From 702a88de0c0d3603158cd2c183389ba6bf79535e Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 30 Sep 2025 11:33:19 +0930 Subject: [PATCH] pytest: fix flake in test_coinmoves_unilateral_htlc_fulfill / test_coinmoves_unilateral_htlc_timeout DER sigs! Normally, the commitment weight is: ``` Anchorspend for local commit tx fee 9751sat (w=722), commit_tx fee 4866sat (w=1284): package feerate 7286 perkw Creating anchor spend for local commit tx 6a0816ca60d499edc70bfb786ebd164fb7a55d234c84d926102f5bd35087fd45: we're paying fee 9751sat ``` But if we're "lucky" the commitment tx is shorter: ``` Anchorspend for local commit tx fee 9744sat (w=722), commit_tx fee 4866sat (w=1283): package feerate 7286 perkw Creating anchor spend for local commit tx acf78532a9448dd62a4e6319a3d2712189a88b6e59abc637260067d60df70782: we're paying fee 9744sat ``` The resulting failure: ``` 2025-08-21T02:30:34.1906751Z > assert moves == expected ... ... 2025-08-21T02:30:34.1965346Z E { 2025-08-21T02:30:34.1965529Z E 'account_id': 'wallet', 2025-08-21T02:30:34.1965767Z E 'blockheight': 104, 2025-08-21T02:30:34.1965997Z E 'created_index': 6, 2025-08-21T02:30:34.1966229Z E - 'credit_msat': 15579000, 2025-08-21T02:30:34.1966467Z E ? ^^ 2025-08-21T02:30:34.1966698Z E + 'credit_msat': 15586000, 2025-08-21T02:30:34.1966927Z E ? ^^ 2025-08-21T02:30:34.1967150Z E 'debit_msat': 0, 2025-08-21T02:30:34.1967376Z E 'extra_tags': [], 2025-08-21T02:30:34.1967599Z E - 'output_msat': 15579000, 2025-08-21T02:30:34.1967832Z E ? ^^ 2025-08-21T02:30:34.1968061Z E + 'output_msat': 15586000, 2025-08-21T02:30:34.1968294Z E ? ^^ 2025-08-21T02:30:34.1968540Z E 'primary_tag': 'deposit', 2025-08-21T02:30:34.1968908Z E 'utxo': 'acf78532a9448dd62a4e6319a3d2712189a88b6e59abc637260067d60df70782:0', 2025-08-21T02:30:34.1969366Z E }, ``` Signed-off-by: Rusty Russell --- tests/test_coinmoves.py | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/tests/test_coinmoves.py b/tests/test_coinmoves.py index 0cdefe83f..21f6dea8f 100644 --- a/tests/test_coinmoves.py +++ b/tests/test_coinmoves.py @@ -727,6 +727,11 @@ def test_coinmoves_unilateral_htlc_timeout(node_factory, bitcoind): line = l1.daemon.is_in_log('Tracking output.*/OUR_HTLC') htlc = int(re.search(r'output [0-9a-f]{64}:([0-9]):', line).group(1)) + # commitment tx weight can vary (DER sigs, FML) and so even though the feerate target + # is fixed, the amount of the child tx we create will vary, hence the change varies. + # So it's usually 15579000, but one in 128 it will be 15586000... + anchor_change_msats = bitcoind.rpc.gettxout(anchor_spend_txid, 0)['value'] * 100_000_000_000 + expected_chain1 += [{'account_id': 'wallet', # Anchor spend from fundchannel change 'blockheight': 104, 'credit_msat': 0, @@ -738,10 +743,10 @@ def test_coinmoves_unilateral_htlc_timeout(node_factory, bitcoind): 'utxo': f"{fundchannel['txid']}:{fundchannel['outnum'] ^ 1}"}, {'account_id': 'wallet', # change from anchor spend 'blockheight': 104, - 'credit_msat': 15579000, + 'credit_msat': anchor_change_msats, 'debit_msat': 0, 'extra_tags': [], - 'output_msat': 15579000, + 'output_msat': anchor_change_msats, 'primary_tag': 'deposit', 'utxo': f"{anchor_spend_txid}:0"}, {'account_id': fundchannel['channel_id'], @@ -1221,6 +1226,11 @@ def test_coinmoves_unilateral_htlc_fulfill(node_factory, bitcoind): line = l1.daemon.is_in_log('Tracking output.*/OUR_HTLC') htlc = int(re.search(r'output [0-9a-f]{64}:([0-9]):', line).group(1)) + # commitment tx weight can vary (DER sigs, FML) and so even though the feerate target + # is fixed, the amount of the child tx we create will vary, hence the change varies. + # So it's usually 15579000, but one in 128 it will be 15586000... + anchor_change_msats = bitcoind.rpc.gettxout(anchor_spend_txid, 0)['value'] * 100_000_000_000 + expected_chain1 += [{'account_id': 'wallet', # Anchor spend from fundchannel change 'blockheight': 104, 'credit_msat': 0, @@ -1232,10 +1242,10 @@ def test_coinmoves_unilateral_htlc_fulfill(node_factory, bitcoind): 'utxo': f"{fundchannel['txid']}:{fundchannel['outnum'] ^ 1}"}, {'account_id': 'wallet', # Change from anchor spend 'blockheight': 104, - 'credit_msat': 15579000, + 'credit_msat': anchor_change_msats, 'debit_msat': 0, 'extra_tags': [], - 'output_msat': 15579000, + 'output_msat': anchor_change_msats, 'primary_tag': 'deposit', 'utxo': f"{anchor_spend_txid}:0"}, {'account_id': fundchannel['channel_id'],