The aboutToQuit-based teardown wired in v0.1.2 only fires when something
calls QCoreApplication::quit() — typically a window close. `kill -TERM`
to the host process bypasses Qt entirely (no default SIGTERM handler),
so teardownChild never ran on signal-driven shutdown. Local tests
passed on lucky timing because PR_SET_PDEATHSIG made the kernel SIGTERM
frankenphp once the host died, but the timing was racy and surfaced on
CI as "frankenphp child PID outlived the host (supervisor didn't clean
up)".
Fix: install a SIGTERM/SIGINT handler in BackendConnection that uses
the self-pipe pattern — the C signal handler writes one byte (the only
truly async-signal-safe primitive), a QSocketNotifier on the read end
calls QCoreApplication::quit() in the main thread, and aboutToQuit runs
the existing teardownChild before app.exec() returns. The host now
exits cleanly under `kill -TERM` from service managers, launchers, and
the test harness.
Also bumps the bundled-supervisor.sh first-relaunch grace from 2s to
3s — teardownChild itself waits up to 2s for frankenphp to finish after
SIGTERM, so the host needs ~2.x seconds to exit. The graceful-shutdown
step further down was already at 3s.
No public-API change; production-correctness fix.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
magdev
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