Add test coverage for holder commitment rebroadcast after reorg

Author: wpaulino

lightning/src/ln/reorg_tests.rs

@@ -759,3 +759,74 @@ fn test_htlc_preimage_claim_prev_counterparty_commitment_after_current_counterpa
 	// commitment (still unrevoked) is the currently confirmed closing transaction.
 	assert_eq!(htlc_preimage_tx.input[0].witness.second_to_last().unwrap(), &payment_preimage.0[..]);
 }
+
+#[test]
+fn test_retries_own_commitment_broadcast_after_reorg() {
+	// Tests that a node will retry broadcasting its own commitment after seeing a confirmed
+	// counterparty commitment be reorged out.
+	let chanmon_cfgs = create_chanmon_cfgs(2);
+	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
+	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+
+	let (_, _, chan_id, funding_tx) = create_announced_chan_between_nodes(&nodes, 0, 1);
+
+	// Route a payment so we have an HTLC to claim as well.
+	let _ = route_payment(&nodes[0], &[&nodes[1]], 1_000_000);
+
+	// Connect blocks until the HTLC expiry is met, prompting a commitment broadcast by A.
+	connect_blocks(&nodes[0], TEST_FINAL_CLTV + LATENCY_GRACE_PERIOD_BLOCKS + 1);
+	check_closed_broadcast(&nodes[0], 1, true);
+	check_added_monitors(&nodes[0], 1);
+	check_closed_event(&nodes[0], 1, ClosureReason::HolderForceClosed, false, &[nodes[1].node.get_our_node_id()], 100_000);
+
+	{
+		let mut txn = nodes[0].tx_broadcaster.txn_broadcast();
+		assert_eq!(txn.len(), 2);
+		let htlc_tx_a = txn.pop().unwrap();
+		let commitment_tx_a = txn.pop().unwrap();
+		check_spends!(commitment_tx_a, funding_tx);
+		check_spends!(htlc_tx_a, commitment_tx_a);
+	};
+
+	// B will also broadcast its own commitment.
+	nodes[1].node.force_close_broadcasting_latest_txn(&chan_id, &nodes[0].node.get_our_node_id()).unwrap();
+	check_closed_broadcast(&nodes[1], 1, true);
+	check_added_monitors(&nodes[1], 1);
+	check_closed_event(&nodes[1], 1, ClosureReason::HolderForceClosed, false, &[nodes[0].node.get_our_node_id()], 100_000);
+
+	let commitment_b = {
+		let mut txn = nodes[1].tx_broadcaster.txn_broadcast();
+		assert_eq!(txn.len(), 1);
+		let tx = txn.pop().unwrap();
+		check_spends!(tx, funding_tx);
+		tx
+	};
+
+	// Confirm B's commitment, A should now broadcast an HTLC timeout for commitment B.
+	mine_transaction(&nodes[0], &commitment_b);
+	{
+		let mut txn = nodes[0].tx_broadcaster.txn_broadcast();
+		if nodes[0].connect_style.borrow().updates_best_block_first() {
+			// `commitment_a` and `htlc_timeout_a` are rebroadcast because the best block was
+			// updated prior to seeing `commitment_b`.
+			assert_eq!(txn.len(), 3);
+			check_spends!(txn[2], commitment_b);
+		} else {
+			assert_eq!(txn.len(), 1);
+			check_spends!(txn[0], commitment_b);
+		}
+	}
+
+	// Disconnect the block, allowing A to retry its own commitment. Note that we connect two
+	// blocks, one to get us back to the original height, and another to retry our pending claims.
+	disconnect_blocks(&nodes[0], 1);
+	connect_blocks(&nodes[0], 2);
+	{
+		let mut txn = nodes[0].tx_broadcaster.unique_txn_broadcast();
+		assert_eq!(txn.len(), 2);
+		check_spends!(txn[0], txn[1]); // HTLC timeout A
+		check_spends!(txn[1], funding_tx); // Commitment A
+		assert_ne!(txn[1].txid(), commitment_b.txid());
+	}
+}