Ensure minimum RBF feerate satisfies BIP125#4494

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TheBlueMatt merged 1 commit into from
Apr 1, 2026
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Ensure minimum RBF feerate satisfies BIP125 #4494

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23 changes: 15 additions & 8 deletions lightning/src/ln/channel.rs
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Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -6484,6 +6484,19 @@ fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satos
cmp::min(channel_value_satoshis, cmp::max(q, dust_limit_satoshis))
}

/// Returns the minimum feerate for our own RBF attempts given a previous feerate.
///
/// The spec (tx_init_rbf) requires the new feerate to be >= 25/24 of the previous feerate.
/// However, at low feerates that multiplier doesn't always satisfy BIP125's relay requirement of
/// an absolute fee increase, so we take the max of a flat +25 sat/kwu (0.1 sat/vB) increment
/// and the spec's multiplicative rule. We still accept the bare 25/24 rule from counterparties
/// in [`FundedChannel::validate_tx_init_rbf`].
fn min_rbf_feerate(prev_feerate: u32) -> FeeRate {
let flat_increment = (prev_feerate as u64).saturating_add(25);
let spec_increment = ((prev_feerate as u64) * 25).div_ceil(24);
FeeRate::from_sat_per_kwu(cmp::max(flat_increment, spec_increment))
}
Comment thread
wpaulino marked this conversation as resolved.

/// Context for negotiating channels (dual-funded V2 open, splicing)
#[derive(Debug)]
pub(super) struct FundingNegotiationContext {
Expand DownExpand Up@@ -12019,10 +12032,7 @@ where
prev_feerate.is_some(),
"pending_splice should have last_funding_feerate or funding_negotiation",
);
let min_rbf_feerate = prev_feerate.map(|f| {
let min_feerate_kwu = ((f as u64) * 25).div_ceil(24);
FeeRate::from_sat_per_kwu(min_feerate_kwu)
});
let min_rbf_feerate = prev_feerate.map(min_rbf_feerate);
let prior = if pending_splice.last_funding_feerate_sat_per_1000_weight.is_some() {
self.build_prior_contribution()
} else {
Expand DownExpand Up@@ -12114,10 +12124,7 @@ where
}

match pending_splice.last_funding_feerate_sat_per_1000_weight {
Some(prev_feerate) => {
let min_feerate_kwu = ((prev_feerate as u64) * 25).div_ceil(24);
Ok(FeeRate::from_sat_per_kwu(min_feerate_kwu))
},
Some(prev_feerate) => Ok(min_rbf_feerate(prev_feerate)),
None => Err(format!(
"Channel {} has no prior feerate to compute RBF minimum",
self.context.channel_id(),
Expand Down
26 changes: 14 additions & 12 deletions lightning/src/ln/funding.rs
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -218,8 +218,9 @@ impl PriorContribution {
/// prior contribution logic internally — reusing an adjusted prior when possible, re-running
/// coin selection when needed, or creating a fee-bump-only contribution.
///
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (25/24 of
/// the previous feerate). Use [`FundingTemplate::prior_contribution`] to inspect the prior
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (the greater of
/// the previous feerate + 25 sat/kwu and the spec's 25/24 rule). Use
/// [`FundingTemplate::prior_contribution`] to inspect the prior
/// contribution's parameters (e.g., [`FundingContribution::value_added`],
/// [`FundingContribution::outputs`]) before deciding whether to reuse it via the RBF methods
/// or build a fresh contribution with different parameters using the splice methods above.
Expand All@@ -232,8 +233,9 @@ pub struct FundingTemplate {
/// transaction.
shared_input: Option<Input>,

/// The minimum RBF feerate (25/24 of the previous feerate), if this template is for an
/// RBF attempt. `None` for fresh splices with no pending splice candidates.
/// The minimum RBF feerate (the greater of previous feerate + 25 sat/kwu and the spec's
/// 25/24 rule), if this template is for an RBF attempt. `None` for fresh splices with no
/// pending splice candidates.
min_rbf_feerate: Option<FeeRate>,

/// The user's prior contribution from a previous splice negotiation, if available.
Expand DownExpand Up@@ -2262,8 +2264,8 @@ mod tests {
// When the caller's max_feerate is below the minimum RBF feerate, rbf_sync should
// return Err(()).
let prior_feerate = FeeRate::from_sat_per_kwu(2000);
let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
let max_feerate = FeeRate::from_sat_per_kwu(3000);
let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
let max_feerate = FeeRate::from_sat_per_kwu(2020);

let prior = FundingContribution {
value_added: Amount::from_sat(50_000),
Expand All@@ -2276,7 +2278,7 @@ mod tests {
is_splice: true,
};

// max_feerate (3000) < min_rbf_feerate (5000).
// max_feerate (2020) < min_rbf_feerate (2025).
let template = FundingTemplate::new(
None,
Some(min_rbf_feerate),
Expand DownExpand Up@@ -2359,8 +2361,8 @@ mod tests {
// When the prior contribution's feerate is below the minimum RBF feerate and no
// holder balance is available, rbf_sync should run coin selection to add inputs that
// cover the higher RBF fee.
let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
let prior_feerate = FeeRate::from_sat_per_kwu(2000);
let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
let withdrawal = funding_output_sats(20_000);

let prior = FundingContribution {
Expand DownExpand Up@@ -2397,7 +2399,7 @@ mod tests {
fn test_rbf_sync_no_prior_fee_bump_only_runs_coin_selection() {
// When there is no prior contribution (e.g., acceptor), rbf_sync should run coin
// selection to add inputs for a fee-bump-only contribution.
let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);

let template =
FundingTemplate::new(Some(shared_input(100_000)), Some(min_rbf_feerate), None);
Expand All@@ -2419,7 +2421,7 @@ mod tests {
// When the prior contribution's feerate is below the minimum RBF feerate and no
// holder balance is available, rbf_sync should use the caller's max_feerate (not the
// prior's) for the resulting contribution.
let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
let prior_max_feerate = FeeRate::from_sat_per_kwu(50_000);
let callers_max_feerate = FeeRate::from_sat_per_kwu(10_000);
let withdrawal = funding_output_sats(20_000);
Expand DownExpand Up@@ -2458,8 +2460,8 @@ mod tests {
// When splice_out_sync is called on a template with min_rbf_feerate set (user
// choosing a fresh splice-out instead of rbf_sync), coin selection should NOT run.
// Fees come from the channel balance.
let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
let feerate = FeeRate::from_sat_per_kwu(5000);
let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
let feerate = FeeRate::from_sat_per_kwu(2025);
let withdrawal = funding_output_sats(20_000);

let template =
Expand Down
Loading
Loading
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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Ensure minimum RBF feerate satisfies BIP125#4494

