PR #21561 migrated liveness probes across 14 call sites from
`os.kill(pid, 0)` to `gateway.status._pid_exists` (psutil-first) so
the gateway doesn't Ctrl+C-itself on Windows via bpo-14484. A handful of
tests still patched the old `os.kill` seam and either happened to pass
on POSIX (when PID 12345 incidentally wasn't alive on the CI worker) or
failed outright — on CI runs they surfaced as 7 flaky/stable failures.
Migrate each affected test to patch the correct seam:
- tests/tools/test_browser_orphan_reaper.py (5 tests)
Patch `gateway.status._pid_exists` instead of `os.kill`.
Rename test_permission_error_on_kill_check_skips to
test_alive_legacy_daemon_is_reaped — the old assertion was
"PermissionError on sig 0 → skip dir"; post-migration the
untracked-alive-daemon path always reaps the dir after SIGTERM
(best-effort semantics were preserved).
- tests/tools/test_windows_native_support.py (4 tests)
Replace tests that asserted `os.kill` seam behavior with tests
that exercise `ProcessRegistry._is_host_pid_alive` as a
delegator and split out a new TestPidExistsOSErrorWidening class
that hits `gateway.status._pid_exists` directly via the POSIX
fallback branch (so Windows-style `OSError(WinError 87)` + `PermissionError`
widening is still covered on Linux CI).
- tests/tools/test_process_registry.py (1 test)
Mock `psutil.Process` + `_pid_exists` instead of `os.kill`
for the detached-session kill path.
- tests/tools/test_mcp_stability.py::test_kill_orphaned_uses_sigkill_when_available
SIGTERM → alive-check → SIGKILL flow now uses `_pid_exists`
for the middle step; assertion count drops from 3 to 2.
- tests/gateway/test_status.py::TestScopedLocks (2 tests)
`acquire_scoped_lock` consults `_pid_exists`; patch that
seam directly instead of trying to control the nested psutil
call via os.kill monkeypatch.
- tests/hermes_cli/test_gateway.py::test_stop_profile_gateway_keeps_pid_file_when_process_still_running
The stop loop sends one SIGTERM via os.kill then polls 20x via
_pid_exists; instrument both separately. Old assertion
`calls["kill"] == 21` split into `kill == 1` + `alive_probes == 20`.
- tests/hermes_cli/test_auth_toctou_file_modes.py::test_shared_nous_store_writes_0o600_with_0o700_parent
Commit c34884ea2 switched the pytest seat-belt guard in
`_nous_shared_store_path()` from `Path.home() / ".hermes"`
to `get_default_hermes_root()`, which honors HERMES_HOME. The
test sets both HERMES_HOME and HERMES_SHARED_AUTH_DIR to
subpaths of the same tmp_path, and the override now collapses
onto the same path the guard is refusing. Renamed the override
subdirectory so the two paths diverge — guard passes, test runs.
All 21 original CI failures and their local-flaky siblings now pass
(278 tests across the touched files, 0 failures).
`_save_auth_store`, `_save_qwen_cli_tokens`, and `_write_shared_nous_state`
all created the temp file via `Path.open('w')` / `Path.write_text` and only
tightened permissions to 0o600 afterward. Between create and chmod the file
existed at the process umask (commonly 0o644 = world-readable on multi-user
hosts), briefly exposing OAuth access/refresh tokens for Nous, Codex,
Copilot, Claude, Qwen, Gemini, and every other native OAuth provider that
flows through auth.json.
Switch all three to `os.open(O_WRONLY|O_CREAT|O_EXCL, 0o600)` + `os.fdopen`
+ `fsync` so the file is atomic at 0o600 on creation. Tighten each parent
directory (`~/.hermes/`, Qwen auth dir, Nous shared auth dir) to 0o700 so
siblings can't traverse to the creds. `_save_auth_store` also gains a
per-process random temp suffix to match `agent/google_oauth.py` (#19673)
and `tools/mcp_oauth.py` (#21148).
Adds `tests/hermes_cli/test_auth_toctou_file_modes.py` asserting final
file mode 0o600 and parent dir mode 0o700 across all three writers, plus
an explicit `os.open(flags, mode)` check on the main auth.json writer
that would fail if anyone reintroduces the `Path.open('w')` pattern.
POSIX-only (mode bits skipped on Windows).
