assert.deepEqual is not reflexive

[jugglinmike]

The behavior of assert.deepEqual is dependent on the ordering of arguments.

var assert = require('assert');
var args = (function() { return arguments; })();

assert.deepEqual([], args); // passes
assert.deepEqual(args, []); // throws

I recognize that this module's stability index is 5, but this non-reflexive behavior seems to be limited to the case of comparing an arguments object with an array and therefore inconsistent enough to warrant a patch.

In addition, the in-line comment immediately preceding the branch suggests that using Objects.keys on an arguments object can cause unexpected results. This operation currently occurs any time only the second argument is an arguments object.

Relevant source: https://github.com/joyent/node/blob/dbae8b569fd1afa04cddac47b30379e4ebf3388a/lib/assert.js#L204-L211

[trevnorris]

Agreed. This is a bug. The operation should be reflexive.

This won't be high on our priorities list, but any PR's will be entertained. :)

[Nodejs-Jenkins]

Thank you for contributing this pull request! Here are a few pointers to make sure your submission will be considered for inclusion.

The following commiters were not found in the CLA:

• Mike Pennisi

You can fix all these things without opening another issue.

Please see CONTRIBUTING.md for more information

[jugglinmike]

Alright, I've pushed up a commit and signed the CLA. The Jenkins build is currently failing, but I'm told that may be due to expected instability. Let me know if there's anything else I can do!

[indutny]

May be do it in a less experimental way? ;) I mean without bit operations.

[indutny]

Also, please omit braces here.

[indutny]

Minor nits, otherwise LGTM

[jugglinmike]

@indutny Thanks for the feedback. I've pushed a few new commits; let me know if you'd prefer me to squash them.

I also realized that, using the XOR operator, we don't need a variable named bIsArgs (the result of isArguments(b) is only referenced once in that case). Not sure if reducing local variables is important to you, but I thought I'd mention it just in case.

[indutny]

Thank you, landed in aae51ec

[jugglinmike]

My pleasure