python segfaulting, MemoryError (PyQt)

Denis L no at spam.com
Tue Apr 28 14:54:41 CEST 2009


"Phil Thompson" <phil at riverbankcomputing.com> wrote in message 
news:mailman.4664.1240907352.11746.python-list at python.org...
> On Tue, 28 Apr 2009 03:53:34 +0200, "Denis L" <no at spam.com> wrote:
>> Hello,
>>
>> I'm experiencing odd errors on both windows and linux with the following
>> code:
>>
>> import sys
>> from PyQt4.QtCore import *
>> from PyQt4.QtGui import *
>>
>> class Options(QDialog):
>>     def __init__(self, values):
>>         QDialog.__init__(self)
>>
>>         self.values = values
>>
>>         fooEdit = QLineEdit(values['foo'])
>>         self.connect(fooEdit, SIGNAL('textChanged(QString)'),
>>                      lambda value: self.optionChanged('foo', value))
>>
>>         barEdit = QLineEdit(values['bar'])
>>         self.connect(barEdit, SIGNAL('textChanged(QString)'),
>>                      lambda value: self.optionChanged('bar', value))
>>
>>         layout = QVBoxLayout()
>>         layout.addWidget(fooEdit)
>>         layout.addWidget(barEdit)
>>
>>         self.setLayout(layout)
>>
>>     def optionChanged(self, option, value):
>>         self.values[option] = value
>>         print self.values
>>
>> def main(args):
>>     app = QApplication(args)
>>     values = dict(foo='', bar='')
>>     dialog = Options(values)
>>     dialog.show()
>>     app.exec_()
>>
>> if __name__ == '__main__':
>>     main(sys.argv)
>>
>>
>> If I type a character in fooEdit, another character in barEdit, and then
>> delete the character from barEdit I get an unhandled win32 exception
>> occured
>> in python.exe on windows and segfault on linux.
>>
>> If I type a character in fooEdit, delete it, and then type a character in
>
>> barEdit I get:
>>
>> {'foo': PyQt4.QtCore.QString(u'a'), 'bar': ''}
>> {'foo': PyQt4.QtCore.QString(u''), 'bar': ''}
>> {'foo': Traceback (most recent call last):
>>   File "L:\home\dev\python\test.py", line 17, in <lambda>
>>     lambda value: self.optionChanged('bar', value))
>>   File "L:\home\dev\python\test.py", line 27, in optionChanged
>>     print self.values
>> MemoryError
>>
>> I'm using Python 2.5.4 and PyQt 4.4.3-1
>>
>> Thanks in advance for any help.
>
> Works fine for me with current versions.
>
> Phil

I have noticed that if I do "self.values[option] = QString(value)"
instead of "self.values[option] = value" in optionChanged I don't get any 
errors.

Is it perhaps not safe to keep the reference to the lambda QString argument? 





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