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 Merged

TheBlueMatt
merged 1 commit into

from

Apr 1, 2026
 Merged


Ensure minimum RBF feerate satisfies BIP125
#4494
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23 changes: 15 additions & 8 deletions
lightning/src/ln/channel.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -6484,6 +6484,19 @@ fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satos
	cmp::min(channel_value_satoshis, cmp::max(q, dust_limit_satoshis))
}

/// Returns the minimum feerate for our own RBF attempts given a previous feerate.
///
/// The spec (tx_init_rbf) requires the new feerate to be >= 25/24 of the previous feerate.
/// However, at low feerates that multiplier doesn't always satisfy BIP125's relay requirement of
/// an absolute fee increase, so we take the max of a flat +25 sat/kwu (0.1 sat/vB) increment
/// and the spec's multiplicative rule. We still accept the bare 25/24 rule from counterparties
/// in [`FundedChannel::validate_tx_init_rbf`].
fn min_rbf_feerate(prev_feerate: u32) -> FeeRate {
	let flat_increment = (prev_feerate as u64).saturating_add(25);
	let spec_increment = ((prev_feerate as u64) * 25).div_ceil(24);
	FeeRate::from_sat_per_kwu(cmp::max(flat_increment, spec_increment))
}
Comment thread
wpaulino marked this conversation as resolved.


/// Context for negotiating channels (dual-funded V2 open, splicing)
#[derive(Debug)]
pub(super) struct FundingNegotiationContext {
Expand DownExpand Up@@ -12019,10 +12032,7 @@ where
 prev_feerate.is_some(),
 "pending_splice should have last_funding_feerate or funding_negotiation",
 );
 let min_rbf_feerate = prev_feerate.map(|f| {
 let min_feerate_kwu = ((f as u64) * 25).div_ceil(24);
 FeeRate::from_sat_per_kwu(min_feerate_kwu)
 });
 let min_rbf_feerate = prev_feerate.map(min_rbf_feerate);
 let prior = if pending_splice.last_funding_feerate_sat_per_1000_weight.is_some() {
 self.build_prior_contribution()
 } else {
Expand DownExpand Up@@ -12114,10 +12124,7 @@ where
 }

 match pending_splice.last_funding_feerate_sat_per_1000_weight {
 Some(prev_feerate) => {
 let min_feerate_kwu = ((prev_feerate as u64) * 25).div_ceil(24);
 Ok(FeeRate::from_sat_per_kwu(min_feerate_kwu))
 },
 Some(prev_feerate) => Ok(min_rbf_feerate(prev_feerate)),
 None => Err(format!(
 "Channel {} has no prior feerate to compute RBF minimum",
 self.context.channel_id(),
Expand Down

26 changes: 14 additions & 12 deletions
lightning/src/ln/funding.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -218,8 +218,9 @@ impl PriorContribution {
/// prior contribution logic internally — reusing an adjusted prior when possible, re-running
/// coin selection when needed, or creating a fee-bump-only contribution.
///
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (25/24 of
/// the previous feerate). Use [`FundingTemplate::prior_contribution`] to inspect the prior
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (the greater of
/// the previous feerate + 25 sat/kwu and the spec's 25/24 rule). Use
/// [`FundingTemplate::prior_contribution`] to inspect the prior
/// contribution's parameters (e.g., [`FundingContribution::value_added`],
/// [`FundingContribution::outputs`]) before deciding whether to reuse it via the RBF methods
/// or build a fresh contribution with different parameters using the splice methods above.
Expand All@@ -232,8 +233,9 @@ pub struct FundingTemplate {
	/// transaction.
	shared_input: Option<Input>,

	/// The minimum RBF feerate (25/24 of the previous feerate), if this template is for an
	/// RBF attempt. `None` for fresh splices with no pending splice candidates.
	/// The minimum RBF feerate (the greater of previous feerate + 25 sat/kwu and the spec's
	/// 25/24 rule), if this template is for an RBF attempt. `None` for fresh splices with no
	/// pending splice candidates.
	min_rbf_feerate: Option<FeeRate>,

	/// The user's prior contribution from a previous splice negotiation, if available.
Expand DownExpand Up@@ -2262,8 +2264,8 @@ mod tests {
 // When the caller's max_feerate is below the minimum RBF feerate, rbf_sync should
 // return Err(()).
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let max_feerate = FeeRate::from_sat_per_kwu(3000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let max_feerate = FeeRate::from_sat_per_kwu(2020);

 let prior = FundingContribution {
 value_added: Amount::from_sat(50_000),
Expand All@@ -2276,7 +2278,7 @@ mod tests {
 is_splice: true,
 };

 // max_feerate (3000) < min_rbf_feerate (5000).
 // max_feerate (2020) < min_rbf_feerate (2025).
 let template = FundingTemplate::new(
 None,
 Some(min_rbf_feerate),
Expand DownExpand Up@@ -2359,8 +2361,8 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should run coin selection to add inputs that
 // cover the higher RBF fee.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let prior = FundingContribution {
Expand DownExpand Up@@ -2397,7 +2399,7 @@ mod tests {
	fn test_rbf_sync_no_prior_fee_bump_only_runs_coin_selection() {
 // When there is no prior contribution (e.g., acceptor), rbf_sync should run coin
 // selection to add inputs for a fee-bump-only contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);

 let template =
 FundingTemplate::new(Some(shared_input(100_000)), Some(min_rbf_feerate), None);
Expand All@@ -2419,7 +2421,7 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should use the caller's max_feerate (not the
 // prior's) for the resulting contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let prior_max_feerate = FeeRate::from_sat_per_kwu(50_000);
 let callers_max_feerate = FeeRate::from_sat_per_kwu(10_000);
 let withdrawal = funding_output_sats(20_000);
Expand DownExpand Up@@ -2458,8 +2460,8 @@ mod tests {
 // When splice_out_sync is called on a template with min_rbf_feerate set (user
 // choosing a fresh splice-out instead of rbf_sync), coin selection should NOT run.
 // Fees come from the channel balance.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let template =
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Ensure minimum RBF feerate satisfies BIP125#4494

