PySide6: Why QSpacerItem uses kwargs [hv]Data instead of [hv]Policy?

anonyumu

Could this be some sort of a bug? Or is it just undocumented/hard to find change?

Got an error saying AttributeError: PySide6.QtWidgets.QSpacerItem.__init__(): unsupported keyword 'hPolicy', so checked Qt6 doc for changes, but everything seemed fine. After checking PySide6 doc it turned out that keyword args [hv]Policy were specified as [hv]Data in call signature, yet doc body still mentioned [hv]Policy...

Update.

Damn... The same happened with PySide6.QtGui.PySide6.QtGui.QPixmap.scaled: aspectRatioMode is aspectMode and transformMode is mode...

eyllanesc

@anonyumu please provide a minimun and reproducible example

anonyumu

Sorry it took so long...

pip install PySide6==6.0.1

PySide6.QtWidgets.QSpacerItem:

from PySide6.QtWidgets import QSpacerItem, QSizePolicy

QSpacerItem(0, 0, hPolicy = QSizePolicy.Expanding)
QSpacerItem(0, 0, vPolicy = QSizePolicy.Fixed)

PySide6.QtGui.QPixmap.scaled:

from PySide6.QtCore import Qt, QSize
from PySide6.QtGui import QPixmap
from PySide6.QtWidgets import QApplication

app = QApplication()

QPixmap().scaled(QSize(640, 480), aspectRatioMode=Qt.IgnoreAspectRatio)
QPixmap().scaled(QSize(640, 480), transformMode=Qt.FastTransformation)

app.exec_()

In both cases AttributeError: PySide6.{module}.{class}.{method}(): unsupported keyword '{kwarg}' is raised.

eyllanesc

@anonyumu It seems that it is a PySide6 bug that has changed the name of the kwargs, for example using help you get the names of the kwargs:

dir(QSpacerItem)

output

Help on class QSpacerItem in module PySide6.QtWidgets:

