A timed-out script is abandoned, not stopped, and every seam re-ran it on the
next trigger, leaking one pool thread per trigger (R03:1.1, R05:2, R07:L1).
A shared ScriptRunGuard, keyed per script instance, now:
- refuses a run while that script's previous orphan is still executing
(Bad "previous evaluation still running" + otopcua.script.run_refused);
- quarantines after 3 consecutive non-completions or an allocation-budget
breach (sampled with GC.GetAllocatedBytesForCurrentThread; default 64 MB):
no further dispatch, Bad quality, one Error, otopcua.script.quarantined,
cleared on source change / redeploy / reset;
- starts the budget clock when the pool picks the run up, so starvation is
no longer charged to the script (R07:P5), and cancels the evaluator token
on timeout.
Wired into RoslynVirtualTagEvaluator, CalculationEvaluator (new async
EvaluateAsync; the driver's pump and timer ticks now await the run behind a
SemaphoreSlim gate) and ScriptedAlarmEngine (a non-completing predicate
holds state and annotates the condition BadInternalError). ScriptingOptions
(Scripting:MaxAllocBytesPerRun, Scripting:QuarantineAfterConsecutiveTimeouts)
carries the knobs; the Calculation driver config accepts the same two keys.
Tests: guard unit suite (incl. the 30-trigger runaway leaving one orphan with
a healthy sibling as positive control), per-seam refusal/quarantine/reset
tests. The S12 race test now uses one vtag id per loop: twelve concurrent
evaluations of ONE id is a shape production never produces and the guard
refuses by design.
Refs #734
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty