>().unwrap());
+    }
+
     #[test]
     fn test_put_del() {
         let dir = TempDir::new("test").unwrap();