self.central_widget.findChildren() has inaccurate output type

[HoseynAAmiri]

if I install the stubs the returned type seems incorrect. For instance, given the code below:

input_widgets = self.central_widget.findChildren(
    (QPushButton, QSlider, QLineEdit, QComboBox))
for widget in input_widgets:
    widget.setEnabled(activate)

pylance shows: (variable) input_widgets: List[QObject] and I see this error:
Cannot access attribute "setEnabled" for class "QObject"
Attribute "setEnabled" is unknown

while without stubs,

pylance says: (variable) input_widgets: List[QPushButton | QSlider | QLineEdit | QComboBox] and I can autocomplete setEnabled()

I had to install PyQt5-stubs because I noticed that if I inherit from QMainWindow and and use it later like this:

from dataclasses import dataclass
from PyQt5.QtWidgets import QMainWindow

class MainWindow(QMainWindow):
    attr1: int
    def __init__(self):
        super().__init__()

@dataclass
class SubWindow:
    main: MainWindow


sub = SubWindow(MainWindow())

pylance cannot see main in SubWindow properly without stubs so you cannot autocomplete attr1 for instance. I tested defining Subwindow regularly without dataclass but it didn't help. The problem will be fixed only if I remove QMainWindow. I don't know why!

But installing stubs fixes the later issue. Yet it causes the former issue of getting objects from children and not the exact queries.

I tested the same code with PyQt6 without stubs, and it worked.

[altendky]

It does indeed appear that this could be made more aware potentially. I'm not exactly sure offhand how to express this without as many typevars being defined as we want to support, but maybe there's a way. That said, I'm not betting that I personally will get this improved. But who knows, maybe someone, or I, will. Thanks for pointing it out.

PyQt5-stubs/PyQt5-stubs/QtCore.pyi

Lines 3361 to 3376 in 5047549

	@typing.overload
	def findChildren(self, type: typing.Type[QObjectT], name: str = ..., options: typing.Union[Qt.FindChildOptions, Qt.FindChildOption] = ...) -> typing.List[QObjectT]: ...
	@typing.overload
	def findChildren(self, types: typing.Tuple[typing.Type[QObject], ...], name: str = ..., options: typing.Union[Qt.FindChildOptions, Qt.FindChildOption] = ...) -> typing.List['QObject']: ...
	@typing.overload
	def findChildren(self, type: typing.Type[QObjectT], regExp: 'QRegExp', options: typing.Union[Qt.FindChildOptions, Qt.FindChildOption] = ...) -> typing.List[QObjectT]: ...
	@typing.overload
	def findChildren(self, types: typing.Tuple[typing.Type[QObject], ...], regExp: 'QRegExp', options: typing.Union[Qt.FindChildOptions, Qt.FindChildOption] = ...) -> typing.List['QObject']: ...
	@typing.overload
	def findChildren(self, type: typing.Type[QObjectT], re: 'QRegularExpression', options: typing.Union[Qt.FindChildOptions, Qt.FindChildOption] = ...) -> typing.List[QObjectT]: ...
	@typing.overload
	def findChildren(self, types: typing.Tuple[typing.Type[QObject], ...], re: 'QRegularExpression', options: typing.Union[Qt.FindChildOptions, Qt.FindChildOption] = ...) -> typing.List['QObject']: ...
	@typing.overload
	def findChild(self, type: typing.Type[QObjectT], name: str = ..., options: typing.Union[Qt.FindChildOptions, Qt.FindChildOption] = ...) -> typing.Optional[QObjectT]: ...
	@typing.overload
	def findChild(self, types: typing.Tuple[typing.Type[QObject], ...], name: str = ..., options: typing.Union[Qt.FindChildOptions, Qt.FindChildOption] = ...) -> 'typing.Optional[QObject]': ...

[HoseynAAmiri]

I moved to PyQt6. It has less type errors.