fix(roslyn): drop Workspaces-layer formatting so USE_ROSLYN compiles with the installer's DLLs

MCPForUnity/Editor/Tools/ManageScript.cs

@@ -14,7 +14,6 @@
 #if USE_ROSLYN
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
-using Microsoft.CodeAnalysis.Formatting;
 #endif
 
 #if UNITY_EDITOR
@@ -740,16 +739,6 @@ private static object ApplyTextEdits(
                     int endLineRos = firstLine + 5;
                     return new ErrorResponse("syntax_error", new { status = "syntax_error", diagnostics, evidenceWindow = new { startLine = startLineRos, endLine = endLineRos } });
                 }
-
-                // Optional formatting
-                try
-                {
-                    var root = tree.GetRoot();
-                    var workspace = new AdhocWorkspace();
-                    root = Microsoft.CodeAnalysis.Formatting.Formatter.Format(root, workspace);
-                    working = root.ToFullString();
-                }
-                catch { }
             }
 #endif
 

TestProjects/UnityMCPTests/Assets/Tests/EditMode/Setup/RoslynAsmdefReferenceTests.cs

@@ -39,6 +39,43 @@ public void EditorAsmdef_ReferencesEveryDllRoslynInstallerInstalls()
                 + string.Join(", ", missing));
         }
 
+        /// <summary>
+        /// RoslynInstaller ships the compiler layer only (Microsoft.CodeAnalysis + CSharp). The
+        /// Workspaces layer (AdhocWorkspace, Formatter, Microsoft.CodeAnalysis.Formatting) lives in
+        /// Microsoft.CodeAnalysis.Workspaces.dll / Microsoft.CodeAnalysis.CSharp.Workspaces.dll, which
+        /// the installer does not download and the asmdef does not reference. Any use of it under
+        /// USE_ROSLYN turns into CS0234 the moment the define is enabled (issue #1391).
+        /// </summary>
+        [Test]
+        public void EditorSources_DoNotUseRoslynWorkspacesLayer()
+        {
+            string[] workspacesApis =
+            {
+                "Microsoft.CodeAnalysis.Formatting",
+                "Microsoft.CodeAnalysis.Workspaces",
+                "AdhocWorkspace",
+            };
+
+            string editorRoot = Path.GetDirectoryName(ReadEditorAsmdefPath());
+            List<string> offenders = new List<string>();
+            foreach (string file in Directory.GetFiles(editorRoot, "*.cs", SearchOption.AllDirectories))
+            {
+                string source = File.ReadAllText(file);
+                foreach (string api in workspacesApis)
+                {
+                    if (source.IndexOf(api, StringComparison.Ordinal) >= 0)
+                    {
+                        offenders.Add($"{Path.GetFileName(file)} uses {api}");
+                    }
+                }
+            }
+
+            CollectionAssert.IsEmpty(offenders,
+                "MCPForUnity.Editor must only use the Roslyn compiler layer that RoslynInstaller installs; "
+                + "the Workspaces layer is not shipped or referenced, so USE_ROSLYN would fail to compile. Found: "
+                + string.Join(", ", offenders));
+        }
+
         private static List<string> GetInstallerDllNames()
         {
             FieldInfo field = typeof(RoslynInstaller).GetField(
@@ -57,11 +94,16 @@ private static List<string> GetInstallerDllNames()
         }
 
         private static string ReadEditorAsmdefJson()
+        {
+            return File.ReadAllText(ReadEditorAsmdefPath());
+        }
+
+        private static string ReadEditorAsmdefPath()
         {
             string path = CompilationPipeline.GetAssemblyDefinitionFilePathFromAssemblyName("MCPForUnity.Editor");
             Assert.IsFalse(string.IsNullOrEmpty(path), "Could not locate MCPForUnity.Editor.asmdef");
             Assert.IsTrue(File.Exists(path), $"asmdef path does not exist: {path}");
-            return File.ReadAllText(path);
+            return path;
         }
     }
 }