ScriptContext.CancellationToken is backed by an AsyncLocal that
ScriptEvaluator.RunAsync scopes around the compiled delegate, so it is
exactly the token ScriptRunGuard cancels on timeout. A polling script
can now end its own abandoned run and free the slot. AsyncLocal rather
than a field because the scripted-alarm engine reuses one context per
alarm: an orphan keeps seeing its own cancelled token. The scoping
entry point is internal (IVT to Core.Scripting) so a script cannot
replace its own token.
Editor parity: ScriptAnalysisService dot-completion now walks the
receiver's base chain (instance members only, stopping before
System.Object). Before this, a member declared only on ScriptContext
compiled and published but never completed. DiagnoseTests pins the
member as allow-listed; CompletionTests pins the completion.
Refs #731#734
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
R05:10 — the namespace deny-list covered System.Threading.Tasks but not
System.Threading, so SemaphoreSlim / Monitor / SpinWait / Mutex /
EventWaitHandle could park a script's pool thread past its budget (or touch a
system-global kernel object); System.Type.GetType(string) / GetMethod* /
InvokeMember and System.Runtime.CompilerServices.RuntimeHelpers resolved and
reach a forbidden type without naming it syntactically.
ForbiddenTypeAnalyzer now denies the whole System.Threading namespace with a
type-granular allow-list (CancellationToken, Interlocked, Volatile — the
sync-free primitives), adds a member deny-list for System.Type's reflection
entry points (GetType/GetMethod(s)/InvokeMember/GetProperty(ies)/GetField(s)/
GetMember(s)/GetConstructor(s)/GetEvent(s)/GetDefaultMembers; instance
object.GetType() stays allowed) and puts RuntimeHelpers on the type deny-list.
Thread/ThreadPool/Timer leave the type list — the prefix rule reaches them.
R05:11 — the allocation budget landed with E1's ScriptRunGuard
(Scripting:MaxAllocBytesPerRun, default 64 MB): sampled around each run,
breach quarantines. It is observation after the fact; a pre-emptive OOM guard
still needs an out-of-process runner (follow-up issue in the lane report).
The Monaco editor shares the analyzer, so DiagnoseTests pins every new form
as an OTSCRIPT_FORBIDDEN marker and every allow-listed form as clean.
Refs #734
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty