PyQt 5.15.1: Signals are unhashable

[Florian Bruhin]

On Mon, Sep 14, 2020 at 06:21:33PM +0100, Phil Thompson wrote:
> 
> On 13/09/2020 13:00, Florian Bruhin wrote:
> > Hey,
> > 
> > With PyQt 5.15.1 (which seems to have appeared on PyPI), this example:
> > 
> >     from PyQt5.QtCore import QTimer
> >     t = QTimer()
> >     d = {}
> >     d[t.timeout] = None
> > 
> > Fails with:
> > 
> >     Traceback (most recent call last):
> >       File "test.py", line 5, in <module>
> >         d[t.timeout] = None
> >     TypeError: unhashable type: 'PyQt5.QtCore.pyqtBoundSignal'
> > 
> > Which breaks pytest-qt's "qtbot.waitSignals" helper (and I'm guessing
> > also some other code using PyQt5).
> > 
> > The same kind of thing worked fine with PyQt 5.15.0. I'm guessing this
> > is because of "Bound signals can now be tested for equality." - probably
> > __eq__ was defined, but __hash__ was not. From the Python docs:
> > 
> >     A class that overrides __eq__() and does not define __hash__() will
> >     have its __hash__() implicitly set to None. When the __hash__()
> >     method of a class is None, instances of the class will raise an
> >     appropriate TypeError when a program attempts to retrieve their hash
> >     value [...]
> > 
> > https://docs.python.org/3/reference/datamodel.html#object.__hash__
> > 
> > Florian
> 
> Fixed in tonight's PyQt5 snapshot.

Thank you!

FWIW when using pytest-qt's "with waitSignals([sig1, sig2], order='strict'):",
this can be worked around via "with waitSignal(sig1), waitSignal(sig2):"
instead (as long as the returned "blocker" value isn't needed):
https://github.com/qutebrowser/qutebrowser/commit/b55675ad4afe12be7e4a4f39960bb58818c502f8

Florian

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