module,win: fix long path resolve

Fixes: #50753

Author: StefanStojanovic

src/node_file.cc

@@ -2905,6 +2905,9 @@ void BindingData::LegacyMainResolve(const FunctionCallbackInfo<Value>& args) {
 
     for (int i = 0; i < legacy_main_extensions_with_main_end; i++) {
       file_path = *initial_file_path + std::string(legacy_main_extensions[i]);
+#ifdef _WIN32
+      file_path = "\\\\?\\" + file_path;
+#endif
 
       switch (FilePathIsFile(env, file_path)) {
         case BindingData::FilePathIsFileReturnType::kIsFile:
@@ -2942,6 +2945,9 @@ void BindingData::LegacyMainResolve(const FunctionCallbackInfo<Value>& args) {
        i < legacy_main_extensions_package_fallback_end;
        i++) {
     file_path = *initial_file_path + std::string(legacy_main_extensions[i]);
+#ifdef _WIN32
+    file_path = "\\\\?\\" + file_path;
+#endif
 
     switch (FilePathIsFile(env, file_path)) {
       case BindingData::FilePathIsFileReturnType::kIsFile:

src/node_modules.cc

@@ -256,8 +256,13 @@ void BindingData::ReadPackageJSON(const FunctionCallbackInfo<Value>& args) {
       permission::PermissionScope::kFileSystemRead,
       path.ToStringView());
 
+#ifdef _WIN32
+  auto package_json = GetPackageJSON(
+      realm, "\\\\?\\" + path.ToString(), is_esm ? &error_context : nullptr);
+#else
   auto package_json =
       GetPackageJSON(realm, path.ToString(), is_esm ? &error_context : nullptr);
+#endif
   if (package_json == nullptr) {
     return;
   }

test/es-module/test-GH-50753.js

@@ -0,0 +1,42 @@
+'use strict';
+
+// Flags: --expose-internals
+
+const common = require('../common');
+if (!common.isWindows) {
+  common.skip('this test is Windows-specific.');
+}
+
+const fs = require('fs');
+const path = require('path');
+const tmpdir = require('../common/tmpdir');
+
+// https://github.com/nodejs/node/issues/50753
+// Make a path that is more than 260 chars long.
+// Module layout will be the following:
+//  package.json
+//  main
+//    main.js
+
+const packageDirNameLen = Math.max(260 - tmpdir.path.length, 1);
+const packageDirName = tmpdir.resolve('x'.repeat(packageDirNameLen));
+const packageDirPath = path.resolve(packageDirName);
+const packageJsonFilePath = path.join(packageDirPath, 'package.json');
+const mainDirName = 'main';
+const mainDirPath = path.resolve(packageDirPath, mainDirName);
+const mainJsFile = 'main.js';
+const mainJsFilePath = path.resolve(mainDirPath, mainJsFile);
+
+tmpdir.refresh();
+
+fs.mkdirSync(packageDirPath);
+fs.writeFileSync(
+  packageJsonFilePath,
+  `{"main":"${mainDirName}/${mainJsFile}"}`
+);
+fs.mkdirSync(mainDirPath);
+fs.writeFileSync(mainJsFilePath, 'console.log("hello world");');
+
+require('internal/modules/run_main').executeUserEntryPoint(packageDirPath);
+
+tmpdir.refresh();