Add a fixture registering via the deprecated napi_module_register

The host gained support for addons that register themselves by calling
napi_module_register while their library loads (#445), but nothing in the
repo exercises that path — every other addon here exports
napi_register_module_v1, which the loader finds first.

This addon exports no such symbol, so it only loads if the fallback works.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013ugFE6vmMUVMTuoupvhMhX

Author: claude

packages/node-addon-examples/src/index.ts

@@ -86,6 +86,8 @@ export const suites: Record<
       require("../tests/buffers/addon.js");
     },
     async: () => require("../tests/async/addon.js") as () => Promise<void>,
+    "module-register": () =>
+      require("../tests/module-register/addon.js") as () => void,
     "threadsafe-function": () =>
       require("../tests/threadsafe-function/addon.js") as () => Promise<void>,
   },

packages/node-addon-examples/tests/module-register/CMakeLists.txt

@@ -0,0 +1,28 @@
+cmake_minimum_required(VERSION 3.15...3.31)
+project(module-register-test)
+
+find_package(weak-node-api REQUIRED CONFIG)
+
+add_library(module-register-test-addon SHARED addon.c)
+
+option(BUILD_APPLE_FRAMEWORK "Wrap addon in an Apple framework" ON)
+
+if(APPLE AND BUILD_APPLE_FRAMEWORK)
+  set_target_properties(module-register-test-addon PROPERTIES
+    FRAMEWORK TRUE
+    MACOSX_FRAMEWORK_IDENTIFIER module-register-test.addon
+    MACOSX_FRAMEWORK_SHORT_VERSION_STRING 1.0
+    MACOSX_FRAMEWORK_BUNDLE_VERSION 1.0
+    XCODE_ATTRIBUTE_SKIP_INSTALL NO
+    OUTPUT_NAME addon
+   )
+else()
+  set_target_properties(module-register-test-addon PROPERTIES
+    PREFIX ""
+    SUFFIX .node
+    OUTPUT_NAME addon
+   )
+endif()
+
+target_link_libraries(module-register-test-addon PRIVATE weak-node-api)
+target_compile_features(module-register-test-addon PRIVATE cxx_std_17)

packages/node-addon-examples/tests/module-register/addon.c

@@ -0,0 +1,42 @@
+#include <node_api.h>
+
+// This addon registers itself the deprecated way — a napi_module_register call
+// made while the library loads — and deliberately exports no
+// napi_register_module_v1 symbol, so a host that only looks for that symbol
+// cannot load it.
+//
+// The constructor is hand-rolled because node_api.h no longer offers a macro
+// that emits one: NAPI_MODULE_X is now an alias of the symbol-based
+// NAPI_MODULE.
+
+static napi_value Registration(napi_env env, napi_callback_info info) {
+  (void)info;
+  napi_value result;
+  if (napi_create_string_utf8(env, "napi_module_register", NAPI_AUTO_LENGTH,
+                              &result) != napi_ok) {
+    return NULL;
+  }
+  return result;
+}
+
+static napi_value Init(napi_env env, napi_value exports) {
+  napi_property_descriptor properties[] = {
+      {"registration", NULL, Registration, NULL, NULL, NULL, napi_default,
+       NULL},
+  };
+  if (napi_define_properties(env, exports,
+                             sizeof(properties) / sizeof(properties[0]),
+                             properties) != napi_ok) {
+    return NULL;
+  }
+  return exports;
+}
+
+static napi_module addon_module = {
+    NAPI_MODULE_VERSION, 0,    __FILE__, Init, "module-register-test",
+    NULL,                {0},
+};
+
+__attribute__((constructor)) static void RegisterAddon(void) {
+  napi_module_register(&addon_module);
+}

packages/node-addon-examples/tests/module-register/addon.js

@@ -0,0 +1,6 @@
+const assert = require("assert");
+const addon = require("bindings")("addon.node");
+
+module.exports = () => {
+  assert.strictEqual(addon.registration(), "napi_module_register");
+};

packages/node-addon-examples/tests/module-register/binding.gyp

@@ -0,0 +1,8 @@
+{
+  "targets": [
+    {
+      "target_name": "addon",
+      "sources": [ "addon.c" ]
+    }
+  ]
+}

packages/node-addon-examples/tests/module-register/package.json

@@ -0,0 +1,14 @@
+{
+  "name": "module-register-test",
+  "version": "0.0.0",
+  "description": "Tests of the deprecated napi_module_register registration",
+  "main": "addon.js",
+  "private": true,
+  "dependencies": {
+    "bindings": "~1.5.0"
+  },
+  "scripts": {
+    "test": "node addon.js"
+  },
+  "gypfile": true
+}