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 Merged

TheBlueMatt
merged 1 commit into

from

Apr 1, 2026
 Merged


Ensure minimum RBF feerate satisfies BIP125
#4494
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23 changes: 15 additions & 8 deletions
lightning/src/ln/channel.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -6484,6 +6484,19 @@ fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satos
	cmp::min(channel_value_satoshis, cmp::max(q, dust_limit_satoshis))
}

/// Returns the minimum feerate for our own RBF attempts given a previous feerate.
///
/// The spec (tx_init_rbf) requires the new feerate to be >= 25/24 of the previous feerate.
/// However, at low feerates that multiplier doesn't always satisfy BIP125's relay requirement of
/// an absolute fee increase, so we take the max of a flat +25 sat/kwu (0.1 sat/vB) increment
/// and the spec's multiplicative rule. We still accept the bare 25/24 rule from counterparties
/// in [`FundedChannel::validate_tx_init_rbf`].
fn min_rbf_feerate(prev_feerate: u32) -> FeeRate {
	let flat_increment = (prev_feerate as u64).saturating_add(25);
	let spec_increment = ((prev_feerate as u64) * 25).div_ceil(24);
	FeeRate::from_sat_per_kwu(cmp::max(flat_increment, spec_increment))
}
Comment thread
wpaulino marked this conversation as resolved.


/// Context for negotiating channels (dual-funded V2 open, splicing)
#[derive(Debug)]
pub(super) struct FundingNegotiationContext {
Expand DownExpand Up@@ -12019,10 +12032,7 @@ where
 prev_feerate.is_some(),
 "pending_splice should have last_funding_feerate or funding_negotiation",
 );
 let min_rbf_feerate = prev_feerate.map(|f| {
 let min_feerate_kwu = ((f as u64) * 25).div_ceil(24);
 FeeRate::from_sat_per_kwu(min_feerate_kwu)
 });
 let min_rbf_feerate = prev_feerate.map(min_rbf_feerate);
 let prior = if pending_splice.last_funding_feerate_sat_per_1000_weight.is_some() {
 self.build_prior_contribution()
 } else {
Expand DownExpand Up@@ -12114,10 +12124,7 @@ where
 }

 match pending_splice.last_funding_feerate_sat_per_1000_weight {
 Some(prev_feerate) => {
 let min_feerate_kwu = ((prev_feerate as u64) * 25).div_ceil(24);
 Ok(FeeRate::from_sat_per_kwu(min_feerate_kwu))
 },
 Some(prev_feerate) => Ok(min_rbf_feerate(prev_feerate)),
 None => Err(format!(
 "Channel {} has no prior feerate to compute RBF minimum",
 self.context.channel_id(),
Expand Down

26 changes: 14 additions & 12 deletions
lightning/src/ln/funding.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -218,8 +218,9 @@ impl PriorContribution {
/// prior contribution logic internally — reusing an adjusted prior when possible, re-running
/// coin selection when needed, or creating a fee-bump-only contribution.
///
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (25/24 of
/// the previous feerate). Use [`FundingTemplate::prior_contribution`] to inspect the prior
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (the greater of
/// the previous feerate + 25 sat/kwu and the spec's 25/24 rule). Use
/// [`FundingTemplate::prior_contribution`] to inspect the prior
/// contribution's parameters (e.g., [`FundingContribution::value_added`],
/// [`FundingContribution::outputs`]) before deciding whether to reuse it via the RBF methods
/// or build a fresh contribution with different parameters using the splice methods above.
Expand All@@ -232,8 +233,9 @@ pub struct FundingTemplate {
	/// transaction.
	shared_input: Option<Input>,

	/// The minimum RBF feerate (25/24 of the previous feerate), if this template is for an
	/// RBF attempt. `None` for fresh splices with no pending splice candidates.
	/// The minimum RBF feerate (the greater of previous feerate + 25 sat/kwu and the spec's
	/// 25/24 rule), if this template is for an RBF attempt. `None` for fresh splices with no
	/// pending splice candidates.
	min_rbf_feerate: Option<FeeRate>,

	/// The user's prior contribution from a previous splice negotiation, if available.
Expand DownExpand Up@@ -2262,8 +2264,8 @@ mod tests {
 // When the caller's max_feerate is below the minimum RBF feerate, rbf_sync should
 // return Err(()).
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let max_feerate = FeeRate::from_sat_per_kwu(3000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let max_feerate = FeeRate::from_sat_per_kwu(2020);

 let prior = FundingContribution {
 value_added: Amount::from_sat(50_000),
Expand All@@ -2276,7 +2278,7 @@ mod tests {
 is_splice: true,
 };

 // max_feerate (3000) < min_rbf_feerate (5000).
 // max_feerate (2020) < min_rbf_feerate (2025).
 let template = FundingTemplate::new(
 None,
 Some(min_rbf_feerate),
Expand DownExpand Up@@ -2359,8 +2361,8 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should run coin selection to add inputs that
 // cover the higher RBF fee.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let prior = FundingContribution {
Expand DownExpand Up@@ -2397,7 +2399,7 @@ mod tests {
	fn test_rbf_sync_no_prior_fee_bump_only_runs_coin_selection() {
 // When there is no prior contribution (e.g., acceptor), rbf_sync should run coin
 // selection to add inputs for a fee-bump-only contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);

 let template =
 FundingTemplate::new(Some(shared_input(100_000)), Some(min_rbf_feerate), None);
Expand All@@ -2419,7 +2421,7 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should use the caller's max_feerate (not the
 // prior's) for the resulting contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let prior_max_feerate = FeeRate::from_sat_per_kwu(50_000);
 let callers_max_feerate = FeeRate::from_sat_per_kwu(10_000);
 let withdrawal = funding_output_sats(20_000);
Expand DownExpand Up@@ -2458,8 +2460,8 @@ mod tests {
 // When splice_out_sync is called on a template with min_rbf_feerate set (user
 // choosing a fresh splice-out instead of rbf_sync), coin selection should NOT run.
 // Fees come from the channel balance.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let template =
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Ensure minimum RBF feerate satisfies BIP125#4494

