From f464aa97c3c534666991c6cb3496058bc0d0de4e Mon Sep 17 00:00:00 2001
From: Wilmer Paulino <wilmer@wilmerpaulino.com>
Date: Thu, 28 Sep 2023 12:31:43 -0700
Subject: [PATCH] Expose witness_script for StaticPaymentOutputDescriptor

---
 lightning/src/sign/mod.rs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/lightning/src/sign/mod.rs b/lightning/src/sign/mod.rs
index 9a3025304..39f1001c4 100644
--- a/lightning/src/sign/mod.rs
+++ b/lightning/src/sign/mod.rs
@@ -134,6 +134,22 @@ pub struct StaticPaymentOutputDescriptor {
 	pub channel_transaction_parameters: Option<ChannelTransactionParameters>,
 }
 impl StaticPaymentOutputDescriptor {
+	/// Returns the `witness_script` of the spendable output.
+	///
+	/// Note that this will only return `Some` for [`StaticPaymentOutputDescriptor`]s that
+	/// originated from an anchor outputs channel, as they take the form of a P2WSH script.
+	pub fn witness_script(&self) -> Option<Script> {
+		self.channel_transaction_parameters.as_ref()
+			.and_then(|channel_params|
+				 if channel_params.channel_type_features.supports_anchors_zero_fee_htlc_tx() {
+					let payment_point = channel_params.holder_pubkeys.payment_point;
+					Some(chan_utils::get_to_countersignatory_with_anchors_redeemscript(&payment_point))
+				 } else {
+					 None
+				 }
+			)
+	}
+
 	/// The maximum length a well-formed witness spending one of these should have.
 	/// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
 	/// shorter.
-- 
2.39.5