Both VirtualTagEngine.Load and ScriptedAlarmEngine.LoadAsync were calling
ScriptEvaluator.Compile directly, bypassing CompiledScriptCache. The
Core.Scripting-008 collectible-ALC fix wired Dispose only through the cache's
Clear()/Dispose(), so the per-publish accretion the -008 fix was meant to
eliminate was still in effect on the actual production path — the headline
'no more restarts needed' guarantee wasn't delivered.
Resolution:
- VirtualTagEngine + ScriptedAlarmEngine each gained a private
CompiledScriptCache<TContext, TResult> instance.
- Both Load methods now call _compileCache.GetOrCompile(source).
- Publish-replace path: _compileCache.Clear() runs alongside the existing
_tags / _alarms clears so the prior generation's ALCs are disposed
before recompile.
- Engine Dispose now calls _compileCache.Dispose() so shutdown actually
releases the emitted assemblies.
Side-fix in CompiledScriptCache: Dispose() set _disposed=true then called
Clear(), but Clear() had a pre-existing 'if (_disposed) return' guard that
aborted the drain unconditionally — making the Dispose-triggered cleanup a
silent no-op. Removed the disposed-guard on Clear() (clearing an empty/
cleared cache is idempotent).
Side-fix in ScriptedAlarmEngine.Dispose: cleared _alarms AFTER the
Task.WhenAll drain. The drain guarantees no background callback is mid-
flight, so clearing is safe. Previously _alarms was deliberately NOT
cleared on Dispose (per Core.ScriptedAlarms-005), but that left the
AlarmState records holding TimedScriptEvaluator → ScriptEvaluator → delegate
references that rooted the emitted assemblies, defeating the cache's
Dispose work on the engine side.
Regression tests:
- VirtualTagEngineTests.Dispose_unloads_compiled_script_assembly
- ScriptedAlarmEngineTests.Dispose_unloads_compiled_predicate_assembly
Both use WeakReference + bounded GC.Collect() to prove the emitted
assembly is reclaimable after engine.Dispose(). The alarms test had to
be synchronous (not 'async Task<WeakReference>') because async state
machines capture locals as state-struct fields, keeping them alive past
the method's apparent end and defeating GC.
Verification:
- Core.Scripting.Tests: 104/104 (unchanged).
- VirtualTags.Tests: 57/57 (was 56 — +1 unload test).
- ScriptedAlarms.Tests: 67/67 (was 66 — +1 unload test).
- All other consumer suites still green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Core.Scripting-008 resolution: replace the legacy CSharpScript.CreateDelegate
path with hand-rolled CSharpCompilation + Emit + collectible AssemblyLoadContext,
so per-publish compile accretion no longer requires a server restart to reclaim.
Why this was needed:
Roslyn's CSharpScript path emits dynamically-compiled script assemblies into
the default AssemblyLoadContext, which is non-collectible. Across config-
publish generations each Clear() drops dictionary entries but the emitted
assemblies stay loaded for process lifetime, so memory grows steadily on
long-running servers with frequent publishes. The accepted-limitation note
in docs/VirtualTags.md recommended scheduled restarts as the workaround;
operator feedback was that restarts are difficult, so the underlying
limitation was the right thing to fix.
Implementation:
- New ScriptAssemblyLoadContext(name, isCollectible: true) hosts one emitted
script assembly per evaluator.
- ScriptEvaluator.Compile synthesises a wrapper class around the user source
(CompiledScript.Run(globals) — explicit return required per ordinary C#
semantics, which every existing script already uses), builds a
CSharpCompilation against the sandbox references, runs the
ForbiddenTypeAnalyzer over the semantic model unchanged, emits to an
in-memory PE stream, loads via ScriptAssemblyLoadContext.LoadFromStream,
and binds a strongly-typed Func<ScriptGlobals<TContext>, TResult> delegate
via reflection.
- ScriptEvaluator now implements IDisposable — Dispose calls
AssemblyLoadContext.Unload(), which makes the emitted assembly eligible
for GC at the next collection cycle.
- CompiledScriptCache.Clear() disposes every materialised evaluator before
dropping its dictionary entry; CompiledScriptCache itself is now
IDisposable for graceful server shutdown.
- ScriptSandbox.Build returns a new SandboxConfig (References + Imports)
instead of a Roslyn ScriptOptions; references now span BCL via the
TRUSTED_PLATFORM_ASSEMBLIES set filtered to System.* + netstandard +
Microsoft.Win32.Registry, so forbidden BCL types resolve at compile and
ForbiddenTypeAnalyzer is the sole security gate (consistent with the
Core.Scripting-001 / -002 model — references-list-only restriction is
porous against type forwarding, so the analyzer must be the real gate).
Verification:
- All 104 Core.Scripting tests pass (was 101 — three new regression tests
locking the unload contract).
- All 56 VirtualTags tests pass (unchanged).
- All 63 ScriptedAlarms tests pass (unchanged).
- New CompiledScriptCacheTests:
- Dispose_unloads_compiled_script_assembly_load_context — proves single-
evaluator ALC unload via WeakReference + bounded GC.Collect() loop.
- Clear_disposes_every_materialised_evaluator — proves publish-replace
releases every prior generation's ALC.
- GetOrCompile_after_Dispose_throws_ObjectDisposedException — locks the
post-dispose contract.
Docs:
- docs/VirtualTags.md "Compile cache" section rewritten: the accepted-
limitation note replaced with the unload contract + the new authoring
convention (explicit return).
- docs/ScriptedAlarms.md cross-reference updated to drop the obsolete
restart guidance.
