Drop RevokedOutput::is_counterparty_balance_on_anchors

When we added anchors support we declined to aggregate claims
across different types of outputs for anchor channels, requiring
that we track whether a `RevokedOutput` claim came from an anchor
channel or not. This was only ever used to decide whether the claim
was aggregable or not.

In 0fe90c6 we started aggregating
by determining whether a claim is pinnable or not, rather than the
much-too-coarse aggregable flag, leaving
`is_counterparty_balance_on_anchors` unused.

Here we remove it entirely (as it would become ambiguous with
zero-commitment-fee anchor channels).

We always write `Some(())`, marking the claim as an anchor claim
and resulting in LDK prior to 0.1 refusing to aggregate the claim
(which is the more conservative stance). This breaks downgrade to
LDK 0.0.115 and earlier.

Author: TheBlueMatt

lightning/src/chain/channelmonitor.rs

@@ -4656,7 +4656,6 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 				if outp.script_pubkey == revokeable_p2wsh {
 					let revk_outp = RevokedOutput::build(
 						per_commitment_point, per_commitment_key, outp.value,
-						funding_spent.channel_type_features().supports_anchors_zero_fee_htlc_tx(),
 						funding_spent.channel_parameters.clone(), height,
 					);
 					let justice_package = PackageTemplate::build_package(
@@ -4869,9 +4868,8 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 			if input.previous_output.txid == *commitment_txid && input.witness.len() == 5 && tx.output.get(idx).is_some() {
 				log_error!(logger, "Got broadcast of revoked counterparty HTLC transaction, spending {}:{}", htlc_txid, idx);
 				let revk_outp = RevokedOutput::build(
-					per_commitment_point, per_commitment_key, tx.output[idx].value, false,
-					funding_spent.channel_parameters.clone(),
-					height,
+					per_commitment_point, per_commitment_key, tx.output[idx].value,
+					self.funding.channel_parameters.clone(), height,
 				);
 				let justice_package = PackageTemplate::build_package(
 					htlc_txid, idx as u32, PackageSolvingData::RevokedOutput(revk_outp),

lightning/src/chain/package.rs

@@ -144,7 +144,6 @@ pub(crate) struct RevokedOutput {
 	weight: u64,
 	amount: Amount,
 	on_counterparty_tx_csv: u16,
-	is_counterparty_balance_on_anchors: Option<()>,
 	channel_parameters: Option<ChannelTransactionParameters>,
 	// Added in LDK 0.1.4/0.2 and always set since.
 	outpoint_confirmation_height: Option<u32>,
@@ -154,7 +153,7 @@ impl RevokedOutput {
 	#[rustfmt::skip]
 	pub(crate) fn build(
 		per_commitment_point: PublicKey, per_commitment_key: SecretKey, amount: Amount,
-		is_counterparty_balance_on_anchors: bool, channel_parameters: ChannelTransactionParameters,
+		channel_parameters: ChannelTransactionParameters,
 		outpoint_confirmation_height: u32,
 	) -> Self {
 		let directed_params = channel_parameters.as_counterparty_broadcastable();
@@ -170,7 +169,6 @@ impl RevokedOutput {
 			weight: WEIGHT_REVOKED_OUTPUT,
 			amount,
 			on_counterparty_tx_csv,
-			is_counterparty_balance_on_anchors: if is_counterparty_balance_on_anchors { Some(()) } else { None },
 			channel_parameters: Some(channel_parameters),
 			outpoint_confirmation_height: Some(outpoint_confirmation_height),
 		}
@@ -186,7 +184,9 @@ impl_writeable_tlv_based!(RevokedOutput, {
 	(8, weight, required),
 	(10, amount, required),
 	(12, on_counterparty_tx_csv, required),
-	(14, is_counterparty_balance_on_anchors, option),
+	// Unused since 0.1, this setting causes downgrades to before 0.1 to refuse to
+	// aggregate `RevokedOutput` claims, which is the more conservative stance.
+	(14, is_counterparty_balance_on_anchors, (legacy, (), |_| Some(()))),
 	(15, channel_parameters, (option: ReadableArgs, None)), // Added in 0.2.
 });
 
@@ -1821,16 +1821,13 @@ mod tests {
 
 	#[rustfmt::skip]
 	macro_rules! dumb_revk_output {
-		($is_counterparty_balance_on_anchors: expr) => {
+		() => {
 			{
 				let secp_ctx = Secp256k1::new();
 				let dumb_scalar = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
 				let dumb_point = PublicKey::from_secret_key(&secp_ctx, &dumb_scalar);
 				let channel_parameters = ChannelTransactionParameters::test_dummy(0);
-				PackageSolvingData::RevokedOutput(RevokedOutput::build(
-					dumb_point, dumb_scalar, Amount::ZERO, $is_counterparty_balance_on_anchors,
-					channel_parameters, 0,
-				))
+				PackageSolvingData::RevokedOutput(RevokedOutput::build(dumb_point, dumb_scalar, Amount::ZERO, channel_parameters, 0))
 			}
 		}
 	}
@@ -2132,9 +2129,9 @@ mod tests {
 	#[test]
 	#[rustfmt::skip]
 	fn test_package_split_malleable() {
-		let revk_outp_one = dumb_revk_output!(false);
-		let revk_outp_two = dumb_revk_output!(false);
-		let revk_outp_three = dumb_revk_output!(false);
+		let revk_outp_one = dumb_revk_output!();
+		let revk_outp_two = dumb_revk_output!();
+		let revk_outp_three = dumb_revk_output!();
 
 		let mut package_one = PackageTemplate::build_package(fake_txid(1), 0, revk_outp_one, 1100);
 		let package_two = PackageTemplate::build_package(fake_txid(1), 1, revk_outp_two, 1100);
@@ -2166,7 +2163,7 @@ mod tests {
 
 	#[test]
 	fn test_package_timer() {
-		let revk_outp = dumb_revk_output!(false);
+		let revk_outp = dumb_revk_output!();
 
 		let mut package = PackageTemplate::build_package(fake_txid(1), 0, revk_outp, 1000);
 		assert_eq!(package.timer(), 0);
@@ -2190,7 +2187,7 @@ mod tests {
 		let weight_sans_output = (4 + 4 + 1 + 36 + 4 + 1 + 1 + 8 + 1) * WITNESS_SCALE_FACTOR as u64 + 2;
 
 		{
-			let revk_outp = dumb_revk_output!(false);
+			let revk_outp = dumb_revk_output!();
 			let package = PackageTemplate::build_package(fake_txid(1), 0, revk_outp, 0);
 			assert_eq!(package.package_weight(&ScriptBuf::new()),  weight_sans_output + WEIGHT_REVOKED_OUTPUT);
 		}