[hellices]

Closes #476

Summary

test_stop_then_immediate_shutdown_injects_cancellation_once failed on test (3.12) in #471's CI with NoMatches: No nodes match '#agent-status' on AgentPanel(), raised out of KorvidApp.on_unmount.

Textual's App._shutdown does three things in order:

1. Clears _running.
2. Removes every screen and widget (_close_all).
3. Only then sends the App its Unmount.

Unmount is where KorvidApp calls begin_shutdown. A turn the user interrupted just before quitting can settle inside step 2. _finish_interrupted_turn then still sees _shutting_down as False and hands TurnInterrupted to the panel port, which looks the panel up on a pruned screen. The NoMatches fails the turn task, shutdown() re-raises it from wait_for_turn, and it escapes app shutdown. A user could hit this by stopping a turn and quitting at once. A loaded runner widens the window.

• The fix: AppAgentPanel.apply_event, the one place agent events reach the panel, now drops an event once the app is no longer running. Textual clears that flag before it removes anything, so the guard covers both orderings: the panel already gone, and the panel left with no children.
• Not changed: the session's own _shutting_down bookkeeping. The controller's FakePanel in test_agent_ui_controller.py doesn't go through this adapter. This is the same family as DeploymentOutcomeScreen.on_mount can raise NoMatches when pushed during app shutdown #455/fix: tolerate the outcome screen mounting during shutdown #456, where a screen was mounted during shutdown.

Verification

tests/ui/test_agent_interrupt.py::test_a_turn_that_settles_after_the_panel_is_pruned_does_not_raise reproduces the ordering deterministically. The interrupted turn's cleanup waits for the panel's Unmount, so it settles after Textual has pruned the panel and before the App's Unmount.

• RED: without the guard it failed three runs out of three with NoMatches.
• GREEN: with the guard it passes three runs out of three.

An earlier version that polled for the pruned children every 10 ms passed even without the fix. By the time it noticed, begin_shutdown had already run, which is why the final test waits on the panel's Unmount itself.

Run locally on macOS with Python 3.13 and the frozen lock. Each step ran directly with the project's environment rather than through make, because this machine cannot sync from PyPI:

Command	Result
pytest -p no:tach tests/ui/test_agent_interrupt.py tests/ui/test_agent_ui_controller.py tests/ui/test_app_structure.py tests/ui/test_agent_wiring.py	192 passed
python scripts/check_source_size.py	passed
ruff check src/ tests/ and ruff format --check src/ tests/	passed; 659 files already formatted
SKIP=mypy,source-size pre-commit run --files <changed files>	passed
mypy	no issues in 659 source files
tach check	all modules validated
pytest -n 8 -q	13,750 passed, 25 skipped

This PR's CI (run 39992085249, hosted runners, four xdist workers) passed every required check:

Job	Result
test (3.11)	passed, 13m43s
test (3.12)	passed, 11m14s
test (3.13)	passed, 14m26s
windows-test	passed, 9m24s

Checklist

• This closes an accepted issue in this repository that is assigned to me.
• Tests cover the change, written to fail first where behavior changed.
• make check passes locally.
• User-facing docs and the README match the change, or nothing user-facing changed.
• No security invariant is weakened: writes still need a keystroke approval
  and a fail-closed audit entry, and sensitive reads are still masked.

[Copilot]

🔵 Needs a closer look

No blocking code issues were identified, but completion of the required Python-version and Windows CI checks remains unconfirmed.

No open issues 🎉

What changed in this PR

Prevents late agent events from updating dismantled UI widgets during shutdown, addressing the NoMatches failure reported in #476.

Changes:

• Drops agent panel events once Textual marks the app as no longer running, without changing session cleanup.
• Adds a regression test that makes an interrupted turn settle after the panel is pruned.

File	Description
tests/​ui/​test_agent_interrupt.py	Adds coverage for an interrupted turn settling during UI teardown.
src/​korvid/​ui/​app_surfaces.py	Guards panel event delivery with the app’s running state.

_{Review effort: Balanced}

[my-reviewer-agent]

검토 범위에서 보고할 이슈가 없습니다.

[Copilot]

🟢 Approval recommended

The narrowly scoped guard addresses the reported race, with targeted regression coverage and no unresolved findings.

No open issues 🎉

_{Review effort: Balanced}

[hellices]

Superseded by #482, which carries this pull request's commits unchanged (d64ad2b) together with the other open fixes and the dependency security bumps, so all of them need one CI run and one merge instead of a rebase after each merge. Closing in favour of #482; the branch stays, so this can be reopened if needed.