module: prioritize current dir for local lookups

This fixes a bug where a 3rd party module found in node_modules,
would be preferred over a ./local module with the same name.

Fixes: #5684
PR-URL: #5689
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

lib/module.js

@@ -250,8 +250,7 @@ Module._resolveLookupPaths = function(request, parent) {
   if (!parent || !parent.id || !parent.filename) {
     // make require('./path/to/foo') work - normally the path is taken
     // from realpath(__filename) but with eval there is no filename
-    var mainPaths = ['.'].concat(modulePaths);
-    mainPaths = Module._nodeModulePaths('.').concat(mainPaths);
+    var mainPaths = ['.'].concat(Module._nodeModulePaths('.'), modulePaths);
     return [request, mainPaths];
   }
 

test/parallel/test-module-relative-lookup.js

@@ -0,0 +1,10 @@
+'use strict';
+
+require('../common');
+const assert = require('assert');
+const _module = require('module'); // avoid collision with global.module
+const lookupResults = _module._resolveLookupPaths('./lodash');
+const paths = lookupResults[1];
+
+assert.strictEqual(paths[0], '.',
+  'Current directory is prioritized before node_modules for local modules');