U2 (Critical): RoslynVirtualTagEvaluator ran scripts with a CancellationToken
that a synchronous Roslyn script can never observe, so one CPU-bound/infinite-
loop virtual-tag script hung the owning VirtualTagActor forever (no timeout, no
recovery). Route evaluation through the existing TimedScriptEvaluator (Task.Run
+ WaitAsync) so the wall-clock budget is real; a runaway script now returns Bad
within the timeout instead of wedging the actor.
U3 (High): the live path cached evaluators in a raw ConcurrentDictionary never
cleared on republish, leaking a collectible AssemblyLoadContext per edited
script forever. Swap in the purpose-built CompiledScriptCache (Lazy single-
compile, dispose-on-Clear) and add an apply-boundary clear: a new narrow
IScriptCacheOwner seam the VirtualTagHostActor calls on each ApplyVirtualTags
generation (mirrors ScriptedAlarmEngine's per-generation clear).
Tests: infinite-loop-fails-within-timeout (bounded by WaitAsync so a regression
fails instead of hanging), happy-path-after-wrapping, ClearCompiledScripts-
empties-cache, and a host-actor wiring guard asserting each apply generation
calls ClearCompiledScripts (theme #1 production-caller assertion). Host.Integration
VT suite 18/18, Runtime VT suite 12/12.
Joseph Doherty
7fd44f0fa7