tests: fix flaky test_simple_close_dust_output_omitted mempool race#9299
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The test snapshots getrawmempool() and then calls getrawtransaction() on each txid. In simple close both peers broadcast conflicting closer txs: here l2's tx pays only 400sat fee (its entire 400sat balance goes to fees since its own output is dust) while l1's pays 3375sat, so l1's tx can RBF-replace l2's between the snapshot and the fetch. The getrawtransaction() call on the replaced txid then fails with error -5 (No such mempool or blockchain transaction). A CI failure showed exactly this ordering: l2 broadcast its closer tx, l1's higher-fee tx replaced it 14ms later, and the test's per-txid fetch raced the replacement. Retry the whole snapshot-and-check loop when a txid vanishes mid-iteration, keeping the single-output assertion hard. This is the same class of mempool race fixed for test_simple_close_delay_broadcast in 5ae0705 ("tests: fix flaky test_simple_close_delay_broadcast mempool race"). Changelog-None
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Hmm never seen this one before: Not sure what is going on there. |
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Observed on a CI run for #9286 (postgres full integration, 1 failed / 1012 passed):
https://github.com/ElementsProject/lightning/actions/runs/28971841260
The test snapshots getrawmempool() and then fetches each txid with
getrawtransaction(). Both peers broadcast conflicting closer txs; in
the dust scenario l2's tx pays only 400sat fee (its whole balance)
while l1's pays 3375sat, so l1's tx RBF-replaces l2's. When the
replacement lands between the snapshot and the fetch,
getrawtransaction() fails with error -5 (No such mempool or blockchain
transaction). The captured node logs show l2's tx replaced 14ms after
broadcast.
The fix retries the snapshot-and-check loop when a txid vanishes
mid-iteration; the single-output assertion still fails hard. Same
class of race as the test_simple_close_delay_broadcast fix in
5ae0705.
Changelog-None