qt paytoedit: properly handle multiple max ('!') outputs

electrum/gui/qt/main_window.py

@@ -61,7 +61,7 @@ from electrum.util import (format_time, format_satoshis, format_fee_satoshis,
                            UnknownBaseUnit, DECIMAL_POINT_DEFAULT, UserFacingException,
                            get_new_wallet_name, send_exception_to_crash_reporter,
                            InvalidBitcoinURI, maybe_extract_bolt11_invoice, NotEnoughFunds,
-                           NoDynamicFeeEstimates)
+                           NoDynamicFeeEstimates, MultipleSpendMaxTxOutputs)
 from electrum.util import PR_TYPE_ONCHAIN, PR_TYPE_LN
 from electrum.transaction import (Transaction, PartialTxInput,
                                   PartialTransaction, PartialTxOutput)
@@ -1317,7 +1317,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
 
         try:
             tx = make_tx(None)
-        except (NotEnoughFunds, NoDynamicFeeEstimates) as e:
+        except (NotEnoughFunds, NoDynamicFeeEstimates, MultipleSpendMaxTxOutputs) as e:
             self.max_button.setChecked(False)
             self.show_error(str(e))
             return

electrum/util.py

@@ -155,6 +155,11 @@ class NoDynamicFeeEstimates(Exception):
         return _('Dynamic fee estimates not available')
 
 
+class MultipleSpendMaxTxOutputs(Exception):
+    def __str__(self):
+        return _('At most one output can be set to spend max')
+
+
 class InvalidPassword(Exception):
     def __str__(self):
         return _("Incorrect password")

electrum/wallet.py

@@ -48,7 +48,7 @@ from .bip32 import BIP32Node
 from .crypto import sha256
 from .util import (NotEnoughFunds, UserCancelled, profiler,
                    format_satoshis, format_fee_satoshis, NoDynamicFeeEstimates,
-                   WalletFileException, BitcoinException,
+                   WalletFileException, BitcoinException, MultipleSpendMaxTxOutputs,
                    InvalidPassword, format_time, timestamp_to_datetime, Satoshis,
                    Fiat, bfh, bh2u, TxMinedInfo, quantize_feerate, create_bip21_uri, OrderedDictWithIndex)
 from .util import PR_TYPE_ONCHAIN, PR_TYPE_LN
@@ -993,7 +993,7 @@ class Abstract_Wallet(AddressSynchronizer, ABC):
         for i, o in enumerate(outputs):
             if o.value == '!':
                 if i_max is not None:
-                    raise Exception("More than one output set to spend max")
+                    raise MultipleSpendMaxTxOutputs()
                 i_max = i
 
         if fee is None and self.config.fee_per_kb() is None: