Improve readability of special handling for electrum error

The default path through the function would be to propagate every
error. However, we want to inspect whether it is one very specific
error.

Make this clear in the code structure by having a dedicated `if let`
for the special case but keep using `?` afterwards.

daemon/src/wallet.rs

@@ -1,11 +1,11 @@
 use crate::model::WalletInfo;
-use anyhow::{anyhow, Context, Result};
+use anyhow::{Context, Result};
 use bdk::bitcoin::util::bip32::ExtendedPrivKey;
 use bdk::bitcoin::util::psbt::PartiallySignedTransaction;
 use bdk::bitcoin::{Amount, PublicKey, Transaction, Txid};
 use bdk::blockchain::{ElectrumBlockchain, NoopProgress};
 use bdk::wallet::AddressIndex;
-use bdk::{electrum_client, Error, KeychainKind, SignOptions};
+use bdk::{electrum_client, KeychainKind, SignOptions};
 use cfd_protocol::{PartyParams, WalletExt};
 use rocket::serde::json::Value;
 use std::path::Path;
@@ -98,29 +98,24 @@ impl Wallet {
         let wallet = self.wallet.lock().await;
         // TODO: Optimize this match to be a map_err / more readable in general
         let txid = tx.txid();
-        match wallet.broadcast(tx) {
+
-            Ok(txid) => Ok(txid),
+        let result = wallet.broadcast(tx);
-            Err(e) => {
+
-                if let Error::Electrum(electrum_client::Error::Protocol(ref value)) = e {
+        if let Err(&bdk::Error::Electrum(electrum_client::Error::Protocol(ref value))) =
-                    let error_code = match parse_rpc_protocol_error_code(value) {
+            result.as_ref()
-                        Ok(error_code) => error_code,
+        {
-                        Err(inner) => {
+            let error_code = parse_rpc_protocol_error_code(value).with_context(|| {
-                            tracing::error!(
+                format!("Failed to parse electrum error response '{:?}'", value)
-                                "Failed to parse error code from RPC message: {}",
+            })?;
-                                inner
-                            );
-                            return Err(anyhow!(e));
-                        }
-                    };
 
             if error_code == i64::from(RpcErrorCode::RpcVerifyAlreadyInChain) {
                 return Ok(txid);
             }
         }
 
-                Err(anyhow!(e))
+        let txid = result?;
-            }
+
-        }
+        Ok(txid)
     }
 }