If $NODE_PATH ends with a colon, require will act unexpected

[chrisyip]

Here is a repo that explains the difference: https://github.com/chrisyip/NODE_PATH_DEMO.

Using node v1.8.1
Current NODE_PATH is '/usr/local/lib/node_modules'
Executing 'node foo/bar.js', you should seeing an error...

In foo/bar.js
module.js:336
    throw err;
          ^
Error: Cannot find module 'index.js'
    at Function.Module._resolveFilename (module.js:334:15)
    at Function.Module._load (module.js:276:25)
    at Module.require (module.js:363:17)
    at require (module.js:382:17)
    at Object.<anonymous> (/Users/Chris/Workspace/node/NODE_PATH_DEMO/foo/bar.js:2:13)
    at Module._compile (module.js:428:26)
    at Object.Module._extensions..js (module.js:446:10)
    at Module.load (module.js:353:32)
    at Function.Module._load (module.js:308:12)
    at Function.Module.runMain (module.js:469:10)

Appeding a trailing colon to NODE_PATH
NODE_PATH now is '/usr/local/lib/node_modules:' <- notice the colon in the end
Executing 'node foo/bar.js'...

In foo/bar.js
index.js loaded
index.js: I should not be required

After separation, nodePath will become [ '/usr/local/lib/node_modules', '' ] (in the above case).

I know node should not take the responsibility for env variables, but since '' is meaningless, I suggest to remove '' from nodePath before using it.

[popomore]

LGTM

PS: where is the CI?

[chrisyip]

@popomore I added test cases, but I can't find CI guide on wiki page, and because there's no .travis.yml, don't know how to trigger CI. What should I do?

PS: should I use a new branch for PR?

[jbergstroem]

@chrisyip for now, collaborators of io.js has access to start a CI run for you. Our ambition is to improve this so all PR's at some point gets testing. Btw -- when forking and doing PR's, it's always good to create a new branch for your work instead of using master.

CI run here: https://jenkins-iojs.nodesource.com/job/iojs+any-pr+multi/567/

[chrisyip]

OK, I will create a new branch and make a PR again.

Sorry for the trouble.