From 34e1a78e68fb8b4ad7c9c662eccda71bc207988b Mon Sep 17 00:00:00 2001
From: Joseph Doherty <dohejw01@gmail.com>
Date: Wed, 12 Aug 2026 16:39:38 -0400
Subject: [PATCH] fix(scripts): memoize missing-assembly resolution in the UI
 script editor/sandbox

---
 .../ScriptAnalysis/ScriptAnalysisService.cs      | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/ZB.MOM.WW.ScadaBridge.CentralUI/ScriptAnalysis/ScriptAnalysisService.cs b/src/ZB.MOM.WW.ScadaBridge.CentralUI/ScriptAnalysis/ScriptAnalysisService.cs
index dd1d3698..5157ed09 100644
--- a/src/ZB.MOM.WW.ScadaBridge.CentralUI/ScriptAnalysis/ScriptAnalysisService.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.CentralUI/ScriptAnalysis/ScriptAnalysisService.cs
@@ -41,6 +41,21 @@ namespace ZB.MOM.WW.ScadaBridge.CentralUI.ScriptAnalysis;
 /// </summary>
 public class ScriptAnalysisService
 {
+    /// <summary>
+    /// Base Roslyn scripting options for every editor analysis, shared by
+    /// <see cref="SandboxOptions"/> and by the per-request options derived from it
+    /// (<c>ScriptOptions</c> is immutable-with-copy, so derivations inherit this).
+    ///
+    /// <para>
+    /// Editor diagnostics compile on EVERY analysis request — one per debounced
+    /// keystroke burst — and Roslyn's default resolver re-resolves the transitive
+    /// closure of these references through <c>MetadataReference.CreateFromFile</c> on
+    /// every one of them, minting fresh <c>AssemblyMetadata</c> → <c>PEReader</c> →
+    /// <c>NativeHeapMemoryBlock</c> copies that nothing disposes. The shared
+    /// <see cref="SharedTrust.CachingScriptMetadataResolver"/> memoizes those
+    /// resolutions process-wide; see its doc for the full mechanism.
+    /// </para>
+    /// </summary>
     private static readonly ScriptOptions DefaultOptions = ScriptOptions.Default
         .AddReferences(
             typeof(object).Assembly,
@@ -50,6 +65,7 @@ public class ScriptAnalysisService
             typeof(Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo).Assembly,
             typeof(Commons.Types.ScriptParameters).Assembly,
             typeof(SandboxScriptHost).Assembly)
+        .WithMetadataResolver(SharedTrust.CachingScriptMetadataResolver.Instance)
         .AddImports(
             "System",
             "System.Collections.Generic",