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Subclass QUiLoader

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  • SGaistS Offline
    SGaistS Offline
    SGaist
    Lifetime Qt Champion
    wrote on last edited by
    #4

    Can you add a minimal sample code that uses this class and triggers the issue ?

    Interested in AI ? www.idiap.ch
    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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    • 3 Offline
      3 Offline
      3beezer
      wrote on last edited by
      #5

      test.py

      import sys
      from importlib import import_module
      
      from PySide2.QtCore import QFile
      from PySide2.QtUiTools import QUiLoader
      from PySide2.QtWidgets import QApplication
      
      class MyLoader(QUiLoader):
          def __init__(self):
              super().__init__()
              self.widget_mod = import_module("PySide2.QtWidgets")
      
          def createWidget(self, class_name, parent=None, name=''):
              orig_widget_inst = QUiLoader.createWidget(self, class_name, parent=None, name='')
              print("orig_widget_inst =", orig_widget_inst)
      
              widget_class = getattr(self.widget_mod, class_name)
              my_widget_inst = widget_class(parent)
              print("my_widget_inst =", my_widget_inst)
      
              return orig_widget_inst
              #return my_widget_inst
      
      if __name__ == "__main__":
          app = QApplication(sys.argv)
          ui_file = QFile(sys.argv[1])
          ui_file.open(QFile.ReadOnly)
          loader = MyLoader()
          loader.load(ui_file)
          ui_file.close()
      

      and test.ui

      <?xml version="1.0" encoding="UTF-8"?>
      <ui version="4.0">
       <class>test_panel</class>
       <widget class="QWidget" name="test_panel"/>
       <resources/>
       <connections/>
      </ui>
      

      Run the program using

      python test.py test.ui
      

      Switch the comment on the two return statements to see the crash.

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      • 3 Offline
        3 Offline
        3beezer
        wrote on last edited by
        #6

        I'm new here. Should I report this problem as a bug? If so, where?

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        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #7

          What version of PySide2 are you currently using ?
          On what OS ?

          PySide2 5.11.1 and 5.13.0 on macOS are working with your test example.

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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          • SGaistS SGaist

            What version of PySide2 are you currently using ?
            On what OS ?

            PySide2 5.11.1 and 5.13.0 on macOS are working with your test example.

            3 Offline
            3 Offline
            3beezer
            wrote on last edited by
            #8

            @sgaist Interesting! I am using version 5.12.4 on Kubuntu 19.04 with Python 3.7.3. Oh, I see that I can upgrade PySide2 to 5.13.0 using pip. I will do so and report back.

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            • 3 Offline
              3 Offline
              3beezer
              wrote on last edited by
              #9

              Nope. Still crashes. You did switch the # to the other return, right?

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              • SGaistS Offline
                SGaistS Offline
                SGaist
                Lifetime Qt Champion
                wrote on last edited by
                #10

                No I didn't because I overlooked it and I must say I expect to run crashing examples with the "working" version in comment rather than the contrary.

                Before digging further, can you just explain what you want to do exactly in createWidget ?

                Interested in AI ? www.idiap.ch
                Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                • 3 Offline
                  3 Offline
                  3beezer
                  wrote on last edited by
                  #11

                  I would like to wrap the widget and return an instance of the wrapped widget. Since I can't return an instance of the exact same widget without getting a crash, it doesn't seem to be possible to override createWidget, despite claims to the contrary.

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                  • SGaistS Offline
                    SGaistS Offline
                    SGaist
                    Lifetime Qt Champion
                    wrote on last edited by
                    #12

                    What wrapping do you have in mind ?

                    Interested in AI ? www.idiap.ch
                    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                    • 3 Offline
                      3 Offline
                      3beezer
                      wrote on last edited by
                      #13

                      I have several ideas. One I would have liked to implement earlier today is a subclass with __del__ so that I can confirm that I haven't created a cyclic reference. I do this in portions of the GUI I design manually, but I can't do it in portions I design using Qt Designer.

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                      • SGaistS Offline
                        SGaistS Offline
                        SGaist
                        Lifetime Qt Champion
                        wrote on last edited by
                        #14

                        I wonder if it's a python specific issue.

                        Can you test if the same issue happens in C++ ?

                        Interested in AI ? www.idiap.ch
                        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                        • 3 Offline
                          3 Offline
                          3beezer
                          wrote on last edited by
                          #15

                          I think it is, but I don't know C++ well enough to write a test program.

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                          • 3 Offline
                            3 Offline
                            3beezer
                            wrote on last edited by
                            #16

                            The problem is officially a bug:

                            bug 1070

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