Commit 1ed8e6cbd changed process_running(pid) to shell out to `ps` on
every call to distinguish running processes from zombies. That cost
~2 ms per invocation on macOS (fork + exec + wait), and the test
harness calls process_running O(tests × markers) times under session
flock contention. Across a `cargo nextest run -p fabro-cli` that added
up to ~90 s of suite time, and the zombie-aware semantics turned out
to have no production caller on Unix (the server's worker-termination
loop uses process_group_alive; the CLI stop/status paths don't need
zombie detection for a daemon that reparents to init).
Restore the pre-1ed8e6cbd body: process_running is now a straight
kill(pid, 0) via process_exists on Unix, true on non-unix. Delete
unix_process_state (the `ps` helper) and its zombie regression test,
since they describe behavior we're rolling back. process_group_alive
and its tests are unchanged.
Measured on this branch against baseline db953c838:
reap_nextest p50: 172 ms -> 0.3 ms
TestContext:🆕 316 ms mean -> 15 ms mean
If a future caller genuinely needs zombie-aware semantics, add it back
alongside that caller with a benchmark in context.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
da87f978cd