app._fatal_error never completes and ooms

[alefminus]

Have you checked closed issues? https://github.com/Textualize/textual/issues?q=is%3Aissue+is%3Aclosed

• yes, looked for _fatal_error, excepthook, did not find anything

Please give a brief but clear explanation of the issue. If you can, include a complete working example that demonstrates the bug. Check it can run without modifications.

Using aarch64, textual 0.32, python 3.9 on raspbian, on a raspberery pi 4.

I cannot share a reproducer yet (happens in a closed project source).

I could not provide a reproducer yet, but the problem is an exception triggered by a timer callback which goes into _fatal_error (I can see via py-spy, stack trace below), and does not complete, the process is eventually terminated by the oom-killer (I'm running on linux aarch64 raspbian on a raspberry pi 4 with 2 GB of ram, app normally takes ~60 MB).

I will try to produce a reproducer, I acknowledge this issue may be closed without one, I hoped to provide some "this happens" hook for future lookers.

I propose there should be a way to avoid this expensive / potentially buggy flow for a simpler "traceback.print_exc" or even "just exit" policy, perhaps by an environment variable or some configurable parameter via the textual module at runtime.

Here is the stack trace

Process 4334: /home/greenvibe/.cache/pypoetry/virtualenvs/devicecomm-o89zaWGP-py3.9/bin/python3 -m devicecomm.manual_mux
Python v3.9.2 (/usr/bin/python3.9)

Thread 0xB6FBB980 (active+gil): "MainThread"
    divide (rich/text.py:1114)
    split (rich/text.py:1089)
    wrap (rich/text.py:1222)
    __rich_console__ (rich/text.py:690)
    render (rich/console.py:1331)
    render (rich/console.py:1335)
    split_and_crop_lines (rich/segment.py:292)
    render_lines (rich/console.py:1371)
    __rich_console__ (rich/padding.py:97)
    render (rich/console.py:1331)
    split_and_crop_lines (rich/segment.py:292)
    render_lines (rich/console.py:1371)
    _render (rich/table.py:824)
    __rich_console__ (rich/table.py:511)
    render (rich/console.py:1331)
    split_and_crop_lines (rich/segment.py:292)
    render_lines (rich/console.py:1371)
    __rich_console__ (rich/padding.py:97)
    render (rich/console.py:1331)
    split_and_crop_lines (rich/segment.py:292)
    render_lines (rich/console.py:1371)
    __rich_console__ (rich/panel.py:220)
    render (rich/console.py:1331)
    split_and_crop_lines (rich/segment.py:292)
    render_lines (rich/console.py:1371)
    __rich_console__ (rich/padding.py:97)
    render (rich/console.py:1331)
    split_and_crop_lines (rich/segment.py:292)
    render_lines (rich/console.py:1371)
    _render (rich/table.py:824)
    __rich_console__ (rich/table.py:511)
    render (rich/console.py:1331)
    render (rich/console.py:1335)
    render (rich/console.py:1335)
    split_and_crop_lines (rich/segment.py:292)
    render_lines (rich/console.py:1371)
    __rich_console__ (rich/padding.py:97)
    render (rich/console.py:1331)
    split_and_crop_lines (rich/segment.py:292)
    render_lines (rich/console.py:1371)
    __rich_console__ (rich/panel.py:220)
    render (rich/console.py:1331)
    render (rich/console.py:1335)
    render (rich/console.py:1335)
    __init__ (rich/segment.py:668)
    _fatal_error (textual/app.py:1937)
    _handle_exception (textual/app.py:1928)
    _tick (textual/timer.py:157)
    _run (textual/timer.py:142)
    _run_timer (textual/timer.py:113)
    _run (asyncio/events.py:80)
    _run_once (asyncio/base_events.py:1890)
    run_forever (asyncio/base_events.py:596)
    run_until_complete (asyncio/base_events.py:629)
    run (textual/app.py:1317)
    main (devicecomm/manual_mux.py:647)
    <module> (devicecomm/manual_mux.py:654)
    _run_code (runpy.py:87)
    _run_module_as_main (runpy.py:197)
Thread 0xB2D06440 (idle): "Thread-1"
    wait (threading.py:312)
    get (queue.py:171)
    run (textual/drivers/_writer_thread.py:57)
    _bootstrap_inner (threading.py:954)
    _bootstrap (threading.py:912)
Thread 0xB23FF440 (idle): "Thread-2"
    select (selectors.py:469)
    run_input_thread (textual/drivers/linux_driver.py:260)
    run (threading.py:892)
    _bootstrap_inner (threading.py:954)
    _bootstrap (threading.py:912)
Thread 0xB19BF440 (active): "asyncio_0"
    _worker (concurrent/futures/thread.py:75)
    run (threading.py:892)
    _bootstrap_inner (threading.py:954)
    _bootstrap (threading.py:912)
Thread 0xB0F7F440 (active): "waitpid-0"
    _do_waitpid (asyncio/unix_events.py:1396)
    run (threading.py:892)
    _bootstrap_inner (threading.py:954)
    _bootstrap (threading.py:912)

It will be helpful if you run the following command and paste the results:

textual diagnose

<!-- This is valid Markdown, do not quote! -->
# Textual Diagnostics

## Versions

| Name    | Value  |
|---------|--------|
| Textual | 0.32.0 |
| Rich    | 13.5.2 |

## Python

| Name           | Value                                                                            |
|----------------|----------------------------------------------------------------------------------|
| Version        | 3.9.2                                                                            |
| Implementation | CPython                                                                          |
| Compiler       | GCC 10.2.1 20210110                                                              |
| Executable     | /home/greenvibe/.cache/pypoetry/virtualenvs/devicecomm-o89zaWGP-py3.9/bin/python |

## Operating System

| Name    | Value                                  |
|---------|----------------------------------------|
| System  | Linux                                  |
| Release | 6.1.21-v7l+                            |
| Version | #1642 SMP Mon Apr  3 17:22:30 BST 2023 |

## Terminal

| Name                 | Value     |
|----------------------|-----------|
| Terminal Application | *Unknown* |
| TERM                 | screen    |
| COLORTERM            | *Not set* |
| FORCE_COLOR          | *Not set* |
| NO_COLOR             | *Not set* |

## Rich Console options

| Name           | Value                |
|----------------|----------------------|
| size           | width=145, height=32 |
| legacy_windows | False                |
| min_width      | 1                    |
| max_width      | 145                  |
| is_terminal    | False                |
| encoding       | utf-8                |
| max_height     | 32                   |
| justify        | None                 |
| overflow       | None                 |
| no_wrap        | False                |
| highlight      | None                 |
| markup         | None                 |
| height         | None                 |

(note - I ran it in a different window then the one producing the exception, under tmux, so the actual height is more like 60, width is correct approximately)

Feel free to add screenshots and / or videos. These can be very helpful!

[github-actions]

We found the following entries in the FAQ which you may find helpful:

• How do I center a widget in a screen?
• Why doesn't the DataTable scroll programmatically?

Feel free to close this issue if you found an answer in the FAQ. Otherwise, please give us a little time to review.

This is an automated reply, generated by FAQtory

[alefminus]

(just an additional note: for now my workaround is to override App._fatal_error in my inheriting app)

[willmcgugan]

Are you updating the UI from a thread (other than the main thread) ?

[willmcgugan]

Assuming stale. Will need more information to reopen.

[github-actions]

Don't forget to star the repository!

Follow @textualizeio for Textual updates.