QIODevice.read and QIODevice.readLine return values of different types in PyQt5/6 and PySide6

[StSav012]

The following code demonstrates the difference. It uses QBuffer, as QIODevice is an abstract class and cannot be instantiated.

from qtpy.QtCore import QBuffer

# `data` should be a variable. It has 
buffer: QBuffer = QBuffer()
buffer.open(QBuffer.OpenModeFlag.ReadWrite)
buffer.write(b"abc")
buffer.seek(0)

# `QByteArray(b'abc')` in PySide6, `b'abc'` in PyQt5/6
print(f'1. {buffer.read(3) = !r}')

# `QByteArray(b'')` in PySide6, `b''` in PyQt5/6
print(f'2. {buffer.read(3) = !r}')

buffer.close()

# `QByteArray(b'')` in PySide6, `None` in PyQt5/6. And a warning to `stderr`.
print(f'3. {buffer.read(3) = !r}')

I could write a wrapper. I'm unsure which way to make it:

• Make PyQt5/6 behave like PySide6:

if PYQT5 or PYQT6:

    def _read_wrapper(
        self: QIODevice,
        maxLength: int,
        *,
        _old_read: Callable[[QIODevice, int], bytes | None],
    ) -> QByteArray:
        return QByteArray(_old_read(self, maxLength) or b"")

    QIODevice.read = partialmethod(_read_wrapper, _old_read=QIODevice.read)
    QIODevice.readLine = partialmethod(_read_wrapper, _old_read=QIODevice.readLine)

• Or the other way around:

if PYSIDE2 or PYSIDE6:

    def _read_wrapper(
        self: QIODevice,
        maxLength: int,
        *,
        _old_read: Callable[[QIODevice, int], QByteArray],
    ) -> bytes | None:
        if self.isOpen():
            return _old_read(self, maxLength).data()

    QIODevice.read = partialmethod(_read_wrapper, _old_read=QIODevice.read)
    QIODevice.readLine = partialmethod(_read_wrapper, _old_read=QIODevice.readLine)

I haven't checked PySide2, having too modern Python at hand.