BUG: PySide6 6.9+ "Signal source has been deleted"

[larsoner]

Using the latest 6.1.0alpha4 on conda-forge with PySide6 6.9.0 and trying to add it to an installer and test it I see:

    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/plugins/application/container.py", line 194, in setup
      self.inapp_appeal_status = InAppAppealStatus(self)
                                 ~~~~~~~~~~~~~~~~~^^^^^^
    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/plugins/application/widgets/status.py", line 104, in __init__
      self.sig_clicked.connect(self._on_click)
      ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
  RuntimeError: Signal source has been deleted
  timeout: the monitored command dumped core
  tests/test_spyder.sh: line 17:  5119 Segmentation fault      timeout $TO spyder

Full traceback

  Running Spyder with a timeout of 20s:
  which spyder: /home/runner/mne-python/1.10.0_0/bin/spyder
  Traceback (most recent call last):
    File "/home/runner/mne-python/1.10.0_0/bin/spyder", line 10, in <module>
      sys.exit(main())
               ~~~~^^
    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/app/start.py", line 279, in main
      mainwindow.main(options, args)
      ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/app/mainwindow.py", line 1443, in main
      mainwindow = create_window(MainWindow, app, splash, options, args)
    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/app/utils.py", line 360, in create_window
      main.setup()
      ~~~~~~~~~~^^
    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/app/mainwindow.py", line 757, in setup
      PLUGIN_REGISTRY.register_plugin(self, PluginClass,
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
                                      external=False)
                                      ^^^^^^^^^^^^^^^
    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/api/plugin_registration/registry.py", line 344, in register_plugin
      instance = self._instantiate_spyder5_plugin(
          main_window, PluginClass, external)
    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/api/plugin_registration/registry.py", line 186, in _instantiate_spyder5_plugin
      plugin_instance = PluginClass(main_window, configuration=CONF)
    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/plugins/application/plugin.py", line 62, in __init__
      super().__init__(parent, configuration)
      ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/api/plugins/new_api.py", line 353, in __init__
      container.setup()
      ~~~~~~~~~~~~~~~^^
    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/plugins/application/container.py", line 194, in setup
      self.inapp_appeal_status = InAppAppealStatus(self)
                                 ~~~~~~~~~~~~~~~~~^^^^^^
    File "/home/runner/mne-python/1.10.0_0/lib/python3.13/site-packages/spyder/plugins/application/widgets/status.py", line 104, in __init__
      self.sig_clicked.connect(self._on_click)
      ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
  RuntimeError: Signal source has been deleted
  timeout: the monitored command dumped core
  tests/test_spyder.sh: line 17:  5119 Segmentation fault      timeout $TO spyder
  Spyder failed with error code 139 (should be 124 for timeout)

It's a bit of a mystery to me how this can happen. But locally I can replicate the issue on Ubuntu 25.10, PySide 6.9.0, and spyder 6.1.0a4 (and also I just checked latest master as well, same problem).

If I take the naive step of just putting the above problematic line in a try/except I get:

  File "/home/larsoner/python/spyder/spyder/utils/qthelpers.py", line 376, in create_action
    action.triggered.connect(triggered)
RuntimeError: Signal source has been deleted

and if I nest that one I just hit a different one, etc. So it seems like this is a widespread problem, and the status widget just happens to be the first widget to hit it.

I also checked #24752 and the issue remains there as well.

[larsoner]

... and I just checked PySide6 6.9.1 has this problem as well, but 6.8.3 does not (at least when on #24752). So this appears to be an issue specific to PySide6 6.9+.

[ccordoba12]

Hey @larsoner, thanks for reporting. This seems a side effect of PySide6 not having WebEngine packages in Conda-forge.

Could you test with the Pyside6 pip packages? I did that locally (I work on Linux) and I'm not seeing this error.

[larsoner]

Could you test with the Pyside6 pip packages? I did that locally (I work on Linux) and I'm not seeing this error.

Yeah I'm using PyPI and have PySide6-Addons installed (which should have the WebEngine) and I get the error. Are you on 6.9.0 or later? Things are okay on 6.8.3, but not (for me) 6.9.0 or 6.9.1.

[rear1019]

I also encountered this error while working on #24752. I dont't think it's related to WebEngine, though I haven't looked into it.

[ccordoba12]

Hey guys, are you still seeing this problem? I can start Spyder just fine with PySide6 6.9.

As a matter of fact, I'd like to require it as our minimal supported version in 6.1 because it fixes some very serious issues in Qt's css engine that made Spyder look bad.

[larsoner]

Yeah same error as before for me on latest master of spyder and spyder-kernels with PySide 6.9.0 (and also 6.9.2) installed via PyPI on Linux. I also tested on my macOS ARM laptop and replicated the same issue on PySide 6.9.0.

[ccordoba12]

Ok, thanks for checking @larsoner. I'll take a look at it.