Tweak PSBT signing for bindings compatibility

In bindings we can't practically pass a mutable PSBT, and instead
need to pass an owned transaction and have the sign method return a
signed copy. We do this here for all build modes as its not a
material API change for Rust users.

diff --git a/lightning/src/sign/mod.rs b/lightning/src/sign/mod.rs
index c11d47e9ff9c32e119c34961017b79be1665573f..a71bdae88768c1b7f97da626af9291589205e736 100644 (file)
--- a/lightning/src/sign/mod.rs
+++ b/lightning/src/sign/mod.rs
@@ -1312,7 +1312,7 @@ impl KeysManager {
        ///
        /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
        /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
-       pub fn sign_spendable_outputs_psbt<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], psbt: &mut PartiallySignedTransaction, secp_ctx: &Secp256k1<C>) -> Result<(), ()> {
+       pub fn sign_spendable_outputs_psbt<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], mut psbt: PartiallySignedTransaction, secp_ctx: &Secp256k1<C>) -> Result<PartiallySignedTransaction, ()> {
                let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
                for outp in descriptors {
                        match outp {
@@ -1374,7 +1374,7 @@ impl KeysManager {
                        }
                }
 
-               Ok(())
+               Ok(psbt)
        }
 
        /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
@@ -1396,7 +1396,7 @@ impl KeysManager {
        /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
        pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, locktime: Option<PackedLockTime>, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
                let (mut psbt, expected_max_weight) = SpendableOutputDescriptor::create_spendable_outputs_psbt(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime)?;
-               self.sign_spendable_outputs_psbt(descriptors, &mut psbt, secp_ctx)?;
+               psbt = self.sign_spendable_outputs_psbt(descriptors, psbt, secp_ctx)?;
 
                let spend_tx = psbt.extract_tx();