module: fix main resolution and not found updates

This simplifies the top-level load when ES modules are enabled
as we can entirely delegate the module resolver, which will hand
over to CommonJS where appropriate.

All not found errors are made consistent to throw during resolve
and have the MODULE_NOT_FOUND code.

Includes the test case from https://github.com/nodejs/node/pull/15736.

Fixes: https://github.com/nodejs/node/issues/15732
PR-URL: https://github.com/nodejs/node/pull/16147
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/src/module_wrap.cc b/src/module_wrap.cc
index 829248b681..bda760369e 100644
--- a/src/module_wrap.cc
+++ b/src/module_wrap.cc
@@ -442,6 +442,11 @@ URL resolve_directory(const URL& search, bool read_pkg_json) {
 URL Resolve(std::string specifier, const URL* base, bool read_pkg_json) {
   URL pure_url(specifier);
   if (!(pure_url.flags() & URL_FLAGS_FAILED)) {
+    // just check existence, without altering
+    auto check = check_file(pure_url, true);
+    if (check.failed) {
+      return URL("");
+    }
     return pure_url;
   }
   if (specifier.length() == 0) {
@@ -493,9 +498,8 @@ void ModuleWrap::Resolve(const FunctionCallbackInfo<Value>& args) {
 
   URL result = node::loader::Resolve(*specifier_utf, &url, true);
   if (result.flags() & URL_FLAGS_FAILED) {
-    std::string msg = "module ";
+    std::string msg = "Cannot find module ";
     msg += *specifier_utf;
-    msg += " not found";
     env->ThrowError(msg.c_str());
     return;
   }