require has issues when run from / #6679

mhart · 2016-05-10T18:55:54Z

Version: 6.1.0
Platform: Darwin ReBuke-Pro.local 15.4.0 Darwin Kernel Version 15.4.0: Fri Feb 26 22:08:05 PST 2016; root:xnu-3248.40.184~3/RELEASE_X86_64 x86_64 and Linux f50a089ff63e 4.4.8-boot2docker #1 SMP Mon Apr 25 21:57:27 UTC 2016 x86_64 Linux
Subsystem: require/modules

The following command works in v5/v4/v0.12/v0.10 with npm@2.15.5 or npm@3.8.9, works in v6 with npm@2.15.5, but fails in v6 with npm@3.8.9:

$ cd /
$ sudo npm install express
$ sudo node -p "require('express')"
...
module.js:440
    throw err;
    ^
Error: Cannot find module 'merge-descriptors'
    at Function.Module._resolveFilename (module.js:438:15)
    at Function.Module._load (module.js:386:25)
    at Module.require (module.js:466:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> (/node_modules/express/lib/express.js:16:13)
    at Module._compile (module.js:541:32)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:456:32)
    at tryModuleLoad (module.js:415:12)
    at Function.Module._load (module.js:407:3)

The following command works in v6 (and below):

$ sudo mkdir /app && cd /app && sudo npm install express && sudo node -p "require('express')"

You can reproduce this fairly easily without messing up your filesystem if you have docker (can use mhart/alpine-node instead of node below if you want a smaller download):

$ docker run node:5 sh -c 'npm install express && node -p "require(\"express\")"'

(^works)

$ docker run node:6 sh -c 'npm install express && node -p "require(\"express\")"'

(^doesn't work)

$ docker run node:6 sh -c 'mkdir app && cd app && npm install express && node -p "require(\"express\")"'

(^works)

It's unclear to me whether it's the fact that it's being run from the root directory specifically that's causing it to fail – or whether it's the presence of one of the other directories (eg, bin) that's getting in the way

The text was updated successfully, but these errors were encountered:

MylesBorins · 2016-05-10T19:06:37Z

@mhart thanks for reporting! would you be able to test this on v4 to see that it is indeed a regression in v6.

MylesBorins · 2016-05-10T19:11:21Z

It appears that this behavior is broken on v6, but works on v4 and v5.

I have a sneaking suspicion that #6537 is going to fix this.

What would be the best way of writing a regression test for this? I doubt we are going to want to be writing to "/" in ci

mhart · 2016-05-10T19:18:19Z

Building jasnell:revert-5950 as we speak – will let you know if it fixes the issue

mhart · 2016-05-10T19:35:09Z

Ok, I built jasnell:revert-5950 (468096d3f57a052c0d1ffc20a4464b9532c3dfb4), but no dice unfortunately...

$ node --version
v7.0.0-pre
$ cd /
$ npm install express
$ node -p "require('express')"
module.js:431
    throw err;
    ^
Error: Cannot find module 'merge-descriptors'
    at Function.Module._resolveFilename (module.js:429:15)
    at Function.Module._load (module.js:377:25)
    at Module.require (module.js:457:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> (/node_modules/express/lib/express.js:16:13)
    at Module._compile (module.js:532:32)
    at Object.Module._extensions..js (module.js:541:10)
    at Module.load (module.js:447:32)
    at tryModuleLoad (module.js:406:12)
    at Function.Module._load (module.js:398:3)

MylesBorins · 2016-05-10T19:40:11Z

This leads me to believe it might be something in libuv /cc @saghul

mhart · 2016-05-10T19:43:55Z

Some more fuel to add to the fire: It works with v6 and npm@2 – so it must be something to do with the directory layout of node_modules and the way node is searching it – because with npm@3, all the modules (including merge-descriptors) are in /node_modules, whereas with npm@2 they're in /node_modules/express/node_modules

mhart · 2016-05-10T19:53:13Z

So if I do:

$ npm --version
3.8.9
$ node --version
v7.0.0-pre
$ npm install express
$ node -p "require('express')"
# errors
$ mkdir node_modules/express/node_modules
$ mv node_modules/* node_modules/express/node_modules/
# (ignore rename error)
$ ls node_modules
express
$ node -p "require('express')"
# works

evanlucas · 2016-05-10T19:54:47Z

@mhart can you try running with the NODE_DEBUG=module environment variable set?

mhart · 2016-05-10T19:55:49Z

@evanlucas sure thing!

MODULE 27040: Module._load REQUEST vm parent: [eval]
MODULE 27040: load native module vm
MODULE 27040: Module._load REQUEST express parent: [eval]
MODULE 27040: looking for "express" in ["/node_modules","/root/.node_modules","/root/.node_libraries","/usr/lib/node"]
MODULE 27040: load "/node_modules/express/index.js" for module "/node_modules/express/index.js"
MODULE 27040: Module._load REQUEST ./lib/express parent: /node_modules/express/index.js
MODULE 27040: RELATIVE: requested: ./lib/express set ID to: /node_modules/express/index.js/lib/express from /node_modules/express/index.js
MODULE 27040: looking for "/node_modules/express/index.js/lib/express" in ["/node_modules/express"]
MODULE 27040: load "/node_modules/express/lib/express.js" for module "/node_modules/express/lib/express.js"
MODULE 27040: Module._load REQUEST events parent: /node_modules/express/lib/express.js
MODULE 27040: load native module events
MODULE 27040: Module._load REQUEST merge-descriptors parent: /node_modules/express/lib/express.js
MODULE 27040: looking for "merge-descriptors" in ["/node_modules/express/lib/node_modules","/node_modules/express/node_modules","/root/.node_modules","/root/.node_libraries","/usr/lib/node"]
module.js:431
    throw err;
    ^
Error: Cannot find module 'merge-descriptors'
    at Function.Module._resolveFilename (module.js:429:15)
    at Function.Module._load (module.js:377:25)
    at Module.require (module.js:457:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> (/node_modules/express/lib/express.js:16:13)
    at Module._compile (module.js:532:32)
    at Object.Module._extensions..js (module.js:541:10)
    at Module.load (module.js:447:32)
    at tryModuleLoad (module.js:406:12)
    at Function.Module._load (module.js:398:3)

