[pitboss/grind] deferred session-0015 (20260520T233019Z-6958)

src/dynamic/lang/go.rs

@@ -1101,6 +1101,7 @@ fn generate_go_mod() -> String {
 fn emit_class_method_harness(class: &str, method: &str) -> HarnessSource {
     let shim = probe_shim();
     let go_mod = generate_go_mod();
+    let auto_registry = generate_auto_receiver_registry(class);
     let source = format!(
         r##"// Nyx dynamic harness — class method (Phase 19 / Track M.1).
 package main
@@ -1118,9 +1119,13 @@ import (
 func nyxBuildReceiver(structName string) (reflect.Value, error) {{
 	// Look up the exported type by name on the entry package.  Go's
 	// reflect API does not expose package-level reflection over types
-	// directly, so the dispatcher uses the package's well-known
-	// `NyxReceivers` registry the entry file is expected to publish.
-	if r, ok := entry.NyxReceivers[structName]; ok {{
+	// directly, so the dispatcher uses a generated `NyxAutoReceivers`
+	// registry that the harness ships into the entry package at
+	// compile time (see `entry/nyx_auto_registry.go`).  Real-world
+	// projects under test never need to hand-declare the registry —
+	// the auto-generated file references the target type by name and
+	// the Go compiler enforces the contract.
+	if r, ok := entry.NyxAutoReceivers[structName]; ok {{
 		return reflect.ValueOf(r), nil
 	}}
 	return reflect.Value{{}}, fmt.Errorf("class not found: %s", structName)
@@ -1180,11 +1185,40 @@ func main() {{
         source,
         filename: "main.go".to_owned(),
         command: vec!["./nyx_harness".to_owned()],
-        extra_files: vec![("go.mod".to_owned(), go_mod)],
+        extra_files: vec![
+            ("go.mod".to_owned(), go_mod),
+            (
+                "entry/nyx_auto_registry.go".to_owned(),
+                auto_registry,
+            ),
+        ],
         entry_subpath: Some("entry/entry.go".to_owned()),
     }
 }
 
+/// Generate an `entry/nyx_auto_registry.go` source that publishes a
+/// `NyxAutoReceivers` map keyed by the target class name to a
+/// zero-constructed instance.  The generated file lives in package
+/// `entry` so it can reference `class` by bare identifier without
+/// re-exporting through the harness package.  Compile-time enforcement
+/// of the contract is delegated to the Go compiler — if the entry
+/// package does not declare `class`, the build fails with a clear
+/// `undefined: <class>` error.
+fn generate_auto_receiver_registry(class: &str) -> String {
+    format!(
+        r##"// Code generated by Nyx — DO NOT EDIT.
+package entry
+
+// NyxAutoReceivers maps a class name to a zero-constructed instance
+// the dynamic harness uses to reflect on methods at runtime.
+var NyxAutoReceivers = map[string]interface{{}}{{
+	"{class}": {class}{{}},
+}}
+"##,
+        class = class,
+    )
+}
+
 /// Phase 20 (Track M.2) — message-handler harness for Go.
 ///
 /// The entry package is expected to declare a top-level handler