v5.2.0: `require` doesn't work in REPL

[shinnn]

Environment

$ sw_vers
ProductName:    Mac OS X
ProductVersion: 10.11.1
BuildVersion:   15B42

$ node --version
v5.2.0

$ npm --version
3.3.12

$ pwd
/Users/shinnn/test

$ npm ls underscore
test@ /Users/shinnn/test
└── underscore@1.8.3

Problem

When I try to require locally installed "underscore" module, Node throws the following error.

$ node --version
v5.2.0
$ node
> require('underscore')
Error: Cannot find module 'underscore'
    at Function.Module._resolveFilename (module.js:327:15)
    at Function.Module._load (module.js:278:25)
    at Module.require (module.js:355:17)
    at require (internal/module.js:13:17)
    at repl:1:1
    at REPLServer.defaultEval (repl.js:252:27)
    at bound (domain.js:281:14)
    at REPLServer.runBound [as eval] (domain.js:294:12)
    at REPLServer.<anonymous> (repl.js:417:12)
    at emitOne (events.js:83:20)

With Node v5.1.1 it works fine.

$ node --version
v5.1.1
$ node
> require('underscore')
{ [Function]
  _: [Circular],
  VERSION: '1.8.3',
  [...] }

Also, when I directly specify the script path instead of the simple package name underscore, it can load the module as expected.

$ node --version
v5.2.0
$ node
> require('./node_modules/underscore/underscore.js')
{ [Function]
  _: [Circular],
  VERSION: '1.8.3',
  [...] }

[ChALkeR]

Reproduced.

[ChALkeR]

/cc @bnoordhuis and @cjihrig for ee72ee7, though I didn't bisect and I am not sure which commit broke that.

[silverwind]

Also confirmed here. I wonder how that got through our tests.

[MylesBorins]

Doesn't appear to be a test that checks the repl loading a module atm.. trying to put together a test right now to make the bisect easier

[MylesBorins]

edit: ignore original comment, test was throwing but it appears I didn't wire it up correctly

[silverwind]

bisect confirms it's ee72ee7.

[bnoordhuis]

Found the cause, the REPL's module object is missing the .paths property. Diff to illustrate what I mean:

diff --git a/lib/repl.js b/lib/repl.js
index 989e2e9..4d117e5 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -35,6 +35,7 @@ const Module = require('module');
 const domain = require('domain');
 const debug = util.debuglog('repl');

+const parentModule = module;
 const replMap = new WeakMap();

 try {
@@ -525,7 +526,8 @@ REPLServer.prototype.createContext = function() {
     context.global.global = context;
   }

-  const module = new Module('<repl>');
+  const module = new Module('<repl>', parentModule);
+  module.paths = parentModule.paths.slice(0);
   const require = internalModule.makeRequireFunction.call(module);
   context.module = module;
   context.require = require;

I'll put together a proper fix.

[silverwind]

@bnoordhuis looking good, but I see a unnecessary lookup path repl/node_modules. Maybe it should be parentModule.paths.slice(1) to slice that off the lookup path array?

$ pwd
/Users/silverwind/git/test
$ NODE_DEBUG=module ../iojs/node
> require("underscore")
MODULE 1402: Module._load REQUEST underscore parent: <repl>
MODULE 1402: looking for "underscore" in ["/Users/silverwind/git/test/repl/node_modules","/Users/silverwind/git/test/node_modules","/Users/silverwind/git/node_modules","/Users/silverwind/node_modules","/Users/node_modules","/node_modules","/Users/silverwind/.node_modules","/Users/silverwind/.node_libraries","/Users/silverwind/git/iojs/out/lib/node"]
MODULE 1402: load "/Users/silverwind/git/test/node_modules/underscore/underscore.js" for module "/Users/silverwind/git/test/node_modules/underscore/underscore.js"

[bnoordhuis]

#4215 - using Module._resolveLookupPaths().