perf(scripting): cache ScriptSandbox BCL + pinned metadata references (#603)

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
2026-10-08 06:52:35 -04:00
parent a8703c6afe
commit 1b37b2f2b0
2 changed files with 26 additions and 3 deletions
@@ -57,4 +57,18 @@ public sealed class ScriptSandboxBuildTests
            """return (double)ctx.GetTag("X").Value;""");
        evaluator.ShouldNotBeNull();
    }
+
+    /// <summary>#603: the BCL reference set is built once per process, so two Build calls share the same
+    /// <c>MetadataReference</c> instances rather than re-reading ~170 DLLs per compile.</summary>
+    [Fact]
+    public void Build_reuses_metadata_reference_instances_across_calls()
+    {
+        var first = ScriptSandbox.Build(typeof(ScriptContext));
+        var second = ScriptSandbox.Build(typeof(ScriptContext));
+
+        first.References.Count.ShouldBeGreaterThan(50);
+        first.References.Count.ShouldBe(second.References.Count);
+        for (var i = 0; i < first.References.Count; i++)
+            ReferenceEquals(first.References[i], second.References[i]).ShouldBeTrue($"reference {i} was rebuilt");
+    }
 }