fix(napi): clear currently registering module slot (#19249)

This commit fixes problem with loading N-API modules that use 
the "old" way of registration (using "napi_module_register" API).
The slot was not cleared after loading modules, causing subsequent
calls that use the new way of registration (using 
"napi_register_module_v1" API) to try and load the previous module.

Ref https://github.com/denoland/deno/issues/16460

---------

Co-authored-by: Divy Srivastava <dj.srivastava23@gmail.com>

1 files changed, 68 insertions, 0 deletions

diff --git a/test_napi/module.c b/test_napi/module.c
new file mode 100644
index 000000000..4548aa37f
--- /dev/null
+++ b/test_napi/module.c
@@ -0,0 +1,68 @@
+typedef struct napi_module {
+  int nm_version;
+  unsigned int nm_flags;
+  const char* nm_filename;
+  void* nm_register_func;
+  const char* nm_modname;
+  void* nm_priv;
+  void* reserved[4];
+} napi_module;
+
+#ifdef _WIN32
+#define NAPI_EXTERN __declspec(dllexport)
+#define NAPI_CDECL __cdecl
+#else
+#define NAPI_EXTERN __attribute__((visibility("default")))
+#define NAPI_CDECL
+#endif
+
+NAPI_EXTERN void NAPI_CDECL
+napi_module_register(napi_module* mod);
+
+#if defined(_MSC_VER)
+#if defined(__cplusplus)
+#define NAPI_C_CTOR(fn)                                                        \
+  static void NAPI_CDECL fn(void);                                             \
+  namespace {                                                                  \
+  struct fn##_ {                                                               \
+    fn##_() { fn(); }                                                          \
+  } fn##_v_;                                                                   \
+  }                                                                            \
+  static void NAPI_CDECL fn(void)
+#else  // !defined(__cplusplus)
+#pragma section(".CRT$XCU", read)
+// The NAPI_C_CTOR macro defines a function fn that is called during CRT
+// initialization.
+// C does not support dynamic initialization of static variables and this code
+// simulates C++ behavior. Exporting the function pointer prevents it from being
+// optimized. See for details:
+// https://docs.microsoft.com/en-us/cpp/c-runtime-library/crt-initialization?view=msvc-170
+#define NAPI_C_CTOR(fn)                                                        \
+  static void NAPI_CDECL fn(void);                                             \
+  __declspec(dllexport, allocate(".CRT$XCU")) void(NAPI_CDECL * fn##_)(void) = \
+      fn;                                                                      \
+  static void NAPI_CDECL fn(void)
+#endif  // defined(__cplusplus)
+#else
+#define NAPI_C_CTOR(fn)                                                        \
+  static void fn(void) __attribute__((constructor));                           \
+  static void fn(void)
+#endif
+
+#define NAPI_MODULE_TEST(modname, regfunc)                                     \
+  static napi_module _module = {                                               \
+      1,                                                                       \
+      0,                                                                       \
+      __FILE__,                                                                \
+      regfunc,                                                                 \
+      #modname,                                                                \
+      0,                                                                       \
+      {0},                                                                     \
+  };                                                                           \
+  NAPI_C_CTOR(_register_##modname) { napi_module_register(&_module); }         \
+
+void* init(void* env __attribute__((unused)), void* exports) {
+  return exports;
+}
+
+NAPI_MODULE_TEST(TEST_NAPI_MODULE_NAME, init)