feat: Return feerate from transaction builder

examples/electrum.rs

@@ -88,7 +88,7 @@ fn main() -> Result<(), anyhow::Error> {
     tx_builder.add_recipient(address.script_pubkey(), SEND_AMOUNT);
     tx_builder.fee_rate(target_fee_rate);
 
-    let mut psbt = tx_builder.finish()?;
+    let mut psbt = tx_builder.finish()?.psbt;
     let finalized = wallet.sign(&mut psbt, SignOptions::default())?;
     assert!(finalized);
     let original_fee = psbt.fee_amount().unwrap();
@@ -123,7 +123,7 @@ fn main() -> Result<(), anyhow::Error> {
     let feerate = FeeRate::from_sat_per_vb(tx_feerate.to_sat_per_vb_ceil() + 1).unwrap();
     let mut builder = wallet.build_fee_bump(txid).expect("failed to bump tx");
     builder.fee_rate(feerate);
-    let mut bumped_psbt = builder.finish().unwrap();
+    let mut bumped_psbt = builder.finish().unwrap().psbt;
     let finalize_btx = wallet.sign(&mut bumped_psbt, SignOptions::default())?;
     assert!(finalize_btx);
     let new_fee = bumped_psbt.fee_amount().unwrap();

examples/esplora_async.rs

@@ -82,7 +82,7 @@ async fn main() -> Result<(), anyhow::Error> {
     tx_builder.add_recipient(address.script_pubkey(), SEND_AMOUNT);
     tx_builder.fee_rate(target_fee_rate);
 
-    let mut psbt = tx_builder.finish()?;
+    let mut psbt = tx_builder.finish()?.psbt;
     let finalized = wallet.sign(&mut psbt, SignOptions::default())?;
     assert!(finalized);
     let original_fee = psbt.fee_amount().unwrap();
@@ -116,7 +116,7 @@ async fn main() -> Result<(), anyhow::Error> {
     let feerate = FeeRate::from_sat_per_vb(tx_feerate.to_sat_per_vb_ceil() + 1).unwrap();
     let mut builder = wallet.build_fee_bump(txid).expect("failed to bump tx");
     builder.fee_rate(feerate);
-    let mut bumped_psbt = builder.finish().unwrap();
+    let mut bumped_psbt = builder.finish().unwrap().psbt;
     let finalize_btx = wallet.sign(&mut bumped_psbt, SignOptions::default())?;
     assert!(finalize_btx);
     let new_fee = bumped_psbt.fee_amount().unwrap();

examples/esplora_blocking.rs

@@ -77,7 +77,7 @@ fn main() -> Result<(), anyhow::Error> {
     tx_builder.add_recipient(address.script_pubkey(), SEND_AMOUNT);
     tx_builder.fee_rate(target_fee_rate);
 
-    let mut psbt = tx_builder.finish()?;
+    let mut psbt = tx_builder.finish()?.psbt;
     let finalized = wallet.sign(&mut psbt, SignOptions::default())?;
     assert!(finalized);
     let original_fee = psbt.fee_amount().unwrap();
@@ -112,7 +112,7 @@ fn main() -> Result<(), anyhow::Error> {
     let feerate = FeeRate::from_sat_per_vb(tx_feerate.to_sat_per_vb_ceil() + 1).unwrap();
     let mut builder = wallet.build_fee_bump(txid).unwrap();
     builder.fee_rate(feerate);
-    let mut new_psbt = builder.finish().unwrap();
+    let mut new_psbt = builder.finish().unwrap().psbt;
     let finalize_tx = wallet.sign(&mut new_psbt, SignOptions::default())?;
     assert!(finalize_tx);
     let new_fee = new_psbt.fee_amount().unwrap();

src/wallet/mod.rs

@@ -1363,7 +1363,7 @@ impl Wallet {
         coin_selection: Cs,
         params: TxParams,
         rng: &mut impl RngCore,
-    ) -> Result<Psbt, CreateTxError> {
+    ) -> Result<tx_builder::BuilderResult, CreateTxError> {
         let keychains: BTreeMap<_, _> = self.indexed_graph.index.keychains().collect();
         let external_descriptor = keychains.get(&KeychainKind::External).expect("must exist");
         let internal_descriptor = keychains.get(&KeychainKind::Internal);
@@ -1679,7 +1679,7 @@ impl Wallet {
             }
         }
 
