Switching to v0.1.11 Caused a Crash

[JosephTLyons]

I upgraded to v0.1.11 and trying to run an app using v0.1.10 immediately crashed (no other changes were introduced, just the version bump:

❯ python main.py
Traceback (most recent call last):
  File "/Users/josephlyons/Programming/Python/termifind/main.py", line 34, in <module>
    main()
  File "/Users/josephlyons/Programming/Python/termifind/main.py", line 30, in main
    TermiFindApplication.run(log="termifind.log")
  File "/Users/josephlyons/Programming/Python/termifind/virtual_environment/lib/python3.10/site-packages/textual/app.py", line 187, in run
    asyncio.run(run_app())
  File "/Users/josephlyons/.pyenv/versions/3.10.0b3/lib/python3.10/asyncio/runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "/Users/josephlyons/.pyenv/versions/3.10.0b3/lib/python3.10/asyncio/base_events.py", line 641, in run_until_complete
    return future.result()
  File "/Users/josephlyons/Programming/Python/termifind/virtual_environment/lib/python3.10/site-packages/textual/app.py", line 184, in run_app
    app = cls(console=console, screen=screen, driver_class=driver, **kwargs)
  File "/Users/josephlyons/Programming/Python/termifind/main.py", line 14, in __init__
    self.ui: UI = UI(self.path_container)
  File "/Users/josephlyons/Programming/Python/termifind/src/ui/ui.py", line 22, in __init__
    self.previous_directory_container_scroll_view: TermiFindScrollView = self.__get_scroll_view(
  File "/Users/josephlyons/Programming/Python/termifind/src/ui/ui.py", line 38, in __get_scroll_view
    item_buttons_view: TermiFindButtonsView = self.__get_item_buttons_view(directory_container, should_style_text)
  File "/Users/josephlyons/Programming/Python/termifind/src/ui/ui.py", line 66, in __get_item_buttons_view
    termifind_buttons_view.add(TermiFindButton(item_name_text))
  File "/Users/josephlyons/Programming/Python/termifind/src/ui/custom_views.py", line 10, in add
    self.layout.add(button)
  File "/Users/josephlyons/Programming/Python/termifind/virtual_environment/lib/python3.10/site-packages/textual/layouts/vertical.py", line 27, in add
    self._max_widget_width = max(widget.app.measure(widget), self._max_widget_width)
  File "/Users/josephlyons/Programming/Python/termifind/virtual_environment/lib/python3.10/site-packages/textual/message_pump.py", line 58, in app
    return active_app.get()
LookupError: <ContextVar name='active_app' at 0x1031a4f90>
sys:1: ResourceWarning: unclosed file <_io.TextIOWrapper name='termifind.log' mode='wt' encoding='UTF-8'>

I will try to post a minimal working piece of code that causes the crash, just wanted to get this logged before I forgot about it.

Repo & Branch I'm working on is here: https://github.com/JosephTLyons/termifind-python/tree/Continue-Adapting-Code-To-Use-Textual

[willmcgugan]

I think I see the problem. You may be constructing widgets or views from the App constructor, prior to the asyncio context running. This may have worked in a previous version, but you will need to create widgets in a handler, on_mount is the best place for that.

[JosephTLyons]

That solved the original issue here. I have a few other issues that have come up, but I will close this one and open new issues if I can't solve it on my own. Thank you.

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