Check HTLC output status before funding HTLC tx #2944
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When a channel force-closes, we publish our commit tx and HTLC txs. HTLC transactions conflict with our peer's transactions that also spend the HTLC outputs. If our peer is able to get their transaction confirmed before ours, we should stop retrying to publish our HTLC transaction as that will never succeed. Since we didn't check the output status, we kept retrying until the channel was closed (which requires waiting for the `to_self_delay`). The retries always fail at funding time: `bitcoind` returns an error saying that the UTXO cannot be found (which is expected because it has already been spent by our peer). This creates a lot of unnecessary retries and a lot of noise in the logs. This scenario usually happens when our peer didn't send the preimage before force-closing the channel, but reveals it on-chain before the HTLC timeout: when that happens we kept retrying to publish our HTLC timeout transaction, which cannot succeed. We now check the output status in our publishing preconditions, and immediately abort if the output has already been spent by a confirmed transaction.
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pm47
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Dec 3, 2024
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When a channel force-closes, we publish our commit tx and HTLC txs. HTLC transactions conflict with our peer's transactions that also spend the HTLC outputs. If our peer is able to get their transaction confirmed before ours, we should stop retrying to publish our HTLC transaction as that will never succeed.
Since we didn't check the output status, we kept retrying until the channel was closed (which requires waiting for the
to_self_delay). The retries always fail at funding time:bitcoindreturns an error saying that the UTXO cannot be found (which is expected because it has already been spent by our peer). This creates a lot of unnecessary retries and a lot of noise in the logs.This scenario usually happens when our peer didn't send the preimage before force-closing the channel, but reveals it on-chain before the HTLC timeout: when that happens we kept retrying to publish our HTLC timeout transaction, which cannot succeed.
We now check the output status in our publishing preconditions, and immediately abort if the output has already been spent by a confirmed transaction.