[TST] Qt/Pyside 6.5.1 dependency test failures #25988

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1. QuLogic commented on May 27, 2023

   

   QuLogic

   on May 27, 2023

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   This seems to be something to do with the PySide6 release earlier today.
2. QuLogic commented on May 29, 2023

   

   QuLogic

   on May 29, 2023

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   I can reproduce this locally, and the timer works, is called, the quit key is triggered, and the script exits, but something appears wrong getting the close event.
3. QuLogic commented on May 30, 2023

   

   QuLogic

   on May 30, 2023

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   FWICT, the problem seems to be mixed signals across multiple figures. The test in question has a second portion (for Agg-based backends only, which is why Cairo ones don't fail) which opens a figure to lock in the backend, then attempts to switch backends and confirm that it fails. This occurs before running the main test of opening a window, and closing it after the first draw event. In that case, the Matplotlib side does correctly close the Qt window, but the closing signal emitted through Qt seems to trigger the callback from the first figure. The first figure manager/canvas doesn't have any callbacks connected to it to print the CloseEvent, so the test fails.

   Using this patch to run a copy of the test:

   diff --git a/lib/matplotlib/backends/backend_qt.py b/lib/matplotlib/backends/backend_qt.py
   index faeb0d6bb7..4cfa294c6e 100644
   --- a/lib/matplotlib/backends/backend_qt.py
   +++ b/lib/matplotlib/backends/backend_qt.py
   @@ -501,6 +501,7 @@ class MainWindow(QtWidgets.QMainWindow):
        closing = QtCore.Signal()
   
        def closeEvent(self, event):
   +        print('closeEvent', self, event, self.closing)
            self.closing.emit()
            super().closeEvent(event)
   
   @@ -522,9 +523,11 @@ class FigureManagerQT(FigureManagerBase):
        def __init__(self, canvas, num):
            self.window = MainWindow()
            super().__init__(canvas, num)
   -        self.window.closing.connect(
   -            # The lambda prevents the event from being immediately gc'd.
   -            lambda: CloseEvent("close_event", self.canvas)._process())
   +        print('Creating new figure manager', self, canvas, num, self.window, self.window.closing)
   +        def foo():
   +            print('close event is happening!', self, self.canvas, self.window)
   +            CloseEvent("close_event", self.canvas)._process()
   +        self.window.closing.connect(foo)
            self.window.closing.connect(self._widgetclosed)
   
            if sys.platform != "darwin":
   @@ -604,6 +607,7 @@ class FigureManagerQT(FigureManagerBase):
                self.window.raise_()
   
        def destroy(self, *args):
   +        print('FigureManagerQT.destroy', self, self.window)
            # check for qApp first, as PySide deletes it in its atexit handler
            if QtWidgets.QApplication.instance() is None:
                return

   outputs:

   Creating new figure manager <matplotlib.backends.backend_qt.FigureManagerQT object at 0x7fc90fe38a60> <matplotlib.backends.backend_qtagg.FigureCanvasQTAgg(0x560b8d915020) at 0x7fc90fcc1f80> 1 <matplotlib.backends.backend_qt.MainWindow(0x560b8d91b750) at 0x7fc90fcc24c0> <PySide6.QtCore.SignalInstance closing() at 0x7fc90fffa1b0>
   FigureManagerQT.destroy <matplotlib.backends.backend_qt.FigureManagerQT object at 0x7fc90fe38a60> <matplotlib.backends.backend_qt.MainWindow(0x560b8d91b750) at 0x7fc90fcc24c0>
   closeEvent <matplotlib.backends.backend_qt.MainWindow(0x560b8d91b750) at 0x7fc90fcc24c0> <PySide6.QtCore.QEvent(QEvent::Close)> <PySide6.QtCore.SignalInstance closing() at 0x7fc90fffa1b0>
   close event is happening! <matplotlib.backends.backend_qt.FigureManagerQT object at 0x7fc90fe38a60> <matplotlib.backends.backend_qtagg.FigureCanvasQTAgg(0x560b8d915020) at 0x7fc90fcc1f80> <matplotlib.backends.backend_qt.MainWindow(0x560b8d91b750) at 0x7fc90fcc24c0>
   