class QSpacerItem(QLayoutItem)
 |  QSpacerItem(self, w: int, h: int, hData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum, vData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum) -> None
 |  
 |  QSpacerItem(self, w: int, h: int, hData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum, vData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum) -> None
 |  
 |  Method resolution order:
 |      QSpacerItem
 |      QLayoutItem
 |      Shiboken.Object
 |      builtins.object
 |  
 |  Methods defined here:
 |  
 |  __delattr__(self, name, /)
 |      Implement delattr(self, name).
 |  
 |  __init__(self, w: int, h: int, hData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum, vData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum) -> None
 |      __init__(self, w: int, h: int, hData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum, vData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum) -> None
 |      
 |      Initialize self.  See help(type(self)) for accurate signature.
 |  
 |  __setattr__(self, name, value, /)
 |      Implement setattr(self, name, value).
 |  
 |  changeSize(self, w: int, h: int, hData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum, vData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum) -> None
 |      changeSize(self, w: int, h: int, hData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum, vData: PySide6.QtWidgets.QSizePolicy.Policy = PySide6.QtWidgets.QSizePolicy.Policy.Minimum) -> None
 |  
 |  expandingDirections(self) -> PySide6.QtCore.Qt.Orientations
 |      expandingDirections(self) -> PySide6.QtCore.Qt.Orientations
 |  
 |  geometry(self) -> PySide6.QtCore.QRect
 |      geometry(self) -> PySide6.QtCore.QRect
 |  
 |  isEmpty(self) -> bool
 |      isEmpty(self) -> bool
 |  
 |  maximumSize(self) -> PySide6.QtCore.QSize
 |      maximumSize(self) -> PySide6.QtCore.QSize
 |  
 |  minimumSize(self) -> PySide6.QtCore.QSize
 |      minimumSize(self) -> PySide6.QtCore.QSize
 |  
 |  setGeometry(self, arg__1: PySide6.QtCore.QRect) -> None
 |      setGeometry(self, arg__1: PySide6.QtCore.QRect) -> None
 |  
 |  sizeHint(self) -> PySide6.QtCore.QSize
 |      sizeHint(self) -> PySide6.QtCore.QSize
 |  
 |  sizePolicy(self) -> PySide6.QtWidgets.QSizePolicy
 |      sizePolicy(self) -> PySide6.QtWidgets.QSizePolicy
 |  
 |  spacerItem(self) -> PySide6.QtWidgets.QSpacerItem
 |      spacerItem(self) -> PySide6.QtWidgets.QSpacerItem
 |  
 |  ----------------------------------------------------------------------
 |  Static methods defined here:
 |  
 |  __new__(*args, **kwargs) from Shiboken.ObjectType
 |      Create and return a new object.  See help(type) for accurate signature.
 |  
 |  ----------------------------------------------------------------------
 |  Methods inherited from QLayoutItem:
 |  
 |  alignment(self) -> PySide6.QtCore.Qt.Alignment
 |      alignment(self) -> PySide6.QtCore.Qt.Alignment
 |  
 |  controlTypes(self) -> PySide6.QtWidgets.QSizePolicy.ControlTypes
 |      controlTypes(self) -> PySide6.QtWidgets.QSizePolicy.ControlTypes
 |  
 |  hasHeightForWidth(self) -> bool
 |      hasHeightForWidth(self) -> bool
 |  
 |  heightForWidth(self, arg__1: int) -> int
 |      heightForWidth(self, arg__1: int) -> int
 |  
 |  invalidate(self) -> None
 |      invalidate(self) -> None
 |  
 |  layout(self) -> PySide6.QtWidgets.QLayout
 |      layout(self) -> PySide6.QtWidgets.QLayout
 |  
 |  minimumHeightForWidth(self, arg__1: int) -> int
 |      minimumHeightForWidth(self, arg__1: int) -> int
 |  
 |  setAlignment(self, a: PySide6.QtCore.Qt.Alignment) -> None
 |      setAlignment(self, a: PySide6.QtCore.Qt.Alignment) -> None
 |  
 |  widget(self) -> PySide6.QtWidgets.QWidget
 |      widget(self) -> PySide6.QtWidgets.QWidget
 |  
 |  ----------------------------------------------------------------------
 |  Data descriptors inherited from QLayoutItem:
 |  
 |  align
 |  
 |  ----------------------------------------------------------------------
 |  Methods inherited from Shiboken.Object:
 |  
 |  __getattribute__(self, name, /)
 |      Return getattr(self, name).
 |  
 |  ----------------------------------------------------------------------
 |  Data descriptors inherited from Shiboken.Object:
 |  
 |  __dict__

Considering the above then the solution is:

QSpacerItem(0, 0, hData = QSizePolicy.Expanding)
QSpacerItem(0, 0, vData = QSizePolicy.Fixed)

Same for scaled:

help(QPixmap.scaled)

Help on method_descriptor:

scaled(...)
    scaled(self, s: PySide6.QtCore.QSize, aspectMode: PySide6.QtCore.Qt.AspectRatioMode = PySide6.QtCore.Qt.AspectRatioMode.IgnoreAspectRatio, mode: PySide6.QtCore.Qt.TransformationMode = PySide6.QtCore.Qt.TransformationMode.FastTransformation) -> PySide6.QtGui.QPixmap
    scaled(self, w: int, h: int, aspectMode: PySide6.QtCore.Qt.AspectRatioMode = PySide6.QtCore.Qt.AspectRatioMode.IgnoreAspectRatio, mode: PySide6.QtCore.Qt.TransformationMode = PySide6.QtCore.Qt.TransformationMode.FastTransformation) -> PySide6.QtGui.QPixmap

then

QPixmap().scaled(QSize(640, 480), aspectMode=Qt.AspectRatioMode.IgnoreAspectRatio)
QPixmap().scaled(QSize(640, 480), mode=Qt.TransformationMode.FastTransformation)