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TheBlueMatt
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Apr 1, 2026
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Ensure minimum RBF feerate satisfies BIP125
#4494
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23 changes: 15 additions & 8 deletions
lightning/src/ln/channel.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -6484,6 +6484,19 @@ fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satos
	cmp::min(channel_value_satoshis, cmp::max(q, dust_limit_satoshis))
}

/// Returns the minimum feerate for our own RBF attempts given a previous feerate.
///
/// The spec (tx_init_rbf) requires the new feerate to be >= 25/24 of the previous feerate.
/// However, at low feerates that multiplier doesn't always satisfy BIP125's relay requirement of
/// an absolute fee increase, so we take the max of a flat +25 sat/kwu (0.1 sat/vB) increment
/// and the spec's multiplicative rule. We still accept the bare 25/24 rule from counterparties
/// in [`FundedChannel::validate_tx_init_rbf`].
fn min_rbf_feerate(prev_feerate: u32) -> FeeRate {
	let flat_increment = (prev_feerate as u64).saturating_add(25);
	let spec_increment = ((prev_feerate as u64) * 25).div_ceil(24);
	FeeRate::from_sat_per_kwu(cmp::max(flat_increment, spec_increment))
}
Comment thread
wpaulino marked this conversation as resolved.


/// Context for negotiating channels (dual-funded V2 open, splicing)
#[derive(Debug)]
pub(super) struct FundingNegotiationContext {
Expand DownExpand Up@@ -12019,10 +12032,7 @@ where
 prev_feerate.is_some(),
 "pending_splice should have last_funding_feerate or funding_negotiation",
 );
 let min_rbf_feerate = prev_feerate.map(|f| {
 let min_feerate_kwu = ((f as u64) * 25).div_ceil(24);
 FeeRate::from_sat_per_kwu(min_feerate_kwu)
 });
 let min_rbf_feerate = prev_feerate.map(min_rbf_feerate);
 let prior = if pending_splice.last_funding_feerate_sat_per_1000_weight.is_some() {
 self.build_prior_contribution()
 } else {
Expand DownExpand Up@@ -12114,10 +12124,7 @@ where
 }

 match pending_splice.last_funding_feerate_sat_per_1000_weight {
 Some(prev_feerate) => {
 let min_feerate_kwu = ((prev_feerate as u64) * 25).div_ceil(24);
 Ok(FeeRate::from_sat_per_kwu(min_feerate_kwu))
 },
 Some(prev_feerate) => Ok(min_rbf_feerate(prev_feerate)),
 None => Err(format!(
 "Channel {} has no prior feerate to compute RBF minimum",
 self.context.channel_id(),
Expand Down

26 changes: 14 additions & 12 deletions
lightning/src/ln/funding.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -218,8 +218,9 @@ impl PriorContribution {
/// prior contribution logic internally — reusing an adjusted prior when possible, re-running
/// coin selection when needed, or creating a fee-bump-only contribution.
///
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (25/24 of
/// the previous feerate). Use [`FundingTemplate::prior_contribution`] to inspect the prior
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (the greater of
/// the previous feerate + 25 sat/kwu and the spec's 25/24 rule). Use
/// [`FundingTemplate::prior_contribution`] to inspect the prior
/// contribution's parameters (e.g., [`FundingContribution::value_added`],
/// [`FundingContribution::outputs`]) before deciding whether to reuse it via the RBF methods
/// or build a fresh contribution with different parameters using the splice methods above.
Expand All@@ -232,8 +233,9 @@ pub struct FundingTemplate {
	/// transaction.
	shared_input: Option<Input>,

	/// The minimum RBF feerate (25/24 of the previous feerate), if this template is for an
	/// RBF attempt. `None` for fresh splices with no pending splice candidates.
	/// The minimum RBF feerate (the greater of previous feerate + 25 sat/kwu and the spec's
	/// 25/24 rule), if this template is for an RBF attempt. `None` for fresh splices with no
	/// pending splice candidates.
	min_rbf_feerate: Option<FeeRate>,

	/// The user's prior contribution from a previous splice negotiation, if available.
Expand DownExpand Up@@ -2262,8 +2264,8 @@ mod tests {
 // When the caller's max_feerate is below the minimum RBF feerate, rbf_sync should
 // return Err(()).
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let max_feerate = FeeRate::from_sat_per_kwu(3000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let max_feerate = FeeRate::from_sat_per_kwu(2020);

 let prior = FundingContribution {
 value_added: Amount::from_sat(50_000),
Expand All@@ -2276,7 +2278,7 @@ mod tests {
 is_splice: true,
 };

 // max_feerate (3000) < min_rbf_feerate (5000).
 // max_feerate (2020) < min_rbf_feerate (2025).
 let template = FundingTemplate::new(
 None,
 Some(min_rbf_feerate),
Expand DownExpand Up@@ -2359,8 +2361,8 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should run coin selection to add inputs that
 // cover the higher RBF fee.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let prior = FundingContribution {
Expand DownExpand Up@@ -2397,7 +2399,7 @@ mod tests {
	fn test_rbf_sync_no_prior_fee_bump_only_runs_coin_selection() {
 // When there is no prior contribution (e.g., acceptor), rbf_sync should run coin
 // selection to add inputs for a fee-bump-only contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);

 let template =
 FundingTemplate::new(Some(shared_input(100_000)), Some(min_rbf_feerate), None);
Expand All@@ -2419,7 +2421,7 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should use the caller's max_feerate (not the
 // prior's) for the resulting contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let prior_max_feerate = FeeRate::from_sat_per_kwu(50_000);
 let callers_max_feerate = FeeRate::from_sat_per_kwu(10_000);
 let withdrawal = funding_output_sats(20_000);
Expand DownExpand Up@@ -2458,8 +2460,8 @@ mod tests {
 // When splice_out_sync is called on a template with min_rbf_feerate set (user
 // choosing a fresh splice-out instead of rbf_sync), coin selection should NOT run.
 // Fees come from the channel balance.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let template =
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

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Ensure minimum RBF feerate satisfies BIP125#4494

