Object.defineProperty called on non-object with mocha

[MitMaro]

Description

I believe that may be related to #51 given it produces the same error.

When using mocha and rewire with a module that exports a named function directly, an error occurs:

TypeError: Object.defineProperty called on non-object

Running without mocha and using node directly works correctly.

Changing from a named function to assigning the function (see test files below) and exporting the variable instead works.

Example

var foo = function () {};
module.exports = foo;

Test Files

index.js

var rewire = require('rewire');
var test = rewire('./test');

test.js

function run() {}
module.exports = run;

Gist

https://gist.github.com/MitMaro/eb09a24817bcc58f9421

Running

npm install
mocha index.js

Stacktrace

/Users/mitmaro/Code/rewire.mocha.bug/test.js:4
Object.defineProperty(module.exports, '__get__', {enumerable: false, value: fu
       ^
TypeError: Object.defineProperty called on non-object   
    at Function.defineProperty (native)
    at Object.<anonymous> (/Users/mitmaro/Code/rewire.mocha.bug/test.js:4:8)
    at Module._compile (module.js:446:26)
    at Object.Module._extensions..js (module.js:464:10)
    at Module.load (module.js:341:32)
    at Object.load (/Users/mitmaro/Code/rewire.mocha.bug/node_modules/rewire/lib/moduleEnv.js:19:18)
    at internalRewire (/Users/mitmaro/Code/rewire.mocha.bug/node_modules/rewire/lib/rewire.js:50:15)
    at rewire (/Users/mitmaro/Code/rewire.mocha.bug/node_modules/rewire/lib/index.js:11:12)
    at Object.<anonymous> (/Users/mitmaro/Code/rewire.mocha.bug/index.js:2:12)
    at Module._compile (module.js:446:26)
    at Object.Module._extensions..js (module.js:464:10)
    at Module.load (module.js:341:32)
    at Function.Module._load (module.js:296:12)
    at Module.require (module.js:351:17)
    at require (module.js:370:17)
    at /Users/mitmaro/Code/rewire.mocha.bug/node_modules/mocha/lib/mocha.js:192:27
    at Array.forEach (native)
    at Mocha.loadFiles (/Users/mitmaro/Code/rewire.mocha.bug/node_modules/mocha/lib/mocha.js:189:14)
    at Mocha.run (/Users/mitmaro/Code/rewire.mocha.bug/node_modules/mocha/lib/mocha.js:422:31)
    at Object.<anonymous> (/Users/mitmaro/Code/rewire.mocha.bug/node_modules/mocha/bin/_mocha:398:16)
    at Module._compile (module.js:446:26)
    at Object.Module._extensions..js (module.js:464:10)
    at Module.load (module.js:341:32)
    at Function.Module._load (module.js:296:12)
    at Function.Module.runMain (module.js:487:10)
    at startup (node.js:111:16)
    at node.js:799:3

[MitMaro]

I noticed the issue I had linked was the incorrect one. It's been fixed.

[jhnns]

Thx for the detailed report. Unfortunately I can't reproduce the error. After downloading the gist and running mocha test.js everything is just fine.

Pecorino:eb09a24817bcc58f9421 jhnns$ mocha test.js 

  0 passing (2ms)

[MitMaro]

Little mistake in the command, should be mocha index.js not mocha test.js.

The node version case it is useful:

node --version
v0.10.38

If I get a chance this week I will try to debug the issue.

[MitMaro]

Did a quick look and it is because of the function name. global.run is a global that seems to be added by mocha but is undefined.

The getImportGlobalSrc.js file adds var run = global.run; which would hide the function run() {} in my test case.

I don't know if there is a way to alert the user of this, or perhaps it can just be documented - if it's not already.

edit: Added info on source of run global

[MitMaro]

After looking into the source a little more I can't see a way to warn a user if a local variable is being overwritten by a injected global without using some sort of JavaScript parser.

[jhnns]

Thx for the detailed research. I was able to fix that problem by wrapping the source code inside an IIFE.