nft-nd-nns: clean up old entries on re-registration, fix #2570

examples/nft-nd-nns/nns.go

@@ -265,6 +265,10 @@ func Register(name string, owner interop.Hash160) bool {
 		}
 		oldOwner = ns.Owner
 		updateBalance(ctx, []byte(name), oldOwner, -1)
+		it := storage.Find(ctx, append([]byte{prefixRecord}, tokenKey...), storage.KeysOnly)
+		for iterator.Next(it) {
+			storage.Delete(ctx, iterator.Value(it))
+		}
 	} else {
 		updateTotalSupply(ctx, +1)
 	}

examples/nft-nd-nns/nns_test.go

@@ -132,6 +132,9 @@ func TestExpiration(t *testing.T) {
 	b5.Timestamp = b4.Timestamp + 1000
 	require.NoError(t, bc.AddBlock(e.SignBlock(b5)))
 	e.CheckFault(t, tx.Hash(), "name has expired")
+
+	cAcc.Invoke(t, true, "register", "first.com", acc.ScriptHash()) // Re-register.
+	cAcc.Invoke(t, stackitem.Null{}, "resolve", "first.com", int64(nns.TXT))
 }
 
 const millisecondsInYear = 365 * 24 * 3600 * 1000