module: fix node_modules search path in edge case

The `p < nmLen` condition will fail when a module's name is end with
`node_modules` like `foo_node_modules`. The old logic will miss the
`foo_node_modules/node_modules` in node_modules paths.

TL;TR, a module named like `foo_node_modules` can't require any module
 in the node_modules folder.

Fixes: https://github.com/nodejs/node/issues/6679
PR-URL: https://github.com/nodejs/node/pull/6670
Reviewed-By: Evan Lucas <evanlucas@me.com>

1 files changed, 101 insertions, 16 deletions

diff --git a/test/parallel/test-module-nodemodulepaths.js b/test/parallel/test-module-nodemodulepaths.js
index 0c70de9f28..02ea79b49e 100644
--- a/test/parallel/test-module-nodemodulepaths.js
+++ b/test/parallel/test-module-nodemodulepaths.js
@@ -1,20 +1,105 @@
 'use strict';
-var common = require('../common');
-var assert = require('assert');
 
-var module = require('module');
+const common = require('../common');
+const assert = require('assert');
+const _module = require('module');
 
-var file, delimiter, paths;
+const cases = {
+  'WIN': [{
+    file: 'C:\\Users\\hefangshi\\AppData\\Roaming\
+\\npm\\node_modules\\npm\\node_modules\\minimatch',
+    expect: [
+      'C:\\Users\\hefangshi\\AppData\\Roaming\
+\\npm\\node_modules\\npm\\node_modules\\minimatch\\node_modules',
+      'C:\\Users\\hefangshi\\AppData\\Roaming\
+\\npm\\node_modules\\npm\\node_modules',
+      'C:\\Users\\hefangshi\\AppData\\Roaming\\npm\\node_modules',
+      'C:\\Users\\hefangshi\\AppData\\Roaming\\node_modules',
+      'C:\\Users\\hefangshi\\AppData\\node_modules',
+      'C:\\Users\\hefangshi\\node_modules',
+      'C:\\Users\\node_modules',
+      'C:\\node_modules'
+    ]
+  }, {
+    file: 'C:\\Users\\Rocko Artischocko\\node_stuff\\foo',
+    expect: [
+      'C:\\Users\\Rocko Artischocko\\node_stuff\\foo\\node_modules',
+      'C:\\Users\\Rocko Artischocko\\node_stuff\\node_modules',
+      'C:\\Users\\Rocko Artischocko\\node_modules',
+      'C:\\Users\\node_modules',
+      'C:\\node_modules'
+    ]
+  }, {
+    file: 'C:\\Users\\Rocko Artischocko\\node_stuff\\foo_node_modules',
+    expect: [
+      'C:\\Users\\Rocko \
+Artischocko\\node_stuff\\foo_node_modules\\node_modules',
+      'C:\\Users\\Rocko Artischocko\\node_stuff\\node_modules',
+      'C:\\Users\\Rocko Artischocko\\node_modules',
+      'C:\\Users\\node_modules',
+      'C:\\node_modules'
+    ]
+  }, {
+    file: 'C:\\node_modules',
+    expect: [
+      'C:\\node_modules'
+    ]
+  }, {
+    file: 'C:\\',
+    expect: [
+      'C:\\node_modules'
+    ]
+  }],
+  'POSIX': [{
+    file: '/usr/lib/node_modules/npm/node_modules/\
+node-gyp/node_modules/glob/node_modules/minimatch',
+    expect: [
+      '/usr/lib/node_modules/npm/node_modules/\
+node-gyp/node_modules/glob/node_modules/minimatch/node_modules',
+      '/usr/lib/node_modules/npm/node_modules/\
+node-gyp/node_modules/glob/node_modules',
+      '/usr/lib/node_modules/npm/node_modules/node-gyp/node_modules',
+      '/usr/lib/node_modules/npm/node_modules',
+      '/usr/lib/node_modules',
+      '/usr/node_modules',
+      '/node_modules'
+    ]
+  }, {
+    file: '/usr/test/lib/node_modules/npm/foo',
+    expect: [
+      '/usr/test/lib/node_modules/npm/foo/node_modules',
+      '/usr/test/lib/node_modules/npm/node_modules',
+      '/usr/test/lib/node_modules',
+      '/usr/test/node_modules',
+      '/usr/node_modules',
+      '/node_modules'
+    ]
+  }, {
+    file: '/usr/test/lib/node_modules/npm/foo_node_modules',
+    expect: [
+      '/usr/test/lib/node_modules/npm/foo_node_modules/node_modules',
+      '/usr/test/lib/node_modules/npm/node_modules',
+      '/usr/test/lib/node_modules',
+      '/usr/test/node_modules',
+      '/usr/node_modules',
+      '/node_modules'
+    ]
+  }, {
+    file: '/node_modules',
+    expect: [
+      '/node_modules'
+    ]
+  }, {
+    file: '/',
+    expect: [
+      '/node_modules'
+    ]
+  }]
+};
 
-if (common.isWindows) {
-  file = 'C:\\Users\\Rocko Artischocko\\node_stuff\\foo';
-  delimiter = '\\';
-} else {
-  file = '/usr/test/lib/node_modules/npm/foo';
-  delimiter = '/';
-}
-
-paths = module._nodeModulePaths(file);
-
-assert.ok(paths.indexOf(file + delimiter + 'node_modules') !== -1);
-assert.ok(Array.isArray(paths));
+const platformCases = common.isWindows ? cases.WIN : cases.POSIX;
+platformCases.forEach((c) => {
+  const paths = _module._nodeModulePaths(c.file);
+  assert.deepStrictEqual(c.expect, paths, 'case ' + c.file +
+    ' failed, actual paths is ' + JSON.stringify(paths));
+});