- code-reviews/Core.Scripting/findings.md Core.Scripting-008 flipped
Won't Fix → Resolved with the implementation summary.
- code-reviews/README.md regenerated.
Pre-existing breakage note: Driver.Galaxy fails the solution-wide build on
master because its ProjectReference to the sibling mxaccessgw repo's
MxGateway.Client targets a path that the sibling repo no longer has after a
recent restructuring. This is unrelated to Core.Scripting-008 and was
verified to exist on master before this branch was cut.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
- Core.Scripting-005: DependencyExtractor.HandleTagCall now recognises
raw-string literal paths by checking the StringLiteralExpression node
kind instead of the legacy StringLiteralToken kind.
- Core.Scripting-006: scope CompiledScriptCache failed-compile eviction
with TryRemove(KeyValuePair) so a racing retry entry is not evicted.
- Core.Scripting-008: document the per-publish assembly accretion as an
accepted limitation in docs/VirtualTags.md.
- Core.Scripting-009: enumerate the authoritative deny-list (namespace
prefixes + type-granular denies) in the Phase 7 decision-#6 entry to
match ForbiddenTypeAnalyzer.
- Core.Scripting-011: pin ScriptSandbox.Build, ScriptContext.Deadband
boundary semantics, and end-to-end factory + companion-sink
integration.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
System.Threading.Thread is in the System.Threading namespace (not
System.Threading.Thread), so the existing ForbiddenNamespacePrefixes
entry "System.Threading.Thread" never matched — the namespace prefix
check compared against the type's containing namespace, which is
System.Threading. Move Thread into ForbiddenFullTypeNames (alongside
Environment / AppDomain / GC / Activator) where it is matched by exact
fully-qualified type name, which actually fires. Remove the dead
namespace-prefix entry and document why. The Rejects_Thread_new_at_compile
test now passes. (Core.Scripting-010.)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
In TimedScriptEvaluator.RunAsync, the catch (TimeoutException) block
now checks ct.IsCancellationRequested before throwing
ScriptTimeoutException, so a caller cancellation that races a timeout
deterministically surfaces as OperationCanceledException regardless of
which WaitAsync observes first. Regression test
Caller_cancellation_wins_even_when_timeout_fires_first added.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
DependencyExtractor.VisitInvocationExpression now additionally checks
that the member-access receiver is the identifier "ctx" before treating
a GetTag / SetVirtualTag call as a ScriptContext dependency. This
prevents spurious dependencies when a script defines a local helper type
with a matching method name and calls it as other.GetTag("X"). Test
Ignores_member_access_GetTag_on_non_ctx_receiver added.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Add System.Threading.Tasks to ForbiddenNamespacePrefixes so scripts
cannot use Task.Run / Parallel to spawn background work that outlives
the per-evaluation timeout. Document the unbounded-memory accepted
trade-off and the Task denial rationale in docs/VirtualTags.md (new
"Known resource limits" subsection) and cross-reference from
docs/ScriptedAlarms.md.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The ForbiddenTypeAnalyzer syntax walker only inspected four node kinds
(ObjectCreation, Invocation-with-member-access, MemberAccess, bare
Identifier), so a forbidden type named through typeof, a generic type
argument, a cast, an is/as type pattern, default(T), an array-creation
element type, or an explicitly-typed local declaration produced no
examined node and bypassed the sandbox check.
Analyze now runs a second pass that resolves GetTypeInfo on every
TypeSyntax node and recursively unwraps array element types and generic
type arguments, so forbidden types nested at any depth are rejected at
compile. The original member/call node-kind switch is kept deliberately
narrow (rather than resolving GetSymbolInfo on every node) to avoid
flagging harmless inherited members such as typeof(int).Name, whose Name
property is declared by System.Reflection.MemberInfo. A span+type dedupe
keeps the two passes from emitting duplicate rejections.
Regression tests added in ScriptSandboxTests cover typeof, generic type
arguments, casts, default(T), is/as patterns, array element types, and
typed local declarations with forbidden types, plus over-block guards
asserting allowed generics and typeof still compile.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
ForbiddenTypeAnalyzer used only a namespace-prefix deny-list. System.Environment,
System.AppDomain, System.GC and System.Activator live directly in the System
namespace, which must stay allowed for primitives (Math, String, ...), so they
were never caught — an operator-authored predicate could call
System.Environment.Exit(0) and terminate the in-process OPC UA server.
Add a type-granular deny-list (ForbiddenFullTypeNames) checked by
fully-qualified type name after the namespace-prefix check; legitimate System
types are unaffected.
Regression tests assert scripts referencing Environment/AppDomain/GC/Activator
are rejected at analysis time. Core.Scripting suite: 68/68 pass.
Resolves code-review finding Core.Scripting-001 (Critical).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Group all 69 projects into category subfolders under src/ and tests/ so the
Rider Solution Explorer mirrors the module structure. Folders: Core, Server,
Drivers (with a nested Driver CLIs subfolder), Client, Tooling.
- Move every project folder on disk with git mv (history preserved as renames).
- Recompute relative paths in 57 .csproj files: cross-category ProjectReferences,
the lib/ HintPath+None refs in Driver.Historian.Wonderware, and the external
mxaccessgw refs in Driver.Galaxy and its test project.
- Rebuild ZB.MOM.WW.OtOpcUa.slnx with nested solution folders.
- Re-prefix project paths in functional scripts (e2e, compliance, smoke SQL,
integration, install).
Build green (0 errors); unit tests pass. Docs left for a separate pass.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Joseph Doherty