QValidator.State TypeError

[Ognyan Moore]

Sure enough, that's working; I should get in the habit of calling help, not
sure why that never crossed my mind.

Sorry for the noise,

Thanks Florian.

On Wed, Jun 14, 2023 at 8:37 AM Florian Bruhin <me at the-compiler.org> wrote:

> Hey,
>
> > When implementing my own subclass of QValidator, I get a "TypeError:
> > invalid result from Validator.validate()" error followed by a segfault on
> > macOS for the following code:
> >
> > Example:
> >
> > [...]
> >
> > class Validator(QtGui.QValidator):
> >
> >     def validate(self, index_, pos):
> >         return QtGui.QValidator.State.Acceptable
>
> This should return (QtGui.QValidator.State.Acceptable, index_, pos)
> instead.
>
> > Running this file generates a QLineEdit, but the moment you edit the
> > contents and have the widget lose focus the following error is emitted:
> >
> > TypeError: invalid result from Validator.validate()
>
> That's correct. This is one of the instances where Qt in C++ expects you
> (or at least allows you) to modify the contents of one of the references
> given as arguments:
>
> https://doc.qt.io/qt-6/qvalidator.html#validate
> "The function can change both input and pos (the cursor position) if
> required."
>
> However, in Python, this isn't possible (both str and int are
> immutable), so PyQt solves this by returning a
> tuple[QValidator.State, str, int] instead. See help() in Python:
>
>     >>> help(QValidator.validate)
>     Help on built-in function validate:
>
>     validate(...) method of PyQt6.sip.wrappertype instance
>         validate(self, a0: str, a1: int) -> Tuple[QValidator.State, str,
> int]
>
> or the PyQt docs:
>
> https://www.riverbankcomputing.com/static/Docs/PyQt6/api/qtgui/qvalidator.html
>
> Florian
>
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