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.
Adds <summary>/<param>/<returns>/<inheritdoc> where missing and removes
project bookkeeping IDs (task/tracking refs) from shipped code comments,
so the docs read cleanly and CommentChecker is quiet except for known
false positives (PLC/protocol terms, event/IEqualityComparer inheritdoc).
Doc/comment-only; no logic changed; solution builds clean.
Adds <summary>, <param>, <typeparam>, and <inheritdoc/> tags to public
members surfaced by commentchecker — resolves 5,847 of 5,869 issues
(99.6%) across three /fixdocs passes.
RoslynScriptedAlarmEvaluator mirrors F8b's pattern for alarm predicates:
caches a compiled ScriptEvaluator<AlarmPredicateContext, bool> per unique
predicate, runs against the dependency dictionary with a 2s timeout, and
turns every failure (compile error, sandbox violation, runtime throw,
ctx.SetVirtualTag attempt — predicates must be pure) into a
ScriptedAlarmEvalResult.Failure. ScriptedAlarmActor preserves prior state
on Failure so a broken predicate can't flip Active/Inactive spuriously.
Program.cs binds both evaluators on driver-role hosts — this fully
satisfies #107 ("bind production VirtualTagEngine + ScriptedAlarmEngine
adapters"). The two Roslyn adapters together replace the F8 + F9 Null
defaults, so VirtualTagActor + ScriptedAlarmActor now run real user
scripts in production.
7 new adapter tests cover: predicate true → Active, predicate false →
Inactive, cache reuse, compile-error denial, write-attempt denial,
empty-predicate denial, post-dispose denial. Host.IntegrationTests now
17/17 green.
Closes#80 + #107. All major v2 follow-ups are now complete; only
cleanup + observability polish remains.
RoslynVirtualTagEvaluator wraps Core.Scripting.ScriptEvaluator + Core
.VirtualTags.VirtualTagContext into a single-tag IVirtualTagEvaluator
adapter. Caches the compiled ScriptEvaluator per unique expression so
the second-and-onwards Evaluate is an in-process method call against the
dependency dictionary. Compile/sandbox/runtime errors all surface as
VirtualTagEvalResult.Failure rather than propagating exceptions through
the VirtualTagActor message loop.
Single-tag scope: cross-tag ctx.SetVirtualTag writes are dropped + logged
because fan-out between actors is owned by DependencyMuxActor. Cycle
detection + cascade ordering stay in Core.VirtualTags.VirtualTagEngine
where they belong (loaded fleet-wide); this adapter keeps the actor
message handler simple.
Host adds Core.Scripting + Core.VirtualTags project refs, plus a
TargetWarningsAsErrors NU1608 suppression — Microsoft.CodeAnalysis.CSharp
.Scripting 4.12.0 pins Common to 4.12.0 but ASP.NET Core transitively
brings Microsoft.CodeAnalysis.Common 5.0.0; the surface we use is stable
across the drift (verified by Core.Scripting.Tests).
Program.cs binds RoslynVirtualTagEvaluator → IVirtualTagEvaluator on
driver-role hosts, replacing the F8-default NullVirtualTagEvaluator so
VirtualTagActor evaluates real user scripts at runtime.
6 new adapter tests cover: simple expression sums, cache reuse across
calls, compile-error denial, runtime-throw denial, empty-expression
denial, post-dispose denial. Host.IntegrationTests now 10/10 green.
Closes#79. F9b + #107 next.
Joseph Doherty