SystemAddon._on_shutdown guard is a tautology — always True, sentinel branch is dead code

[asheimo]

Version: pm_auto 2.0.4 (commit 373e30f)
File: pm_auto/addons/system.py, _on_shutdown (around line 59)

Description

The guard condition in _on_shutdown always evaluates to True for every possible value of reason, so it provides no protection:

def _on_shutdown(self, *args):
    if len(args) == 0:
        reason = 'None'
    else:
        reason = args[0]
    if reason != 'None' or reason != None or reason != 0:   # always True
        ...
        shutdown()

Because the three comparisons are OR'd, at least one is always true regardless of reason:

• reason = 'None' → 'None' != None is True → passes
• reason = None → None != 'None' is True → passes
• reason = 0 → 0 != 'None' is True → passes

The if len(args) == 0: reason = 'None' branch directly above implies the intent was for a missing/empty reason to be a no-op sentinel that skips shutdown. That suppression never happens — the condition can't reject anything.

Current impact

In 2.0.4 this is latent rather than active: every event mapped to shutdown is published with a truthy value (e.g. pipower5.py publishes shutdown_req of 1/2/3), so real shutdowns carry a real reason and behave correctly. The defect is that the guard offers no safety for any future or external caller that publishes shutdown with no args or a falsy reason — that would trigger a real shutdown() / shutdown -h now.

Corroborating evidence the sentinel path is vestigial

The no-args case appears never to have been exercised: OLEDAddon.show_shutdown_screen(self, reason) (in addons/oled/__init__.py) is also subscribed to shutdown and takes reason as a required positional argument, so a bare shutdown publish would raise TypeError there before _on_shutdown even ran.

Suggested fix

Change the OR to AND so the sentinels are correctly treated as no-ops (and use is not None):

if reason != 'None' and reason is not None and reason != 0:

Happy to open a PR with this one-line change against whichever branch you prefer if that's useful.