SPRINT9 task for B+D. The demoted guard compared the worst corner's mean LOAD
across two windows and called the difference a "trend". The integrator's
diagnosis was that its clock was wrong — held at t=0, storm_02's compressed
rain ponds the cloth during the guard's own windows. That mechanism is real,
but it is not the bug, and neither of the two suggested fixes works. Measured
on the dressed yard, 0 s settle vs 12 s:
probe under CALM, held in prep 13% vs 17%
probe under STORM, held clock 24% vs 104%
probe under STORM, advancing clock 24% vs 104%
probe under STORM, RAINLESS 17% vs 96%
Every variant is either flat — calm cannot excite the cloth, so the guard is
vacuous and passes forever — or INVERTED, firing hardest on the properly
settled rig. Rain is not the culprit: the rainless probe ponds 1 kg and still
inverts. Advancing the clock isn't a fix either, because RAIN_TIME_COMPRESSION
is 40× and 4 s of storm is 160 s of rain regardless.
What a load-trend measures is the rig LOADING UP when the wind changes, and a
taut settled cloth ramps harder than a limp unsettled one (0.63 -> 1.23 kN vs
0.44 -> 0.52). The observable was pointed at the storm's arrival, not at the
cloth. No threshold, clock or rain switch fixes that.
"Settled" is a statement about the cloth, so ask the cloth. sail.js gains
nodeSpeed(): RMS node speed out of verlet. Sampled over 2 s of the same calm
prep the rig already stands in — no wind change to ramp against, no compressed
rain, and nothing left in the rig but two more seconds of prep a player does
anyway. Measured:
settle 0 s 4 s 12 s 30 s
speed 0.19 0.014 0.017 0.007 m/s (pyrrhic quad: 0.23 -> 0.028)
An order of magnitude, in the direction the word means. Absolute check at
0.08 m/s, not a trend: the cloth breathes at 0.02 and the transient sits at
0.19, so there is real room for a line.
Promoted back from warn to a hard failure — and it earns that by being able to
fail. `the settled-at-entry guard can fail` flies the same line with NO settle
and asserts the guard refuses it. A guard nobody has seen fail is
indistinguishable from one that cannot, which is exactly how this one survived
two sprints being both vacuous and inverted. The control is flown up front in
run(), because Suite.test() does not await.
The old guard also left 43 kg of water and 4 s of storm load in the rig before
the storm started; the suite was flying a wet rig into a dry entry. It didn't
move the peaks (the storm's own peak dwarfs it) but it was never true.
D: this is yours to veto. Selftest 277 passed, 0 failed, 0 skipped.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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