[doqhu]

Problem

On Windows and Linux machines with an NVIDIA GPU and CPU-only torch, MainWindow._maybe_show_cuda_prompt opens the CUDA installer prompt 500 ms after the window opens, via QTimer.singleShot(500, _show).

If the window is closed and deleted within those 500 ms, the timer still fires, and CudaInstallerDialog(self) raises:

RuntimeError: wrapped C/C++ object of type MainWindow has been deleted

This makes tests/widgets/main_window_test.py::TestMainWindow::test_should_run_file_transcription_task flaky on such machines. When a fast transcription lets the test close the window before the timer fires, pytest-qt reports the exception from the Qt event loop. CI runners have no NVIDIA GPU, so CI never hits it.

Fix

The prompt now uses a QTimer that the window owns, so Qt destroys the timer together with the window and it can't fire on a deleted one. PyQt6's QTimer.singleShot has no overload that takes a context object, so a parented timer is the way to tie the timer's lifetime to the window.

Testing

• New test_cuda_prompt_shows_after_delay: on a simulated NVIDIA + CPU-torch machine, the prompt opens for the window.
• New test_cuda_prompt_does_not_fire_after_window_is_deleted: fails without the fix and passes with it.
• Both tests mock window.settings, so they don't write CUDA_PROMPT_SHOWN to the real user settings.
• tests/widgets/main_window_test.py and tests/widgets/cuda_installer_widget_test.py pass locally (37 tests, two runs) on Fedora 44 with an RTX 3070.

Found while working on #1667.

🤖 Generated with Claude Code

https://claude.ai/code/session_012ozoVtp2JvfpDkZ1SpBgvW

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.21%. Comparing base (23d848b) to head (7c10840).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1668      +/-   ##
==========================================
+ Coverage   84.13%   84.21%   +0.08%     
==========================================
  Files         115      115              
  Lines       13928    13931       +3     
==========================================
+ Hits        11718    11732      +14     
+ Misses       2210     2199      -11     

Flag	Coverage Δ
Linux	83.47% <100.00%> (+0.07%)	⬆️
macOS	83.74% <100.00%> (+0.11%)	⬆️

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