-        Ok(psbt)
+        Ok(tx_builder::BuilderResult { psbt, fee_rate })
     }
 
     /// Bump the fee of a transaction previously created with this wallet.
@@ -1707,8 +1707,8 @@ impl Wallet {
     ///         .add_recipient(to_address.script_pubkey(), Amount::from_sat(50_000));
     ///     builder.finish()?
     /// };
-    /// let _ = wallet.sign(&mut psbt, SignOptions::default())?;
-    /// let tx = psbt.clone().extract_tx().expect("tx");
+    /// let _ = wallet.sign(&mut psbt.psbt, SignOptions::default())?;
+    /// let tx = psbt.psbt.clone().extract_tx().expect("tx");
     /// // broadcast tx but it's taking too long to confirm so we want to bump the fee
     /// let mut psbt =  {
     ///     let mut builder = wallet.build_fee_bump(tx.compute_txid())?;
@@ -1717,8 +1717,8 @@ impl Wallet {
     ///     builder.finish()?
     /// };
     ///
-    /// let _ = wallet.sign(&mut psbt, SignOptions::default())?;
-    /// let fee_bumped_tx = psbt.extract_tx();
+    /// let _ = wallet.sign(&mut psbt.psbt, SignOptions::default())?;
+    /// let fee_bumped_tx = psbt.psbt.extract_tx();
     /// // broadcast fee_bumped_tx to replace original
     /// # Ok::<(), anyhow::Error>(())
     /// ```
@@ -1883,7 +1883,7 @@ impl Wallet {
     ///     builder.add_recipient(to_address.script_pubkey(), Amount::from_sat(50_000));
     ///     builder.finish()?
     /// };
-    /// let finalized = wallet.sign(&mut psbt, SignOptions::default())?;
+    /// let finalized = wallet.sign(&mut psbt.psbt, SignOptions::default())?;
     /// assert!(finalized, "we should have signed all the inputs");
     /// # Ok::<(),anyhow::Error>(())
     pub fn sign(&self, psbt: &mut Psbt, sign_options: SignOptions) -> Result<bool, SignerError> {

src/wallet/tx_builder.rs

@@ -95,7 +95,7 @@ use crate::{KeychainKind, LocalOutput, Utxo, WeightedUtxo};
 ///     builder.finish()?
 /// };
 ///
-/// assert_eq!(psbt1.unsigned_tx.output[..2], psbt2.unsigned_tx.output[..2]);
+/// assert_eq!(psbt1.psbt.unsigned_tx.output[..2], psbt2.psbt.unsigned_tx.output[..2]);
 /// # Ok::<(), anyhow::Error>(())
 /// ```
 ///
@@ -759,7 +759,7 @@ impl<Cs: CoinSelectionAlgorithm> TxBuilder<'_, Cs> {
     /// **WARNING**: To avoid change address reuse you must persist the changes resulting from one
     /// or more calls to this method before closing the wallet. See [`Wallet::reveal_next_address`].
     #[cfg(feature = "std")]
-    pub fn finish(self) -> Result<Psbt, CreateTxError> {
+    pub fn finish(self) -> Result<BuilderResult, CreateTxError> {
         self.finish_with_aux_rand(&mut bitcoin::key::rand::thread_rng())
     }
 
@@ -773,11 +773,25 @@ impl<Cs: CoinSelectionAlgorithm> TxBuilder<'_, Cs> {
     ///
     /// **WARNING**: To avoid change address reuse you must persist the changes resulting from one
     /// or more calls to this method before closing the wallet. See [`Wallet::reveal_next_address`].
-    pub fn finish_with_aux_rand(self, rng: &mut impl RngCore) -> Result<Psbt, CreateTxError> {
+    pub fn finish_with_aux_rand(
+        self,
+        rng: &mut impl RngCore,
+    ) -> Result<BuilderResult, CreateTxError> {
         self.wallet.create_tx(self.coin_selection, self.params, rng)
     }
 }
 
