qt: better handle unparseable URIs

fixes https://github.com/spesmilo/electrum/issues/7941

electrum/gui/qt/__init__.py

@@ -382,12 +382,11 @@ class ElectrumGui(BaseElectrumGui, Logger):
                     path = os.path.join(wallet_dir, filename)
                 self.start_new_window(path, uri=None, force_wizard=True)
             return
-        if uri:
-            window.handle_payment_identifier(uri)
         window.bring_to_top()
         window.setWindowState(window.windowState() & ~QtCore.Qt.WindowMinimized | QtCore.Qt.WindowActive)
-
         window.activateWindow()
+        if uri:
+            window.handle_payment_identifier(uri)
         return window
 
     def _start_wizard_to_select_or_create_wallet(self, path) -> Optional[Abstract_Wallet]:

electrum/gui/qt/main_window.py

@@ -58,7 +58,7 @@ from electrum.i18n import _
 from electrum.util import (format_time, get_asyncio_loop,
                            UserCancelled, profiler,
                            bh2u, bfh, InvalidPassword,
-                           UserFacingException,
+                           UserFacingException, FailedToParsePaymentIdentifier,
                            get_new_wallet_name, send_exception_to_crash_reporter,
                            AddTransactionException, BITCOIN_BIP21_URI_SCHEME, os_chmod)
 from electrum.invoices import PR_PAID, Invoice
@@ -1316,7 +1316,10 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger, QtEventListener):
         return clayout.selected_index()
 
     def handle_payment_identifier(self, *args, **kwargs):
+        try:
             self.send_tab.handle_payment_identifier(*args, **kwargs)
+        except FailedToParsePaymentIdentifier as e:
+            self.show_error(str(e))
 
     def set_frozen_state_of_addresses(self, addrs, freeze: bool):
         self.wallet.set_frozen_state_of_addresses(addrs, freeze)

electrum/gui/qt/paytoedit.py

@@ -32,7 +32,7 @@ from PyQt5.QtGui import QFontMetrics, QFont
 from PyQt5.QtWidgets import QApplication
 
 from electrum import bitcoin
-from electrum.util import bfh, parse_max_spend
+from electrum.util import bfh, parse_max_spend, FailedToParsePaymentIdentifier
 from electrum.transaction import PartialTxOutput
 from electrum.bitcoin import opcodes, construct_script
 from electrum.logging import Logger
@@ -212,7 +212,7 @@ class PayToEdit(CompletionTextEdit, ScanQRTextEdit, Logger):
             except LNURLError as e:
                 self.logger.exception("")
                 self.send_tab.show_error(e)
-            except ValueError:
+            except FailedToParsePaymentIdentifier:
                 pass
             else:
                 return

electrum/gui/qt/send_tab.py

@@ -15,7 +15,7 @@ from electrum import util, paymentrequest
 from electrum import lnutil
 from electrum.plugin import run_hook
 from electrum.i18n import _
-from electrum.util import (get_asyncio_loop, bh2u,
+from electrum.util import (get_asyncio_loop, bh2u, FailedToParsePaymentIdentifier,
                            InvalidBitcoinURI, maybe_extract_lightning_payment_identifier, NotEnoughFunds,
                            NoDynamicFeeEstimates, InvoiceError, parse_max_spend)
 from electrum.invoices import PR_PAID, Invoice
@@ -477,7 +477,8 @@ class SendTab(QWidget, MessageBoxMixin, Logger):
         elif text.lower().startswith(util.BITCOIN_BIP21_URI_SCHEME + ':'):
             self.set_bip21(text, can_use_network=can_use_network)
         else:
-            raise ValueError("Could not handle payment identifier.")
+            truncated_text = f"{text[:100]}..." if len(text) > 100 else text
+            raise FailedToParsePaymentIdentifier(f"Could not handle payment identifier:\n{truncated_text}")
         # update fiat amount
         self.amount_e.textEdited.emit("")
         self.window.show_send_tab()

electrum/util.py

@@ -1111,6 +1111,10 @@ def is_uri(data: str) -> bool:
     return False
 
 
+class FailedToParsePaymentIdentifier(Exception):
+    pass
+
+
 # Python bug (http://bugs.python.org/issue1927) causes raw_input
 # to be redirected improperly between stdin/stderr on Unix systems
 #TODO: py3