Improve error output from OrchardWallet::get_spend_info

src/rust/src/wallet.rs

@@ -42,14 +42,14 @@ pub struct LastObserved {
 }
 
 /// A pointer to a particular action in an Orchard transaction output.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub struct OutPoint {
     txid: TxId,
     action_idx: usize,
 }
 
 /// A pointer to a previous output being spent in an Orchard action.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub struct InPoint {
     txid: TxId,
     action_idx: usize,
@@ -195,6 +195,14 @@ pub enum BundleLoadError {
     InvalidActionIndex(usize),
 }
 
+#[derive(Debug, Clone)]
+pub enum SpendRetrievalError {
+    DecryptedNoteNotFound(OutPoint),
+    NoIvkForRecipient(Address),
+    FvkNotFound(IncomingViewingKey),
+    NoteNotPositioned(OutPoint),
+}
+
 /// A struct used to return metadata about how a bundle was determined
 /// to be involved with the wallet.
 #[derive(Debug, Clone)]
@@ -652,42 +660,55 @@ impl Wallet {
     ///
     /// Returns `None` if the `OutPoint` is not known to the wallet, or the Orchard bundle
     /// containing the note has not been passed to `Wallet::append_bundle_commitments`.
-    pub fn get_spend_info(&self, outpoint: OutPoint) -> Option<OrchardSpendInfo> {
+    pub fn get_spend_info(
+        &self,
+        outpoint: OutPoint,
+    ) -> Result<OrchardSpendInfo, SpendRetrievalError> {
         // TODO: Take `confirmations` parameter and obtain the Merkle path to the root at
         // that checkpoint, not the latest root.
-        self.wallet_received_notes
+        let dnote = self
+            .wallet_received_notes
             .get(&outpoint.txid)
             .and_then(|tx_notes| tx_notes.decrypted_notes.get(&outpoint.action_idx))
-            .and_then(|dnote| {
+            .ok_or(SpendRetrievalError::DecryptedNoteNotFound(outpoint))?;
-                self.key_store
+
+        let fvk = self
+            .key_store
             .ivk_for_address(&dnote.note.recipient())
-                    .and_then(|ivk| self.key_store.viewing_keys.get(ivk))
+            .ok_or_else(|| SpendRetrievalError::NoIvkForRecipient(dnote.note.recipient()))
-                    .zip(
+            .and_then(|ivk| {
-                        self.wallet_note_positions
+                self.key_store
+                    .viewing_keys
+                    .get(ivk)
+                    .ok_or_else(|| SpendRetrievalError::FvkNotFound(ivk.clone()))
+            })?;
+
+        let position = self
+            .wallet_note_positions
             .get(&outpoint.txid)
-                            .and_then(|tx_notes| tx_notes.note_positions.get(&outpoint.action_idx)),
+            .and_then(|tx_notes| tx_notes.note_positions.get(&outpoint.action_idx))
-                    )
+            .ok_or(SpendRetrievalError::NoteNotPositioned(outpoint))?;
-                    .map(|(fvk, position)| {
+
         assert_eq!(
             self.witness_tree
                 .get_witnessed_leaf(*position)
                 .expect("tree has witnessed the leaf for this note."),
             &MerkleHashOrchard::from_cmx(&dnote.note.commitment().into()),
         );
+
         let path = self
             .witness_tree
             .authentication_path(*position)
             .expect("wallet always has paths to positioned notes");
-                        OrchardSpendInfo::from_parts(
+
+        Ok(OrchardSpendInfo::from_parts(
             fvk.clone(),
             dnote.note,
             MerklePath::from_parts(
                 u64::from(*position).try_into().unwrap(),
                 path.try_into().unwrap(),
             ),
-                        )
+        ))
-                    })
-            })
     }
 }
 
@@ -1158,16 +1179,17 @@ pub extern "C" fn orchard_wallet_get_spend_info(
 
     let outpoint = OutPoint { txid, action_idx };
 
-    if let Some(ret) = wallet.get_spend_info(outpoint) {
+    match wallet.get_spend_info(outpoint) {
-        Box::into_raw(Box::new(ret))
+        Ok(ret) => Box::into_raw(Box::new(ret)),
-    } else {
+        Err(e) => {
             tracing::error!(
-            "Requested note in action {} of transaction {} wasn't in the wallet",
+                "Error obtaining spend info for outpoint {:?}: {:?}",
-            outpoint.action_idx,
+                outpoint,
-            outpoint.txid
+                e
             );
             ptr::null_mut()
         }
+    }
 }
 
 #[no_mangle]