+/// Result of building a transaction.
+///
+/// Contains the unsigned PSBT and the feerate that was used during construction.
+#[derive(Debug, Clone)]
+pub struct BuilderResult {
+    /// The constructed PSBT (unsigned transaction)
+    pub psbt: Psbt,
+    /// The feerate used for this transaction (sat/vB)
+    pub fee_rate: FeeRate,
+}
+
 #[derive(Debug)]
 /// Error returned from [`TxBuilder::add_utxo`] and [`TxBuilder::add_utxos`]
 pub enum AddUtxoError {
@@ -1224,7 +1238,12 @@ mod test {
                 .drain_wallet()
                 .drain_to(recipient.script_pubkey());
             let tx = builder.finish().unwrap();
-            let output = tx.unsigned_tx.output.first().expect("must have one output");
+            let output = tx
+                .psbt
+                .unsigned_tx
+                .output
+                .first()
+                .expect("must have one output");
             assert_eq!(output.value, Amount::ONE_BTC * 6);
         }
 
@@ -1237,7 +1256,12 @@ mod test {
                 .drain_wallet()
                 .drain_to(recipient.script_pubkey());
             let tx = builder.finish().unwrap();
-            let output = tx.unsigned_tx.output.first().expect("must have one output");
+            let output = tx
+                .psbt
+                .unsigned_tx
+                .output
+                .first()
+                .expect("must have one output");
             assert_eq!(output.value, Amount::ONE_BTC * 3);
         }
 
@@ -1250,7 +1274,12 @@ mod test {
                 .drain_wallet()
                 .drain_to(recipient.script_pubkey());
             let tx = builder.finish().unwrap();
-            let output = tx.unsigned_tx.output.first().expect("must have one output");
+            let output = tx
+                .psbt
+                .unsigned_tx
+                .output
+                .first()
+                .expect("must have one output");
             assert_eq!(output.value, Amount::ONE_BTC);
         }
     }
@@ -1286,7 +1315,7 @@ mod test {
         builder.fee_absolute(Amount::from_sat(1_000));
         let psbt = builder.finish().unwrap();
 
-        let tx = psbt.extract_tx().unwrap();
+        let tx = psbt.psbt.extract_tx().unwrap();
         let txid = tx.compute_txid();
         let feerate = wallet.calculate_fee_rate(&tx).unwrap().to_sat_per_kwu();
         insert_tx(&mut wallet, tx);

tests/add_foreign_utxo.rs

@@ -35,7 +35,7 @@ fn test_add_foreign_utxo() {
         .only_witness_utxo()
         .add_foreign_utxo(utxo.outpoint, psbt_input, foreign_utxo_satisfaction)
         .unwrap();
-    let mut psbt = builder.finish().unwrap();
+    let mut psbt = builder.finish().unwrap().psbt;
     wallet1.insert_txout(utxo.outpoint, utxo.txout);
     let fee = check_fee!(wallet1, psbt);
     let (sent, received) =
@@ -109,7 +109,7 @@ fn test_calculate_fee_with_missing_foreign_utxo() {
         .only_witness_utxo()
         .add_foreign_utxo(utxo.outpoint, psbt_input, foreign_utxo_satisfaction)
         .unwrap();
-    let psbt = builder.finish().unwrap();
+    let psbt = builder.finish().unwrap().psbt;
     let tx = psbt.extract_tx().expect("failed to extract tx");
     let res = wallet1.calculate_fee(&tx);
     assert!(
@@ -270,7 +270,7 @@ fn test_taproot_foreign_utxo() {
         .add_recipient(addr.script_pubkey(), Amount::from_sat(60_000))
         .add_foreign_utxo(utxo.outpoint, psbt_input, foreign_utxo_satisfaction)
         .unwrap();
-    let psbt = builder.finish().unwrap();
+    let psbt = builder.finish().unwrap().psbt;
     let (sent, received) =
         wallet1.sent_and_received(&psbt.clone().extract_tx().expect("failed to extract tx"));
     wallet1.insert_txout(utxo.outpoint, utxo.txout);