mhart · 2016-05-10T19:56:27Z

So for some reason /node_modules isn't listed there in the final search

mhart · 2016-05-10T19:56:58Z

But it is in the first search (which is why express is found)

mhart · 2016-05-10T19:59:40Z

Here's the relevant output from v5:

MODULE 15: Module._load REQUEST vm parent: [eval]
MODULE 15: load native module vm
MODULE 15: Module._load REQUEST express parent: [eval]
MODULE 15: looking for "express" in ["//node_modules","/node_modules","/root/.node_modules","/root/.node_libraries","/usr/lib/node"]
MODULE 15: load "/node_modules/express/index.js" for module "/node_modules/express/index.js"
MODULE 15: Module._load REQUEST ./lib/express parent: /node_modules/express/index.js
MODULE 15: RELATIVE: requested: ./lib/express set ID to: /node_modules/express/index.js/lib/express from /node_modules/express/index.js
MODULE 15: looking for "/node_modules/express/index.js/lib/express" in ["/node_modules/express"]
MODULE 15: load "/node_modules/express/lib/express.js" for module "/node_modules/express/lib/express.js"
MODULE 15: Module._load REQUEST events parent: /node_modules/express/lib/express.js
MODULE 15: load native module events
MODULE 15: Module._load REQUEST merge-descriptors parent: /node_modules/express/lib/express.js
MODULE 15: looking for "merge-descriptors" in ["/node_modules/express/lib/node_modules","/node_modules/express/node_modules","/node_modules","/root/.node_modules","/root/.node_libraries","/usr/lib/node"]
MODULE 15: load "/node_modules/merge-descriptors/index.js" for module "/node_modules/merge-descriptors/index.js"
...

evanlucas · 2016-05-10T20:00:12Z

yea, I wonder if this could be related to @mscdex's perf improvements?

targos · 2016-05-11T07:33:37Z

This patch fixes the issue:

diff --git a/lib/module.js b/lib/module.js
index 344ea97..4589f21 100644
--- a/lib/module.js
+++ b/lib/module.js
@@ -253,7 +253,7 @@ if (process.platform === 'win32') {
     // note: this approach *only* works when the path is guaranteed
     // to be absolute.  Doing a fully-edge-case-correct path.split
     // that works on both Windows and Posix is non-trivial.
-    const paths = [];
+    const paths = ['/node_modules'];
     var p = 0;
     var last = from.length;
     for (var i = from.length - 1; i >= 0; --i) {

I'm not sure it is the correct approach and if a similar change has to be done for win32.

saghul · 2016-05-11T07:35:07Z

This leads me to believe it might be something in libuv /cc @saghul

The only relation between libuv and the module system is the use of realpath, I guess. Maybe an strace will show what paths are attempted, but we (libuv) have no control over that.

targos · 2016-05-11T11:57:28Z

#6670 may fix this issue actually

mhart · 2016-05-11T14:14:50Z

@targos – confirmed, #6670 fixes this 👍

ghost · 2016-05-20T04:59:00Z

I have a similar issue having v6.1.0 node and project in UNC share which I serve in Windows through a network drive Z:\ (or that could be any letter it does not matter).

...
module.js:440
throw err;
^
Error: Cannot find module 'orchestrator'

omokehinde · 2016-05-29T15:51:16Z

am having this issue trying to use nodeunit too test my code. it shows this error `module.js:440
throw err;
^

Error: Cannot find module '../modules/math'
at Function.Module._resolveFilename (module.js:438:15)
at Function.Module._load (module.js:386:25)
at Module.require (module.js:466:17)
at require (internal/module.js:20:19)
at Object. (C:\Users\omokehine1\workspace\my1stproject\test\test-
math.js:1:74)
at Module._compile (module.js:541:32)
at Object.Module._extensions..js (module.js:550:10)
at Module.load (module.js:456:32)
at tryModuleLoad (module.js:415:12)
at Function.Module._load (module.js:407:3)`

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: #6679 PR-URL: #6670 Reviewed-By: Evan Lucas <evanlucas@me.com>

mhart changed the title ~~require fails when run from /~~ require has issues when run from / May 10, 2016

mhart mentioned this issue May 10, 2016

Missing package 'debug' for Express Application mhart/alpine-node#36

Closed

MylesBorins added the module Issues and PRs related to the module subsystem. label May 10, 2016

MylesBorins mentioned this issue May 10, 2016

keypress events not working in windows cmd.exe & powershell #5384

Closed

mhart mentioned this issue May 11, 2016

module: fix wrong condition in early return logic for node_module path #6670

Closed

3 tasks

silverwind added the confirmed-bug Issues with confirmed bugs. label May 11, 2016

mhart mentioned this issue Jul 9, 2016

Cannot find module nan when compiling native modules in 6.3.0 mhart/alpine-node#49

Closed

evanlucas closed this as completed in 55852e1 Aug 9, 2016

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require has issues when run from / #6679

require has issues when run from / #6679

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