wallet: fix payment ID decryption for construction data

src/wallet/wallet2.cpp

@@ -719,9 +719,8 @@ uint64_t calculate_fee(bool use_per_byte_fee, const cryptonote::transaction &tx,
     return calculate_fee(base_fee, blob_size, fee_multiplier);
 }
 
-crypto::hash8 get_short_payment_id(const tools::wallet2::pending_tx &ptx, hw::device &hwdev)
+bool get_short_payment_id(crypto::hash8 &payment_id8, const tools::wallet2::pending_tx &ptx, hw::device &hwdev)
 {
-  crypto::hash8 payment_id8 = null_hash8;
   std::vector<tx_extra_field> tx_extra_fields;
   parse_tx_extra(ptx.tx.extra, tx_extra_fields); // ok if partially parsed
   cryptonote::tx_extra_nonce extra_nonce;
@@ -732,19 +731,19 @@ crypto::hash8 get_short_payment_id(const tools::wallet2::pending_tx &ptx, hw::de
       if (ptx.dests.empty())
       {
         MWARNING("Encrypted payment id found, but no destinations public key, cannot decrypt");
-        return crypto::null_hash8;
+        return false;
       }
-      hwdev.decrypt_payment_id(payment_id8, ptx.dests[0].addr.m_view_public_key, ptx.tx_key);
+      return hwdev.decrypt_payment_id(payment_id8, ptx.dests[0].addr.m_view_public_key, ptx.tx_key);
     }
   }
-  return payment_id8;
+  return false;
 }
 
 tools::wallet2::tx_construction_data get_construction_data_with_decrypted_short_payment_id(const tools::wallet2::pending_tx &ptx, hw::device &hwdev)
 {
   tools::wallet2::tx_construction_data construction_data = ptx.construction_data;
-  crypto::hash8 payment_id = get_short_payment_id(ptx,hwdev);
-  if (payment_id != null_hash8)
+  crypto::hash8 payment_id = null_hash8;
+  if (get_short_payment_id(payment_id, ptx, hwdev))
   {
     // Remove encrypted
     remove_field_from_tx_extra(construction_data.extra, typeid(cryptonote::tx_extra_nonce));