Every field was read under its own lock, so an unload running concurrently
could be observed half-done: 'state' read before clear_state() removed it
and 'state_history_count' read after, handing PluginManager.get_plugin_info()
a plugin that is ENABLED with zero transitions.
The whole payload is now built in one critical section. _lock is an RLock,
so the helpers called inside it can still take it.
The regression test runs a reader against a thread that repeatedly fills and
clears the same plugin, and fails on the first torn snapshot. Verified by
removing only the lock: fails on 3 of 3 runs, passes on 3 of 3 with it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01STMbQE4YctTacQXfbYqKuW
Follow-up to the cap in this PR. A flat entry count answers the wrong
question: what a reader wants from this history is "the last couple of
hours", and how many transitions that is depends entirely on the plugin's
update interval. On a real board those span 2s to 3600s, so 200 entries is
interval 200 entries covers
2s 3.3 minutes (flights, live)
10s 16.7 minutes (jellyfin)
60s 1.7 hours (default)
300s 8.3 hours (news)
3600s 4.2 days
-- the plugin churning hardest, the one worth looking at, keeps the least.
So transitions are now trimmed by AGE first
(STATE_HISTORY_MAX_AGE_SECONDS, two hours), which makes the retained window
comparable whatever the cadence, and the count cap becomes purely a memory
ceiling for pollers fast enough to exceed it inside that window. The
ceiling rises 200 -> 2000: at ~230 bytes an entry that is ~0.5MB per plugin
worst case, and only plugins updating faster than roughly every 4s can
reach it. Steady-state memory is unchanged for everything slower, since the
age trim binds first.
Two details worth stating:
- The trim reads time.monotonic(), stored alongside each transition,
rather than the datetime already inside it. A DST shift or an NTP step
would otherwise make every entry look ancient and flush the history in
one go. The human-readable timestamp is untouched and still what
get_state_history() returns.
- Trimming happens on append, so a plugin that goes quiet keeps its last
window until it writes again. That is deliberate: it is bounded either
way, and a lazy trim costs nothing on the hot scheduling path. The
guarantee is therefore about the SPAN of retained history, not its age
against the current clock, and the test asserts it that way.
The public shape is unchanged: get_state_history() still returns the same
list of transition dicts, and state_history_count is still the lifetime
total.
test_plugin_state_history_retention.py adds 7 tests. Verified against this
branch with only the age trim removed: 4 fail, 3 pass -- the three that
survive are testing the count ceiling and the monotonic clock, which this
commit does not change. Full suite 3753 passed, 60 skipped.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01STMbQE4YctTacQXfbYqKuW
