Merge bitcoin/bitcoin#26675: wallet: For feebump, ignore abandoned descendant spends

f9ce0eadf4eb58d1e2207c27fabe69a5642482e7 For feebump, ignore abandoned descendant spends (John Moffett)

Pull request description:

  Closes #26667

  To be eligible for fee-bumping, a transaction must not have any of its outputs (eg - change) spent in other unconfirmed transactions in the wallet. This behavior is currently [enforced](https://github.com/bitcoin/bitcoin/blob/9e229a542ff2107be43eff2e4b992841367f0366/src/wallet/feebumper.cpp#L25-L28) and [tested](https://github.com/bitcoin/bitcoin/blob/9e229a542ff2107be43eff2e4b992841367f0366/test/functional/wallet_bumpfee.py#L270-L286).

  However, this check shouldn't apply to spends in abandoned descendant transactions, as explained by #26667.

  `CWallet::IsSpent` already carves out an exception for abandoned transactions, so we can just use that.

  I've also added a new test to cover this case.

ACKs for top commit:
  Sjors:
    re-utACK f9ce0eadf4eb58d1e2207c27fabe69a5642482e7
  achow101:
    ACK f9ce0eadf4eb58d1e2207c27fabe69a5642482e7
  furszy:
    ACK f9ce0ead

Tree-SHA512: 19d957d1cf6747668bb114e27a305027bfca5a9bed2b1d9cc9e1b0bd4666486c7c4b60b045a7fe677eb9734d746f5de76390781fb1e9e0bceb4a46d20acd1749

1 files changed, 30 insertions, 0 deletions

diff --git a/test/functional/wallet_bumpfee.py b/test/functional/wallet_bumpfee.py
index 1cb3f434e8..a2ae997ecb 100755
--- a/test/functional/wallet_bumpfee.py
+++ b/test/functional/wallet_bumpfee.py
@@ -88,6 +88,7 @@ class BumpFeeTest(BitcoinTestFramework):
         test_nonrbf_bumpfee_fails(self, peer_node, dest_address)
         test_notmine_bumpfee(self, rbf_node, peer_node, dest_address)
         test_bumpfee_with_descendant_fails(self, rbf_node, rbf_node_address, dest_address)
+        test_bumpfee_with_abandoned_descendant_succeeds(self, rbf_node, rbf_node_address, dest_address)
         test_dust_to_fee(self, rbf_node, dest_address)
         test_watchonly_psbt(self, peer_node, rbf_node, dest_address)
         test_rebumping(self, rbf_node, dest_address)
@@ -286,6 +287,35 @@ def test_bumpfee_with_descendant_fails(self, rbf_node, rbf_node_address, dest_ad
     self.clear_mempool()
 
 
+def test_bumpfee_with_abandoned_descendant_succeeds(self, rbf_node, rbf_node_address, dest_address):
+    self.log.info('Test that fee can be bumped when it has abandoned descendant')
+    # parent is send-to-self, so we don't have to check which output is change when creating the child tx
+    parent_id = spend_one_input(rbf_node, rbf_node_address)
+    # Submit child transaction with low fee
+    child_id = rbf_node.send(outputs={dest_address: 0.00020000},
+                             options={"inputs": [{"txid": parent_id, "vout": 0}], "fee_rate": 2})["txid"]
+    assert child_id in rbf_node.getrawmempool()
+
+    # Restart the node with higher min relay fee so the descendant tx is no longer in mempool so that we can abandon it
+    self.restart_node(1, ['-minrelaytxfee=0.00005'] + self.extra_args[1])
+    rbf_node.walletpassphrase(WALLET_PASSPHRASE, WALLET_PASSPHRASE_TIMEOUT)
+    self.connect_nodes(1, 0)
+    assert parent_id in rbf_node.getrawmempool()
+    assert child_id not in rbf_node.getrawmempool()
+    # Should still raise an error even if not in mempool
+    assert_raises_rpc_error(-8, "Transaction has descendants in the wallet", rbf_node.bumpfee, parent_id)
+    # Now abandon the child transaction and bump the original
+    rbf_node.abandontransaction(child_id)
+    bumped_result = rbf_node.bumpfee(parent_id, {"fee_rate": HIGH})
+    assert bumped_result['txid'] in rbf_node.getrawmempool()
+    assert parent_id not in rbf_node.getrawmempool()
+    # Cleanup
+    self.restart_node(1, self.extra_args[1])
+    rbf_node.walletpassphrase(WALLET_PASSPHRASE, WALLET_PASSPHRASE_TIMEOUT)
+    self.connect_nodes(1, 0)
+    self.clear_mempool()
+
+
 def test_small_output_with_feerate_succeeds(self, rbf_node, dest_address):
     self.log.info('Testing small output with feerate bump succeeds')