Merge pull request #2749 from TheBlueMatt/2023-11-2744-followups

Add `channel_keys_id` to `SpendableOutputDescriptor::StaticOutput`

Author: wpaulino

lightning/src/chain/channelmonitor.rs

@@ -4082,6 +4082,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 				spendable_outputs.push(SpendableOutputDescriptor::StaticOutput {
 					outpoint: OutPoint { txid: tx.txid(), index: i as u16 },
 					output: outp.clone(),
+					channel_keys_id: Some(self.channel_keys_id),
 				});
 			}
 			if let Some(ref broadcasted_holder_revokable_script) = self.broadcasted_holder_revokable_script {
@@ -4110,6 +4111,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 				spendable_outputs.push(SpendableOutputDescriptor::StaticOutput {
 					outpoint: OutPoint { txid: tx.txid(), index: i as u16 },
 					output: outp.clone(),
+					channel_keys_id: Some(self.channel_keys_id),
 				});
 			}
 		}

lightning/src/sign/mod.rs

@@ -202,6 +202,15 @@ pub enum SpendableOutputDescriptor {
 		outpoint: OutPoint,
 		/// The output which is referenced by the given outpoint.
 		output: TxOut,
+		/// The `channel_keys_id` for the channel which this output came from.
+		///
+		/// For channels which were generated on LDK 0.0.119 or later, this is the value which was
+		/// passed to the [`SignerProvider::get_destination_script`] call which provided this
+		/// output script.
+		///
+		/// For channels which were generated prior to LDK 0.0.119, no such argument existed,
+		/// however this field may still be filled in if such data is available.
+		channel_keys_id: Option<[u8; 32]>
 	},
 	/// An output to a P2WSH script which can be spent with a single signature after an `OP_CSV`
 	/// delay.
@@ -265,6 +274,7 @@ pub enum SpendableOutputDescriptor {
 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
 	(0, StaticOutput) => {
 		(0, outpoint, required),
+		(1, channel_keys_id, option),
 		(2, output, required),
 	},
 ;
@@ -365,7 +375,7 @@ impl SpendableOutputDescriptor {
 					{ witness_weight -= 1; } // Guarantees a low R signature
 					input_value += descriptor.output.value;
 				},
-				SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
+				SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
 					if !output_set.insert(*outpoint) { return Err(()); }
 					input.push(TxIn {
 						previous_output: outpoint.into_bitcoin_outpoint(),
@@ -1640,7 +1650,7 @@ impl KeysManager {
 					let witness = keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?;
 					psbt.inputs[input_idx].final_script_witness = Some(witness);
 				},
-				SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
+				SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
 					let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == outpoint.into_bitcoin_outpoint()).ok_or(())?;
 					let derivation_idx = if output.script_pubkey == self.destination_script {
 						1