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 Merged

TheBlueMatt
merged 1 commit into

from

Apr 1, 2026
 Merged


Ensure minimum RBF feerate satisfies BIP125
#4494
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23 changes: 15 additions & 8 deletions
lightning/src/ln/channel.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -6484,6 +6484,19 @@ fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satos
	cmp::min(channel_value_satoshis, cmp::max(q, dust_limit_satoshis))
}

/// Returns the minimum feerate for our own RBF attempts given a previous feerate.
///
/// The spec (tx_init_rbf) requires the new feerate to be >= 25/24 of the previous feerate.
/// However, at low feerates that multiplier doesn't always satisfy BIP125's relay requirement of
/// an absolute fee increase, so we take the max of a flat +25 sat/kwu (0.1 sat/vB) increment
/// and the spec's multiplicative rule. We still accept the bare 25/24 rule from counterparties
/// in [`FundedChannel::validate_tx_init_rbf`].
fn min_rbf_feerate(prev_feerate: u32) -> FeeRate {
	let flat_increment = (prev_feerate as u64).saturating_add(25);
	let spec_increment = ((prev_feerate as u64) * 25).div_ceil(24);
	FeeRate::from_sat_per_kwu(cmp::max(flat_increment, spec_increment))
}
Comment thread
wpaulino marked this conversation as resolved.


/// Context for negotiating channels (dual-funded V2 open, splicing)
#[derive(Debug)]
pub(super) struct FundingNegotiationContext {
Expand DownExpand Up@@ -12019,10 +12032,7 @@ where
 prev_feerate.is_some(),
 "pending_splice should have last_funding_feerate or funding_negotiation",
 );
 let min_rbf_feerate = prev_feerate.map(|f| {
 let min_feerate_kwu = ((f as u64) * 25).div_ceil(24);
 FeeRate::from_sat_per_kwu(min_feerate_kwu)
 });
 let min_rbf_feerate = prev_feerate.map(min_rbf_feerate);
 let prior = if pending_splice.last_funding_feerate_sat_per_1000_weight.is_some() {
 self.build_prior_contribution()
 } else {
Expand DownExpand Up@@ -12114,10 +12124,7 @@ where
 }

 match pending_splice.last_funding_feerate_sat_per_1000_weight {
 Some(prev_feerate) => {
 let min_feerate_kwu = ((prev_feerate as u64) * 25).div_ceil(24);
 Ok(FeeRate::from_sat_per_kwu(min_feerate_kwu))
 },
 Some(prev_feerate) => Ok(min_rbf_feerate(prev_feerate)),
 None => Err(format!(
 "Channel {} has no prior feerate to compute RBF minimum",
 self.context.channel_id(),
Expand Down

26 changes: 14 additions & 12 deletions
lightning/src/ln/funding.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -218,8 +218,9 @@ impl PriorContribution {
/// prior contribution logic internally — reusing an adjusted prior when possible, re-running
/// coin selection when needed, or creating a fee-bump-only contribution.
///
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (25/24 of
/// the previous feerate). Use [`FundingTemplate::prior_contribution`] to inspect the prior
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (the greater of
/// the previous feerate + 25 sat/kwu and the spec's 25/24 rule). Use
/// [`FundingTemplate::prior_contribution`] to inspect the prior
/// contribution's parameters (e.g., [`FundingContribution::value_added`],
/// [`FundingContribution::outputs`]) before deciding whether to reuse it via the RBF methods
/// or build a fresh contribution with different parameters using the splice methods above.
Expand All@@ -232,8 +233,9 @@ pub struct FundingTemplate {
	/// transaction.
	shared_input: Option<Input>,

	/// The minimum RBF feerate (25/24 of the previous feerate), if this template is for an
	/// RBF attempt. `None` for fresh splices with no pending splice candidates.
	/// The minimum RBF feerate (the greater of previous feerate + 25 sat/kwu and the spec's
	/// 25/24 rule), if this template is for an RBF attempt. `None` for fresh splices with no
	/// pending splice candidates.
	min_rbf_feerate: Option<FeeRate>,

	/// The user's prior contribution from a previous splice negotiation, if available.
Expand DownExpand Up@@ -2262,8 +2264,8 @@ mod tests {
 // When the caller's max_feerate is below the minimum RBF feerate, rbf_sync should
 // return Err(()).
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let max_feerate = FeeRate::from_sat_per_kwu(3000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let max_feerate = FeeRate::from_sat_per_kwu(2020);

 let prior = FundingContribution {
 value_added: Amount::from_sat(50_000),
Expand All@@ -2276,7 +2278,7 @@ mod tests {
 is_splice: true,
 };

 // max_feerate (3000) < min_rbf_feerate (5000).
 // max_feerate (2020) < min_rbf_feerate (2025).
 let template = FundingTemplate::new(
 None,
 Some(min_rbf_feerate),
Expand DownExpand Up@@ -2359,8 +2361,8 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should run coin selection to add inputs that
 // cover the higher RBF fee.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let prior = FundingContribution {
Expand DownExpand Up@@ -2397,7 +2399,7 @@ mod tests {
	fn test_rbf_sync_no_prior_fee_bump_only_runs_coin_selection() {
 // When there is no prior contribution (e.g., acceptor), rbf_sync should run coin
 // selection to add inputs for a fee-bump-only contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);

 let template =
 FundingTemplate::new(Some(shared_input(100_000)), Some(min_rbf_feerate), None);
Expand All@@ -2419,7 +2421,7 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should use the caller's max_feerate (not the
 // prior's) for the resulting contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let prior_max_feerate = FeeRate::from_sat_per_kwu(50_000);
 let callers_max_feerate = FeeRate::from_sat_per_kwu(10_000);
 let withdrawal = funding_output_sats(20_000);
Expand DownExpand Up@@ -2458,8 +2460,8 @@ mod tests {
 // When splice_out_sync is called on a template with min_rbf_feerate set (user
 // choosing a fresh splice-out instead of rbf_sync), coin selection should NOT run.
 // Fees come from the channel balance.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let template =
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Ensure minimum RBF feerate satisfies BIP125#4494

