[rdoupe]

Fixes #1402

What and why

SIGTERM now quits OBS while it records or streams, also with "Show confirmation on exit while outputs are active" on (the default), and finishes the recording. It also quits while a modal dialog waits, including during startup. Before, OBS stayed up until the sender killed it, which cut the recording off (upstream obsproject/obs-studio#10011, reported by Mikilio).

• OBSApp::processSigTerm() called quit(), which closes the main window. With an output active, OBSBasic::closeEvent() ignored that close and opened the "exit anyway?" dialog. systemctl stop, logind at shutdown and kill send SIGTERM, and nobody answers that dialog.
• While a modal dialog waited (for example the "encoder missing" warning the main window opens during startup), the quit ended nothing: the dialog runs its own event loop, and before the main event loop has started quit() does nothing at all.
• processSigTerm() now calls OBSBasic::closeWithoutPrompt(), after which shouldPromptForClose() is false. closeWindow() then runs as when the dialog is answered with Yes: it stops the outputs and waits for the recording to finish (the wait from frontend: Recording shutdown waits for the stop signal instead of polling the UI thread (#1283) #1342/fix: recording shutdown waits for inactive after deactivate #1392).
• If a modal dialog is open, processSigTerm() dismisses it and quits once its loop has returned. main() quits right after a startup that SIGTERM interrupted, as soon as the main event loop runs. Startup itself is not cut short, so nothing it still uses is freed under it.
• Unchanged: closing the window and Exit in the menus still ask, and SIGINT is not touched.

Headless (private Xvfb, private D-Bus, fresh HOME), driven over obs-websocket: Simple output, x264, MKV, exit confirmation on.

Build	Case	Result	Recording
v0.1.0-beta.20261014 AppImage	recording 4 s, SIGTERM	still running 30 s later	unfinished, no duration
master 3fa2833	recording 4 s, SIGTERM	still running 30 s later (the dialog is open)	0 bytes
master 3fa2833	"encoder missing" startup dialog, SIGTERM	still running 30 s later	none
This branch	recording 4 s, SIGTERM	quits after 1.2 s, clean shutdown in the log	complete, ffprobe duration 4.97 s
This branch	"encoder missing" startup dialog, SIGTERM	quits, clean shutdown in the log	none
Release and this branch	idle, SIGTERM	quit within 0.3 s	none

RED → GREEN

• RED: 9838f29 test: Tier 4 checks that SIGTERM while recording quits OBS. A new Tier 4 phase (run_tier4.py --only shutdown, also part of the full run) records with the exit confirmation on, sends SIGTERM and expects OBS gone within 30 s with one finished recording (ffprobe duration at least 2 s). Then it starts OBS with a profile whose encoder is missing, sends SIGTERM while that dialog is up and expects a clean shutdown. On master: 3 of 6 fail ("still running 30 s after SIGTERM (the exit confirmation dialog is open)"; a 0-byte MKV; "still running 30 s after SIGTERM" during the startup dialog). The other Tier 4 phases turn the confirmation off, so they never saw this.
• GREEN: 64a5e33 frontend: Quit on SIGTERM while outputs run or a dialog waits. 6 of 6, three runs. Full build (C libobs lane) and full ctest -j4 (private Xvfb, private D-Bus, fresh HOME, system libobs-opengl masked): 303/303; the only skipped case is open_crashes_without_obs_core, as on master. The change is frontend-only.

Checklist

• Base is master
• I claimed the issue, or no one else has an open PR for it
• Characterization test (if the unit had none), then RED, then GREEN commits
• (Optional) Local gate passed and the pushed head is stamped; otherwise PR CI runs the full suite
• Warning or flag changes (-W..., ratchets): none
• Intentional differences from C listed in the parity test header and rust/README.md (ports): not a port

AI note: Claude Code (Claude Opus 5.5) wrote the code, the test, the commit messages and this text under the submitter's direction, and ran the tests above on the submitter's machines.