Split DiscardFunding from SpliceFailed event
#4388
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👋 Hi! I see this is a draft PR. |
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DiscardFunding from SpliceFudning eventDiscardFunding from SpliceFunding event
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DiscardFunding from SpliceFunding eventDiscardFunding from SpliceFailed event
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A forthcoming commit will change CoinSelection to include FundingTxInput instead of Utxo, though the former will probably be renamed. This is so CoinSelectionSource can be used when funding a splice. Further updating WalletSource to use FundingTxInput is not desirable, however, as it would result in looking up each confirmed UTXOs previous transaction even if it is not selected. See Wallet's implementation of CoinSelectionSource, which delegates to WalletSource for listing all confirmed UTXOs. This commit moves FundingTxInput::sequence to Utxo, and thus the responsibility for setting it to WalletSource implementations. Doing so will allow Wallet's CoinSelectionSource implementation to delegate looking up previous transactions to WalletSource without having to explicitly set the sequence on any FundingTxInput.
In order to reuse CoinSelectionSource for splicing, the previous transaction of each UTXO is needed. Update CoinSelection to use FundingTxInput (renamed to ConfirmedUtxo) so that it is available. This requires adding a method to WalletSource to look up a previous transaction for a UTXO. Otherwise, Wallet's implementation of CoinSelectionSource would need WalletSource to include the previous transactions when listing confirmed UTXOs to select from. But this would be inefficient since only some UTXOs are selected.
CoinSelectionSource is used for anchor bumping where a ClaimId is passed in to avoid double spending other claims. To re-use this trait for funding a splice, the ClaimId must be optional. And, if None, then any locked UTXOs may be considered ineligible by an implementation.
Rather than requiring the user to pass FundingTxInputs when initiating a splice, generate a FundingNeeded event once the channel has become quiescent. This simplifies error handling and UTXO / change address clean-up by consolidating it in SpliceFailed event handling. Later, this event will be used for opportunistic contributions (i.e., when the counterparty wins quiescence or initiates), dual-funding, and RBF.
Now that CoinSelection is used to fund a splice funding transaction, use that for determining of a change output should be used. Previously, the initiator could either provide a change script upfront or let LDK generate one using SignerProvider::get_destination_script. Since older versions may have serialized a SpliceInstruction without a change script while waiting on quiescence, LDK must still generate a change output in this case.
Instead of logging both inside propose_quiescence and at the call site, only log inside it. This simplifies the return type.
Wallet-related types were tightly coupled to bump_transaction, making them less accessible for other use cases like channel funding and splicing. Extract these utilities to a dedicated module for improved code organization and reusability across the codebase. Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
Synchronous wallet utilities were coupled to bump_transaction::sync, limiting their reusability for other features like channel funding and splicing which need synchronous wallet operations. Consolidate all wallet utilities in a single module for consistency and improved code organization. Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
FundingTxInput was originally designed for channel funding but is now used more broadly for coin selection and splicing. The name ConfirmedUtxo better reflects its general-purpose nature as a confirmed UTXO with previous transaction data. Make ConfirmedUtxo the real struct in wallet_utils and alias FundingTxInput to it for backward compatibility. Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
Add a helper function to assert that SpliceFailed events contain the expected channel_id and contributed inputs/outputs. This ensures that tests verify the contributions match what was originally provided. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
When a splice fails, users need to reclaim UTXOs they contributed to the funding transaction. Previously, the contributed inputs and outputs were included in the SpliceFailed event. This commit splits them into a separate DiscardFunding event with a new FundingInfo::Contribution variant, providing a consistent interface for UTXO cleanup across all funding failure scenarios. Changes: - Add FundingInfo::Contribution variant to hold inputs/outputs for DiscardFunding events - Remove contributed_inputs/outputs fields from SpliceFailed event - Add QuiescentError enum for better error handling in funding_contributed - Emit DiscardFunding on all funding_contributed error paths - Filter duplicate inputs/outputs when contribution overlaps existing pending contribution - Return Err(APIError) from funding_contributed on all error cases - Add comprehensive test coverage for funding_contributed error paths Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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ChannelManager::funding_contributedconsumes the passed inFundingContribution. Normally, the associated inputs and outputs should be given back via aSpliceFailedevent. However, there are cases where the splice hasn't actually failed, so using that event would be misleading. The inputs and outputs still need to be returned to the user, which is done here via a dedicatedDiscardFundingevent.Based on #4382.