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 Merged

TheBlueMatt
merged 1 commit into

from

Apr 1, 2026
 Merged


Ensure minimum RBF feerate satisfies BIP125
#4494
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23 changes: 15 additions & 8 deletions
lightning/src/ln/channel.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -6484,6 +6484,19 @@ fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satos
	cmp::min(channel_value_satoshis, cmp::max(q, dust_limit_satoshis))
}

/// Returns the minimum feerate for our own RBF attempts given a previous feerate.
///
/// The spec (tx_init_rbf) requires the new feerate to be >= 25/24 of the previous feerate.
/// However, at low feerates that multiplier doesn't always satisfy BIP125's relay requirement of
/// an absolute fee increase, so we take the max of a flat +25 sat/kwu (0.1 sat/vB) increment
/// and the spec's multiplicative rule. We still accept the bare 25/24 rule from counterparties
/// in [`FundedChannel::validate_tx_init_rbf`].
fn min_rbf_feerate(prev_feerate: u32) -> FeeRate {
	let flat_increment = (prev_feerate as u64).saturating_add(25);
	let spec_increment = ((prev_feerate as u64) * 25).div_ceil(24);
	FeeRate::from_sat_per_kwu(cmp::max(flat_increment, spec_increment))
}
Comment thread
wpaulino marked this conversation as resolved.


/// Context for negotiating channels (dual-funded V2 open, splicing)
#[derive(Debug)]
pub(super) struct FundingNegotiationContext {
Expand DownExpand Up@@ -12019,10 +12032,7 @@ where
 prev_feerate.is_some(),
 "pending_splice should have last_funding_feerate or funding_negotiation",
 );
 let min_rbf_feerate = prev_feerate.map(|f| {
 let min_feerate_kwu = ((f as u64) * 25).div_ceil(24);
 FeeRate::from_sat_per_kwu(min_feerate_kwu)
 });
 let min_rbf_feerate = prev_feerate.map(min_rbf_feerate);
 let prior = if pending_splice.last_funding_feerate_sat_per_1000_weight.is_some() {
 self.build_prior_contribution()
 } else {
Expand DownExpand Up@@ -12114,10 +12124,7 @@ where
 }

 match pending_splice.last_funding_feerate_sat_per_1000_weight {
 Some(prev_feerate) => {
 let min_feerate_kwu = ((prev_feerate as u64) * 25).div_ceil(24);
 Ok(FeeRate::from_sat_per_kwu(min_feerate_kwu))
 },
 Some(prev_feerate) => Ok(min_rbf_feerate(prev_feerate)),
 None => Err(format!(
 "Channel {} has no prior feerate to compute RBF minimum",
 self.context.channel_id(),
Expand Down

26 changes: 14 additions & 12 deletions
lightning/src/ln/funding.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -218,8 +218,9 @@ impl PriorContribution {
/// prior contribution logic internally — reusing an adjusted prior when possible, re-running
/// coin selection when needed, or creating a fee-bump-only contribution.
///
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (25/24 of
/// the previous feerate). Use [`FundingTemplate::prior_contribution`] to inspect the prior
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (the greater of
/// the previous feerate + 25 sat/kwu and the spec's 25/24 rule). Use
/// [`FundingTemplate::prior_contribution`] to inspect the prior
/// contribution's parameters (e.g., [`FundingContribution::value_added`],
/// [`FundingContribution::outputs`]) before deciding whether to reuse it via the RBF methods
/// or build a fresh contribution with different parameters using the splice methods above.
Expand All@@ -232,8 +233,9 @@ pub struct FundingTemplate {
	/// transaction.
	shared_input: Option<Input>,

	/// The minimum RBF feerate (25/24 of the previous feerate), if this template is for an
	/// RBF attempt. `None` for fresh splices with no pending splice candidates.
	/// The minimum RBF feerate (the greater of previous feerate + 25 sat/kwu and the spec's
	/// 25/24 rule), if this template is for an RBF attempt. `None` for fresh splices with no
	/// pending splice candidates.
	min_rbf_feerate: Option<FeeRate>,

	/// The user's prior contribution from a previous splice negotiation, if available.
Expand DownExpand Up@@ -2262,8 +2264,8 @@ mod tests {
 // When the caller's max_feerate is below the minimum RBF feerate, rbf_sync should
 // return Err(()).
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let max_feerate = FeeRate::from_sat_per_kwu(3000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let max_feerate = FeeRate::from_sat_per_kwu(2020);

 let prior = FundingContribution {
 value_added: Amount::from_sat(50_000),
Expand All@@ -2276,7 +2278,7 @@ mod tests {
 is_splice: true,
 };

 // max_feerate (3000) < min_rbf_feerate (5000).
 // max_feerate (2020) < min_rbf_feerate (2025).
 let template = FundingTemplate::new(
 None,
 Some(min_rbf_feerate),
Expand DownExpand Up@@ -2359,8 +2361,8 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should run coin selection to add inputs that
 // cover the higher RBF fee.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let prior = FundingContribution {
Expand DownExpand Up@@ -2397,7 +2399,7 @@ mod tests {
	fn test_rbf_sync_no_prior_fee_bump_only_runs_coin_selection() {
 // When there is no prior contribution (e.g., acceptor), rbf_sync should run coin
 // selection to add inputs for a fee-bump-only contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);

 let template =
 FundingTemplate::new(Some(shared_input(100_000)), Some(min_rbf_feerate), None);
Expand All@@ -2419,7 +2421,7 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should use the caller's max_feerate (not the
 // prior's) for the resulting contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let prior_max_feerate = FeeRate::from_sat_per_kwu(50_000);
 let callers_max_feerate = FeeRate::from_sat_per_kwu(10_000);
 let withdrawal = funding_output_sats(20_000);
Expand DownExpand Up@@ -2458,8 +2460,8 @@ mod tests {
 // When splice_out_sync is called on a template with min_rbf_feerate set (user
 // choosing a fresh splice-out instead of rbf_sync), coin selection should NOT run.
 // Fees come from the channel balance.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let template =
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Ensure minimum RBF feerate satisfies BIP125#4494

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 Merged

TheBlueMatt
merged 1 commit into

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Apr 1, 2026
 Merged


Ensure minimum RBF feerate satisfies BIP125
#4494
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23 changes: 15 additions & 8 deletions
lightning/src/ln/channel.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -6484,6 +6484,19 @@ fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satos
	cmp::min(channel_value_satoshis, cmp::max(q, dust_limit_satoshis))
}

