fix(wallet): advance internal keychain when needed

i.e. when processing a transaction that uses the next internal address

wallet/src/actors/app/routes.rs

@@ -15,7 +15,7 @@ macro_rules! routes {
         {
             let api_addr = $api.clone();
             $io.add_method($method_jsonrpc, move |params: Params| {
-                log::debug!("Handling request for method: {}", $method_jsonrpc);
+                log::debug!("Handling request for method {}: {:?}", $method_jsonrpc, params);
                 let addr = api_addr.clone();
                 // Try to parse the request params into the actor message
                 let fut03 = future::ready(params.parse::<$actor_msg>())

wallet/src/repository/wallet/mod.rs

@@ -1342,10 +1342,15 @@ where
         let index = state.next_internal_index;
         let parent_key = &state.keychains[keychain as usize];
 
+        // `preview` is negated because it turns into `persist_db`
         let (address, next_index) =
             self.derive_and_persist_address(label, parent_key, account, keychain, index, !preview)?;
 
-        state.next_internal_index = next_index;
+        // Don't advance the internal index if we are simply previewing
+        if !preview {
+            state.next_internal_index = next_index;
+            log::debug!("Internal keychain advanced to index #{next_index}");
+        }
 
         Ok(address)
     }
@@ -1461,6 +1466,18 @@ where
         // - Cannot borrow `state` as mutable because it is also borrowed as immutable
         let state = &mut *state;
 
+        // Move internal keychain forward if we used a new change address
+        let next = self._gen_internal_address(state, None, true)?;
+        if match &txn.transaction {
+            Transaction::ValueTransfer(vtt) => {
+                vtt.body.outputs.iter().any(|vto| vto.pkh == next.pkh)
+            }
+            Transaction::DataRequest(dr) => dr.body.outputs.iter().any(|vto| vto.pkh == next.pkh),
+            _ => false,
+        } {
+            let _ = self._gen_internal_address(state, None, false);
+        }
+
         // Mark UTXOs as used so we don't double spend
         // Save the timestamp to after which the UTXO can be spent again
         let tx_pending_timeout = self.params.pending_transactions_timeout_seconds;