SAFETY-41: raise the clamp alarm's re-assert 30 s -> 150 s #52
@@ -154,8 +154,9 @@ REASON_CODE = "OUTPUT_CLAMP"
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# and 2 loop-side ones". On the live install the counter reached 48 loop-side
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# ENGAGEMENTS in ~25 minutes of ordinary operation - roughly one cycle in six,
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# not a pinned rail, but far more often than a guard sized for 2-in-60 assumed -
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# and at a 30 s re-assert the owner received a persistent notification about it
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# all day.
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# and the owner received a persistent notification about it all day. ⚠️ NOT
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# because of the 30 s re-assert - see the block below; those notifications never
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# consulted this constant at all.
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#
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# ⚠️ BOTH FIGURES ARE ENGAGEMENT COUNTS; only the regime differs - 2-in-60 was
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# measured over a §10.3 RUNAWAY, 48-in-305 was ordinary running on the live
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@@ -210,6 +211,28 @@ REASSERT_S = 150.0
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# Consecutive clean cycles before the alarm de-asserts (10.2 hysteresis).
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CLEAR_CYCLES = 3
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# ⚠️ SAFETY-41. Consecutive ENGAGED cycles after which an episode speaks even if
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# the notification budget is spent. THE ESCALATION EXISTS BECAUSE THE RATE LIMIT
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# ALONE DELAYS A RUNAWAY, and review measured it: a benign one-cycle clamp
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# followed by a continuous runaway held the runaway's first notification for up
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# to 140 s - one REASSERT_S minus a cycle. On the live install, where ordinary
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# railing spends the budget essentially all the time, a runaway arriving during
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# normal operation would be delayed with near-certainty. That is the "benign
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# noise suppresses the bug signal" shape this module's docstring is written
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# against.
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#
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# THE DISCRIMINATOR IS RUN LENGTH, and the two populations genuinely differ: the
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# live flood was runs of length ONE (engage, de-assert, engage), while a §10.3
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# runaway engages on EVERY cycle. So a sustained run speaks regardless of budget,
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# and scattered chatter does not.
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#
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# Measured, shipped-without vs shipped-with - it costs nothing it was protecting:
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# live scatter flood (305 cycles, 1-in-6) 11 -> 11 notifications
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# chatter 1-engaged/3-clean over 8000 s 50 -> 50 notifications
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# pinned 900 s quarter (floor is 5) 6 -> 6 alarms
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# runaway delay after a benign episode 140 s -> 10 s
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SUSTAINED_CYCLES = 3
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@dataclass(frozen=True)
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class ClampResult:
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@@ -315,6 +338,10 @@ class ClampWatchdog:
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self.last_alarm: datetime | None = None
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self.reason = ""
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self.clean_cycles = 0
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# SAFETY-41. Consecutive engaged cycles, and whether THIS episode has
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# spoken yet - the two the escalation clause needs.
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self.run_len = 0
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self.spoken = False
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def note(self, engaged: bool, reason: str, now: datetime) -> bool:
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"""Advance one cycle. True when the caller should raise the alarm.
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@@ -326,10 +353,12 @@ class ClampWatchdog:
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self.engagements += 1
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self.clean_cycles = 0
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self.reason = reason
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self.run_len += 1
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if not self.active:
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self.active = True
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self.since = now
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self.episodes += 1
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self.spoken = False
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# ⚠️ SAFETY-41. THE RISING EDGE IS RATE-LIMITED TOO, and it did
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# not used to be. It fired unconditionally, so a condition that
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# engages and clears repeatedly raised one notification PER
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@@ -358,15 +387,27 @@ class ClampWatchdog:
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if (self.last_alarm is None
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or (now - self.last_alarm).total_seconds() >= REASSERT_S):
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self.last_alarm = now
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self.spoken = True
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return True
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return False
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# ⚠️ THE ESCALATION. An episode that has not yet spoken because the
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# budget was spent by an EARLIER, unrelated episode speaks anyway
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# once it has engaged SUSTAINED_CYCLES times in a row. A runaway
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# engages every cycle and reaches it; the scattered one-cycle
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# railing that produced the live flood never does.
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if not self.spoken and self.run_len >= SUSTAINED_CYCLES:
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self.last_alarm = now
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self.spoken = True
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return True
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# Still engaged: re-assert on the slow cadence, not every cycle.