/// Returns the minimum feerate for our own RBF attempts given a previous feerate.
///
/// The spec (tx_init_rbf) requires the new feerate to be >= 25/24 of the previous feerate.
/// However, at low feerates that multiplier doesn't always satisfy BIP125's relay requirement of
/// an absolute fee increase, so we take the max of a flat +25 sat/kwu (0.1 sat/vB) increment
/// and the spec's multiplicative rule. We still accept the bare 25/24 rule from counterparties
/// in [`FundedChannel::validate_tx_init_rbf`].
fn min_rbf_feerate(prev_feerate: u32) -> FeeRate {
	let flat_increment = (prev_feerate as u64).saturating_add(25);
	let spec_increment = ((prev_feerate as u64) * 25).div_ceil(24);
	FeeRate::from_sat_per_kwu(cmp::max(flat_increment, spec_increment))
}
Comment thread
wpaulino marked this conversation as resolved.


/// Context for negotiating channels (dual-funded V2 open, splicing)
#[derive(Debug)]
pub(super) struct FundingNegotiationContext {
Expand DownExpand Up@@ -12019,10 +12032,7 @@ where
 prev_feerate.is_some(),
 "pending_splice should have last_funding_feerate or funding_negotiation",
 );
 let min_rbf_feerate = prev_feerate.map(|f| {
 let min_feerate_kwu = ((f as u64) * 25).div_ceil(24);
 FeeRate::from_sat_per_kwu(min_feerate_kwu)
 });
 let min_rbf_feerate = prev_feerate.map(min_rbf_feerate);
 let prior = if pending_splice.last_funding_feerate_sat_per_1000_weight.is_some() {
 self.build_prior_contribution()
 } else {
Expand DownExpand Up@@ -12114,10 +12124,7 @@ where
 }

 match pending_splice.last_funding_feerate_sat_per_1000_weight {
 Some(prev_feerate) => {
 let min_feerate_kwu = ((prev_feerate as u64) * 25).div_ceil(24);
 Ok(FeeRate::from_sat_per_kwu(min_feerate_kwu))
 },
 Some(prev_feerate) => Ok(min_rbf_feerate(prev_feerate)),
 None => Err(format!(
 "Channel {} has no prior feerate to compute RBF minimum",
 self.context.channel_id(),
Expand Down

26 changes: 14 additions & 12 deletions
lightning/src/ln/funding.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -218,8 +218,9 @@ impl PriorContribution {
/// prior contribution logic internally — reusing an adjusted prior when possible, re-running
/// coin selection when needed, or creating a fee-bump-only contribution.
///
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (25/24 of
/// the previous feerate). Use [`FundingTemplate::prior_contribution`] to inspect the prior
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (the greater of
/// the previous feerate + 25 sat/kwu and the spec's 25/24 rule). Use
/// [`FundingTemplate::prior_contribution`] to inspect the prior
/// contribution's parameters (e.g., [`FundingContribution::value_added`],
/// [`FundingContribution::outputs`]) before deciding whether to reuse it via the RBF methods
/// or build a fresh contribution with different parameters using the splice methods above.
Expand All@@ -232,8 +233,9 @@ pub struct FundingTemplate {
	/// transaction.
	shared_input: Option<Input>,

	/// The minimum RBF feerate (25/24 of the previous feerate), if this template is for an
	/// RBF attempt. `None` for fresh splices with no pending splice candidates.
	/// The minimum RBF feerate (the greater of previous feerate + 25 sat/kwu and the spec's
	/// 25/24 rule), if this template is for an RBF attempt. `None` for fresh splices with no
	/// pending splice candidates.
	min_rbf_feerate: Option<FeeRate>,

	/// The user's prior contribution from a previous splice negotiation, if available.
Expand DownExpand Up@@ -2262,8 +2264,8 @@ mod tests {
 // When the caller's max_feerate is below the minimum RBF feerate, rbf_sync should
 // return Err(()).
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let max_feerate = FeeRate::from_sat_per_kwu(3000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let max_feerate = FeeRate::from_sat_per_kwu(2020);

 let prior = FundingContribution {
 value_added: Amount::from_sat(50_000),
Expand All@@ -2276,7 +2278,7 @@ mod tests {
 is_splice: true,
 };

 // max_feerate (3000) < min_rbf_feerate (5000).
 // max_feerate (2020) < min_rbf_feerate (2025).
 let template = FundingTemplate::new(
 None,
 Some(min_rbf_feerate),
Expand DownExpand Up@@ -2359,8 +2361,8 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should run coin selection to add inputs that
 // cover the higher RBF fee.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let prior = FundingContribution {
Expand DownExpand Up@@ -2397,7 +2399,7 @@ mod tests {
	fn test_rbf_sync_no_prior_fee_bump_only_runs_coin_selection() {
 // When there is no prior contribution (e.g., acceptor), rbf_sync should run coin
 // selection to add inputs for a fee-bump-only contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);

 let template =
 FundingTemplate::new(Some(shared_input(100_000)), Some(min_rbf_feerate), None);
Expand All@@ -2419,7 +2421,7 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should use the caller's max_feerate (not the
 // prior's) for the resulting contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let prior_max_feerate = FeeRate::from_sat_per_kwu(50_000);
 let callers_max_feerate = FeeRate::from_sat_per_kwu(10_000);
 let withdrawal = funding_output_sats(20_000);
Expand DownExpand Up@@ -2458,8 +2460,8 @@ mod tests {
 // When splice_out_sync is called on a template with min_rbf_feerate set (user
 // choosing a fresh splice-out instead of rbf_sync), coin selection should NOT run.
 // Fees come from the channel balance.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let template =
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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Ensure minimum RBF feerate satisfies BIP125#4494

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 Merged

TheBlueMatt
merged 1 commit into

from

Apr 1, 2026
 Merged


Ensure minimum RBF feerate satisfies BIP125
#4494
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23 changes: 15 additions & 8 deletions
lightning/src/ln/channel.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -6484,6 +6484,19 @@ fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satos
	cmp::min(channel_value_satoshis, cmp::max(q, dust_limit_satoshis))
}

/// Returns the minimum feerate for our own RBF attempts given a previous feerate.
///
/// The spec (tx_init_rbf) requires the new feerate to be >= 25/24 of the previous feerate.
/// However, at low feerates that multiplier doesn't always satisfy BIP125's relay requirement of
/// an absolute fee increase, so we take the max of a flat +25 sat/kwu (0.1 sat/vB) increment
/// and the spec's multiplicative rule. We still accept the bare 25/24 rule from counterparties
/// in [`FundedChannel::validate_tx_init_rbf`].
fn min_rbf_feerate(prev_feerate: u32) -> FeeRate {
	let flat_increment = (prev_feerate as u64).saturating_add(25);
	let spec_increment = ((prev_feerate as u64) * 25).div_ceil(24);
	FeeRate::from_sat_per_kwu(cmp::max(flat_increment, spec_increment))
}
Comment thread
wpaulino marked this conversation as resolved.


