qt: PayToEdit: fix input_qr_from_camera

closes https://github.com/spesmilo/electrum/issues/8342

probably regression from 1f4cedf56a

electrum/gui/qt/paytoedit.py

@@ -129,6 +129,7 @@ class PayToEdit(Logger, GenericInputHandler):
             allow_multi=False,
             show_error=self.win.show_error,
             setText=self._on_input_btn,
+            parent=self.win,
         )
         self.on_qr_from_screenshot_input_btn = partial(
             self.input_qr_from_screenshot,

electrum/gui/qt/qrreader/__init__.py

@@ -49,6 +49,7 @@ def scan_qrcode(
         callback: Callable[[bool, str, Optional[str]], None],
 ) -> None:
     """Scans QR code using camera."""
+    assert parent is None or isinstance(parent, QWidget), f"parent should be a QWidget, not {parent!r}"
     if sys.platform == 'darwin' or sys.platform in ('windows', 'win32'):
         _scan_qrcode_using_qtmultimedia(parent=parent, config=config, callback=callback)
     else:  # desktop Linux and similar

electrum/gui/qt/qrreader/qtmultimedia/camera_dialog.py

@@ -27,10 +27,10 @@ import time
 import math
 import sys
 import os
-from typing import List
+from typing import List, Optional
 
 from PyQt5.QtMultimedia import QCameraInfo, QCamera, QCameraViewfinderSettings
-from PyQt5.QtWidgets import QDialog, QVBoxLayout, QHBoxLayout, QCheckBox, QPushButton, QLabel
+from PyQt5.QtWidgets import QDialog, QVBoxLayout, QHBoxLayout, QCheckBox, QPushButton, QLabel, QWidget
 from PyQt5.QtGui import QImage, QPixmap
 from PyQt5.QtCore import QSize, QRect, Qt, pyqtSignal, PYQT_VERSION
 
@@ -68,7 +68,7 @@ class QrReaderCameraDialog(Logger, MessageBoxMixin, QDialog):
 
     qr_finished = pyqtSignal(bool, str, object)
 
-    def __init__(self, parent, *, config: SimpleConfig):
+    def __init__(self, parent: Optional[QWidget], *, config: SimpleConfig):
         ''' Note: make sure parent is a "top_level_window()" as per
         MessageBoxMixin API else bad things can happen on macOS. '''
         QDialog.__init__(self, parent=parent)

electrum/gui/qt/util.py

@@ -547,6 +547,7 @@ class GenericInputHandler:
             allow_multi: bool = False,
             show_error: Callable[[str], None],
             setText: Callable[[str], None] = None,
+            parent: QWidget = None,
     ) -> None:
         if setText is None:
             setText = self.setText
@@ -564,7 +565,9 @@ class GenericInputHandler:
             setText(new_text)
 
         from .qrreader import scan_qrcode
-        scan_qrcode(parent=self, config=config, callback=cb)
+        if parent is None:
+            parent = self if isinstance(self, QWidget) else None
+        scan_qrcode(parent=parent, config=config, callback=cb)
 
     def input_qr_from_screenshot(
             self,