Well, you're quite merciless with my amateur programming skills... Anyway, thanks for taking the time to take care of it. For what it's worth, I prefer a rough exception than a silent fail. So your conclusion is fine with me.
-Pierre Le 4 mars 2012 à 14:49, Phil Thompson <p...@riverbankcomputing.com> a écrit : > On Sun, 26 Feb 2012 16:23:26 +0100, Pierre Raybaut > <pierre.rayb...@gmail.com> wrote: >> Hi Phil, >> >> I recently found out that a feature succesfully tested with older >> versions of PyQt was broken >> (http://code.google.com/p/spyderlib/issues/detail?id=951) and at the >> same time the Matplotlib developers contacted me for a similar issue >> (https://github.com/matplotlib/matplotlib/issues/711). >> >> To explain our problem, I wrote this test script: >> >> > #----------------------------------------------------------------------------- >> from PyQt4.QtGui import QApplication, QWidget >> from PyQt4.QtCore import Qt >> >> def print_from_function(): >> print "Callback = Function" >> >> class TestWidget(QWidget): >> def __init__(self, parent=None): >> QWidget.__init__(self, parent) >> self.destroyed.connect(print_from_function) >> self.destroyed.connect(self.print_from_method) >> self.destroyed.connect(self.print_from_static_method) >> self.destroyed.connect(lambda: > self.print_from_lambda_function()) >> self.setAttribute(Qt.WA_DeleteOnClose) >> >> def print_from_method(self): >> print "Callback = method" >> >> @staticmethod >> def print_from_static_method(self): >> print "Callback = static method" >> >> def print_from_lambda_function(self): >> print "Callback = lambda function" >> >> app = QApplication([]) >> widget = TestWidget() >> widget.show() >> app.exec_() >> > #----------------------------------------------------------------------------- >> >> The issue with the test script above is that all callbacks connected >> to the 'destroyed' signal are triggered except for the callback which >> is a method (bound to the object to be destroyed). >> >> So the question is: is this a regression from PyQt v4.8.5? (or earlier) > > First off I think that connecting the destroyed() signal to a method of > the object being destroyed is a bug. There are no guarantees about the > state of the object when the signal is emitted. > > The change in behaviour was introduced in SIP v4.10.3 released July 2010. > As far as I can tell the change was made because I thought it was a good > idea rather than in response to a bug report. The intent would have been to > eliminate any "C/C++ object has been deleted" exceptions - but, as in this > case, the slot may not make any calls that would trigger an exception. > > With hindsight I think I will back out the change. I dislike the > inconsistency in behaviour more than I dislike the buggy application code. > > Phil _______________________________________________ PyQt mailing list PyQt@riverbankcomputing.com http://www.riverbankcomputing.com/mailman/listinfo/pyqt
