Use +25 sat/kwu increment for our minimum RBF feerate#4494
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jkczyz wants to merge 4 commits intolightningdevkit:mainfrom
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Use +25 sat/kwu increment for our minimum RBF feerate#4494jkczyz wants to merge 4 commits intolightningdevkit:mainfrom
jkczyz wants to merge 4 commits intolightningdevkit:mainfrom
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…plate The user doesn't choose the feerate at splice_channel/rbf_channel time — they choose it when performing coin selection. Moving feerate to the FundingTemplate::splice_* methods gives users more control and lets rbf_channel expose the minimum RBF feerate (25/24 of previous) on the template so users can choose an appropriate feerate. splice_channel and rbf_channel no longer take min_feerate/max_feerate. Instead, FundingTemplate gains a min_rbf_feerate() accessor that returns the RBF floor when applicable (from negotiated candidates or in-progress funding negotiations). The feerate parameters move to the splice_in_sync, splice_out_sync, and splice_in_and_out_sync methods (and their async variants), which validate that min_feerate >= min_rbf_feerate before coin selection. Fee estimation documentation moves from splice_channel/rbf_channel to funding_contributed, where the contribution (and its feerate range) is actually provided and the splice process begins. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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👋 Hi! I see this is a draft PR. |
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…uted When splice_channel is called before a counterparty's splice exists, the user builds a contribution at their chosen feerate without a minimum RBF feerate. If the counterparty completes a splice before funding_contributed is called, the contribution's feerate may be below the 25/24 RBF requirement. Rather than always waiting for the pending splice to lock (which would proceed as a fresh splice), funding_contributed now attempts to adjust the contribution's feerate upward to the minimum RBF feerate when the budget allows, enabling an immediate RBF. When the adjustment isn't possible (max_feerate too low or insufficient fee buffer), the contribution is left unchanged and try_send_stfu delays until the pending splice locks, at which point the splice proceeds at the original feerate. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Users previously had to choose between splice_channel (fresh splice) and rbf_channel (fee bump) upfront. Since splice_channel already detects pending splices and computes the minimum RBF feerate, rbf_channel was redundant. Merging into a single API lets the user call one method and discover from the returned FundingTemplate whether an RBF is possible. The FundingTemplate now carries the user's prior contribution from the previous splice negotiation when one is available. This lets users reuse their existing contribution for an RBF without performing new coin selection. A PriorContribution enum distinguishes whether the contribution has been adjusted to the minimum RBF feerate (Adjusted) or could not be adjusted due to insufficient fee buffer or max_feerate constraints (Unadjusted). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
The spec's 25/24 multiplier doesn't always satisfy BIP125's relay requirement of an absolute fee increase. Use a flat +25 sat/kwu (0.1 sat/vB) increment for our own RBFs instead, while still accepting the 25/24 rule from counterparties. Extract a `min_rbf_feerate` helper to consolidate the two call sites and add a test that a counterparty feerate satisfying 25/24 (but not +25) is accepted. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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The spec's 25/24 multiplier doesn't always satisfy BIP125's relay requirement of an absolute fee increase. Use a flat +25 sat/kwu (0.1 sat/vB) increment for our own RBFs instead, while still accepting the 25/24 rule from counterparties.
Extract a
min_rbf_feeratehelper to consolidate the two call sites and add a test that a counterparty feerate satisfying 25/24 (but not +25) is accepted.Based on #4486.