Add PsbtInputExt::update_with_descriptor

This populates all relevant fields in a PSBT input according to a
descriptor. Includes previously not yet implemented logic for populating
bip32_derivation and tap_key_origins. Also optionally checks the
witness_utxo and non_witness_utxo.

I renamed "PsbtExt::update_desc" to
"PsbtExt::update_inp_with_descriptor" which calls update_with_descriptor
internally but retrieves the vout for the input for the non_witness_utxo
check automatically. I removed the derivation range functionality
because it didn't feel useful (and if it is then it probably belongs in
a separate function).

Author: LLFourn

integration_test/src/test_desc.rs

@@ -112,7 +112,7 @@ pub fn test_desc_satisfy(cl: &Client, testdata: &TestData, desc: &str) -> Witnes
     input.witness_utxo = Some(witness_utxo.clone());
     psbt.inputs.push(input);
     psbt.outputs.push(psbt::Output::default());
-    psbt.update_desc(0, &desc, None).unwrap();
+    psbt.update_inp_with_descriptor(0, &desc).unwrap();
 
     // --------------------------------------------
     // Sign the transactions with all keys

src/psbt/mod.rs

@@ -516,14 +516,19 @@ pub trait PsbtExt {
         secp: &Secp256k1<C>,
     ) -> Result<bitcoin::Transaction, Error>;
 
-    /// Update a PSBT with the derived descriptor.
+    /// Update a PSBT with a descriptor.
     ///
-    /// Internally, uses [`PsbtInputExt::update_with_descriptor`] and checks that the `witness_utxo`
+    /// Internally, calls [`update_with_descriptor`] on the input and checks that the `witness_utxo`
     /// and `non_witness_utxo` have the correct `script_pubkey` if applicable.
+    ///
+    /// The `descriptor` **must not have any wildcards** in it otherwise an error will be returned
+    /// however it can (and should) have extended keys in it.
+    ///
+    /// [`update_with_descriptor`]: PsbtInputExt::update_with_descriptor
     fn update_inp_with_descriptor(
         &mut self,
         input_index: usize,
-        desc: &Descriptor<DescriptorPublicKey>,
+        descriptor: &Descriptor<DescriptorPublicKey>,
     ) -> Result<(), UtxoUpdateError>;
 
     /// Get the sighash message(data to sign) at input index `idx` based on the sighash
@@ -806,7 +811,8 @@ pub trait PsbtInputExt {
     /// spend it.
     ///
     /// If the descriptor contains wilcards or otherwise cannot be transformed into a concrete
-    /// descriptor an error will returned.
+    /// descriptor an error will returned. The descriptor *can* (and should) have extended keys in
+    /// it so PSBT fields like `bip32_derivation` and `tap_key_origins` can be populated.
     ///
     /// You can make sure the descriptor is consistent with the `witness_utxo` and/or
     /// `non_witness_utxo` fields of the PSBT by setting `check_witness_utxo` and