From 4671fc3d9e669da8b8781f0cbefee43cb9acd527 Mon Sep 17 00:00:00 2001 From: Jeremy Rubin Date: Mon, 21 Oct 2019 13:43:44 -0700 Subject: [PATCH] Expand on wallet_balance.py comment from https://github.com/bitcoin/bitcoin/pull/16766\#issuecomment-527563982 --- test/functional/wallet_balance.py | 38 +++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/test/functional/wallet_balance.py b/test/functional/wallet_balance.py index 1325681c9cf..a5f9a047edc 100755 --- a/test/functional/wallet_balance.py +++ b/test/functional/wallet_balance.py @@ -109,6 +109,44 @@ class WalletTest(BitcoinTestFramework): self.log.info("Test getbalance and getunconfirmedbalance with unconfirmed inputs") + # Before `test_balance()`, we have had two nodes with a balance of 50 + # each and then we: + # + # 1) Sent 40 from node A to node B with fee 0.01 + # 2) Sent 60 from node B to node A with fee 0.01 + # + # Then we check the balances: + # + # 1) As is + # 2) With transaction 2 from above with 2x the fee + # + # Prior to #16766, in this situation, the node would immediately report + # a balance of 30 on node B as unconfirmed and trusted. + # + # After #16766, we show that balance as unconfirmed. + # + # The balance is indeed "trusted" and "confirmed" insofar as removing + # the mempool transactions would return at least that much money. But + # the algorithm after #16766 marks it as unconfirmed because the 'taint' + # tracking of transaction trust for summing balances doesn't consider + # which inputs belong to a user. In this case, the change output in + # question could be "destroyed" by replace the 1st transaction above. + # + # The post #16766 behavior is correct; we shouldn't be treating those + # funds as confirmed. If you want to rely on that specific UTXO existing + # which has given you that balance, you cannot, as a third party + # spending the other input would destroy that unconfirmed. + # + # For example, if the test transactions were: + # + # 1) Sent 40 from node A to node B with fee 0.01 + # 2) Sent 10 from node B to node A with fee 0.01 + # + # Then our node would report a confirmed balance of 40 + 50 - 10 = 80 + # BTC, which is more than would be available if transaction 1 were + # replaced. + + def test_balances(*, fee_node_1=0): # getbalance without any arguments includes unconfirmed transactions, but not untrusted transactions assert_equal(self.nodes[0].getbalance(), Decimal('9.99')) # change from node 0's send