/// Context for negotiating channels (dual-funded V2 open, splicing)
#[derive(Debug)]
pub(super) struct FundingNegotiationContext {
Expand DownExpand Up@@ -12019,10 +12032,7 @@ where
 prev_feerate.is_some(),
 "pending_splice should have last_funding_feerate or funding_negotiation",
 );
 let min_rbf_feerate = prev_feerate.map(|f| {
 let min_feerate_kwu = ((f as u64) * 25).div_ceil(24);
 FeeRate::from_sat_per_kwu(min_feerate_kwu)
 });
 let min_rbf_feerate = prev_feerate.map(min_rbf_feerate);
 let prior = if pending_splice.last_funding_feerate_sat_per_1000_weight.is_some() {
 self.build_prior_contribution()
 } else {
Expand DownExpand Up@@ -12114,10 +12124,7 @@ where
 }

 match pending_splice.last_funding_feerate_sat_per_1000_weight {
 Some(prev_feerate) => {
 let min_feerate_kwu = ((prev_feerate as u64) * 25).div_ceil(24);
 Ok(FeeRate::from_sat_per_kwu(min_feerate_kwu))
 },
 Some(prev_feerate) => Ok(min_rbf_feerate(prev_feerate)),
 None => Err(format!(
 "Channel {} has no prior feerate to compute RBF minimum",
 self.context.channel_id(),
Expand Down

26 changes: 14 additions & 12 deletions
lightning/src/ln/funding.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -218,8 +218,9 @@ impl PriorContribution {
/// prior contribution logic internally — reusing an adjusted prior when possible, re-running
/// coin selection when needed, or creating a fee-bump-only contribution.
///
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (25/24 of
/// the previous feerate). Use [`FundingTemplate::prior_contribution`] to inspect the prior
/// Check [`FundingTemplate::min_rbf_feerate`] for the minimum feerate required (the greater of
/// the previous feerate + 25 sat/kwu and the spec's 25/24 rule). Use
/// [`FundingTemplate::prior_contribution`] to inspect the prior
/// contribution's parameters (e.g., [`FundingContribution::value_added`],
/// [`FundingContribution::outputs`]) before deciding whether to reuse it via the RBF methods
/// or build a fresh contribution with different parameters using the splice methods above.
Expand All@@ -232,8 +233,9 @@ pub struct FundingTemplate {
	/// transaction.
	shared_input: Option<Input>,

	/// The minimum RBF feerate (25/24 of the previous feerate), if this template is for an
	/// RBF attempt. `None` for fresh splices with no pending splice candidates.
	/// The minimum RBF feerate (the greater of previous feerate + 25 sat/kwu and the spec's
	/// 25/24 rule), if this template is for an RBF attempt. `None` for fresh splices with no
	/// pending splice candidates.
	min_rbf_feerate: Option<FeeRate>,

	/// The user's prior contribution from a previous splice negotiation, if available.
Expand DownExpand Up@@ -2262,8 +2264,8 @@ mod tests {
 // When the caller's max_feerate is below the minimum RBF feerate, rbf_sync should
 // return Err(()).
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let max_feerate = FeeRate::from_sat_per_kwu(3000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let max_feerate = FeeRate::from_sat_per_kwu(2020);

 let prior = FundingContribution {
 value_added: Amount::from_sat(50_000),
Expand All@@ -2276,7 +2278,7 @@ mod tests {
 is_splice: true,
 };

 // max_feerate (3000) < min_rbf_feerate (5000).
 // max_feerate (2020) < min_rbf_feerate (2025).
 let template = FundingTemplate::new(
 None,
 Some(min_rbf_feerate),
Expand DownExpand Up@@ -2359,8 +2361,8 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should run coin selection to add inputs that
 // cover the higher RBF fee.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let prior_feerate = FeeRate::from_sat_per_kwu(2000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let prior = FundingContribution {
Expand DownExpand Up@@ -2397,7 +2399,7 @@ mod tests {
	fn test_rbf_sync_no_prior_fee_bump_only_runs_coin_selection() {
 // When there is no prior contribution (e.g., acceptor), rbf_sync should run coin
 // selection to add inputs for a fee-bump-only contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);

 let template =
 FundingTemplate::new(Some(shared_input(100_000)), Some(min_rbf_feerate), None);
Expand All@@ -2419,7 +2421,7 @@ mod tests {
 // When the prior contribution's feerate is below the minimum RBF feerate and no
 // holder balance is available, rbf_sync should use the caller's max_feerate (not the
 // prior's) for the resulting contribution.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let prior_max_feerate = FeeRate::from_sat_per_kwu(50_000);
 let callers_max_feerate = FeeRate::from_sat_per_kwu(10_000);
 let withdrawal = funding_output_sats(20_000);
Expand DownExpand Up@@ -2458,8 +2460,8 @@ mod tests {
 // When splice_out_sync is called on a template with min_rbf_feerate set (user
 // choosing a fresh splice-out instead of rbf_sync), coin selection should NOT run.
 // Fees come from the channel balance.
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(5000);
 let feerate = FeeRate::from_sat_per_kwu(5000);
 let min_rbf_feerate = FeeRate::from_sat_per_kwu(2025);
 let feerate = FeeRate::from_sat_per_kwu(2025);
 let withdrawal = funding_output_sats(20_000);

 let template =
Expand Down
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