   Creating new figure manager <matplotlib.backends.backend_qt.FigureManagerQT object at 0x7fc90d581900> <matplotlib.backends.backend_qtagg.FigureCanvasQTAgg(0x560b8d9b5ea0) at 0x7fc90d590340> 1 <matplotlib.backends.backend_qt.MainWindow(0x560b8d9e4010) at 0x7fc90d7dfd00> <PySide6.QtCore.SignalInstance closing() at 0x7fc90d715830>
   FigureManagerQT.destroy <matplotlib.backends.backend_qt.FigureManagerQT object at 0x7fc90d581900> <matplotlib.backends.backend_qt.MainWindow(0x560b8d9e4010) at 0x7fc90d7dfd00>
   closeEvent <matplotlib.backends.backend_qt.MainWindow(0x560b8d9e4010) at 0x7fc90d7dfd00> <PySide6.QtCore.QEvent(QEvent::Close)> <PySide6.QtCore.SignalInstance closing() at 0x7fc90d715830>
   close event is happening! <matplotlib.backends.backend_qt.FigureManagerQT object at 0x7fc90fe38a60> <matplotlib.backends.backend_qtagg.FigureCanvasQTAgg(0x560b8d915020) at 0x7fc90fcc1f80> <matplotlib.backends.backend_qt.MainWindow(0x560b8d91b750) at 0x7fc90fcc24c0>
   

   The second figure has a figure.canvas.manager of 0x7fc90d581900 and a figure.canvas.manager.window.closing instance of 0x7fc90d715830, and you can see that closeEvent receives it for that manager (so the correct window should be closed) and the same closing instance. But then when we get the callback for that signal, it's using the manager for the first window.
4. QuLogic commented on May 30, 2023

   

   QuLogic

   on May 30, 2023

   Last edited by QuLogic

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   Looks like there's an upstream issue for this here: https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2346 and https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-2348
5. QuLogic

   added

   status: upstream fix required

   on May 30, 2023
6. oscargus

   closed this as completedin #26005on May 30, 2023
7. ksunden commented on May 30, 2023

   

   ksunden

   on May 30, 2023

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   xref for pyqtgraph also having failures on pyside 6.5.1, seems at least overlapping root cause:

   pyqtgraph/pyqtgraph#2734
8. QuLogic commented on May 30, 2023

   

   QuLogic

   on May 30, 2023

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   Ah, interesting. We have two handlers for the closing signal, one a lambda and one a method, and based on that, the former is the one having trouble. I had considered merging them together, but for some reason never tried that out yesterday.

   Merging them does seem to fix the problem, so I'll try to audit all the signal connections to ensure that's the only place it's needed.
9. QuLogic commented on May 30, 2023

   

   QuLogic

   on May 30, 2023

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   There's another case of a handler with local capture in tool manager:
   

   matplotlib/lib/matplotlib/backends/backend_qt.py

   Lines 937 to 943 in d464cbf

   	def handler():
   	self.trigger_tool(name)
   	if toggle:
   	button.setCheckable(True)
   	button.toggled.connect(handler)
   	else:
   	button.clicked.connect(handler)

   
   I'm not sure if it's possible for us to avoid that one.
10. ksunden

    changed the title [-][TST] Upcoming dependency test failures[/-] [+][TST] Qt/Pyside 6.5.1 dependency test failures[/+] on May 30, 2023
11. ksunden commented on May 30, 2023

    

    ksunden

    on May 30, 2023

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    (renamed to make it more discoverable as an issue since there is some conversation/notes here)
12. QuLogic

    added this to the v3.7.2 milestone on Jul 5, 2023