refactor(wallet)!: remove signers and change_signers

- remove both fields `signers` and `change_signers` from `Wallet`.
- all usage of signers for `extract_policy` fns in `create_tx` and
  `policies` methods now rely on the `SignersContainer::default()`.

Author: oleonardolima

wallet/src/wallet/mod.rs

@@ -94,8 +94,6 @@ pub use utils::TxDetails;
 /// [`take_staged`]: Wallet::take_staged
 #[derive(Debug)]
 pub struct Wallet {
-    signers: Arc<SignersContainer>,
-    change_signers: Arc<SignersContainer>,
     chain: LocalChain,
     indexed_graph: IndexedTxGraph<ConfirmationBlockTime, KeychainTxOutIndex<KeychainKind>>,
     stage: ChangeSet,
@@ -409,17 +407,14 @@ impl Wallet {
         check_wallet_descriptor(&descriptor)?;
         descriptor_keymap.extend(params.descriptor_keymap);
 
-        let signers = Arc::new(SignersContainer::new());
-
-        let (change_descriptor, change_signers) = match params.change_descriptor {
+        let change_descriptor = match params.change_descriptor {
             Some(make_desc) => {
                 let (change_descriptor, mut internal_keymap) = make_desc(&secp, network)?;
                 check_wallet_descriptor(&change_descriptor)?;
                 internal_keymap.extend(params.change_descriptor_keymap);
-                let change_signers = Arc::new(SignersContainer::new());
-                (Some(change_descriptor), change_signers)
+                Some(change_descriptor)
             }
-            None => (None, Arc::new(SignersContainer::new())),
+            None => None,
         };
 
         let index = create_indexer(
@@ -444,8 +439,6 @@ impl Wallet {
         };
 
         Ok(Wallet {
-            signers,
-            change_signers,
             network,
             chain,
             indexed_graph,
@@ -564,7 +557,6 @@ impl Wallet {
                 }));
             }
         }
-        let signers = Arc::new(SignersContainer::new());
 
         let mut change_descriptor = None;
         let mut internal_keymap = params.change_descriptor_keymap;
@@ -617,11 +609,6 @@ impl Wallet {
             },
         }
 
-        let change_signers = match change_descriptor {
-            Some(ref change_descriptor) => Arc::new(SignersContainer::new()),
-            None => Arc::new(SignersContainer::new()),
-        };
-
         let index = create_indexer(
             descriptor,
             change_descriptor,
@@ -637,8 +624,6 @@ impl Wallet {
         let stage = ChangeSet::default();
 
         Ok(Some(Wallet {
-            signers,
-            change_signers,
             chain,
             indexed_graph,
             stage,
@@ -1235,13 +1220,22 @@ impl Wallet {
         let internal_descriptor = keychains.get(&KeychainKind::Internal);
 
         let external_policy = external_descriptor
-            .extract_policy(&self.signers, BuildSatisfaction::None, &self.secp)?
+            .extract_policy(
+                &SignersContainer::default(),
+                BuildSatisfaction::None,
+                &self.secp,
+            )?
             .unwrap();
+
         let internal_policy = internal_descriptor
             .map(|desc| {
                 Ok::<_, CreateTxError>(
-                    desc.extract_policy(&self.change_signers, BuildSatisfaction::None, &self.secp)?
-                        .unwrap(),
+                    desc.extract_policy(
+                        &SignersContainer::default(),
+                        BuildSatisfaction::None,
+                        &self.secp,
+                    )?
+                    .unwrap(),
                 )
             })
             .transpose()?;
@@ -1747,13 +1741,8 @@ impl Wallet {
 
     /// Return the spending policies for the wallet's descriptor
     pub fn policies(&self, keychain: KeychainKind) -> Result<Option<Policy>, DescriptorError> {
-        let signers = match keychain {
-            KeychainKind::External => &self.signers,
-            KeychainKind::Internal => &self.change_signers,
-        };
-
         self.public_descriptor(keychain).extract_policy(
-            signers,
+            &SignersContainer::default(),
             BuildSatisfaction::None,
             &self.secp,
         )