pyqtweakref.out

sys.version: 3.6.2 (default, Sep 15 2017, 22:53:56) 
[GCC 5.4.0 20160609]
sys.platform: linux
QT_VERSION_STR: 5.9.1
PYQT_VERSION_STR: 5.9
o.signal: <bound PYQT_SIGNAL signal of C object at 0x7f9523b1b1f8>
inspect.isdatadescriptor(o.signal): False
inspect.ismethoddescriptor(o.signal): False
inspect.ismemberdescriptor(o.signal): False
a: <bound PYQT_SIGNAL signal of C object at 0x7f9523b1b1f8>
b: <bound PYQT_SIGNAL signal of C object at 0x7f9523b1b1f8>
weak ref succeeded for <PyQt5.QtCore.QObject object at 0x7f9523b1b288>
Traceback (most recent call last):
  File "pyqtweakref.py", line 38, in <module>
    weakref.ref(it)
TypeError: cannot create weak reference to 'PyQt5.QtCore.pyqtBoundSignal' object
c: <bound PYQT_SIGNAL signal of C object at 0x7f9523b1b1f8>

pyqtweakref.py

import inspect
import sys
import traceback
import weakref

import PyQt5.QtCore
import PyQt5.QtWidgets


print('sys.version:', sys.version)
print('sys.platform:', sys.platform)
print('QT_VERSION_STR:', PyQt5.QtCore.QT_VERSION_STR)
print('PYQT_VERSION_STR:', PyQt5.QtCore.PYQT_VERSION_STR)

class C(PyQt5.QtCore.QObject):
    signal = PyQt5.QtCore.pyqtSignal()

o = C()

print('o.signal:', o.signal)
print('inspect.isdatadescriptor(o.signal):', inspect.isdatadescriptor(o.signal))
print('inspect.ismethoddescriptor(o.signal):', inspect.ismethoddescriptor(o.signal))
print('inspect.ismemberdescriptor(o.signal):', inspect.ismemberdescriptor(o.signal))

a = o.signal
b = o.signal
print('a:', a)
print('b:', b)

them = (
    PyQt5.QtCore.QObject(),
    o.signal,
)

for it in them:
    sys.stdout.flush()
    try:
        weakref.ref(it)
    except:
        traceback.print_exc()
    else:
        print('weak ref succeeded for', it)

c = o.signal
print('c:', c)