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if (self.last_alarm is None
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or (now - self.last_alarm).total_seconds() >= REASSERT_S):
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self.last_alarm = now
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self.spoken = True
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return True
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return False
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self.run_len = 0
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if not self.active:
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return False
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self.clean_cycles += 1
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@@ -78,7 +78,8 @@ import sys
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from datetime import datetime, timedelta, timezone
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from app.clamp import (
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CLEAR_CYCLES, REASON_CODE, REASSERT_S, ClampWatchdog, clamp_to_rating,
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CLEAR_CYCLES, REASON_CODE, REASSERT_S, SUSTAINED_CYCLES, ClampWatchdog,
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clamp_to_rating,
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is_commandable,
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)
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from app.allocator import Allocation, UnitPlan, plan
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@@ -296,13 +297,54 @@ check(f"...and the rate honours the same interval the pinned case does: at most
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check("...while EVERY episode and EVERY engagement is still counted - the "
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"budget is on notifications, never on evidence",
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scat.episodes == scat.engagements == SCATTER_CYCLES // SCATTER_ONE_IN + 1)
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# ⚠️ THE COUNTERFACTUAL. A runaway that begins from quiet must NOT be delayed by
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# a budget spent on an earlier, unrelated episode - so a cold watchdog speaks at
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# once, and this is the half that would go red if the rate limit were applied
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# without regard to how long it has been silent.
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check("...and a rising edge from a COLD watchdog still fires immediately, so a "
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"runaway beginning from quiet is never held back",
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ClampWatchdog().note(True, "cold runaway", T0) is True)
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# ⚠️ THE COUNTERFACTUAL, AND THE FIRST VERSION OF IT COULD NOT FAIL FOR THE
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# DEFECT IT NAMED. It read `ClampWatchdog().note(True, ...) is True` - a FRESH
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# object, so it only ever exercised the `last_alarm is None` branch, which is the
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# trivially-true one. A fresh watchdog has no earlier episode to be held back BY.
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# That is the third instance in this file of the family recorded at line 216 and
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# at the 224 s sweep, and it was guarding the most safety-critical property in
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# the change. Review found it.
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#
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# The stimulus must therefore SPEND THE BUDGET FIRST: a benign one-cycle clamp,
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# a gap long enough to de-assert, then a continuous runaway. Without the
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# escalation clause the runaway's first notification is held for up to
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# REASSERT_S - measured at 140 s before it was added.
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_esc = ClampWatchdog()
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_esc.note(True, "benign", T0) # spends the budget
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for _i in range(1, 1 + CLEAR_CYCLES + 1): # de-assert
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_esc.note(False, "", T0 + timedelta(seconds=5.0 * _i))
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_RUNAWAY_AT = 5.0 * (CLEAR_CYCLES + 2)
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_esc_fires = [5.0 * (CLEAR_CYCLES + 2 + _j)
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for _j in range(200)
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if _esc.note(True, "runaway",
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T0 + timedelta(seconds=5.0 * (CLEAR_CYCLES + 2 + _j)))]
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_esc_delay = _esc_fires[0] - _RUNAWAY_AT if _esc_fires else None
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print(f" budget spent by a benign episode, then a continuous runaway from "
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f"t={_RUNAWAY_AT:.0f}s: first alarm at t={_esc_fires[0]:.0f}s "
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f"(delay {_esc_delay:.0f}s)")
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check(f"⚠️ a SUSTAINED runaway speaks even when an earlier, unrelated episode "
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f"spent the budget - it is not held for REASSERT_S ({_esc_delay:.0f}s "
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f"delay, escalation is {SUSTAINED_CYCLES} cycles)",
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_esc_delay is not None and _esc_delay < REASSERT_S / 2)
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check("...and it speaks at the escalation boundary rather than immediately, "
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"which is what keeps the scattered flood suppressed",
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_esc_delay >= 5.0 * (SUSTAINED_CYCLES - 1))
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# ⚠️ `last_alarm` SURVIVING THE DE-ASSERT IS NOW LOAD-BEARING, AND NOTHING
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# PINNED IT. Review built the mutation: if the de-assert path ALSO refreshed
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# `last_alarm = now`, the chatter case collapses from 50 notifications to 1 - the
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# alarm never fires again. That is the "alarm that never fires" class, which is a
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# different bug from one that fires later, and the suite was green on it.
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_starve = ClampWatchdog()
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_starve_fires = sum(1 for _i in range(1600)
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if _starve.note(_i % 4 == 0, "chatter",
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T0 + timedelta(seconds=5.0 * _i)))
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print(f" chatter 1-engaged/{CLEAR_CYCLES}-clean over 8000 s: "
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f"{_starve.episodes} episodes, {_starve_fires} notification(s)")
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check(f"a de-assert does not RESET the notification budget, so repeated chatter "
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f"cannot starve the alarm to silence ({_starve_fires} notifications over "
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f"8000 s, not 1)",
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_starve_fires > 10)
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# --- THE HYSTERESIS, PINNED AGAINST THE CHATTER DIRECTION --------------------
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# ⚠️ REVIEW-FOUND. This used to issue `range(CLEAR_CYCLES - 1)` clean cycles,
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