From dca0c5d095e193b737c5419d7c8f65c72ea96644 Mon Sep 17 00:00:00 2001
From: Libby <libby@noreply.eureka.gamecult.org>
Date: Thu, 12 Nov 2026 18:47:44 +0000
Subject: [PATCH] C#: pin the one-value refusal on codec and Mesh single-file
 reads (#141)

---
 .../BytesAfterVectorTests.cs                   |  9 +++++++++
 .../GameCult.Mesh.Tests/BytesAfterPathTests.cs | 18 ++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/tests/GameCult.Caching.Tests/BytesAfterVectorTests.cs b/tests/GameCult.Caching.Tests/BytesAfterVectorTests.cs
index 86d677e6..65b1d6da 100644
--- a/tests/GameCult.Caching.Tests/BytesAfterVectorTests.cs
+++ b/tests/GameCult.Caching.Tests/BytesAfterVectorTests.cs
@@ -110,6 +110,15 @@ namespace GameCult.Caching.Tests
             Assert.That(message, Does.Contain(typeof(UnionSurface).FullName).And.Contain($"1 {Clause}").And.Contain("refused on read"));
         }
 
+        // The inspector reads documents through CultCodec.Deserialize (type == document), not DecodeDocument: its branch is its own path.
+        [Test]
+        public void CodecDeserializeOfADocumentRefusesATail()
+        {
+            var codec = CultCacheMessagePack.CreateCodec(Registry);
+            var message = Message(() => codec.Deserialize(typeof(UnionSurface), typeof(UnionSurface), Base.Concat(new byte[] { 0xc0 }).ToArray()));
+            Assert.That(message, Does.Contain(typeof(UnionSurface).FullName).And.Contain($"1 {Clause}").And.Contain("refused on read"));
+        }
+
         [Test]
         public void StoreLoadRefuses()
         {
diff --git a/tests/GameCult.Mesh.Tests/BytesAfterPathTests.cs b/tests/GameCult.Mesh.Tests/BytesAfterPathTests.cs
index ed9b904b..28c6d3de 100644
--- a/tests/GameCult.Mesh.Tests/BytesAfterPathTests.cs
+++ b/tests/GameCult.Mesh.Tests/BytesAfterPathTests.cs
@@ -58,4 +58,22 @@ public class BytesAfterPathTests
             .MakeGenericMethod(typeof(CultMeshCdnArtifactManifest));
         Refusal(() => read.Invoke(null, new object[] { snapshot, record.SchemaId, record.RecordKey })).Should().Contain(Clause);
     }
+
+    [Test]
+    public void ASingleFileDocumentReadRefusesATail()
+    {
+        var path = System.IO.Path.Combine(System.IO.Path.GetTempPath(), $"cultlib-bytesafter-mesh-{Guid.NewGuid():N}.cc");
+        try
+        {
+            var descriptor = CultDocumentRegistry.Shared.GetRequired<CultMeshCdnArtifactManifest>();
+            var schema = new CultMeshSingleFileDocumentSchema(descriptor.SchemaId, descriptor.SchemaName, descriptor.SchemaVersion);
+            var payload = WithTail(Manifest()).Payload;
+            CultMesh.WriteSingleFileDocumentPayload(path, new CultRecordKey("k"), schema, null, payload);
+            Refusal(() => CultMesh.ReadSingleFileDocument<CultMeshCdnArtifactManifest>(path, new CultRecordKey("k"))).Should().Contain(Clause);
+        }
+        finally
+        {
+            System.IO.File.Delete(path);
+        }
+    }
 }